Cooperative Institute for Research in Environmental Sciences

WDN Project:
About WDN
Data & Documents
News & Events
WDN Policies
Contact WDN

Journal Articles: River Deltas and Sea Level Rise

Articles  :   Geology  |   Ecosystems  |   Climate Change  |   Sea Level Rise  |   Fauna  |   Birds  |   Fish

Aslan, A., W. A. White, et al. (2003). "Holocene evolution of the western Orinoco Delta, Venezuela." Geological Society of America Bulletin 115(4): 479-498.

The pristine nature of the Orinoco Delta of eastern Venezuela provides unique opportunities to study the geologic processes and environments of a major tropical delta. Remote-sensing images, shallow cores, and radiocarbon-dating of organic remains form the basis for describing deltaic environments and interpreting the Holocene history of the delta. The Orinoco Delta can be subdivided into two major sectors. The southeast sector is dominated by the Rio Grande-the principal distributary-and complex networks of anastomosing fluvial and tidal channels. The abundance of siliciclastic deposits suggests that fluvial processes such as overbank flooding strongly influence this part of the delta. In contrast, the northwest sector is represented by few major distributaries, and overbank sedimentation is less widespread relative to the southeast sector. Peat is abundant and occurs in herbaceous and forested swamps that are individually up to 200 km(2) in area. Northwest-directed littoral currents transport large volumes of suspended sediment and produce prominent mudcapes along the northwest coast. Mapping of surface sediments, vegetation, and major landforms identified four principal geomorphic systems within the western delta plain: (1) distributary channels, (2) interdistributary flood basins, (3) fluvial-marine transitional environments, and (4) marine-influenced coastal environments. Coring and radiocarbon dating of deltaic deposits show that the northern delta shoreline has prograded 20-30 km during the late Holocene sea-level highstand. Progradation has been accomplished by a combination of distributary avulsion and mudcape progradation. This style of deltaic progradation differs markedly from other deltas such as the Mississippi where distributary avulsion leads to coastal land loss, rather than shoreline progradation. The key difference is that the Orinoco Delta coastal zone receives prodigious amounts of sediment from northwest-moving littoral currents that transport sediment from as far away as the Amazon system (similar to1600 km). Late Holocene progradation of the delta has decreased delta-plain gradients, increased water levels, and minimized overbank flooding and siliciclastic sedimentation in the northwest sector. These conditions, coupled with large amounts of direct precipitation, have led to widespread peat accumulation in interdistributary basins. Because peat-forming environments cover up to 5000 km(2) of the delta plain, the Orinoco may be an excellent analogue for interpreting ancient deltaic peat deposits.

Autin, W. J. (1993). "Influences of Relative Sea-Level Rise and Mississippi River Delta Plain Evolution on the Holocene Middle Amite River, Southeastern Louisiana." Quaternary Research 39(1): 68-74.

Bauch, H. A. and Y. I. Polyakova (2003). "Diatom-inferred salinity records from the Arctic Siberian Margin: Implications for fluvial runoff patterns during the Holocene." Paleoceanography 18(2).

Diatom assemblages were employed to study temporal changes of Siberian river runoff on the Laptev Sea shelf. Using a correlation between freshwater diatoms (%) in core-top sediments and summer surface water salinities from the inner Kara Sea, salinity conditions were reconstructed for a site northeast of the Lena River Delta (present water depth 32 m) since 9 calendar years (cal) ka. The reconstruction indicate a strong, near-coastal, and river-influenced environment at the site until about 8.6 cal ka. Corroborated by comparison with other proxy records from further to the east, surface salinities increased from 9 to 14 until about 7.4 cal ka, owing to ongoing global sea level rise and synchronous southward shift of the coastline. Although riverine water became less influential at the site since then, salinities still varied between 12.5 and 15, particularly during the last 3.5 kyr. These more recent salinity fluctuations agree well with reconstructions from just north of the Lena Delta, emphasizing the strong linkage between shelf hydrography and riverine discharge patterns in Arctic Siberia.

Blake, J. (1994). "Hong-Kong New Airport - the Related Infrastructure Program." Proceedings of the Institution of Civil Engineers-Transport 105(3): 165-171.

Hong Kong is often referred to as a city-state, but is in fact a land area of 1075 km2 consisting of two major islands, numerous smaller islands and the Kowloon peninsula, which is divided into urban and regional areas. Land elevations vary from sea level, to a maximum of 957 m above sea level; the terrain ranges from level valley floors to precipitous slopes, and the 31 km land boundary of Hong Kong is the land mass of China, with the Pearl River delta to the west (Fig. 1). In 1997 the peaceful transition of sovereignty from one country to another over a territory that is home to almost six million people will take place. Hong Kong, with its predominantly Chinese population, will become a Special Administrative Region of China. China will become one country, two systems. Rapid economic growth in China, Hong Kong and the Asian region is fuelling the need for investment in new air, land and sea transportation infrastructure projects. Hong Kong's geographic position and its deep-water access, places even greater urgency on the upgrading of its present transport facilities. A port and airport development strategy conceived in the 1980s, is currently being implemented by way of the Airport Core Programme (ACP). This is one of the world's largest completely integrated construction projects and is well underway. It involves the building of an airport as well as full rail and road access extending 35 km from the island of Lantau to the Commercial heart of Hong Kong Island. This Paper describes some of the economic fundamentals and the major components of the ACP project. Brief reference is also made to the project control framework, which involves the most senior officials in the Hong Kong Government.

Blum, M. D., T. J. Misner, et al. (2001). "Middle Holocene sea-level rise and highstand at+2 m, central Texas coast." Journal of Sedimentary Research 71(4): 581-588.

New data suggest a revised picture of middle Holocene sealevel change for the Texas Gulf of Mexico coast, and suggest reevaluation of coastal evolution. First, brackish marsh facies with calibrated radiocarbon ages of 7.7 to 7.8 ka have been recovered from depths of -8.5 to -9 m in a core from the ancestral Colorado River delta, and are interpreted to represent a sea-level pinning point. Second, a series of ridges along the Copano Bay margin farther south consist of shelly mud and fine sand with subtidal foram assemblages, occur at elevations of 1.95 m above the modern intertidal zone, and have produced calibrated radiocarbon ages on foram tests of ca, 6.8 to 4.8 ha, These ridges are interpreted to represent relict shallow subtidal to intertidal spits that provide minimum sea-level positions for the middle Holocene, and are now emergent because of later sea-level fall, In aggregate, these data show rates of sea-level rise during this time period that are very comparable to, or even lower than, published eustatic rates, and suggest a middle Holocene sea-level highstand for this non-uplifting, non-rebounding, and very slowly subsiding part of the North American coastline.

Brooks, G. R., J. L. Kindinger, et al. (1995). "East Louisiana Continental-Shelf Sediments - a Product of Delta Reworking." Journal of Coastal Research 11(4): 1026-1036.

Data from 77 vibracores were integrated with 6,700 line-km of high-resolution seismic reflection profiles collected off the eastern Louisiana coast in the region of the St. Bernard Delta, the first of the Holocene highstand deltas of the Mississippi River. Seismic facies and sediment facies were integrated in order to establish the stratigraphic details within this relict delta. Results provide a regional geologic framework from which comparisons can be made with other areas. Holocene deposits in the study area overlie a heavily dissected surface interpreted to represent a lowstand erosional surface. Resting on this surface is a thin unit of relatively clean, quartz sand interpreted to have been deposited during early transgression. This unit is overlain by sediments of the St. Bernard Delta, a seaward-prograding. coarsening-upward wedge of sands and muds that contain vertically-stacked unite of deltaic succession. Two or more prograding units separated by an unconformity, delineated from regional seismic profiles, may represent laterally shifting subdelta lobes. Surficial sediments consist of a thin unit of sands and muds derived from and reflecting the individual subenvirons of the underlying delta. Holocene inner-shelf development off eastern Louisiana has been controlled by relative sea-level rise and sediment supply. Sediment supply and deposition are a product of delta progradation and delta lobe switching. The modern shelf configuration and surficial sediment distribution patterns reflect reworking of underlying deltaic deposits. The lack of modern sediment input helps to maintain the imprint of this ancient delta on the modern shelf surface.

Cardoch, L., J. W. Day, et al. (2002). "Net primary productivity as an indicator of sustainability in the Ebro and Mississippi deltas." Ecological Applications 12(4): 1044-1055.

This paper focuses on the use of net primary productivity (NPP) as a measure of sustainable management in the Mississippi and Ebro deltas. Temporal changes in NPP were quantified for these two deltas based on the aerial coverage of different habitat types, Human appropriation of net primary productivity (HANPP) Was used as a measure of direct human use of deltaic productivity. In both deltas, NPP has declined since 1900 due to a high level of HANPP in the Ebro and wetland loss in the Mississippi. In the Mississippi, NPP declined from 2500 g.m(-2).yr(-1) in 1900 to 2000 g.m 2-yr(-1) in 1990, with a decline to 1750 g.m(-2)-yr(-1) predicted by 2050. In the Ebro, total system NPP has increased from 700 to 1000 g.m(-2).yr(-1) due to subsidized agricultural production, mostly of rice. High HANPP of 35% reduces remaining NPP to 600 g.m (2).yr(-1). The natural energies and anthropogenic subsidies that maintain natural and human-modified deltaic ecosystems are analyzed, Elimination or reduction of important pulsing cycles has,, led to environmental deterioration and higher economic costs and necessitates high levels of Subsidies,, Incorporating natural energies is the best way to manage deltas sustainably, The use of wetlands for wastewater treatment and river diversions are presented as examples.

Cattaneo, A., A. Correggiari, et al. (2003). "The late-Holocene Gargano subaqueous delta, Adriatic shelf: Sediment pathways and supply fluctuations." Marine Geology 193(1-2): 61-91.

The Gargano subaqueous delta formed on the eastern and southeastern sides of the Gargano promontory, in the western Adriatic. This subaqueous deposit represents the southernmost portion of the late-Holocene highstand systems tract (HST) growing along the western side of the Adriatic as an extensive wedge of deltaic and shallow-marine mud. The late-Holocene HST rests above a regional downlap surface that marks the time of maximum landward shift of the shoreline attained around 5.5 cal. kyr BP, at the end of the late-Pleistocene-Holocene sea-level rise. High-resolution seismic-stratigraphic and tephra correlation indicate the presence of a thin basal unit recording condensed deposition between 5.5 and 3.7 cal. kyr BP over much of the basin. Above this unit, sediment accumulation rates increased to high values (as much as 1.5 cm yr(-1)) reflecting the stabilisation of relative sea level and the forcing from high frequency climatic or anthropogenic changes affecting river dynamics. The late-Holocene mud wedge, of which the Gargano subaqueous delta is a significant component, reaches up to 35 in in thickness and has a volume of ca 180 km(3). The shore-parallel thickness distribution of the mud wedge reflects the dominant oceanographic regime of the basin and the asymmetric location of the mostly western sediment sources (with a combined modern delivery of 51.7x10(6) t yr(-1) of mean suspended load). In sections perpendicular to the coast the late-Holocene mud wedge appears composed of forestepping clinoforms with gently dipping foresets (typically 0.5degrees). The Gargano subaqueous delta is characterised by a submarine topset in water depths shallower than 25-28 m, and accounts for about 1/7th of the total volume of the late-Holocene mud wedge, despite the absence of direct river supply to the Gargano area. In the area of maximum interaction between shore-parallel currents and basin morphology, progradation occurs onto a flat and barren bedrock outcrop in about 50-80 m water depth. The rapid transition from a thickness of 30 m of late-Holocene mud to nil is a good indication of the role of southward-flowing bottom-hugging shelf currents in causing the redistribution of sediment along the Adriatic inner shelf. Additional evidence of this regime comes from: (1) the most recent sigmoid (defined at seismic-stratigraphic scale) deposited since the onset of the Little Ice Age, showing a shore-parallel thickness distribution and a main depocentre to the southeast of the Gargano promontory; (2) the maximum values of sediment accumulation rates over the last century (documented by Pb-210 measurements) defining a narrow shore-parallel belt immediately seaward of the depocentre of the most recent sigmoid. The Gargano subaqueous delta grows from the outbuilding of progressively younger progradational sigmoids that tend to parallel the previous ones. The Gargano subaqueous delta differs from other, documented late-Holocene subaqueous deltas because its growth reflects: (1) sediment transport dominated by bottom currents sub-parallel to the strike of the composing clinoforms; (2) a complex supply regime including the Po delta (350 km to the north) and several coalescing Apennine rivers acting as 'line source', (3) several alternating intervals of enhanced outbuilding and condensed depositions and (4) an in-phase growth of the most recent sigmoid with the major progradation of the Po delta during the Little Ice Age. (C) 2002 Elsevier Science B.V. All rights reserved.

Cearetta, A., M. J. Irabien, et al. (2002). "Recent salt marsh development and natural regeneration of reclaimed areas in the Plentzia estuary, N. Spain." Estuarine Coastal and Shelf Science 54(5): 863-886.

The distribution of benthic foraminifera, a range of elements, and. Cs-137 and Pb-210 were studied in surface sediments and 0.5 m cores from the Plentzia estuarine marshes (northern Spain) to determine the recent development of these previously reclaimed coastal areas. These marshes receive abundant calcium carbonate from regional rocks and this allows calcareous foraminifera to colonize all marsh sub environments. Good preservation of the original foraminiferal assemblages in the buried sediments is also favoured by high regional background carbonate. Benthic foraminifera are shown to be sensitive to both elevation above mean sea level (exposure) and salinity. Results from the chemical analyses indicate moderate anthropogenic pollution in the estuary, and maximum input seems to have occurred in the 1960s. Recent marsh foraminiferal assemblages are good analogues for the palaeo environmental interpretation of historical and Holocene cores, and the combined micropalaeontological/geochemical approach is demonstrated to be successful for the identification of short-term anthropogenic impacts on this coastal region. (C) 2002 Elsevier Science Ltd. All rights reserved.

Chan, C. Y., L. Y. Chan, et al. (2003). "Origin of the springtime tropospheric ozone maximum over east China at LinAn in 2001." Tellus Series B-Chemical and Physical Meteorology 55(5): 982-992.

Tropospheric ozone (O-3) profiles over the east China coast at LinAn (30.30degreesN, 119.75degreesE) were measured by electrochemical concentration cell ozonesondes in the spring of 2001. The measurement revealed that extremely high O-3 with mixing ratios up to 1200 ppbv sometimes penetrated deeply into 8.5-16 km above sea level as a result of lowering of the tropopause across the East Asia strong Subtropical jet stream. In addition, high O-3 in the 75-150 ppbv range penetrated into the upper and middle troposphere following the extreme O-3 regimes and caused an overall high O-3 mixing ratio in these regions. The Occurrence of the high O-3 regimes followed the propagation of dry air with low relative humidity and high potential vorticity suggesting that the O-3 is of stratospheric origin. High O-3 episodes with O-3 mixing ratios in the 75-100 ppbv range were observed in the lower troposphere and especially in the boundary layer. Trajectory analysis suggested that the O-3-rich air masses had passed through the industrialized and urbanized zones of the Pearl River Delta region of south China, northeast China coast and Yangtze River Delta region of east China. The O-3 is probably of anthropogenic origin resulting from photochemical formation from pollutants emitted from these regions. Our analysis thus revealed that over the east China coast at LinAn, sit atospheric O-3 is still the predominant source of O-3 in the middle and upper troposphere, while anthropogenic sources caused a high O-3 Pollution episode in the boundary layer.

Chen, J. S., S. C. Xu, et al. (1994). "The Depositional Characteristics and Oil Potential of Paleo Pearl River Delta Systems in the Pearl River Mouth Basin, South China Sea." Tectonophysics 235(1-2): 1-11.

Delta systems in the Zhuhai, Zhujiang and Hanjiang formations are interpreted as having formed during periods of sea-level rise from the late Oligocene to mid-Miocene (30-10.5 My B.P.). Deltas in the Zhuhai Formation were developed in a shallow water environment on a sandy, wave- or fluvial-dominated coasts. Thick and blanket-like sandstones are common but mudstones are infrequent. Oil-bearing zones have been found only in the upper part of the systems, overlain by mudstone of the Zhujiang Formation. Deltas in the Zhujiang Formation are interpreted as having formed in a deeper water environment on sandy, wave- or fluvial-dominated coasts. Carbonate platforms started growing on the Dongsha massif as the sea-level slowly rose. The moderate sandstone/mudstone ratio in the delta systems and a zone of secondary porosity in the carbonate rocks provide an excellent reservoir rock and seal rock for the basin. Deltas in the Lower Hanjiang Formation are similar to those of the Zhujiang Formation, but the upper part of the Formation is interpreted as having formed in a shelf environment; the thick shelf mudstone, interbedded with offshore bar sandstones, would be one of the better regional seal rocks in the study area. No carbonate rock developed on the Dongsha massif due to the rapid rise in sea-level. All delta systems from the Zhuhai to the Zhujiang Formation are stacked in an onlap pattern indicating a more and more expanding marine transgression, which was caused by eustatic sea-level rise. This marine transgression is almost unique and contrasts to the progradational (offlap) pattern of Cenozoic delta systems in the Gulf of Mexico. It resulted in thick sandstone deposits, immature or poorly mature source rock and no ductile mudstones, with no growth faults or rollover structures. Hydrocarbons generated from Eocene-Oligocene lacustrine source rocks are trapped by drape structures related to local basement highs or by carbonate rock with secondary porosity. Most of the remaining undiscovered reserves in the basin will be found in non-structural, subtle traps, especially stratigraphic traps.

Chen, X. Q. (1996). "An integrated study of sediment discharge from the Changjiang River, China, and the delta development since the mid-holocene." Journal of Coastal Research 12(1): 26-37.

The accelerated growth of the Changjiang River delta since 2,000 BP was formerly attributed to the intensified human activity in the drainage basin. An integrated catchment-deltaic study shows that this rapid growth began at the time when the headward aggradation of the Changjiang river-bed since the last deglaciation had come to an end, which allowed the river to carry more sediments into the sea. Although the Changjiang drainage basin has experienced an unprecedented intensity of human activities in the past 40 years, the sediment discharge either from the upper basin or from the river mouth into the sea did not show any significant increase due to its small sediment delivery ratios. It is proposed that the anthropogenic modification has exerted a dual effect on the sediment discharge into the sea. However, it suggests that the ancient human activities were far from producing any significant difference in the sediment discharge between the two periods before and after 2,000 BP. The development of the Chenier Plain from 6,400 to 3,500 BP was the result of coastal profile adjustment in response to sea-level rise since the postglacial period. Sedimentary evidence suggests that at this time the direct sediment inputs from the river into the shallow-water coast was considerably lower. A preliminary estimate shows that during this period about 46 to 92 million tons of sediments were annually deposited on the middle-lower river-bed and its hood-plains, approximately equivalent to 10% to 20% of the present Changjiang's sediment discharge into the sea. From 3,500 to 2,000 BP was a period of discontinuity of deltaic land progradation. This discontinuity occurred at the time when the process of coastal profile adjustment had largely been completed, whereas the longitudinal river-bed profile of the middle-lower Changjiang River had not yet adjusted to the sealevel. The sediment deficiency into the sea, as a result of the river-bed aggradation before 2,000 BP, may partly account for the land-forming discontinuity. Meanwhile, most of the sediment from the river mouth was trapped by the relatively deep-water sedimentary basin to build the underwater delta and a new coast profile, which paved the way for the rapid seaward growth of deltaic land after 2,000 BP.

Chen, J. Y. (1997). "The impact of sea level rise on China's coastal areas and its disaster hazard evaluation." Journal of Coastal Research 13(3): 925-930.

The coastline of China stretches for about 18,000 km. China's coastal areas concentrate 70% of big cities and 41% of the total population of the nation. Fifty-five percent of the gross national product and 65% of the national industrial output are made in these areas. Although the areas occupy less than 1/7 of the total territory of China, they create more than half of the national wealth. China's coastal areas can be acclaimed as China's ''wealth-belt'', ''lifeblood-belt''. However, most of the areas are low-lying lands with relatively gentle topography. The possible harmful impact caused by the relative sea level rise on the area is studied. This study includes the increase in occurrence frequency of storm surge and flood; the extension of inundation of low-lying land; the acceleration of paralyzation of the existing drainage system; the intensification of erosion and retreat of sea shore; and the increase of the submergence of coastal areas, salt intrusion and the pollution of fresh water resources. Several factors concerning the disaster hazard evaluation for coastal areas resulting from sea level rise are discussed. They include: adopting under-estimated value of sea level rise rate; taking the economic and social developments of a coastal area as a threshold of the hazard evaluation for the area; combining sea level rise with crustal vertical movement; taking account of the capability and adequacy of the protection facilities. The index for these factors and a method of integrative hazard evaluation are presented. Finally, the data for the Chinese regional sea level rise in recent years are also summarized in the paper. The estimated value of future relative sea level rise rate in some main coastal areas of China is 5-8 mm/a. This means that the relative sea level rise in the areas may reach 30-45 cm by 2050 in general, and in a few areas, such as the Old Yellow River Delta, may be 70-80 cm.

Chen, X. Q. (1998). "Changjiang (Yangtze) River delta, China." Journal of Coastal Research 14(3): 838-858.

After a brief review of the previous studies and a description of the geographical setting of the Changjiang River, the Changjiang River delta, and the Changjiang River estuary, this paper first summarizes the geological framework in which the recent vertical tectonic movement is emphasized because of its close connection with relative sea level changes and earthquakes. A systematic description of the stratigraphy reveals the local geologic history. Sedimentary sequences, facies and structures since the Holocene are next briefly reviewed. The historical delta and coast development is examined, with special reference to the coastal response to sediment supply. Recent achievements on the physical and biological processes in estuarine and coastal waters are presented. These processes are found to greatly influence the temporal and spatial variation of water salinity, suspended sediment concentration, sedimentation rate, and primary productivity. The interaction of natural processes with socioeconomic development is discussed in detail, with an emphasis on the major problems of estuarine freshwater resources and the impact of water diversion, harbors and navigation channels, land shortage and the impact of land reclamation, subsiding ground surface, rising sea level and flood hazards. Finally, the probable delta development in the coming decades in response to several large scale engineering works is discussed, such as the Three-Gorges Dam, the planned water transfer to North China, and the Deep Water Navigation Channel.

Chen, X. and Y. Zong (1998). "Coastal erosion along the Changjiang deltaic shoreline, China: History and prospective." Estuarine Coastal and Shelf Science 46(5): 733-742.

There are three large engineering works that are now under construction or to be constructed in the coming decade in the Changjiang (Yangtze) River catchment and its estuary, i.e. the Three-gorge Dam, the south-to-north water diversion schemes and the deepwater navigation channel. These engineering works are expected to reduce significantly the sediment supply into the deltaic coastal system, slow or reverse the development of the Changjiang River delta and enhance coastal erosion processes. Consequently, these changes will reduce land resources for reclamation and threaten the coastal defence, which are of primary importance for the protection of Shanghai's socio-economic development. In order to understand further the mechanism of the Changjiang delta development, especially of coastal erosion, this paper examines historical responses of the Changjiang delta growth and its shoreline movement to the sediment supply from the river basin in a millennium to decade time scale. This study shows that the deltaic growth rate has been very sensitive to the changes in sediment supply to the deltaic coastal system, though the mechanism that induced such changes may be different. Based on an estimate of 10-20% decrease in sediment discharge caused by the three engineering works, not to mention an additional impact of future global sea-level rise, it is believed that coastal erosion along the deltaic shoreline will become inevitable, resulting in a great stress on the land resource and coastal protection for Shanghai in the coming decades. (C) 1998 Academic Press Limited.

Cohen, A. D. and E. M. Stack (1996). "Some observations regarding the potential effects of doming of tropical peat deposits on the composition of coal beds." International Journal of Coal Geology 29(1-3): 39-65.

Several important concepts relative to the origin of coal beds can be gleaned from studies of modern domed and planar peat deposits in tropical-subtropical settings. These are: (1) laterally, some portions of a single continuous peat deposit may be domed and some portions may be planar; (2) domed deposits are most often found to have begun as planar deposits; (3) domed-formed peat facies may be overridden by planar-formed peat facies, due to such factors as sea level rise and/or increased rate of local and basinal subsidence; (4) domed peat facies tend to have less mineral matter and contain fewer inorganic splits than planar facies; (5) sulfur intrusion from marine waters can be retarded by doming, allowing low-sulfur peats to form relatively near to the coastline; (6) marine transgression can cause high-sulfur, marine-influenced, planar, peat facies to override freshwater domed or planar facies, resulting in enrichment of the upper parts of these underlying facies in sulfur and ash; (7) dome-formed peat facies tend to be thicker and more uniform in composition than planar-formed facies, with dome-formed peat facies having the potential to produce the more uniform bright coal types (clarains and vitrains) and planar-formed pear facies often producing duller coal types and/or alternating, durainic (inertinite-rich) and vitrainic (wood-derived) bands; (8) actively developing peat domes in wet settings often exhibit no appreciable increase in inertinitic material toward their tops; although the tops of either domed or planar peat deposits can be enriched in inertinitic material if the water table is lowered by either local or regional changes in hydrology or climate.

Coleman, J. M., H. H. Roberts, et al. (1998). "Mississippi River delta: an overview." Journal of Coastal Research 14(3): 698-716.

Over the last century, the river-dominated Mississippi delta has received increasing attention from geoscientists, biologists, engineers, and environmental planners because of the importance of the river and its deltaic environments to the economic well-being of the state of Louisiana and the nation. Population growth, subsurface resource extraction, and increased land-water use have placed demands on the delta's natural geologic, biologic, and chemical systems, therefore modifying the time and spatial scales of natural processes within the delta and its lower alluvial valley. As a result, the combined effects of natural and human-induced processes, such as subsidence, eustatic sea level rise, salt water intrusion, and wetland loss, have produced a dynamically changing landscape and socioeconomic framework for this complex delta. Under natural conditions, the fundamental changes that result in land-building and land loss in the Holocene Mississippi River delta plain are rooted in the systematic diversion of water and sediment associated with major shifts in the river's course-the process of delta switching. Research over the last half century has shown that major relocations of the Mississippi's course have resulted in five Holocene delta complexes and a sixth one in an early stage of development as a product of the latest Atchafalaya River diversion. Collectively, these Holocene deltas have produced a delta plain that covers an area of similar to 30,000 km(2) and accounts for 41% of the coastal wetlands in the United States. After a river diversion takes place, the resulting delta evolves through a systematic and semipredictable set of stages generally characterized by: (a) rapid progradation with increasing-to-stable discharge, (b) relative stability during initial stages of waning discharge, (c) abandonment by the river in favor of a higher gradient course to the receiving basin, and (d) marine reworking of a sediment-starved delta as it undergoes progressive submergence by the combined processes of subsidence. Delta switching has taken place every 1000 to 2000 years during Holocene times, and resulting deltas have an average thickness of approximately 35 m. Within a single delta there are subdeltas, bayfills, and crevasse-splays that have higher frequency delta cycles ranging from several hundred years to a few decades. These depositional features are usually less than 10 m thick, and some have produced marshland areas of over 300 km2. The net result of these delta-building events is a low-lying landscape with components that are changing(building and deteriorating) at different rates. Geologically, these depositional cycles produce a thick accumulation of coarsening, upward deltaic deposits that have various thicknesses in response to development on a variety of temporal and spatial scales. In this river-dominated delta system, distributaries can prograde seaward at rates of over 100 m/year. The cumulative effect of the Holocene depository has been to depress the underlying Pleistocene surface. In a local setting, e.g., the modern Balize Lobe, differential loading causes the vertical displacement of underlying clay-rich facies (shale diapirs-mudlumps). The delta front of this lobe, which has prograded into deep water of the outer continental shelf, is characterized by rapid deposition of silt- and clay-rich sediments and slope instability, which results in seaward displacement of sediments by a variety of mass-movement processes. Superimposed on the natural processes and forms of the Mississippi deltaic plain and its associated estuarine environments, are human impacts, most of which have been imposed in this century. The most significant impacts have resulted from a decrease in sediment input to the river from its tributaries and the alteration of the river's natural sediment dispersal processes through the construction of levees. Measures are now being taken to reinstate some of the delta's natural processes, thereby mitigating landless so that decline in animal and plant productivity can be mitigated.

Compton, J. S., J. Mulabisana, et al. (2002). "Origin and age of phosphorite from the Last Glacial Maximum to Holocene transgressive succession off the Orange River, South Africa." Marine Geology 186(3-4): 243-261.

A major erosional unconformity between upper Cretaceous sediments and the Last Glacial Maximum (LGM) transgressive succession occurs on the inner continental shelf off the Orange River. Vibracores from 122 in water-depth consist of upper Pleistocene shelly, phosphatic sands deposited in a high-energy shoreface environment during the LGM lowstand between 22 and 19 ka. The gravel-rich shoreface sand grades into condensed shell-rich delta-front sands as sea level rose between 19 and 14.3 ka. An abrupt facies transition to prodelta muddy sands corresponds to the rapid rise in sea level associated with Melt Water Pulse (MWP) 1A at 14.3 ka and the facies transition to clayey silt corresponds to MWP 1B at around 11 ka. A large decrease in macro- and microfossil diversity indicates low-oxygen conditions as the sea level rose. Phosphorite recovered from throughout the succession includes large interior mollusc moulds, sand-size peloids and friable nodules. Sr-derived ages of the phosphorite range from early Miocene to Quaternary. X-ray amorphous friable Ca-phosphate nodules occur in organic-rich Holocene mud deposits. Quaternary sediment on the shelf represents a complex condensed section, in which reworked phosphorite pebbles show multiple episodes of phosphogenesis often separated by millions of years within individual pebbles. The phosphorite indicates that organic-rich mud deposition on the shelf was prevalent during the early to middle Miocene marine transgressions and sea-level highstands that were associated with increased upwelling as indicated by the extensive early to middle Miocene eolianites of the Tsondab Sandstone Formation. Most friable phosphorite that formed during Quaternary marine transgressions and highstands was probably fragmented and transported off shelf during succeeding marine regressions. (C) 2002 Elsevier Science B.V. All rights reserved.

Correa, I. D. and J. L. Gonzalez (2000). "Coastal erosion and village relocation: a Colombian case study." Ocean & Coastal Management 43(1): 51-64.

Because of its tectonic setting, the Pacific coast of Colombia is subject to a variety of geological hazards, including earthquakes, tsunamis and associated phenomena such as regional and local coastal subsidence, flooding and soil liquefaction. Erosional trends are prevalent along much of the 700 km long, low barrier island's shorelines of the Pacific littoral and land losses are enhanced by factors such as 30 cm regional sea level rises associated to the occurrence of El Nino. Marine erosion is threatening more seashore littoral villages and worsening the already difficult socioeconomic conditions of most part of the inhabitants. Because of diverse and strong motivations to stay near the sea, the responses of barriers island's inhabitants to marine erosion has consisted in most cases of repetitive in-shore and along-shore directed relocations of villages, rather than definitive abandonment of the islands. In the long run, this procedure only has postponed the problem and led to repetitive relocations and economical losses. The recent inland relocation of El Choncho village, on the San Juan River delta, illustrates a different response to marine erosion. Although a new along-shore relocation was physically possible, inhabitants decided to abandon the barrier island and migrate to an interior, ancient beach ridge complex, applying a prudent solution which will be the most appropriate for other threatened villages of the Pacific littoral. A detailed geomorphologic mapping program must be conducted in order to identify appropriate sites for inland relocation of existing villages on the barriers islands of the Colombian Pacific coast. (C) 2000 Elsevier Science Ltd. All rights reserved.

Correggiari, A., F. Trincardi, et al. (2001). "Styles of failure in late Holocene highstand prodelta wedges on the Adriatic shelf." Journal of Sedimentary Research 71(2): 218-236.

On the continental shelves of the northern Mediterranean basin, the late Holocene highstand systems tract (HST) prograded under the influence of major rivers, after the attainment of the present sea-level highstand (about 5.5 cal kyr BP), On the Adriatic shelf, the thickness distribution of the late Holocene HST reflects the location of major deltas on the western side of the basin and the geostrophic circulation, which prevents a more uniform sediment dispersal toward the center of the basin. Very high sediment accumulation rates (1 to 10 cm/year) resulted in the construction of a HST depocenter up to 35 m thick. This shore-parallel depocenter is affected by failure of limited displacement over as much as 40% of its extent, Gas impregnation is common in the topset region and occurs at very shallow levels (a few meters) below the sea floor, Five areas are characterized by a variety of sea-floor and subsurface crenulations. Although locally some of these crenulations have an intriguingly regular geometry, sediment failure is the most plausible mechanism for their formation. Sediment failure better explains the large variety of geometries that characterizes the coastal mud prism of the late Holocene HST. Furthermore, we observe that these crenulations occur only where the downlap surface at the base of the HST is disrupted and affected by geometries that are consistent with fluid escape processes, This relationship suggests that the basal surface acts as a weak layer for sediment failure. Failure occurred in variable water depths from the northern slope of the modern Po prodelta (10-20 m water depth) to the narrow shelf offshore Bari (40-110 m water depth). In all these areas the proximal part of the HST prodelta wedge is intensely gas-charged. The thickness and age of the sediment sections affected by failure are slightly different from place to place but appear everywhere younger than 5.5 cal kyr BP, Where failure affects the entire HST the detachment occurs on the downlap surface at its base, Failure geometries characterize the head region whereas compressional features, such as pressure ridges and mud diapirs, dominate in the toe region, ranging in depth between 70 and 110 m, Where failure is limited to the upper few meters of the HST, there is a clear lithologic change (decrease in carbonate fraction and grain size) across the basal surface. This lithological change reflects a switch in sediment supply from local Apennine rivers (below) to Po-derived mud; this change occurred at the onset of the Little Ice Age, documenting the indirect control of short-term climate change and human impact on sediment architecture. The deformations affecting the late Holocene HST in the various areas show differences in internal geometry, but appear everywhere to be characterized by limited downward displacement and can be attributed to shear-dominated retrogressive failure. It is suggested that some degree of consolidation occurred immediately after mobilization, possibly induced by the escape of fluids, Nowhere has failure evolved into disintegration and flow, likely because the type of cyclic loading that triggered it was not prolonged over a long enough interval. Short-lived radionuclides in the uppermost stratigraphic layers, which postdate the failure in the area offshore Ortona, allowed us to quantify systematic changes in sediment accumulation rates as a function of the underlying deformed sea floor. In areas of wavy sea floor, troughs show sediment accumulation rates of greater than 16 mm/yr, a figure that is fourfold the rate measured on the flanks of the troughs. These values document a complex feedback between sea-floor roughness initially caused by failure and subsequent sedimentation.

Dheeradilok, P. (1995). "Quaternary Coastal Morphology and Deposition in Thailand." Quaternary International 26: 49-54.

Thailand is part of the Asian continent that is generally considered to be tectonically stable compared to adjacent regions in southeastern Asia. However, studies of Quaternary stratigraphic sequences, depositional processes and coastal morphology of the Thailand coast, have provided evidence of continuing Cenozoic epeirogenic movement influencing coastal evolution. These movements have affected coastal and river depositional responses to climate and eustatic sea level change. The Quaternary marine formations are extensive along the coastal zone for a distance of about 1850 km in the Gulf of Thailand and occur sporadically along the 865 km west coast of the Thai Peninsula. On the Thai Peninsula, the emergence of the west coast has resulted in the formation of numerous islands, drowned valleys, short and narrow beaches and truncated headlands, in the high energy coastal erosion regime of the Andaman Sea. Steep-gradient, short rivers form floodplains of comparatively thin deposits of Quaternary sediments, and narrow bays backed by crescent shape sand ridges. This contrasts with the east coast where thick sequences of Quaternary fluvial and deltaic aggradational deposits, and Holocene progradational beaches, sand spits, tidal flats and lagoons, are indicative of tectonic subsidence with a coastal current transporting sediment into the region. Along the coastal Central Plain, the Chao Phraya delta is underlain by a thick Plio-Pleistocene deltaic and coastal marine sedimentary sequence. This has accumulated in a basin where the Quaternary tectonic environment is affected by epeirogenic uplift of the western highlands and tilting of the Central Plain. At the western Central Plains margin, rivers have formed distinct alluvial fans while the rest of the coastal plain has landscape features formed in the river delta-prograding coast environment that preceded the postglacial marine transgression.

Evans, K. G., A. W. Stephens, et al. (1992). "Quaternary Sequence Stratigraphy of the Brisbane River Delta, Moreton Bay, Australia." Marine Geology 107(1-2): 61-79.

The Quarternary geological history of the Brisbane River delta front and prodelta was interpreted using seismic stratigraphic and sequence stratigraphic principles. During the last major glacial sea level episode, the floor of the bay was exposed and eroded by stream channels. In the subsequent postglacial marine transgression, the palaeochannels of the Brisbane and Pine Rivers were backfilled with mud. Sea level continued rising until about 6500 years ago and a highstand has persisted since then. During the Quarternary, sediment deposition in Moreton Bay was controlled by sea-level fluctuations, channel migration, and palaeotopography. There were at least four depositional episodes prior to the last glacial period, plus the present postglacial episode. Periods of low sea level occurred between highstands and the sea bed exposed and eroded. Eight major seismic reflectors were recognised and six seismic sequences defined. The seismic sequences represent five highstand systems tracts and one transgressive systems tract. The relationships between eustacy and system tract type were applied to glacio-eustatic sea-level curves to determine relative ages of sequences in Moreton Bay. The application of sequence stratigraphy to high frequency sea-level fluctuations was demonstrated. The stratigraphic system established within the context of sequence stratigraphy will provide a reference for future work within the region.

Evoy, R. W., T. F. Moslow, et al. (1994). "Origin and Variability of Sedimentary Facies of the Fraser-River Delta Foreslope, British-Columbia." Marine Geology 118(1-2): 49-60.

Five sedimentary facies have been recognized in piston cores from the Fraser River delta foreslope: (1) river plume suspension deposited massive silty clay with minor organics, (2) suspension deposited silty clay to clayey silt with rare parallel silt and very fine sand laminations deposited under minor traction, (3) clayey silt with silt or very fine sand interbeds from mixed suspension and low density turbidity current traction deposition, (4) silty, very fine-to medium-grained sand with less than 10% thin clay or silt interbeds, predominantly deposited from high density turbidity currents, and (5) organic-rich, disorganized, chaotic beds. Facies distribution patterns suggest that the Fraser Delta foreslope is dissected by a number of both active and inactive channels. These channels have served as a mechanism for coarse-grained sediment to bypass the delta plain and upper foreslope and be introduced directly to the lower foreslope and basin floor. It is hypothesized that these channels debouch as a series of depositional lobes and slump-related failure deposits in the prodelta/basinal environment. The direct introduction of clastic sediment into water depths exceeding 250 m suggests a process analogue for the interpretation of shelf-edge deltas in the rock record. Thus, the Fraser River delta may offer a unique opportunity to model active sedimentation associated with a lowstand of sea level.

Gambolati, G., P. Teatini, et al. (1999). "Coastline regression of the Romagna region, Italy, due to natural and anthropogenic land subsidence and sea level rise." Water Resources Research 35(1): 163-184.

The Romagna coastal area in the Northern Adriatic Sea has experienced in recent times continuous changes because of its precarious environment and low ground elevation above mean sea level (msl). Major processes that may influence the stability of the coast profile include land subsidence of both natural and anthropogenic origin and the msl rise caused by global climate change. According to the most accredited modeling predictions msl is expected to rise by almost 0.5 m over the next century because of the greenhouse effect. Natural land subsidence is the result of deep downward tectonic movement and consolidation of geologically recent deposits. It may be estimated in the range of 2-2.5 mm/yr in the Ravenna area and twice as much in the Po River delta. Anthropogenic land subsidence is primarily related to groundwater pumping from the upper fresh water aquifer system and gas production from Plio-Pleistocene reservoirs. Geodetic surveys from 1953 to 1990 provide documentary evidence of cumulative land settlement exceeding 0.8 m and 1.2 m at Marina di Ravenna and Cesenatico, respectively. In this study we estimate both natural and anthropogenic land subsidence for the years 2015, 2050, and 2100 with the aid of ad hoc finite element simulation models. The use of these predictions together with the expected msl rise shows that many present lowlands may be permanently submerged at the end of the next century. The extent of the flooded area of the Romagna coastal region can be as much as 690 and 910 km(2), using optimistic and pessimistic land subsidence scenarios, respectively. A local detailed analysis indicates that the areas around the cities of Ravenna and Cesenatico may be seriously affected by sea water ingression while the city of Rimini is well protected because of its relatively high elevation above msl.

Gambolati, G., P. Teatini, et al. (2002). "GIS simulations of the inundation risk in the coastal lowlands of the Northern Adriatic Sea." Mathematical and Computer Modelling 35(9-10): 963-972.

The Northern Adriatic Coastland, between the cities of Monfalcone and Cattolica, is characterized by locations of great tourist interest, such as the Venice Lagoon and the Romagna Riviera, and areas with a very precarious environmental setting, such as the Valli di Comacchio, and the Po River Delta. Therefore, the coastal management and the design of new defence works of the littoral have to be made with the utmost care, possibly with the aid of numerical predictions of the coastal morphodynamics and the flood risk analysis of the lowland involved. In the study area, land may subside due to sediment natural compaction and subsurface fluid (water and gas) withdrawal. At the same time, littoral transport of solid material can contribute appreciably to change the shore morphology. Mean sea level may rise permanently due to global climate change (eustatism) and occasionally due to tides and intensive storm events. The predictions of each individual process is obtained using various ad hoc mathematical models and the outcome of the numerical simulations are managed with a GIS (geographical information system). Coastline evolution until the year 2100 is investigated and risk factor maps of the low-lying coastal areas are generated which account for the hazard of the expected event, and the land economic value and vulnerability. (C) 2002 Elsevier Science Ltd. All rights reserved.

Goodbred, S. L. and S. A. Kuehl (2000). "Enormous Ganges-Brahmaputra sediment discharge during strengthened early Holocene monsoon." Geology 28(12): 1083-1086.

Rivers are the main source of terrigenous sediment delivered to continental margins and thus exert a major control on coastal evolution and sequence development. However, little is known about past changes in fluvial sediment loads despite the recognition of significant variation under changing climatic regimes. In this study we present the first quantified estimate of sediment discharge for a major river system under conditions of an intensified early Holocene monsoon. Development of the Ganges-Brahmaputra River delta began ca. 11 000 yr B.P., when rising sea level flooded the Bengal basin, thereby trapping most of the river's discharge on the inner margin. Chronostratigraphic data from these deltaic deposits are used to calculate the rates of sediment storage on the margin, which provide a minimum estimate of the river's past sediment load. Results reveal that similar to5 x 10(12) m(3) of sediment was stored in the Bengal basin from ca, 11 000 to 7000 yr B.P., which corresponds to a mean load of 2.3 x 10(9) t/yr. In comparison, modern sediment load of the Ganges-Brahmaputra is similar to1 x 109 t/yr, ranking it first among the world's rivers and underscoring the significance of a two-fold increase sustained over 4 k.y. Furthermore, the timing of immense discharge in the early Holocene strongly suggests its relation to a stronger than present southwest monsoon in South Asia. Similar patterns of high monsoon-related sediment discharge have been noted throughout the tropics and subtropics, suggesting a widespread fluviosedimentary response, the potential magnitude of which is show-cased by the Ganges-Brahmaputra system.

Guilbault, J. P., J. J. Clague, et al. (1995). "Amount of Subsidence During a Late Holocene Earthquake - Evidence from Fossil Tidal Marsh Foraminifera at Vancouver-Island, West-Coast of Canada." Palaeogeography Palaeoclimatology Palaeoecology 118(1-2): 49-71.

Fossil foraminifera in intertidal deposits beneath a marsh near Tofino on west-central Vancouver Island, British Columbia, provide a basis for estimating the amount of subsidence during a large earthquake less than 400 years ago. We compared the fossil foraminiferal assemblages with present-day assemblages along a surveyed transect across the marsh, and we estimated paleo-elevation by means of both subjective and quantitative methods. The comparisons suggest that the site subsided at least 0.2 m and perhaps more than 1 m during the earthquake. Most of the subsidence was tectonic, for the deposits rest on a Pleistocene substrate unlikely to have compacted much when shaken. Soon after the earthquake, the land began to rebound tectonically. Most of the 0.2-1 m of recorded subsidence was recovered during deposition of the first 6 cm of sediment above the buried marsh surface, probably within a few decades after the earthquake. Because of the speed at which the land rebounded, some recovery may have occurred before the first post-earthquake sediments were deposited. If so, the actual amount of subsidence is larger than the foraminiferal data indicate.

Guilbault, J. P., J. J. Clague, et al. (1996). "Foraminiferal evidence for the amount of coseismic subsidence during a late Holocene earthquake on Vancouver Island, west coast of Canada." Quaternary Science Reviews 15(8-9): 913-937.

Foraminiferal data from two sites, 6 km apart, on the shores of an inlet near Tofino on the west coast of Vancouver Island, British Columbia, allow estimates to be made of the amount of coseismic subsidence during a large earthquake 100-400 years ago. The sampled sediment succession at the two sites is similar; peat representing a former marsh surface is abruptly overlain by intertidal mud grading upward into peat of the present marsh. At one of the sites, a layer of sand, interpreted to be a tsunami deposit, locally separates the buried peat from the overlying intertidal mud. The abrupt peat-mud contact records sudden crustal subsidence during the earthquake. The paleoelevation of each fossil sample was estimated by comparing its foraminiferal assemblage with modern assemblages of known elevation. The modern assemblages were obtained from surface samples collected along transects across the marsh near the fossil sample sites. Comparisons were made statistically using transfer functions. Estimates of coseismic subsidence, based on differences in paleoelevations just above and below the top of the buried peat, range from 20 cm to 1 m with the most likely value in the 55-70 cm range. Post-seismic crustal rebound began soon after the earthquake and may have been largely complete a few decades later. Copyright (C) 1996 Published by Elsevier Science Ltd

Hart, B. S. and B. F. Long (1996). "Forced regressions and lowstand deltas: Holocene Canadian examples." Journal of Sedimentary Research 66(4): 820-829.

Some Canadian Holocene deltas that formed during and after relative-sea-level falls of over 100 m are modern examples of forced regressions and lowstand deltas. The principal controls on deltaic morphology and stratigraphy are rate of sea-level change, sediment supply (timing, type), basin physiography, and sediment dispersal processes in the receiving basin, Our observations indicate important alongstrike variability in deposition and erosion that affect facies architecture and stratal geometry. During rapid relative-sea-level fall, fluvial channels incise rapidly and do not migrate, Lateral channel migration, which would produce a widespread fluvial unconformity, begins once relative sea-level fall has slowed and continues through the early part of relative-sea-level rise, Parts of the emerging shoreline cut off from the fluvial sediment supply become sites of shoreface incision into prodelta deposits (regressive marine erosion), and wave-cut terraces are developed, Where sandy sediment is then supplied to the shoreface, by rivers or updrift sources, sharp-based littoral sandbodies directly overlie the shoreface erosion surface, Other parts of the deltas below wave base that become abandoned through lobe switching can also be eroded by tidal currents, Deltas that have prograded into deep water show evidence of submarine slope instability, such as submarine channel development, base of-slope turbidites, and thick- and thin-skinned failures that disrupt clinoforms, Isopach trends reflect the existence of underlying structure, with Holocene sediments locally either thinning or pinching over bedrock highs.

Hensel, P. F., J. W. Day, et al. (1998). "Short-term sedimentation dynamics in the Rhone River Delta, France: The importance of riverine pulsing." Estuaries 21(1): 52-65.

Short-term sedimentation patterns were evaluated from August 1992 to May 1993 in different wetland habitats characteristic of the Rhone Delta, including impounded and seasonally-dry saline Arthrocnemum marshes, brackish Juncus, Phraginites, and Scirpus riverine wetlands directly connected to the Rhone River, and Arthrocnemum-dominated marine marshes influenced by the Mediterranean. Short-term sedimentation was measured as sediment accumulation on paper filters which had been placed on the soil surface for several weeks. Total sedimentation and material lost on ignition was significantly related to individual sampling periods, reflecting the importance of short-term processes. High sedimentation at riverine sites (up to 22 g m(-2) d(-1)) was related to a combination of river stage and wind events. Marine and impounded wetlands of the Rhone Delta experienced low sedimentation throughout the period of study. Sedimen tation rates averaged over the study period were 0.8 g m(-2) d(-1), 1.8 g m(-2) d(-1), and 5.4g m(-2) d(-1) for marine, impounded, and riverine sites, respectively. Percent material lost on ignition was low in all habitats (average 15%) and followed a seasonal trend with a minimum in late fall and winter (1%). Soil percent organic matter was also low in the top several centimeters (13%), suggesting that inorganic sedimentation is very important for accretion on these wetland surfaces. Coastal flooding was not a significant mechanism for sedimentation in the marine sites during the period of study. Sedimentation is an important factor in elevation change, and this study shows that impounded habitats, the most common "natural environment" left in the delta, may become vulnerable to sea-level rise in the future if management practices continue to isolate these wetlands from riverine sources of sediment.

Hensel, P. F., J. W. Day, et al. (1999). "Wetland vertical accretion and soil elevation change in the Rhone River delta, France: The importance of riverine flooding." Journal of Coastal Research 15(3): 668-681.

Accretion and surface elevation change were measured in riverine, marine and impounded wetland habitats of the Rhone Delta from 1992 to 1996 using a sedimentation-erosion table (SET) and marker horizons. Riverine habitat accreted at a significantly greater rate than the other habitats throughout the period of study, averaging 13.4 +/- 7.0 mm yr(-1) compared to 1.1 +/- 0.1 and 1.2 +/- 0.5 mm yr(-1) for impounded and marine habitats, respectively. Elevation change was similar to accretion in the riverine habitat (11.3 +/- 6.1 mm yr(-1)), reflecting an average 16% compaction and consolidation of recent, primarily mineral deposits. Over time, elevation change and accretion became more linearly correlated, showing that variation between these two processes decreases with time. Accretion and elevation change in impounded and marine habitats were less than current rates of relative sea-level rise, a result of isolation from riverine flooding and the lack of marine storms during the study period. There was more than 30 mm of accretion in the riverine habitat deposited during the 50 and 90-year floods in the Rhone in 1993 and 1994. Impounded and marine habitats gave no record of these events. Wetlands connected to the Rhone River can therefore accrete rapidly from sediments deposited during floods. Impoundments, the most common "natural areas" left in the delta, are not keeping pace with relative sea-level rise and may become vulnerable to increased sea-level rise if current management practices are continued.

Hinton, A. C. (1997). "Tidal changes." Progress in Physical Geography 21(3): 425-433.

Hippensteel, S. P., R. E. Martin, et al. (2000). "The formation of holocene marsh foraminiferal assemblages, middle Atlantic Coast, USA: Implications for Holocene sea-level change." Journal of Foraminiferal Research 30(4): 272-293.

Substantial spatio-temporal variation in foraminiferal inputs occur over short areal distances at the sediment-water interface and downcore as a result of patchy distributions and seasonal reproduction; foraminiferal assemblages are in turn diagenetically overprinted by seasonal, inter-seasonal, and inter-annual changes in porewater chemistry. Seasonal surface and near-surface assemblages are typically unrepresentative of deeper assemblages that are more likely to be incorporated into the sedimentary record. Cluster analysis of "artificially time-averaged" (ATA) assemblages revealed a distinct change in assemblages at similar to 20 cm depth. Differential preservation of foraminifera in the upper 60 cm, and especially the upper 20 cm, of sediment may produce an apparent paleoenvironmental change that could potentially be misinterpreted as a rapid fall in sea-level over the last similar to 100-200 years.

Hori, K., Y. Saito, et al. (2001). "Sedimentary facies and Holocene progradation rates of the Changjiang (Yangtze) delta, China." Geomorphology 41(2-3): 233-248

.The Changjiang (Yangtze) River, one of the largest rivers in the world, has formed a broad tide-dominated delta at its mouth during the Holocene sea-level highstand. Three boreholes (CM97, JS98, and HQ98) were obtained from the Changjiang delta plain in 1997-1998 to clarify the characteristics of tide-dominated delta sediments and architecture. Based on sediment composition and texture, and faunal content, core sediments were divided into six depositional units. In ascending order, they were interpreted as tidal sand ridge, prodelta, delta-front, subtidal to lower intertidal flat, upper intertidal flat, and surface soil deposits. The deltaic sequence from the prodelta deposits to the delta front deposits showed an upward-coarsening succession, overlain by an upward-fining succession from the uppermost part of the delta front deposits to the surface soil. Thinly interlaminated to thinly interbedded sand and mud (sand-mud couplets), and bidirectional cross laminations in these deposits show that tide is the key factor affecting the formation of Changjiang deltaic facies. Sediment facies and their succession combined with AMS C-14 dating revealed that isochron lines cross unit boundaries clearly, and delta progradation has occurred since about 6000 to 7000 years BP, when the rising sea level neared or reached its present position. The average progradation rate of the delta front was approximately 50 km/kyear over the last 5000 years. The progradation rate, however, increased abruptly ca. 2000 years BP, going from 38 to 80 km/kyear. The possible causes for this active progradation could have been an increase in sediment production in the drainage basin due to widespread human interference and/or decrease in deposition in the middle reaches related to the channel stability caused by human activity and climatic cooling after the mid-Holocene. (C) 2001 Elsevier Science B.V. All rights reserved.

Hori, K., Y. Saito, et al. (2002). "Architecture and evolution of the tide-dominated Changjiang (Yangtze) River delta, China." Sedimentary Geology 146(3-4): 249-264.

The Changjiang (Yangtze) River, China, has formed a large tide-dominated delta on the western coast of the East China Sea. This paper presents the architecture and Holocene evolution of the delta, based on analyses of three borehole samples taken from the present delta plain. The deltaic sediments are 25-30 in thick and composed largely of subaqueous deposits, which can be divided into three facies: prodelta, delta front and delta plain, in ascending order. Tide-influenced sedimentary structures such as sand-mud couplets and bi-directional crosslaminations characterize the delta plain and delta front deposits. An upward-coarsening facies succession from prodelta to delta front is overlain by an upward-fining facies succession from the uppermost delta front to the delta plain. The deposits at the boundary between delta plain and delta front are composed of well-sorted, coarse deposits because it is in the zone of highest energy. The depth from the top of the intertidal facies of the delta plain to this boundary is almost the same, 9 - I I in, among the three cores. Sediment accumulation rates are highest in the delta front facies (ca. 10 m/kyr maximum) and decrease toward both delta plain and prodelta facies (ca, 1 m/kyr). The evolution of the Changjiang delta, which began in a bay approximately 8 kyr BP, can be divided into two stages by its stacking pattern: aggradational and progradational. The aggradational system developed during the slow rise of sea level from 8 to 6 kyr Bp, and the progradational system developed after sea level reached or approached its present position. The evolution of distributary channels and related river-mouth sand bars was an important process of delta migration or progradation. (C) 2002 Elsevier Science B.V. All rights reserved.

Hori, K., S. Tanabe, et al. (2004). "Delta initiation and Holocene sea-level change: example from the Song Hong (Red River) delta, Vietnam." Sedimentary Geology 164(3-4): 237-249.

Delta initiation and subsequent delta growth were investigated by using radiocarbon-dated borehole cores from the Song Hong (Red River) delta, Vietnam. The sediments underlying the present delta plain record three depositional systems since the last glacial maximum: fluvial, estuarine, and deltaic, in ascending order. The landward part of the initial delta was characterized by an active tide-influenced accumulation of sandy sediments. The seaward part of the initial delta is composed of muddy prodelta and seafloor sediments that accumulated slowly. Radiocarbon ages of molluscan shells and organic materials suggest that the transition from estuary to delta occurred at approximately 8500 cal years BR The transition was induced by deceleration of the postglacial sea-level rise, which was coeval with the delta initiation. The stacking pattern of the delta system is very different from that of the estuary system. The sediments of the estuary that developed during the rapid rise in sea level between 11000 and 8500 cal years BP display a retrogradational stacking pattern, forming a thick transgressive systems tract. On the other hand, aggradational as well as progradational stacking with clinoform architecture characterized the delta system between 8500 and 6500 cal years BP as the sea level continued its slow rise. Progradation has been dominant during the last 6500 years because the cessation of sea-level rise resulted in little accommodation being added. The results of this study are similar to those for other major delta systems, such as the Changjiang and the Ganges-Brahmaputra deltas, despite large differences in sediment discharge, tectonics, basin size, and coastal environment. This implies that the postglacial sea-level rise and the change in the rise rate markedly influenced the evolution of depositional systems at river mouths. (C) 2003 Elsevier B.V. All rights reserved.

Horton, B. P. (1999). "The distribution of contemporary intertidal foraminifera at Cowpen Marsh, Tees Estuary, UK: implications for studies of Holocene sea-level changes." Palaeogeography Palaeoclimatology Palaeoecology 149(1-4): 127-149.

Foraminiferal assemblages were collected at 2-weekly intervals over a period of 12-months from the intertidal zone of Cowpen Marsh. Statistical analyses indicate that the foraminiferal distributions for this site are controlled predominantly by altitude. Furthermore, the contemporary foraminiferal assemblages from Cowpen Marsh broadly reflect vertical floral zones based on vascular plants. Cluster analysis separates foraminiferal assemblages into four zones: two high and middle marsh zones consisting of differing abundances of Jadammina macrescens and Trochammina inflata; a low marsh zone dominated by Jadammina macrescens and Miliammina fusca; and a mudflat zone dominated by calcareous foraminiferal species, notably, Elphidium williamsoni, Haynesina germanica and Quinqueloculina spp. The altitudinal ranges of the faunal zones are employed to identify the vertical relationship of the local environment in which the assemblage accumulated to a reference tide level. (C) 1999 Elsevier Science B.V. All rights reserved.

Horton, B. P., R. J. Edwards, et al. (1999). "UK intertidal foraminiferal distributions: implications for sea-level studies." Marine Micropaleontology 36(4): 205-223.

Foraminiferal assemblages have been collected from ten intertidal study areas situated on the east, south and west coasts of the UK, The assemblages display a vertical zonation which indicates that the distribution of foraminifera in these intertidal environments is usually the direct function of altitude with the duration and frequency of intertidal exposure the most important factors. Multivariate analyses separate foraminiferal assemblages into two faunal zones: a high- and middle marsh zone consisting of differing abundances of Jadammina macrescens, Trochammina inflata and Miliammina fusca; and a low-marsh and tidal flat zone dominated by calcareous foraminiferal species, notably Elphidium williamsoni, Haynesina germanica and Quinqueloculina spp. These faunal zones are similar to those in other mid-latitude, cool temperate intertidal environments although there are spatial and temporal variations between areas. The altitudinal ranges of the faunal zones are employed to identify the vertical relationship of the local environment in which the assemblage accumulated to a reference tide level. (C) 1999 Elsevier Science B.V. All rights reserved.

Horton, B. P., R. J. Edwards, et al. (1999). "A foraminiferal-based transfer function: Implications for sea-level studies." Journal of Foraminiferal Research 29(2): 117-129.

A dataset consisting of 165 contemporary foraminiferal samples and associated tide level information was compiled by combining data from ten intertidal study areas situated on the east, south and west coasts of the UK, The relationship between the foraminiferal data and a series of environmental variables (elevation, pH, salinity, substrate and vegetation cover) are examined using canonical correspondence analysis (CCA) and partial CCA, To facilitate comparisons between study areas with different tidal ranges, the elevational data are expressed as a standardised water level index (SWLI), The foraminiferal distributions show a strong and highly statistically significant relationship with SWLI. A predictive transfer function has been developed for SWLIs using weighted averaging calibration with inverse and classical deshrinking regression (inverse r(jack)(2) = 0.74; classical r(jack)(2) = 0.75). Statistical measures assessing the performance of this model suggest that reliable reconstructions of former sea levels are possible. The transfer function has important implications for establishing continuous records of relative sea-level change or sedimentation.

Hoy, R. G. and K. D. Ridgway (2003). "Sedimentology and sequence stratigraphy of fan-delta and river-delta deposystems, Pennsylvanian Minturn Formation, Colorado." Aapg Bulletin 87(7): 1169-1191.

Fan-delta and river-delta strata of the middle Pennsylvanian Min-turn Formation were deposited in the Central Colorado trough and are well exposed in the Sangre de Cristo Mountains. Proximal fandelta strata were deposited in lowstand, transgressive, and highstand systems tracts, whereas distal fan-delta strata were deposited in lowstand, highstand, and forced regressive systems tracts. Fan-delta strata were deposited adjacent to coeval westward-dipping thrust faults along the western margin of the Central Colorado trough. Inferred high subsidence rates caused by thrust loading along the western margin of the basin created, accommodation space closer to the basin margin and resulted in localized aggradation. of fan-delta deposits. Proximal river-delta strata were deposited in transgressive, highstand, and early regressive systems tracts, whereas distal river-delta strata were deposited during all stages of sea level change. River-delta deposystems are interpreted to have formed in parts of the basin that experienced relatively less subsidence associated with Pennsylvanian thrust loading. Lower subsidence rates associated with river-delta deposystems resulted in progradation into more distal parts of the basin. Results of our study point out that lateral changes in depositional systems, related to local variation in tectonic subsidence, may produce significant along-strike differences in the sequence stratigraphic, framework of flexural basins. Our analysis also shows that potential reservoir facies in coeval fan-delta and river-delta deposystems form at different times and in different parts of the basin during sea level fluctuation.

Huang, Z. G., Y. Q. Zong, et al. (2004). "Coastal inundation due to sea level rise in the Pearl River Delta, China." Natural Hazards 33(2): 247-264.

This paper examines the increased potential risk of tidal inundations in the Pearl River delta, China, due to future rises in sea level. The research is based on tidal records of 54 tide gauges distributed across the delta plain, and employs mathematical calculations to predict potential rises of water level in different parts of the delta under a number of flood scenarios. After assessing a 72-year tidal record of Hong Kong and factors such as estuarine backwater effects and long-term geological subsidence, it suggests that a 30 cm rise in relative sea level at the mouth of the estuary is possible by 2030. Based on the prediction and five freshwater discharge scenarios, the potential impacts on water levels across the delta plain are calculated. Three zones are identified as least affected, heavily affected and severely affected. The impacts are also translated into return periods of water level. It is suggested that in a large part of the delta plain, return periods will be shortened and hence will be increasingly vulnerable to tidal inundation. Finally, management implications are discussed along with assessment of the adequacy of the existing tidal flood defences, as well as evaluation of the cost implications if they are to be improved.

Hutchinson, I., M. C. Roberts, et al. (1995). "Stratigraphy, Diatom Biofacies, and Palaeogeomorphology of a Mid Holocene Distributary Channel System, Fraser-River Delta, British-Columbia, Canada." Canadian Journal of Earth Sciences 32(6): 749-757.

A buried distributary channel system that delivered sediment to the currently inactive southern front of the Fraser River delta during the mid Holocene is described from 32 vibracores and 403 core logs. Sedimentary properties in core and cone logs as well as fossil diatom assemblages were used to distinguish channel fill from associated deltaic facies (overbank deposits, tidal flats, and peat bogs). Active-channel fill fines upwards from a coarse base into medium-fine sand capped by thin silt beds. It contains a sparse diatom assemblage dominated by heavily silicified freshwater planktonics. The channel fill deposited during the period of diminishing flow consists of silt with thin sandy interbeds deposited during flood events. Diatoms are abundant in these deposits. The diatom biofacies is dominated by sessile freshwater species at upstream sites and by brackish-marine species at channel mouths. The transition to organic-rich silt and peat and an aerophile diatom assemblage marks channel abandonment. The palaeochannel was 500-800 m wide and 18 m deep, slightly smaller than the present main distributary channel of the Fraser River. Calibrated radiocarbon ages suggest that the palaeochannel was active from around 8000 to 6000 BP and was finally abandoned by 5000 BP.

Ibanez, C., J. W. Day, et al. (1999). "Primary production and decomposition of wetlands of the Rhone delta, France: Interactive impacts of human modifications and relative sea level rise." Journal of Coastal Research 15(3): 717-731.

Above ground primary production and above ground and below ground decomposition of several wetland species were studied in seven wetland sites in the Rhone delta from October 1992 to October 1993. The sites were located in three characteristic zones of the delta: a low salinity area close to the river mouth, a marine site near the Mediterranean Sea and managed, impounded areas. These areas are vegetated by helopytes and glassworts (family Chenopodiaceae). Wetland production was affected by salinity, cattle and horse grazing and water levels. In a grazed freshwater wetland dominated by Scirpus maritimus, production was 452 g m(-2) yr(-1), while in an adjacent ungrazed site dominated by Typha angustifolia production was 2989 g m(-2) yr(-1). The most productive glasswort marshes were dominated by Arthrocnemum fruticosum, one near the river mouth(1123 g m(-2) yr(-1)), and a second with a free connection to the sea (1262 g m(-2) yr(-1)). The least productive glasswort marshes were dominated by Arthrocnemum glaucum. The lowest production (244 g m(-2) yr(-1) was in a grazed, semi-impounded marsh with high soil salinity and high ground water levels, while a second area in the central part of the delta with high soil salinity and grazing had a production of 294 g m(-2) yr(-1). In the non-grazed brackish Phragmites australis-Scirpus maritimus marsh at the river mouth, production was 824 g m(-2) yr(-l), whereas in an unprotected site nearby, grazing was so intense that above ground vegetation was eliminated. Decomposition rates were significantly different among species and plant parts but not among sites when the same species were used. Root decomposition was not significantly different with depth. Shoots had the highest decomposition rates with mean K values of 0.033 wk(-1) for Arthrocnemum fruticosum, 0.024 wk(-1) for Phragmites australis and 0.019 wk(-1) for Typha angustifolia. Root decomposition had mean K values of 0.0042 wk(-1) for Arthrocnemum fruticosum, 0.021 wk(-1) for Phragmites australis and 0.038 wk(-1) for Typha angustifolia. The decomposition rate of woody stems of Arthrocnemum glaucum had a mean K value of 0.0037 wk(-1). The main factors affecting primary production are grazing, soil salinity, waterlogging and nutrients. Human impacts such river and sea dikes, impoundments, and introduction of large grazers have altered productivity, diversity and successional patterns of the vegetation communities. Increases in sea level will exacerbate these impacts because of increased waterlogging and salt stress. These impacts are presently leading to wetland loss and this will likely accelerate unless conditions are changed.

Jennings, A. E. and A. R. Nelson (1992). "Foraminiferal Assemblage Zones in Oregon Tidal Marshes - Relation to Marsh Floral Zones and Sea-Level." Journal of Foraminiferal Research 22(1): 13-29.

Foraminiferal assemblages from three surface transects across estuarine marshes on the central Oregon coast reflect vertical floral zones based on vascular plants. Discriminant analysis distinguishes assemblages of modern mudflat, low marsh, and high marsh zones using the types of percentage data found in fossil assemblages. Upland samples are barren of foraminifera. The high marsh is dominated by Trochammina macrescens f. macrescens and T. inflata. The highest part of the high marsh, above mean higher high water, is usually marked by increases in the percentage of T. inflata and Haplophragmoides sp. Miliammina fusca is found throughout the high and low marsh. The low marsh may be divisible into two subzones: an upper subzone with T. macrescens f. macrescens and T. inflata and a lower subzone with Ammotium salsum and Ammobaculites exiguus. Mudflat assemblages contain Reophax nana, M. fusca, A. salsum, A. exiguus, and low numbers of calcareous species. Assemblages resemble those studied in other cool-temperature tidal marshes, but the elevational range of the high marsh foraminiferal zone in Oregon is greater than the range of equivalent zones in the tidal marshes of eastern North America. Large ranges on low and high marsh assemblage zones limit the precision with which changes in paleosea levels can be estimated from fossil assemblages in Oregon.

Jennings, A. E., A. R. Nelson, et al. (1995). "Marsh Foraminiferal Assemblages in the Valdivia Estuary, South-Central Chile, Relative to Vascular Plants and Sea-Level." Journal of Coastal Research 11(1): 107-123.

High marsh foraminiferal assemblages are distinct from those of the low marsh, mud flat, and upland floral zones in two transects across tidal marshes in the Valdivia estuary of south-central Chile. Assemblages from the high marsh, mapped on the basis of vascular plant communities, consist mostly of Trochamminita salsa and have higher concentrations of foraminifera than samples from lower intertidal zones. Fossil assemblages in a core that records the sudden subsidence of the Valdivia estuary during the great earthquake of 1960 cannot be used to estimate the amount of sudden sea-level rise during the earthquake because the core contains only low marsh/mud dat assemblages, which are indistinguishable from one another. The 0.8-0.5 m vertical range of the high marsh assemblage zone, and the undefined ranges of the low marsh/mud Bat and upland zones also limit the precision of estimates of relative sealevel change. More precise estimates of the amount of land-level change during past great earthquakes in this region will require identification of assemblage zones with narrower elevational ranges. The Valdivia high marsh foraminiferal assemblages differ dramatically from other reported high marsh assemblages from the mid-latitude Americas in being dominated by Trochamminita salsa. Our study of the large populations of the genus Trochamminita Cushman and Bronnimann encountered along the transects indicates that the two species of Trochamminita that have been described previously should be combined into the single species, Trochamminita salsa.

Jonasson, K. E. and R. T. Patterson (1992). "Preservation Potential of Salt-Marsh Foraminifera from the Fraser-River Delta, British-Columbia." Micropaleontology 38(3): 289-301.

Three biofacies were recognized in samples collected at a depth of 10cm along three transects from the marshes of the Fraser River delta, British Columbia. These biofacies, defined by comparison with those previously identified from surface marsh samples, correspond to three elevational zones: the High Marsh Zone, characterized by the Jadammina macrescens biofacies; the Lower High Marsh Zone, characterized by the Ammonia beccarii biofacies; and the Low Marsh Zone, characterized by the Miliammina fusca biofacies. A dramatic decrease in the abundance of Ammonia beccarii at 10cm depth suggests that the calcareous tests of this species are poorly preserved in the low pH subsurface sediments. As a result, the Ammonia beccarii biofacies will no longer be recognizable after extended burial. Although fewer biofacies can be resolved from paleomarshes of the Fraser delta than at the surface, it is still possible to differentiate between a High Marsh fauna (>+0.94m above mean sea level) and a Low Marsh fauna (<+0.94m above mean sea level).

Karner, D. B. and P. R. Renne (1998). "Ar-40/Ar-39 geochronology of Roman volcanic province tephra in the Tiber River valley: Age calibration of middle Pleistocene sea-level changes." Geological Society of America Bulletin 110(6): 740-747.

The close proximity of the Roman volcanic province to the Tyrrhenian Sea coastline provides a unique opportunity to combine clastic stratigraphy with Ar-40/Ar-39 geochronology to constrain the timing of Pleistocene sea-level oscillations. The main eruptions from the Monti Sabatini volcanic district occurred during the interval 568-280 ka, and the Alban Hills volcanic district mails eruptions span 560-350 ka. The interfingering of volcanics from these two centers with fluvial and shallow-marine sediments of the Tiber River and delta provides a datable relative sea-level record for this portion of middle Pleistocene time. We calculate the timing of glacial terminations using analytical errors only, then assess age uncertainties that include analytical plus systematic errors; the latter is required to compare Ar-40/Ar-39 ages with those from other dating methods. Terminations III, V, and VI occur at 278 (261, 285) ha (95% confidence interval), 430 (422, 442) ka, and 534 (520, 541) ka, respectively, when only analytical uncertainties are used to calculate the ages of bracketing volcanic horizons. The confidence interval expands significantly when full external errors are considered, with predicted ages of 276 (258, 289) ka, 430 (416, 448) ka, and 533 (512, 548) ka for the terminations. The resultant Ar-40/Ar-39 chronology is generally consistent with the deep-sea delta(18)O record of sea-level change tuned to Earth's obliquity cycle for glacial terminations VI, V, and III. In addition, the Ar-40/Ar-39 constrained Tiber River delta sea-level record has the added benefit of identifying when coastal sections respond to complex (multistep) terminations.

Kuptsov, V. M. and A. P. Lisitsyn (2003). "Moisture, bulk density, and sedimentary matter fluxes in the bottom sediments of the Laptev Sea." Oceanology 43(1): 121-127.

The moisture and bulk density of wet and dry sediments were determined for the bottom sediments of the Lena River marginal filter within a distance of 700 kin from the outer boundary of the river delta. Earlier, the suspended matter concentrations in the water, grain-size composition, and ages of sediments were estimated along the same profile. The sedimentary matter fluxes (absolute masses, g/cm(3)/ky) and their spatial and temporal (over about 14 ky) variations were inferred from the physical parameters measured. A correlation was established between the physical parameters of the bottom sediments and the changes in the Lena River marginal filter including those caused by sea-level fluctuations.

Lavoie, C., M. Allard, et al. (2002). "Holocene deltaic sedimentation along an emerging coast: Nastapoka River delta, eastern Hudson Bay, Quebec." Canadian Journal of Earth Sciences 39(4): 505-518.

Eastern Hudson Bay is characterized by falling relative sea level as a result of post-glacial isostatic rebound, which makes the region a natural laboratory for rapid forced regression, where the evolution of deltaic systems and offshore sedimentation patterns can be studied. A multidisciplinary approach involving airphoto analysis, offshore geophysical surveys, sediment coring, and facies and diatom analyses was used in this study of the Nastapoka River delta. The delta has formed as a result of the fluvial erosion of emerged Quaternary sediments but is mainly subaqueous. Offshore, in the prodelta zone, the oldest deposits are glaciomarine, laid down when the ice front of the receding Laurentide ice sheet stood on the Nastapoka hills some 7700-6800 years BP. Lateral equivalents of this glaciomarine unit are presently exposed on land. The shallow-water platform of the delta shows a thin surficial unit of wave-worked sand that overlies fine-grained, deeper water deposits derived from erosion of clay soils in the river catchment a few centuries ago, probably during periods of intense thermokarst activity. As the isostatic uplift continues, the deltaic platform will gradually emerge and be incised by the river channel.

Li, C. X., P. Wang, et al. (2002). "Late Quaternary incised-valley fill of the Yangtze delta (China): its stratigraphic framework and evolution." Sedimentary Geology 152(1-2): 133-158.

A Late Quaternary stratigraphic framework of the Yangtze delta, China, has been established based on the analysis and correlation of over 600 cores. Thirty cores were drilled and analyzed during this study, and the rest were collected from numerous publications. The Late Quaternary stratigraphic framework of the Yangtze delta consists of incised-valley fill and two interfluvial sequences. The incised valley roughly coincides with the modem Yangtze delta. From bottom to top, the incised-valley fill sequence is typically composed of channel, floodplain-estuary, estuary-shallow marine, and modem deltaic facies. The interfluvial sequences occur along the two flanks of the incised-valley fill. On the southern flank, seaward of the maximum-transgression line, the interfluvial sequence is typically composed of marsh-nearshore, shallow marine, and tidal flat facies with predominantly muddy deposits. On the northern flank, the interfluvial sequence is typically composed of barrier-lagoon, tidal sand ridge, and littoral-tidal flat facies with predominantly sandy deposits. The interfluvial sequence landward of the maximum-transgression line on both flanks is composed mainly of lacustrine muddy deposits. The post-glacial fining-upward incised-valley fill sequence was formed by retrogressive aggradation in the lower reach of the Yangtze River, induced by sea-level rise. The upstream extent of the retrogressive aggradation exceeds the reach of flood tidal currents, which explains the lack of marine fossil and tidal sedimentary structures in the channel sand deposits. A huge estuary was formed in the present Yangtze delta area when the post-glacial transgression reached maximum at about 7500 years BP. The shallow marine mud was deposited broadly in the estuary and the maximum flooding surface, which separates the underlying transgressive sequence from overlying regressive sequence, located within the muddy stratum. An erosional surface between the channel sand unit and deltaic sand unit exists at the apical area of the Yangtze delta. The modem Yangtze delta developed after the post-glacial transgression maximum was reached. The delta development was dominated by the abundant fluvial sediment supply. Six sub-deltas with a southward migrating trend have developed. (C) 2002 Elsevier Science B.V. All fights reserved.

Li, C. X., V. Ivanov, et al. (2004). "Development of the Volga Delta in response to Caspian sea-level fluctuation during last 100 years." Journal of Coastal Research 20(2): 401-414.

The Volga Delta developed in the closed Caspian basin can be classified as a river-dominated type. The subaqueous part of the delta (avandelta) is characterized by an extremely gentle slope and may be subdivided into shallow and deep parts. The very low-angle slope of the shallow avandelta is a major factor to mitigate impacts of Caspian sea-level (CSL) changes on the Volga Delta during the last 100 years. The CSL has fluctuated 3.46 m in the last 100 years, with a high of -25.55 m relative to the Baku Datum (BD) in 1903 and a low of -29.01 m BD in 1977. Sea-level changes can be grouped into three stages: (1) slowly falling at an average rate of 1.1 cm yr(-1) in 1900-1929; (2) rapidly falling at an average rate of 6.3 cm yr(-1) in 1930-1977; (3) rapidly rising at an average rate of 8.8 cm yr(-1) in 1978-1999. During the rapid fall stage of sea level, the Volga delta-plain expanded at a rate of 2.3 km(2)yr(-1) to 180 km(2)yr(-1) because of alluvial accumulation and exposure of the shallow avandelta. Flourishing subaqueous vegetation promotes this expansion by trapping suspended sediments on the avandelta. The shallow avandelta is primarily covered by freshwater and its geomorphic and sedimentary features are controlled more by the river flow than by the CSL changes, waves or wind-induced currents. The shallow avandelta decelerated delta progradation during sea-level fall and delayed delta retreat during sea-level rise. Significant changes in the delta-plain area have not occurred in the rapid CSL rise stage. Moreover, the distributaries and their distal underwater channels underwent erosion by the river flow at least until the end of the last century. The CSL has risen with an average annual rate of 8.8 cm during the last 20 years, yet coastal erosion, coastal flooding, wetland loss and saltwater intrusion, observed in other deltas, have not occurred here. This may have resulted from the existence of the shallow avandelta and show that the world's deltas respond to sea-level rise in different ways.

Liu, J. P., J. D. Milliman, et al. (2002). "The Shandong mud wedge and post-glacial sediment accumulation in the Yellow Sea." Geo-Marine Letters 21(4): 212-218.

Two well-defined deltaic sequences in the Bohai Sea and in the South Yellow Sea represent post-glacial accumulation of Yellow River-derived sediments. Another prominent depocenter on this epicontinental shelf, a pronounced clinoform in the North Yellow Sea, wraps around the northeastern and southeastern end of the Shandong Peninsula, extending into the South Yellow Sea. This Shandong mud wedge is 20 to 40 m thick and contains an estimated 300 km(3) of sediment. Radiocarbon dating, shallow seismic profiles, and regional sea-level history suggest that the mud wedge formed when the rate of post-glacial sea-level rise slackened and the summer monsoon intensified, at about 11 ka. Geomorphic configuration and mineralogical data indicate that present-day sediment deposited on the Shandong mud wedge comes not only from the Yellow River but also from coastal erosion and local rivers. Basin-wide circulation in the North Yellow Sea may transport and redistribute fine sediments into and out of the mud wedge.

Marra, F., F. Florindo, et al. (1998). "Paleomagnetism and geochronology of early Middle Pleistocene depositional sequences near Rome: comparison with the deep-sea delta O-18 record." Earth and Planetary Science Letters 159(3-4): 147-164.

A sequence-stratigraphic analysis was carried out on elastic coastal deposits (Ponte Galeria Formation - PGF) of the Tiber River delta, cropping out to the southwest of Rome, in order to correlate these sequences to Pleistocene eustasy. Tectonic subsidence affected sedimentation, but is distinguished from the glacio-eustatic signal, showing that the PGF consists of four depositional sequences that correlate to two fourth-order cycles. A paleomagnetic investigation of clay horizons deposited before and after the Brunhes-Matuyama reversal, combined with Ar-40/Ar-39 ages from a tuff horizon within the PGE constrain the timing of the relative sea-level changes and allow us to tie it to the astronomically calibrated deep-sea delta(18)O record. The Brunhes-Matuyama boundary in the PGF postdates a set of highstand systems tract sediments, suggesting that the reversal occurs late in delta(18)O stage 19. This position is consistent with the recent study of deep-sea cores by Bassinot et al. [Earth Planet. Sci. Lett. 126 (1994) 91-108]. The assumption of a common continental stage marking the start of the Middle Pleistocene (delta(18)O stage 22) in the Mediterranean region is not supported by the Tiber River sections which, in our interpretation, begin at stage 20. (C) 1998 Elsevier Science B.V. All rights reserved.

Martin, J. F., M. L. White, et al. (2000). "Evaluation of coastal management plans with a spatial model: Mississippi delta, Louisiana, USA." Environmental Management 26(2): 117-129.

A landscape spatial model that operates with a cellular grid was utilized to evaluate proposed management plans in the Barataria and Terrebonne basins of the Mississippi River delta. By explicitly incorporating system processes and relationships, models of this type can identify both short- and long-term impacts of proposed plans across space and offer a solution to the spatial and temporal isolation that plagues many environmental management decisions. Four management proposals, which included a river diversion, levee plans, and a hydraulic retention scenario, were analyzed with regard to reducing land loss, a pervasive problem in many of the world's deltas. The model simulated 30 years of habitat change for each plan and "no action plans" in each basin were used as a baseline of comparison for the management plans. By restoring natural deltaic functions and increasing wetland elevations, the river diversion proved to be an effective method to reduce land loss in these environments. Habitat changes during the hydraulic retention scenario highlighted the use of the model in recognizing distant spatial impacts of management plans. Simulations of levee plans illustrated limitations of the model and produced ambiguous results, suggesting areas for future model refinement. The river diversion and hydraulic retention scenarios demonstrate that spatial landscape models are tools capable of predicting landscape responses to regional management plans.

Martin, J. F., E. Reyes, et al. (2002). "Landscape modeling of the Mississippi delta." Bioscience 52(4): 357-365.

Masuda, F. and Y. Iwabuchi (2003). "High-accuracy synchronism for seismic reflectors and C-14 ages: Holocene prodelta succession of the Kiso River, central Japan." Marine Geology 199(1-2): 7-12.

Horizons at 500-yr intervals for the past 6000 years can be inferred in two cores drilled along a high-resolution seismic line in the prodelta of the Kiso River, Ise Bay, central Japan. These horizon ages clearly indicate that a given seismic reflection line in the profile is isochronous. Synchronism between ages and reflectors in the succession is especially distinct for the interval from 5000 to 2500 yr BP, despite the reflectors having inclined planes and having the same ages at different depths. These data indicate that the Kiso River delta prograded to form a downlap surface before the maximum flooding stage of the post-glacial relative sea-level rise at about 6000 yr BP. Delta progradation beginning late in the transgressive stage was caused by the flow of large amounts of sediment into this steep river that is part of the active Japanese volcanic arc. (C) 2003 Elsevier Science B.V. All rights reserved.

Mathers, S. and J. Zalasiewicz (1999). "Holocene sedimentary architecture of the Red River Delta, Vietnam." Journal of Coastal Research 15(2): 314-325.

Remotely sensed satellite images, integrated with compilations of shallow geological data, enable elucidation of the Holocene facies architecture of the Red River Delta of Vietnam. The Holocene delta sediments are relatively fine-grained, up to 30 m thick, and represent rapid progradation during the current high sea level stand; they overlie a coarse-grained Pleistocene sequence of braided river and alluvial fan deposits formed during glacial low sea level stands. The Holocene delta shows roughly equal influence by fluvial, wave and tidal processes. In this it resembles the Niger Delta, but with the crucial difference that the facies belts are sectorial rather than concentric, being governed along the coast by differing amounts of shelter from wave action in a uniformly mesotidal setting. The wave-dominated sector appears to have advanced by leapfrogging' seawards, perhaps under the influence of episodic high-discharge fluvial flood events, producing lateral alternations of stacked sandy beach ridges and intervening fine-grained lagoonal deposits in chenier-like architectures.

Mathewes, R. W. and J. J. Clague (1994). "Detection of Large Prehistoric Earthquakes in the Pacific-Northwest by Microfossil Analysis." Science 264(5159): 688-691.

Geologic and palynological evidence for rapid sea level change similar to 3400 and similar to 2000 carbon-14 years ago (3600 and 1900 calendar years ago) has been found at sites up to 110 kilometers apart in southwestern British Columbia. Submergence on southern Vancouver Island and slight emergence on the mainland during the older event are consistent with a great (magnitude M greater than or equal to 8) earthquake on the Cascadia subduction zone. The younger event is characterized by submergence throughout the region and may also record a plate-boundary earthquake or a very large crustal or intraplate earthquake. Microfossil analysis can detect small amounts of coseismic uplift and subsidence that leave little or no lithostratigraphic signature.

McBride, R. A. and M. R. Byrnes (1997). "Regional variations in shore response along barrier island systems of the Mississippi River delta plain: Historical change and future prediction." Journal of Coastal Research 13(3): 628-655.

Long-term changes in shoreline position along Louisiana's rapidly deteriorating barrier coastline were documented from 1855 to 1959 using National Ocean Service (NOS) topographic sheets and near-vertical aerial photography. An interactive computer mapping system was employed to compile and quantify shoreline data at approximately 880 shore-normal transects by magnitude, direction, and rate of change. The study area extends along the barrier coast of the Mississippi River delta plain from Raccoon Point (western Isles Dernieres) to Hewes Point (northern Chandeleur Island). Four barrier systems characterize the study area: (1) Isles Dernieres, (2) Bayou Lafourche, (3) Plaquemines, and (4) Chandeleur Islands. Long-term gulfside rates of change range from -23.1 to +0.9 m/yr, whereas bayside rates range from -5.0 to +24.0 m/yr. Louisiana barrier island systems have experienced landward migration, area loss, bayside erosion, and island narrowing as a result of complex interactions among subsidence, eustatic sea level rise, wave processes, storm impacts (cold Gents and tropical cyclones), inadequate sediment supply, and intense human disturbance (levees; oil, gas, and sulphur extraction activities; access canals; seawalls; jetties). Consequently, the structural continuity of Louisiana's barriers is weakening as the barrier shoreline continues to narrow, fragment, and finally disappear. Seven geomorphic response types characterize the barrier shoreline: 1) lateral movement, 2) advance, 3) dynamic equilibrium, 4) retreat, 5) landward rollover, 6) breakup, and 7) rotational instability. Although the Bayou Lafourche shoreline has the highest rates of erosion through landward rollover and retreat, the Isles Dernieres, Grand Terre Islands, and the eastern Plaquemines shoreline are experiencing the more devastating process of breakup and will probably disappear within the next 25 years. Consequently, these zones of breakup are the most critical coastal land loss areas along Louisiana's barrier shoreline and thus, further threaten productive estuarine habitats in Terrebonne/Timbalier and Barataria Bays.

Meldahl, K. H. (1995). "Pleistocene Shoreline Ridges from Tide-Dominated and Wave-Dominated Coasts - Northern Gulf of California and Western Baja-California, Mexico." Marine Geology 123(1-2): 61-72.

The arid climate of northwestern Mexico preserves Pleistocene beach deposits forming linear, shoreline-parallel ridges on the coastal plains of Sonora, northern Gulf of California, and the Vizcaino Peninsula of Baja California. Beach deposits represent both cheniers (northern Gulf) and beach ridges (Vizcaino Peninsula). They formed during Pleistocene sea-level highstands, most commonly during oxygen-isotope stage 5e (similar to 125 ka). The ridges are 0.5 to 5.0 m thick, < 10 to > 100 m wide, and < 100 to > 1000 m long, coarse-grained with common low- to high-angle cross stratification, and are dominated by bivalve shells. Ridges from the tide-dominated northern Gulf of California and the wave-dominated western Vizcaino Peninsula differ in underlying lithology, size, profile, and shell fragmentation. Northern Gulf ridges progradationally overlie deltaic or marsh deposits, are smaller (median thickness 1.4 m; median width 25 m; median length 300 m), typically have a seaward-dipping upper surface and a linear crest on the landward side, and have low levels of fragmentation of large bivalve shells. In contrast, Vizcaino ridges disconformably overlie bedrock on wave-cut terraces, are larger (median thickness 3.3 m; median width 100 m; median length 2000 m), typically have a landward-dipping upper surface and a linear crest on the seaward side, and contain beds of extensively fragmented large bivalve shells. These differences are interpreted to reflect contrasting processes of ridge formation in the two regions. The ridges of the tide-dominated northern Gulf are true cheniers-transgressive beach deposits produced during episodes of elastic starvation associated with shifts in Colorado River delta deposition. They are modified primarily through episodic washover processes during high tides and storms. The ridges of the wave-dominated Vizcaino Peninsula are regressive beach ridges developed on highstand wave-cut terraces. They are modified primarily through continuous wave accretion to the beach face, and secondarily by washover processes.

Moslow, T. F. and G. R. Davies (1997). "Turbidite reservoir facies in the Lower Triassic Montney Formation, west-central Alberta." Bulletin of Canadian Petroleum Geology 45(4): 507-536.

The Lower Triassic Montney Formation in west-central Alberta is divided into two major third-order sequences separated by a sequence boundary that correlates to an Early Triassic (Smithian/Dienerian) global eustatic sea level fall. This drop in sea level enhanced mass-wasting processes responsible for the formation of a turbidite channel and lobe complex within the lowstand systems tract of the upper Montney sequence. This assemblage of facies constitutes the principal reservoir within the Valhalla-La Glace fields. Most of the turbidite reservoirs facies were derived from the reworking of a southwestward-prograding depositional thick, designated the "Cindy Lobe", of the lower Montney sequence that protrudes basinward from the western extension of the Cindy Graben trend. The Valhalla-La Glace reservoir facies are a complex of turbidite channels and downdip lobes deposited in the subaqueous platform of a prograding lowstand shoreline immediately seaward of a continental ramp slope break. The ramp "edge" trends NNW-SSE through the area, and defines the updip depositional limit of turbidite facies. The ramp-edge orientation is probably fault controlled and marks the onset of rapid and abrupt thickening of lowstand facies associations. The origin of these facies is attributed to mass-wasting and generation of sediment gravity flows due to substrate instability at the slope break. Individual turbidite channels likely have undergone headward retreat, moving upslope and creating their own supply of sediment for turbidity flows. Lateral facies relationships expressed by turbidite channel, channel margin and levee/overbank facies provide a predictive model for determining proximity to the turbidite channel axis. The turbidite channel facies association contains the highest quality reservoir in terms of porosity and permeability. Turbidite channels can be amalgamated or crosscut one another, thus inducing vertical and lateral permeability barriers and reservoir heterogeneity. However, there is a lateral continuity in lithofacies along depositional strike and dip, The reservoir facies are more continuous along depositional dip, Turbidite channel, turbidite channel margin, and turbidite lobe facies associations are recognized within the study area. The latter is found almost exclusively within the Glacier field. Facies associations and their lateral variability within the study area are analogous to turbidite channels and lobes from the subaqueous platform of the Fraser River delta, providing a process sedimentologic and geomorphic analogue for the Valhalla-La Glace field reservoir facies.

Murray, J. W. and E. Alve (1999). "Natural dissolution of modern shallow water benthic foraminifera: taphonomic effects on the palaeoecological record." Palaeogeography Palaeoclimatology Palaeoecology 146(1-4): 195-209.

Comparison of the living and dead assemblages of benthic foraminifera from the coastal areas of the Skagerrak-Kattegat reveals that, although there are considerable similarities in terms of the presence/absence of species, there are major differences in relative abundance at species level. Furthermore, the relative abundance of calcareous tests in the living assemblages is considerably higher than that of the dead assemblages (average values of 67 and 30%, respectively). Since the environments are microtidal, there is little transport of foraminiferal rests due to tidal currents so there are no introduced exotic species although there is local transport caused by waves and wave-induced currents. However, the major taphonomic process appears to be dissolution, of calcareous tests. This is manifested through etching and breakage of test walls, leading to complete decalcification which leaves a residue of organic linings of certain taxa (e.g., Ammonia beccarii), and a marked increase in abundance of agglutinated tests in the dead assemblages. Although dissolution is normal in marsh settings throughout the world, the Skagerrak-Kattegat area is unusual in the intensity of dissolution in the subtidal zone. Whereas most of the calcareous species occur throughout the investigated depth range (except marsh), two of the subtidal agglutinate species (Eggerelloides scaber and Ammotium cassis) show upper depth limits. Consequently, the agglutinated foraminifera are better indicators than calcareous foraminifera of upper depth limits in these shallow subtidal environments. (C) 1999 Elsevier Science B.V. All rights reserved.

Nguyen, V. L., T. K. O. Ta, et al. (2000). "Late holocene depositional environments and coastal evolution of the Mekong River Delta, Southern Vietnam." Journal of Asian Earth Sciences 18(4): 427-439.

The Mekong River Delta in Southern Vietnam is a tide-dominated delta and has been formed by the Mekong River system. The sediments are dominantly fine grained and were deposited in the receiving basin with slight inclination of pre-existing deposits in the South China Sea and Gulf of Thailand. Around 6000 to 5000 yr BP maximum Holocene transgression occurred and seawaves surrounded uplands of the Late Pleistocene terrace, basement rock and weathered land in the northern parts of the delta. Double notches were undercut by seawaves on the limestone hill in Hatien at about 4.5 and 2.5 m above present sea level. Marine deposits prevailed throughout the delta. During the highstand and regressions of relative sea level over the last 4550 yr BP, delta progradation has produced a great flat-plain of 62,520 km(2). This extremely fast progradation could be due to: (a) very high sediment supply depositing in the slight inclination of the receiving basin; (b) neotectonic movements and relative sea-level changes; (c) widespread mangrove forests playing an important role to enhance sediment accumulation. Former mangrove marshy deposits were significantly developed in the Plain of Reeds and Longxuyen Quadrangle. Mangrove marshes have also been developing well in the Camau Peninsula and present coastlines. Moreover, regressions over the last 4550 yr BP have produced many distinct sets of relict beach ridges which are useful in distinguishing the former coastlines and evolutionary history of the delta. (C) 2000 Elsevier Science Ltd. All rights reserved.

Otvos, E. G. and M. J. Giardino (2004). "Interlinked barrier chain and delta lobe development, northern Gulf of Mexico." Sedimentary Geology 169(1-2): 47-73.

A wealth of new data provides a well-constrained chronology of mid- to late Holocene coastal development in the Louisiana-Mississippi borderland that may also be utilized in a globally applicable sedimentation model. Barrier sand and deltaic mud sequences illustrate a process by which potential ground water and hydrocarbon reservoir rocks accumulated unusually rapidly and were preserved. Set against decelerating Holocene sea-level rise and locally variable subsidence rates, the study provides an example of the interplay between an emerging, prograding, and partially stranded barrier island chain, a sizable estuary, and several extensive delta lobes. Utilizing microfossil fauna-based depositional facies information and archaeological data, absolute dates helped to reconstruct the history of the Alabama-Louisiana barrier chain and deltas between ca. 5.7 and ca. 1.5 C-14 ka BP. Protected by the substantial dune cover that prevented island submersion, the regional eustastic transgression paradoxically was synchronous with significant progradational barrier and deltaic regression. The earliest barrier islands emerged ca. 4.6-4.4 C-14 ka BP (ca. 5.7-5.0 cal years) when sea level stood at ca. - 1.0 to - 1.5 m. These islands isolated Mississippi Sound from the greater Gulf of Mexico. The absence of a lagoonal-inshore sediment interval beneath the islands and the 3-15 m thick basal nearshore marine muddy-sandy unit that blankets the Pleistocene surface refutes the transgressive history of barrier initiation. The islands aggraded on a 3.0-16.5 m thick fine sandy shallow-marine regressive platform lithosome that, in turn, overlies a transgressive muddy-sandy nearshore marine lower sediment interval. Avulsion of the Mississippi River had abruptly reduced nearshore salinities by ca. 3.9-3.7 ka C-14 BP. Renewed Mississippi delta growth induced rapid aggradation and progradation on the opposite Pearl River delta-mainland shore as well. Gulf influences have rapidly diminished in areas so affected. A new absolute chronology of the Mississippi-St. Bernard delta lobes constrains these events. Delta growth and mainland progradation first isolated, then severely constricted the Lake Borgne embayment. Accompanied by ongoing subsidence, the western barriers were stranded, then buried. Shoaling, related to St. Bernard delta progradation, interfered with westward littoral drift to maintain Cat Island. Archaeology provided important supplementary data for dating environmental changes. Refuting earlier suggestions that Native colonization rapidly followed delta complex formation, the earliest known Indian sites postdated the start of the associated St. Bernard delta lobe by 1.9-3.1 C-14 ka. (C) 2004 Published by Elsevier B.V.

Overeem, I., S. B. Kroonenberg, et al. (2003). "Small-scale stratigraphy in a large ramp delta: recent and Holocene sedimentation in the Volga delta, Caspian Sea." Sedimentary Geology 159(3-4): 133-157.

The Volga delta differs from all other major deltas in the world by its extremely gentle onshore and offshore gradient (similar to 5 cm/km) and by being affected by the rapid sea-level changes of the Caspian Sea, at rates up to a hundred times the global sea-level rise. This paper reports (1) the morphological and facies development of part of the lower delta during the last full sea-level cycle between 1929 and 1995, as monitored using remote sensing and field mapping, and (2) the Holocene development of the delta from outcrop data and augered transects. During a sea-level fall of 3 m between 1929 and 1977, rapid progradation of levees, composed of fine sand, took place along over 800 distributary channels along the delta front. Smaller distributaries became filled with clay and organics. During the 3-m sea-level rise from 1977 to 1995, aggradation occurred, leading to deposition of silt and clay on the levees and minor filling of the flood basins. Sedimentation rates as established with Cs-137 dating are up to 2-5 cm/year. Total thickness of Holocene deposits in the lower delta plain is 4-10 m. A coarsening-upwards sequence in the Damchik sandpit shows freshening-upwards mollusc assemblages dated around 1000 BP, and has been attributed to the Derbent regression at that time. Four transects with a total of 79 augerings down to 7 m depth show rapid lateral facies changes of: (a) lagoonal clays deposited in the palaeo relief between the dunes, (b) channel sands, (c) levee sands and silts, (d) laminated overbank and interdistributary bay deposits, (e) mouthbar deposits and (f) prodelta clays. Holocene depositional patterns are unrelated to the present drainage network, though the spatial variability is similar to that of the present highly segmented network. Seven C-14 datings give a range of 6000-800 BP, and several phases of progradation seem to be present, but the lateral variability is too large and the age data too limited to make a solid correlation with known Holocene sea-level fluctuations. The Volga delta differs essentially from the classic river-dominated Mississippi delta because the offshore gradient is so gentle that no marine reworking takes place at the outlets, and the friction-controlled bifurcation continues basinward until a very fine maze of distributary outlets is produced. The Volga Holocene sequences more resemble those of the Atchafalaya and Saskatchewan lacustrine deltas. However, they differ from them in not being subsystems of a larger delta but the main depositional facies of the delta as a whole. Moreover, the recent Volga delta development shows that progradation is related to forced regression, not to avulsion triggered by base-level rise and/or subsidence. Thus, the Volga delta provides an excellent example of the impact of high-frequency sea-level changes on a ramp margin-type fluvio-deltaic system. (C) 2002 Elsevier Science B.V. All rights reserved.

Owen, R. B., R. J. Neller, et al. (1998). "Late Quaternary environmental changes in Hong Kong." Palaeogeography Palaeoclimatology Palaeoecology 138(1-4): 151-173.

The offshore Quaternary deposits of Hong Kong include a wide range of elastic sediments that accumulated in a variety of settings including lacustrine. channel, overbank, coastal and marine environments. Detailed studies of the sedimentology and diatoms of several long, continuously-sampled cores, combined with seismic reflection profiles, has enabled the reconstruction of Late Pleistocene and Holocene palaeoenvironments in Hong Kong. The Quaternary sediments comprise several informal seismic units that are separated by marine planation, tidal scour and fluvial erosion surfaces. Seismic Unit 1 represents pre-Quaternary bedrock and weathered bedrock, which is separated from a complex assemblage of Pleistocene channel. floodplain, backswamp and lacustrine deposits (seismic Unit 2) by a major erosion surface (U1). Sediments that represent the basal part of Unit 2 have been dated at about 248.000 yr B.P. Well preserved laminations at several horizons suggest periodic deposition and probably seasonal flooding. The presence of kaolin indicates strong chemical weathering and warm, humid conditions at the time of deposition. Seismic Unit 3 consists of marine mud that unconformably overlies a fluvial erosion surface (FE1) cut into deposits represented by seismic Unit 2. The sediments comprising Unit 3 are tentatively correlated with oxygen isotope stage 5e and high sea levels at about 128,000-105,000 yr B.P. A marine planation surface (R1) terminates Unit 3 and is overlain by coastal and nearshore deposits comprising seismic Unit 4 at about 95,000 to 80,000 yr B.P. This phase of marine deposition was terminated by a major fall in sea level that caused widespread fluvial incision across Hong Kong and produced surface FE2. A subsequent rise in sea level after about 18,000 yr B.P. led to deposition of a complex succession of marine sediments and erosion surfaces. Initially, homogeneous mud (seismic Unit 5A) was laid down. Tidal currents, perhaps related to base level changes, then caused incision and the formation of surface TS1 at several localities. Further shallow marine mud, comprising Unit 5B, was laid down between about 9500 and 8000 yr B.P. A planar erosion surface (R2), with local palaeosols and minor incision, cuts across earlier deposits, The overlying seismic Unit 5C represents diatomaceous marina mud and a basal sand. At one coring sire, these sediments have been divided into five major diatom zones that reflect changes in salinity and sea level. Modern sea level was attained by about 6000 yr B.P. In broad terms, the late Quaternary record is one of two periods of marine flooding separated by a major regressive episode, with no evidence of older Quaternary marine sediments being present. (C) 1998 Elsevier Science B.V.

Ozarko, D. L., R. T. Patterson, et al. (1997). "Marsh foraminifera from Nanaimo, British Columbia (Canada): Implications of infaunal habitat and taphonomic biasing." Journal of Foraminiferal Research 27(1): 51-68.

Marsh foraminiferal faunas from nine cores in two transects in and around Nanaimo inlet were examined to assess the implications of infaunal habitat and taphonomic processes for biofacies formation, High marsh faunas live slightly deeper infaunally compared to those in the low marsh, reflecting harsher conditions in the high marsh, Most living Jadammina macrescens occur from 0-20 cm in the high marsh and from 0-11 cm in the low marsh; the main depth preference is from 2-8 cm, Most living Trochammina inflata occur between 0-25 cm in the high marsh and from 0-20 cm in the low marsh, Haplophragmoides wilberti is most abundant overall between 3-7 cm, being almost absent at the surface in all cores, H, wilberti is found primarily between 0-15 cm in the high marsh, and from 0-12 cm in the low marsh. Most living Miliammina fusca occur from 0-10 cm, with maximum abundance in the top 3 cm, Five cluster analyses of the foraminiferal data using a sample base of 0-1, 0-3, 0-5, 0-7 and 0-10 cm, respectively, discriminated five biofacies in each case, which were then used to determine which near-surface aliquot is most analogous to deeper subsurface biofacies, Results show near-surface sediment sampling should be done through the 0-10 cm interval, This aliquot allows the main infaunal species characteristics to be observed, yet is thin enough that epifaunal species are also accurately represented, These results indicate that at least in coastal British Columbia traditional sampling strategies that assess modern marsh foraminiferal occurrence based only on examination of the uppermost 0-1 cm will not give an accurate representation of actual marsh species distribution, Modern marsh foraminiferal distribution assessment based on the thicker surface interval that we propose will permit researchers to delineate both subtle and dramatic sea level changes more precisely. This precision is critical not only in studies designed to differentiate the magnitude of seismic events but also to recognize subtle relative sea level change events as well.

Patterson, R. T., J. P. Guilbault, et al. (1999). "Taphonomy of tidal marsh foraminifera: implications of surface sample thickness for high-resolution sea-level studies." Palaeogeography Palaeoclimatology Palaeoecology 149(1-4): 199-211.

Previous research has shown that intertidal foraminiferal faunas can be used to document Holocene relative sea-level change and large prehistoric earthquakes. Applications like these, however, require an understanding of the impact of infaunal habitat and taphonomic processes on foraminiferal assemblages. To evaluate these effects, we analyzed surface sediment samples collected along a transect across a tidal marsh at Zeballos on Vancouver Island, British Columbia. Samples of the uppermost 10 cm of sediment in the marsh contain foraminiferal assemblages that permit recognition of a greater number of elevation-controlled marsh assemblages than samples of the top centimeter, which are generally used in sea-level studies, This is because the upper 10 cm contain most infaunal foraminifera species, whereas the top centimeter commonly lacks some of these species. A 10-cm thickness is somewhat arbitrary, but most foraminiferal taphonomic biasing occurs in the top 10 cm of the marsh, (C) 1999 Elsevier Science B.V. All rights reserved.

Patterson, R. T., I. Hutchinson, et al. (2000). "A comparison of the vertical zonation of diatom, foraminifera, and macrophyte assemblages in a coastal marsh: implications for greater paleo-sea level resolution." Micropaleontology 46(3): 229-244.

Researchers generally use only one type of plant or animal to study a particular marsh. Consequently, it has been impossible to directly compare zonations obtained using different groups between sites. To facilitate such comparison, cluster analysis of foraminiferal, diatom, and macrophyte data collected in transects from a tidal marsh at Zeballos, northwestern Vancouver Island, British Columbia, was carried out. These analyses yielded three, six, and four mostly elevation-controlled assemblage zones, respectively. Physical parameters such as salinity and oxygen concentration affect the: various taxa differently, resulting in significantly different assemblage boundaries between groups. A composite analysis of all groups yielded an assemblage zonation very similar to that obtained with the macrophytes alone. Although fewer assemblage zones were resolved with the composite analysis than with the diatom data alone, fewer sample misclassifications resulted in more precise elevation determinations. A second composite analysis using only foraminiferal and diatom data, which is more useful to paleo-sea level researchers, also gave four elevation controlled assemblage zones, although assemblage zone elevational boundaries differed slightly from those obtained with data from all groups. Our results will permit researchers working on diatoms, foraminifera or macrophytes to calibrate their zonations thus making it easier for workers in different fields to compare their results.

Piper, D. J. W., R. N. Hiscott, et al. (1999). "Outcrop-scale acoustic facies analysis and latest Quaternary development of Hueneme and Dume submarine fans, offshore California." Sedimentology 46(1): 47-78.

The uppermost Quaternary deposits of the Hueneme and Dume submarine fans in the Santa Monica Basin have been investigated using a closed-spaced grid of boomer seismic-reflection profiles, which give vertical resolution of a few tens of centimetres with acoustic penetration to 50 m. Acoustic facies integrated with geometry define six architectural elements, some with discrete subelements that are of a scale that can be recognized in outcrops of ancient turbidite systems. In the Santa Monica Basin, the relationship of these elements to fan morphology, stratigraphy and sediment source is precisely known. The width of upper Hueneme fan valley has been reduced from 5 km since the last glacial maximum to 1 km at present by construction of laterally confined sandy levees within the main valley. The middle fan comprises three main subelements: thick sand deposits at the termination of the fan valley, low-gradient sandy lobes typically 5 km long and < 10 m thick, and scoured lobes formed of alternating sand and mud beds with many erosional depressions. The site of thickest lobe sediment accumulation shifts through time, with each sand bed deposited in a previous bathymetric low (i.e. compensation cycles). The lower fan and basin plain consists of sheet-like alternations of sand and mud with shallow channels and lenses. Variations in the rate of late Quaternary sea level rise initiated changes in sediment facies distribution. At lowstand, and during the approximately 11 ka stillstand in sea level, the Hueneme Fan was fed largely by hyperpycnal flow from the Santa Clara River delta, depositing high sediment waves on the right hand levee and thick sandy lobes on the middle fan. At highstand of sea level, most turbidity currents were generated by failure of silty prodelta muds. In contrast, the smaller Dume Fan was apparently always fed from littoral drift of sand through a single-canyon point source.

Polonsky, V. F. (1996). "Physicostatistical approach to river delta hydrology." Journal of Hydraulic Engineering-Asce 122(6): 333-340.

River deltas are characterized by a very complicated and unsteady water regime. They are affected by changes in the river regime at the upper boundary of the delta, changes in the sea level at its lower boundary, and by hydrological and morphological processes within the delta itself. The most significant indicators of all processes affecting the water regime in the delta are changes in water discharges and water levels at various points of the delta hydrographic network as a function of water discharge in the delta head. These dependences are taken as a basis for hydrologic calculations in river deltas. This paper presents a physicostatistical method for plotting, assessing accuracy and establishing the dynamics of water discharges and water levels in delta streams as a function of water discharge in the delta head. The automated technique allows for an operative solution of hydrologic tasks in river mouths. Recommendations to optimize hydrometric works in river deltas are suggested, which would take into account time-specific changes in delta hydromorphology and delta monitoring tasks.

Pont, D., J. W. Day, et al. (2002). "Response scenarios for the deltaic plain of the Rhone in the face of an acceleration in the rate of sea-level rise with special attention to Salicornia-type environments." Estuaries 25(3): 337-358.

One of the most critical problems facing many deltaic wetlands is a high rate of relative sea-level rise due to a combination of eustatic sea-level rise and local subsidence. Within the Rhone delta, the main source of mineral input to soil formation is from die river, due to the low tidal range and the presence of a continuous sea wall. We carried out field and modeling studies to assess the present environmental status and future conditions of the more stressed sites, i.e., Salicornia-type marshes with a shallow, hypersaline groundwater. The impacts of management practices are considered by comparing impounded areas with riverine areas connected to the Rhone River. Analysis of vegetation transects showed differences between mean soil elevation of Arthrocnemum fruticosum (+31.2 cm), Arthrocnemum glaucum (+26.5 cm), bare soil (+16.2 cm), and permanently flooded soil (-12.4 cm). Aboveground and belowground production showed that root:shoot ratio for A. fruticosum and A. glaucum was 2.9 and 1.1, respectively, indicating more stressful environmental conditions for A. glaucum with a higher soil salinity and lack of soil drainage. The annual leaf litter production rate of the two species is 30 times higher than annual stem litter production, but with a higher long-term decomposition rate associated with leaves. We developed a wetland elevation model designed to predict the effect of increasing rates of sea-level rise on wetland elevation and Salicornia production. The model takes into account feedback mechanisms between soil elevation and river mineral input, and primary production. In marshes still connected to the river, mineral input decreased quickly when elevation was over 21 cm. Under current sea-level rise conditions, the annual amount of riverine mineral input needed to maintain the elevation of the study marshes is between 3,000 and 5,000 g m(-2) yr(-1). Simulations showed that under the Intergovernmental Panel on Climate Change best estimate sea-level rise scenario, a mineral input of 6,040 g m(-2) yr(-1) is needed to maintain marsh elevation. The medium term response capacity of the Rhone deltaic plain with rising sea level depends mainly on the possibility of supplying sediment from the river to the delta, even though the Rhone Delta front is wave dominated. Within coastal impounded marshes, isolated from the river, the sediment supply is very low (10 to 50 g m(-2) yr(-1)), and an increase of sea-level rise would increase the flooding duration and dramatically reduce vegetation biomass. New wetland management options involving river input are discussed for a long-term sustainability of low coastal Mediterranean wetlands.

Pruszak, Z., M. Szmytkiewicz, et al. (2002). "Coastal processes in the Red River Delta area, Vietnam." Coastal Engineering Journal 44(2): 97-126.

The economy and life in Vietnam is associated with the existence and development of large river deltas, i.e. the Mekong Delta and the Red River Delta. The latter is located in the northern part of Vietnam and apart from thousands of square kilometers of the area, it includes more than 165 km of coastline as well. In this area, the seashore and the adjacent densely populated, low-lying regions are often subject to intense impacts from the river (floods) and the sea (typhoons, changes in sea level, currents, etc.) and therefore undergo substantial and dynamic changes and destructions. In the current study, one of the coastal segments that are most vulnerable to destruction in Vietnam is analyzed. A synthetic analysis of the available information was carried out first and then the modeling of wave climate, currents and sediment movement patterns in the nearshore zone was done. The formulation of a phenomenological model of sediment budget, adequate for the amount of available information, allowed for assessment of the existing sediment fluxes and their relations to morphodynamic processes taking place in the studied area.

Pulich, W. M. and W. A. White (1991). "Decline of Submerged Vegetation in the Galveston Bay System - Chronology and Relationships to Physical Processes." Journal of Coastal Research 7(4): 1125-1138.

Changes in submerged vascular plant distribution since the 1950's were documented for the Galveston Bay system (excluding the Trinity River delta proper) using aerial photographs and substantiated field reports. Two major regions where seagrasses have declined extensively were compared with nearby sites where vegetation persists. Along the upper bay shoreline, evidence is presented for involvement of Hurricane Carla (1961) and a relative rise in sea level due to subsidence, which resulted in the disappearance of Ruppia maritima beds between 1960 and 1962. In the lower bay (West Bay), mixed beds of R. maritima and Halodule wrightii declined steadily from the 1950's and disappeared by the early 1980's. This area contrasts with Christmas Bay, a secondary protected bay 5 to 7 km south that still contains extensive beds of H. wrightii and small patches of Thalassia testudinum and Halophila engelmanni. In West Bay, urban development, wastewater discharges, chemical spills, and dredging activities, rather than subsidence and Hurricane Carla, are suspected as the principal deleterious agents. Similarities between submerged vegetation declines in Galveston and other bay systems are discussed.

Reed, D. J. (2002). "Sea-level rise and coastal marsh sustainability: geological and ecological factors in the Mississippi delta plain." Geomorphology 48(1-3): 233-243.

Chronostratigraphic approaches to coastal geomorphology frequently include consideration of salt marsh deposits as indicators of past sea-level positions. Continuous horizons of such deposits can be used to infer that salt marshes were keeping pace with local rates of relative sea-level rise (RSLR). Rates of past accumulation, estimated using dating techniques, are then used to hindcast the rate of sea-level rise in that area. Estimates of contemporary sea-level rise rates are often derived from tide gauge records. This approach allows identification of subdecadal variations in mean water level. Accumulation rates of both organic and inorganic sediments can also be derived at these time scales and studies from many coastal marshes demonstrate the episodic nature of inorganic sediment deposition. The frequency and spacing of these events does not necessarily coincide with periods of increased local sea level. In addition, short-term increases in sea level could result in marsh deterioration as soils become excessively waterlogged. A conceptual model of changes in geomorphic and ecological processes contributing to marsh sustainability during the Holocene has been developed for the Mississippi delta plain (MDP). The survival of some marshes in this area, despite high rates of subsidence, indicates that the combined effect of organic and inorganic accumulation processes can be adequate to sustain coastal marshes in the face of sea-level rise. (C) 2002 Elsevier Science B.V. All rights reserved.

Reyes, E., M. L. White, et al. (2000). "Landscape modeling of coastal habitat change in the Mississippi delta." Ecology 81(8): 2331-2349.

A landscape model was developed to investigate and predict the environmental factors affecting wetland habitat change within the Barataria and Terrebonne basins of coastal Louisiana, USA. The model linked an overland-flooding hydrodynamic module, using cells of 100 km(2) in size and operating at a 1-h time step, and a spatially articulated ecosystem module, resolving habitat type and change for 1-km(2) cells in daily time steps. Integration across different temporal and spatial scales was accomplished with interpolation routines and averaging algorithms. Forcing functions included dominant regional processes, such as subsidence, sedimentation, and sea-level rise. Hydrologic functions were calibrated against existing climate and hydrologic time series, while habitat information was compared to maps prepared by the United States Fish and Wildlife Service (USFWS) for 1978 and 1988. Spatial calibration was done by initializing the landscape pattern of the model to a 1978 USFWS habitat map. After a 10-yr simulation, the results were compared against a 1988 USFWS habitat map. Simulated maps had an accuracy of 85-90 (out of a maximum of 100), based on a multiple resolution fit algorithm. For validation the model was initialized with a 1956 USFWS habitat map, and the results from a 32-yr simulation were compared to the 1988 USFWS habitat map. The landscape model produced reasonable regional agreement, despite the fact that small-scale processes and features were not included. The validation runs produced land-loss rates that matched historical trends with an accuracy fit above 75. The model simulated 30 years into the future, starting in 1988, testing for long-term climate variability under diverse scenarios. Results indicated that weather variability impacts land-loss rates more than replication of extreme weather years. Even when extreme dry and wet years were repeated, the model predicted lower land loss when compared to historical records. This is indicative of the ability of the simulated plant communities to adapt to repetitive climatic forcing functions.

Roberts, H. H. and J. M. Coleman (1996). "Holocene evolution of the deltaic plain: A perspective - From Fisk to present." Engineering Geology 45(1-4): 113-138.

Before publication of Fisk's classic scientific papers dealing with the Mississippi River alluvial valley and deltaic plain, geological knowledge of the Holocene deltaic plain was the product of surficial geomorphological studies with a temporal framework provided by archaeology. Fisk and his co-workers provided the third and fourth dimensions, the three-dimensional characteristics of sediment bodies, by numerous deep borings and better chronostratigraphy through C-14 dating. This research, and the emphasis of his work on fluvial processes, was largely responsible for the form-process approach in sedimentary geology and the awareness that depositional environments are represented by unique sedimentary sequences and properties. Although Fisk made many contributions to deltaic geology, six major areas are noteworthy: delta response to base level changes, sedimentary loading, processes of delta switching, delta abandonment and formation of transgressive sands, river diversion (Atchafalaya distributary), and deltaic sedimentary architecture. In order to comprehend the complexly structured Holocene deltaic plain, the processes of channel migration, meander belt formation, avulsion, and delta switching must be understood. Preceding the work of Fisk, landforms resultant from these processes were recognized by geomorphologists, and this body of research formed the foundation for Fisk's major contributions. Using the concept of changing sea levels during the Quaternary, Fisk was one of the initial scientists to recognize the importance of a changing base level and its effect on valley cutting and filling episodes, particularly during the process of valley filling by fluvial and deltaic sediments during rising sea level. In documenting these cyclic processes, he first postulated the development of canyons or trenches carved across the continental shelf, the development of shelf-edge deltas, and the feeding of the deep-sea fans during periods of lowered sea level. Trowbridge (1930) and Russell and Russell (1939) described the dendritic shape of delta lobes and indicated that they were offset and overlapping, resulting in the Holocene deltaic plain configuration; delta chronology was provided by utilizing archeological methods (McIntire, 1954). The pioneering work of Fisk and McFarlan (1955) on the Mississippi delta set the stage for refinement of delta lobe chronology. Details regarding the timing of important depositional events have been added by McFarlan (1961), Frazier (1967), Morgan (1970), Penland and Suter(1989) and, most recently, Autin et al. (1991). In collecting data on offshore Mississippi River delta deposits, Fisk documented the regional subsidence associated with loading by continuous delta deposition as well, as the localized subsidence associated with delta-front deposition and the formation of mud diapirs. He later applied this concept to the accumulation of peat deposits in interdistributary regions and the development of interdistributary bays. This research was the foundation for work by later scientists dealing with wetland loss in the deltaic plain. Fisk was the first major contributor to our current understanding of the stratigraphic-sedimentological architecture of the modern deltaic plain of the Mississippi River. The first cross-sections of the deltaic plain were published by Fisk (1947), prior to which there were little data for establishing the geometry of sediment bodies and spatial relationships of facies beneath the modern surface. Classic examples of this approach were the point bar and backswamp studies in the alluvial valley of the Lower Mississippi River (Fisk, 1944), his bar-finger sand paper (Fisk, 1961), and his more comprehensive sand facies paper (Fisk, 1955). This body of work on sedimentary facies relationships and specifically sand body geometries found wide acceptance among both academic and industry groups. At the time Fisk prepared his appraisal of sand facies in the Mississippi delta he was an employee of Humble Oil and Refining Company, and the paper was obviously directed toward understanding reservoir geometries and spatial relationships in a deltaic complex. In addition to the sedimentary architecture of the delta, Fisk also contributed to understanding of both the constructive and destructive cycles, the geotechnical properties of various delta facies, and subsidence, all of which helped establish an awareness of the critical need for geological knowledge in engineering applications. Since Fisk's contributions, the major advances in understanding the Holocene deltaic plain have been primarily in the realm of filling in the details of Fisk's sedimentary architecture. The mudlump studies of Morgan (1961) and work on crevasse splays and bay-fill sequences by Welder (1959), Coleman and Gagliano (1964), and Morgan (1970), as well as others, are good examples. Later, work on the new lobe of the deltaic plain, the Atchafalaya-Wax Lake delta complex (Shlemon, 1975; Roberts et al., 1980a, van Heerden and Roberts, 1980; van Heerden et al., 1983), added an element to the deltaic plain evolutionary story that was not available during Fisk's era. However, regardless of future research on the Mississippi River deltaic plain, the body of work produced by Fisk and his co-workers will always be recognized as the cornerstone of our understanding of this complex depositional system.

Romanovskii, N. N., H. W. Hubberten, et al. (2000). "Thermokarst and land-ocean interactions, Laptev Sea Region, Russia." Permafrost and Periglacial Processes 11(2): 137-152.

Ice complexes (ICs) formed during the Late Pleistocene regression (marine isotope stages 5-3) on the drained Laptev Sea shelf and coastal lowlands. These sediments can be several dozen metres thick (up to 40-60 m). Over wide areas the lower boundary of the ICs is situated below current sea level. At about 13 ka BP thermokarst processes began to destroy the ICs, both on the shelf and on the coastal lowlands. Thermokarst lakes and depressions (alasses) were formed 11-11.5 to 9.5-8.5 ka BP when the shoreline position lay on isobaths -60 to -45 m. Lakes and alasses became traps for sediments formed via IC decay. Thermokarst processes began before submergence of the shelf in seawater at subzero temperatures. These temperatures created conditions conducive to the repeated freezing of lake taliks and the formation of submarine pingos. As a result of the marine transgression, thermokarst lakes and alasses were transformed into lagoons, particularly on the shallow part of the shelf (between isobath -20 m and the current shoreline). On the Bykovsky Peninsula and in the vast area east of the Yana River Delta, this process still occurs today. The creation of lagoons led to the formation of indented coastlines, an increased shore length subject to thermoerosion, and an acceleration of the shelf's submergence, especially after 7.5 ka BP. Copyright (C) 2000 John Wiley & Sons, Ltd.

Rybczyk, J. M. and D. R. Cahoon (2002). "Estimating the potential for submergence for two wetlands in the Mississippi River Delta." Estuaries 25(5): 985-998.

We used a combined field and modeling approach to estimate the potential for submergence for one rapidly deteriorating (Bayou Chitigue Marsh) and one apparently stable (Old Oyster Bayou Marsh) saltmarsh wetland in coastal Louisiana, given two eustatic sea level rise scenarios: the current rate (0.15 cm year(-1)); and the central value predicted by the Intergovernmental Panel on Climate Change (48 cm. by the year 2100). We also used the model to determine what processes were most critical for maintaining and influencing salt marsh elevation including, mineral matter deposition, organic matter production, shallow subsidence (organic matter decomposition + primary sediment compaction), deep subsidence, and sediment pulsing events (e.g., hurricanes). Eight years of field measurements from feldspar marker horizons and surface elevation tables revealed that the rates of vertical accretion at the Bayou Chitigue Marsh were high (2.26 (0.09) cm yr(-1) (mean +/- SE)) because the marsh exists at the lower end of the tidal range. The rate of shallow subsidence was also high (2.04 (0.1) cm yr(-1)), resulting in little net elevation gain (0.22 (0.06) cm yr(-1)). In contrast, vertical accretion at the Old Oyster Bayou Marsh, which is 10 cm higher in elevation, was 0.48 (0.09) cm yr(-1). However, there was a net elevation gain of 0.36 (0.08) cm yr(-1) because there was no significant shallow subsidence. When these rates of elevation gain were compared to rates of relative sea level rise (deep subsidence plus eustatic sea level rise), both sites showed a net elevation deficit although the Bayou Chitigue site was subsiding at approximately twice the rate of the Old Oyster Bayou site (1.1 cm yr(-1) versus 0.49 cm yr(-1) respectively). These field data were used to modify, initialize, and calibrate a previously published wetland soil development model that simulates primary production and mineral matter deposition as feedback functions of elevation. Sensitivity analyses revealed that wetland elevation was most sensitive to changes in the rates of deep subsidence, a model forcing function that is difficult to measure in the field and for which estimates in the literature vary widely. The model also revealed that, given both the current rate of sea level rise and the central value estimate, surface elevation at both sites would fall below mean sea level over the next 100 years. Although these results were in agreement with the field study, they contradicted long term observations that the Old Oyster Bayou site has been in equilibrium with sea level for at least the past 50 years. Further simulations showed that the elevation at the Old Oyster Bayou site could keep pace with current rates of sea level rise if either a lower rate for deep subsidence was used as a forcing function, or if a periodic sediment pulsing function (e.g., from hurricanes) was programmed into the model.

Schioler, P., J. S. Crampton, et al. (2002). "Palynofacies and sea-level changes in the Middle Coniacian-Late Campanian (Late Cretaceous) of the East Coast Basin, New Zealand." Palaeogeography Palaeoclimatology Palaeoecology 188(3-4): 101-125.

A palynofacies analysis of four sections through the Paton and Herring Formations of the East Coast Basin in southern Marlborough indicates that the two formations were deposited on the inner to mid-shelf in a marine environment with conspicuous input of plant material from adjacent land area. The Paton Formation was deposited on the inner to mid-shelf under oxic conditions and in proximity to a river delta, possibly in a deltafront setting. Its lower part is clearly less marine than its upper part, pointing to an overall deepening trend with time. The deposition of the Herring Formation took place farther offshore, on the mid-shelf, in a mud-dominated environment under poorly oxygenated conditions at the sediment/water interface, following a landward shift of shoreline. A stratigraphic analysis of changes in palynofacies and lithology through the four sections allows a breakdown of the succession into seven depositional sequences, separated by unconformities or their correlative conformities. A regional sea-level curve for the Middle Coniacian-Upper Campanian in the East Coast Basin is proposed on the basis of the inferred sequences and chronostratigraphic control from dinoflagellate biostratigraphy. The sea-level cycles thus inferred for the East Coast Basin show a poor correlation with the re-scaled Haq cycle chart, suggesting that regional tectonics rather than eustasi controlled the East Coast Basin sequences. (C) 2002 Elsevier Science B.V. All rights reserved.

Shi, Y. F., J. W. Zhu, et al. (2000). "Prediction and prevention of the impacts of sea level rise on the Yangtze River Delta and its adjacent areas." Science in China Series D-Earth Sciences 43(4): 412-422.

The Yangtze River Delta region is characterized by high density of population and rapidly developing economy. There are low lying coastal plain and deltaic plain in this region. Thus, the study area could be highly vulnerable to accelerated sea level rise caused by global warming. This paper deals with the scenarios of the relative sea level rise in the early half period of the 21st century in the study area. The authors suggested that relative sea level would rise 25-50 cm by the year 2050 in the study area, of which the magnitude of relative sea level rise in the Yangtze River Delta would double the perspective worldwide average. The impacts of sea level rise include: (i) exacerbation of coastline recession in several sections and vertical erosion of tidal flat, and increase in length of eroding coastline; (ii) decrease in area of tidal flat and coastal wetland due to erosion and inundation; (iii) increase in frequency and intensity of storm surge, which would threaten the coastal protection works; (iv) reduction of drainage capacity due to backwater effect in the Lixiahe lowland and the eastern lowland of Taihu Lake region, and exacerbation of flood and waterlogging disasters; and (v) increase in salt water intrusion into the Yangtze Estuary. Comprehensive evaluation of sea level rise impacts shows that the Yangtze River Delta and eastern lowland of Taihu Lake region, especially Shanghai Municipality, belong in the district in the extreme risk category and the next is the northern bank of Hangzhou Bay, the third is the abandoned Yellow River delta, and the district at low risk includes the central part of north Jiangsu coastal plain and Lixiahe lowland.

Somoza, L., A. Barnolas, et al. (1998). "Architectural stacking patterns of the Ebro delta controlled by Holocene high-frequency eustatic fluctuations, delta-lobe switching and subsidence processes." Sedimentary Geology 117(1-2): 11-32.

During the Late Pleistocene and Holocene (125 ka B.P. to present) a Type 1, 4th-order, depositional sequence, comprising regressive, lowstand, transgressive and highstand system tracts, formed worldwide. The Holocene (10 ka B.P. to present) part of this contains the latest and present highstand systems tract (HST). Within this and the underlying transgressive systems tract (TST) of the Ebro delta, in northeastern Spain, higher-frequency, 5th- to 6th-order, sea-level fluctuations are recognised. These form retrogradational and progradational high-frequency depositional sequence sets within the TST and HST, respectively. Each high-frequency sequence comprises: (1) a basal, highly reflective, shell lag, associated with an erosional (transgressive) surface; (2) aggradational deposits which seawards consist of a wedge of marine clays with transparent seismic facies, but inland are represented by thick peats; (3) progradational deposits: composed of sandy delta-front facies, displaying slope clinoforms; these pass seawards into prodeltaic grey silts, and landwards, into red silts and pebbly sands of delta-plain facies. The progradational deposits downlap towards their bases. The aggradational deposits formed in response to a period of rising sea-level and a rapid increase in accommodation space. Progradation began when sediment supply to the delta exceeded accommodation space as a result of relative sea-level fall. The relative sea-level curve for the delta has a stepped character, caused by the punctuation of the 4th-order sea-level trend by higher-frequency eustatic fluctuations as well as by high subsidence rates, of about 1.75 mm per year. The TST comprises retrogradational parasequences that onlap the underlying Pleistocene gravels. The maximum flooding surface separating the TST from the HST, was formed about 6900 yrs B.P. on the basis of C-14 dating of peats. The HST comprises progradational deltaic and aggradational units, stacked as progradational high-frequency parasequence sets. The HST of the Ebro delta is compared with other deltaic sequences around the world, in particular with that of the Mississippi delta. A tentative chronology of the high-frequency climatic and eustatic oscillations influencing deltaic sedimentation globally over the last 7000 years is presented. (C) 1998 Elsevier Science B.V. All rights reserved.

Spencer, R. S. (2000). "Foraminiferal assemblages from a Virginia salt marsh, Phillips Creek, Virginia." Journal of Foraminiferal Research 30(2): 143-155.

Phillips Creek is a salt marsh located on the seaward side of the southern Delmarva Peninsula of Virginia, Is part of the World Biosphere Reserve designated by the United Nations, and is situated within the Virginia Coast Reserve/Long Term Ecological Research area (VCR/LTER), This marsh does not exhibit well-defined vegetational zones but rather tends to be a patchy mix of vegetation. Cluster analysis indicates that the area can be divided into low, middle or transitional and high marsh, The low marsh zone does not exhibit any unique assemblages of agglutinated foraminifera that would allow further subdivision of this area. The fact that no calcareous species mere found may be due to the season (May) when sampling was done. The low marsh is dominated by M. fusca and T. inflata. The occurrence of a transitional or middle marsh zone appears to be dependent upon gradient. Traverse 1 with a gradient of 3 percent has a poorly defined middle marsh zone while Traverse 2 with a gradient of 0.6 percent has a broad, well defined transitional zone. Tiphotrocha comprimata and T. inflata are the dominant species in this zone. The high marsh can be subdivided into two subzones, The lower part of the high marsh is dominated by T. inflata, T. comprimata and J. macrescens while the upper part has a relief ranging between 5 and 8 cm, has a reduced population and contains J. macrescens and T. salsa almost to the exclusion of all other foraminiferal species. This subzone, marking the occurrence of highest high water, is topographically very narrow, requiring closely spaced sampling to detect its presence. The highest high water zone can be extended southward into Virginia.

Stanley, D. J. and A. G. Warne (1994). "Worldwide Initiation of Holocene Marine Deltas by Deceleration of Sea-Level Rise." Science 265(5169): 228-231.

Radiocarbon-dated deltaic sequences of Holocene age from different parts of the world began to accumulate within a restricted time range, from about 8500 to 6500 years ago. Evaluation of major delta processes indicates that deceleration in sea-level rise was the key factor in Holocene delta formation. Within many deltas, there is as much as a 2000-year age range between basal deposits in seaward and landward cores. This age difference records the progressive landward migration of near mean sea-level depositional environments during the lower to mid-Holocene. Establishment of a chronostratigraphic framework for Holocene delta development provides a fundamental global baseline for distinguishing sea-level change from vertical land motion by tectonism and isostasy, and for evaluating rates of future marine incursion into low-lying deltas.

Stanley, J. D. (2001). "Dating modern deltas: Progress, problems, and prognostics." Annual Review of Earth and Planetary Sciences 29: 257-294.

Radiocarbon dating is the method most frequently used to date Holocene deltaic sequences, but less than one quarter of C-14 dates are within +/- 500 years of predicted age. Such dates tend to be unreliable, in other words, often too old and commonly inverted upsection, and core sample dates obtained near deltaic plain surfaces may be as old as mid- to late Holocene. Stratigraphic irregularities result primarily from downslope reworking of upland alluvial sediment, with displacement of "old carbon" in the sediment that accumulates in lower valleys and deltaic plains. Use of dates that are too old results in inaccurately calculated rates (most often too low) of relative sealevel rise and/or land subsidence. More reliable timing of deltaic sediment requires a multiple-method dating approach, including, where possible, identification of associated archaeological material. Developing an accurate dating strategy is a critical step for implementing reliable coastal protection measures needed fur the rapidly increasing human populations in these low-lying, vulnerable nearshore settings.

Syvitski, J. P. M. and J. M. Alcott (1993). "Grain2 - Predictions of Particle-Size Seaward of River Mouths." Computers & Geosciences 19(3): 399-446.

An ANSI standard FORTRAN-77 numerical model is provided. The model predicts the spatial and temporal change in seafloor particle size seaward of a river mouth. The model needs the input files generated by a sister program DELTA2, a 2-D model that simulates the progradation of a river delta and the resultant fill of one or more marine basins. GRAIN2 tracks four size fractions in the mud-size range: coarse silt, medium silt, fine silt, and clay. Their spatial distribution is determined using (1) a velocity distribution developed from a buoyancy-dominated, free, 2-D jet flowing into a highly stratified marine basin; and (2) a particle-scavenging model that takes into account the biogeochemical affects of settling of particles in a marine environment (i.e. flocculation). This hemipelagic component is predicted seasonally (four times a year) based on fluctuations in river velocity and river mouth shape, and on the suspended load discharged into the sea. Sand deposition is predicted from the seasonal rate of turbidity current deposition, and from DELTA2. The model is sensitive to changes in river mouth position and thus sediment supply and sea level fluctuations.

Ta, T. K. O., V. Nguyen, et al. (2001). "Sedimentary facies, diatom and foraminifer assemblages in a late Pleistocene-Holocene incised-valley sequence from the Mekong River Delta, Bentre Province, Southern Vietnam: the BT2 core." Journal of Asian Earth Sciences 20(1): 83-94.

A detailed description of sediment facies, diatom, mollusca and foraminifer assemblages, and C-14 ages of the Mekong River Delta, Southern Vietnam, is presented in this paper. A 71 m long core, recovered in 1997 at the Bentre province in the eastern part of the Mekong River Delta, is divided into eight units and nine sediment facies on the basis of sedimentary properties, diatom and foraminifer assemblages, and C-14 ages. These units show facies changes from transgression to regression in relation to the late Pleistocene-Holocene sea-level changes. The Postglacial transgression caused by a sea-level rise led to infilling of the incised valley and formation of estuarine sediments and open bay muddy sediments in ascending order. Estuarine sediments consist of slightly oxidized yellowish-grey silty sand and intercalated greenish-grey and stiffly brownish-grey sandy silt and silty clay. The muddy facies, 13.5 m thick, is characterized by abundant marine plank-tonic diatoms and open-sea foraminifers. This facies indicates the maximum Holocene marine influence was around 5300 cal yr BP at the BT2 site. The regressive succession is composed of deltaic sediments from prodelta, delta front, sub- to inter-tidal flat and beach ridge in ascending order. C-14 ages indicate that the delta front passed the core site at approximately 4000-3000 cat yr BP. The coastal progradation rate was 17-18 in yr(-1) during the 5300-3500 cal yr and decreased to 13-14 m yr(-1) during the last 3500 cat yr. (C) 2001 Elsevier Science Ltd. All rights reserved.

Tamura, T., F. Masuda, et al. (2003). "Temporal development of prograding beach-shoreface deposits: the Holocene of Kujukuri coastal plain, eastern Japan." Marine Geology 198(3-4): 191-207.

Prograding beach-foreshore deposits with a basal ravinement bed are recognized from detailed AMS C-14 dating and grain size analyses of Holocene deposits of the Kujukuri coastal plain facing the Pacific coast of Japan. The Holocene deposits are about 20 m thick and consist of an upward-shoaling beach-foreshore succession that has a basal unconformity overlain by a thin layer of relatively coarse sand. The unconformity is a downlap surface, which originated from a ravinement surface. The overall succession was formed by a prograding beach foreshore system during the highstand in sea level of the last 6000 years. Poorly preserved fossil shells, enclosed in the thin layer of coarse sand at the base of the succession, date from the transgressive stage in sea level before 6000 cal yr BP. Grain size distribution patterns are polymodal in the basal sand layer and unimodal in the remainder of the succession. Modal classes of the basal part are fine (3.3-2.6phi), medium (2.3-1.8phi), and coarse (1.2-1.0phi). The fine mode and the unimodal grain sizes define an overall upward-coarsening trend, which correlates with the upward-shoaling succession. In contrast, the medium and coarse modes are restricted to the basal sand, and are interpreted as related to the ravinement process. The thin basal sand layer, an admixture of these modal classes, is interpreted as a type of ravinement deposit preserved during sea-level highstand. No transgressive deposit was preserved on the ravinement surface because sediment supply was so small that the sediment on this surface experienced thorough reworking by storm waves. (C) 2003 Elsevier Science B.V. All rights reserved.

Tanabe, S., K. Hori, et al. (2003). "Song Hong (Red River) delta evolution related to millennium-scale Holocene sea-level changes." Quaternary Science Reviews 22(21-22): 2345-2361.

The Song Hong (Red River) delta occurs on the northwest coast of the South China Sea. Its evolution in response to Holocene sea-level changes was clarified on the basis of sedimentary facies and 14 radiocarbon dates from the 40 m long Duy Tien core from the delta plain, and using previously reported geological, geomorphological, and archaeological data. The delta prograded into the drowned valley as a result of early Holocene inundation from 9 to 6 cal. kyr BP, as sea-level rise decelerated. The sea-level highstand at + 2-3 m from 6 to 4 cal. kyr BP allowed widespread mangrove development on the delta plain and the formation of marine notches in the Ha Long Bay and Ninh Binh areas. During sea-level lowering after 4 cal. kyr BP, the former delta plain emerged as a marine terrace, and the delta changed into the present tide- and wave-influenced delta with accompanying beach ridges. Delta morphology, depositional pattern, and sedimentary facies are closely related to Holocene sea-level changes. In particular, falling sea level at 4 cal. kyr BP had a major impact on the evolution of the Song Hong delta, and is considered to be linked to climate changes. (C) 2003 Elsevier Ltd. All rights reserved.

Tanabe, S., K. Hori, et al. (2003). "Sedimentary facies and radiocarbon dates of the Nam Dinh-1 core from the Song Hong (Red River) delta, Vietnam." Journal of Asian Earth Sciences 21(5): 503-513.

The Song Hong (Red River) delta, which is located on the western coast of the Gulf of Bac Bo (Gulf of Tonkin) in the South China Sea is characterized by three morphological systems that are clearly distinguished spatially: fluvial-, tidal-, and wave-dominated. We obtained a 70-m-long core of sediments (the Nam Dinh-1 core) from the central part of the delta in 1999. This paper presents the first detailed description of sedimentary facies with high-resolution radiocarbon dating for the latest Pleistocene-Holocene sediments of the Song Hong delta. The core sediments were divided into three units on the basis of the sediment facies: in ascending order, Unit 1, fluvial sediments consisting of fining-upward gravels to clay; Unit 2, coarsening-upward marine clay to shelly sand; and Unit 3, coarsening-upward marine clay and laminated sand. Twenty-one radiocarbon dates showed that the core succession was deposited after the Last Glacial Maximum (LGM); the ages were 15-11 cal. kyr BP for Unit 1, 11-9 cal. kyr BP for Unit 2, and 8- 0 cal. kyr BP for Unit 3. These data indicate that sediments were environments formed in the central delta plain of the Song Hong (C) 2002 Elsevier Science Ltd. All rights reserved.

Tanner, W. F. (1991). "The Gulf of Mexico Late Holocene Sea-Level Curve and River Delta-History." Aapg Bulletin-American Association of Petroleum Geologists 75(9): 1539-1539.

van Heijst, M., G. Postma, et al. (2001). "Quantitative analogue flume-model study of river-shelf systems: principles and verification exemplified by the Late Quaternary Colorado river-delta evolution." Basin Research 13(3): 243-268.

Physical modelling of clastic sedimentary systems over geological time spans has to resort to analogue modelling since full scaling cannot be achieved within the spatial and temporal restrictions that are imposed by a laboratory set-up, Such analogue models are suitable for systematic investigation of a sedimentary system's sensitivity to allocyclic changes by isolating governing parameters. Until now, analogue models of landscape evolution were mainly qualitative in nature. In this paper, we present a quantitative approach. The quantitative experimental results are verified and discussed by comparison with high-resolution data from the Colorado river-shelf system of the Texas shelf that we used as a prototype. The model's dimensions are proportionally scaled to the prototype, except for a vertical exaggeration. Time is scaled using a Basin Response factor to maintain a similar ratio between the period of change and the system's equilibrium time for model and prototype. A Basin Fill factor was used to compare the ratio between the time-averaged sedimentation rate and the rate of change in accommodation space of model and prototype. The flume-model results are in the form of sediment budgets that are related to shelf cannibalism and fluvial supply, which are compared with the ancestral Colorado river-delta evolution of the last 40 kyr. Model and prototype have similarities in delta evolution in response to one cycle of sea-level change. With sea-level change as the isolated variable, the flume model generates a significant supply pulse caused by headward erosion of the shelf in response to the sea-level fall. This pulse adds to the yield of the hinterland. The supply induced by sea-level change persists during the early rise, although its rate declines. A similar trend is observed on the east Texas shelf. We argue that shelfal and fluvial degradation cycles induced by sea-level changes can significantly influence the timing and amount of sediment supply to basins and Must therefore be taken into consideration.

Walsh, J. P. and C. A. Nittrouer (2004). "Mangrove-bank sedimentation in a mesotidal environment with large sediment supply, Gulf of Papua." Marine Geology 208(2-4): 225-248.

The most extensive mangrove forests on Earth are associated with major river systems. The Indo-Pacific region has numerous large rivers that discharge onto broad continental shelves, and mangroves occur widely along these coastlines. In the Gulf of Papua (GOP) alone, there are >3350 km(2) of mangrove forests, the majority of which (2900 km(2)) are associated with the Fly, Kikori, and Purari River deltas. This study examines data from 28 vibracores to describe preserved sedimentary strata and to determine rates of sediment accumulation in this dynamic coastal environment. The observations suggest a common stratigraphy is contained in prograding mangrove banks of the mesotidal western GOP, and that it is similar to mud-dominated and physically stratified stratigraphy recorded by other intertidal areas (with and without mangroves) experiencing large tidal range (>2 m) and sediment supply (e.g., Ganges-Brahmaputra and Yangtze River deltas). Grain-size, sedimentary-structure, radionuclide and remotely sensed data are analyzed, and four stratigraphic facies are identified: (1) supratidal to high-tidal muds; (2) mid-tidal sandy muds; (3) low-tidal sand and mud; and (4) subtidal channel sands. Supratidal and high-tidal sediments of GOP mangrove forests are typically muddy, but can have high sand contents (>30%) in areas exposed regularly to ocean waves. These muds can be homogenous, but commonly have physical structures (laminations and bedding), probably reflecting high rates of sediment accumulation relative to bioturbation. Mangrove muds may have low water contents due to infrequent inundation and, because of their cohesive nature and abundant roots, can form steep intertidal banks and erosional scarps. Mid-tidal and low-tidal sediments are thinly laminated (<2 mm), but the latter also contain thick (>2 mm) laminations, likely deposited from fluid-mud transport. Channel sediments have thin and thick mud and sand laminations, but are identified by thick (>5 cm) sand beds. A conceptual model of mangrove-bank progradation is created using sedimentological and radionuclide data. Maximum sediment accumulation rates were determined using steady-state Pb-210 profiles, and greatest mean rates are found in mid-tidal areas (4.4 cm/year; 3.9 g/cm(2)/year). Slower accumulation occurs in high-tidal and low-tidal areas (1.8 and 1.5 cm/ year, respectively; 1.2 and 1.0 g/cm(2)/year, respectively). Remotely sensed data indicate that areas of erosion and accretion co-exist in the Kikori-Purari region. Very large Pb-210 accumulation rates were measured in areas of significant accretion, supporting the validity of the calculated rates. In areas of rapid accretion, cores can have non-steady-state or event-related Pb-210 profiles, reflecting episodic sedimentation or complex radionuclide scavenging dynamics. Most cores from the Fly River delta are of this type. Sediment trapping in western GOP mangroves is estimated to account for 2-14% of the total GOP sediment load. (C) 2004 Elsevier B.V. All rights reserved.

Wang, P. X., Y. H. Bian, et al. (1996). "The Younger Dryas in the West Pacific marginal seas." Science in China Series D-Earth Sciences 39(5): 522-532.

The occurrence and nature of the Younger Dryas (YD) abrupt climatic event in the West Pacific marginal sea are discussed on the basis of 15 sediment cores. This event has been found in all these cores studied with a high-resolution stratigraphy and proved to be common to the West Pacific region. As shown by the isotopic and micropaleontologic analyses, the YD, dated by C-14 at about 11 000 to 10 000 a B.P., is a brief event of sea surface cooling in winter season following a fresh-water pulse about 12 000 a B.P. The ''apparent regression'' of the YD recorded in the Changjiang River delta and the Sea of Japan agrees with the interpretation that the YD is a period of slowed sea level rising between two phases of rapid rising. Both the winter surface water cooling and the increasing salinity in the YD imply a strengthening of the winter, but not summer monsoon circulation. This major climatic event in the marginal seas must have had profound impact on the adjacent continent.

Wang, Y. (1998). "Sea-level changes, human impacts and coastal responses in China." Journal of Coastal Research 14(1): 31-36.

The rate of sea-level rise during the past hundred years has been 2-3 mm/year along China's coasts; sea level will probably continue to rise in the future. The process has decreased wave winnowing of submerged coastal sediment but enhanced erosion by waves breaking on the upper beaches. Following the rise of sea level, river-channel slopes have been reduced, decreasing fluvial sediment discharges to the ocean. Human impacts through diverting river discharge and constructing dams in the lower reaches of rivers for fresh water supplies have also upset coastal processes. Paucity of coastal sediment supply is a world-wide phenomenon which, when combined with the frequency of storm surges and El Nino events to strengthen hydrodynamics, invariably results in beach erosion and the landward retreat of sand barriers along the coastal zone. Overpumping of groundwater and overloading by constructions on the delta plain and lowland coast have had serious effects: the average rate of relative sea-level rise is 24.5-50.0 mm/year in TianJing, the old Yellow River delta area along the Bohai Sea, 4.5-5.5 mm/year in the modern Yellow River delta, and 6.5-11.0 mm/year in the Shanghai area of the Changjiang River mouth. These rates are much higher than the mean annual rate of 1.4 mm/year. Under the circumstances saltwater intrusion has been changing river water salinity and fresh water quality. Storm surges often cause the lowland coast to be inundated and flooded. All such effects are ultimately the result of human activities.

Warne, A. G., E. H. Guevara, et al. (2002). "Late Quaternary evolution of the Orinoco Delta, Venezuela." Journal of Coastal Research 18(2): 225-253.

The modern Orinoco Delta is the latest of a series of stacked deltas that have infilled the Eastern Venezuelan Basin (EVB) since the Oligocene. During the late Pleistocene sea-level lowstand (20,000 to 16,000 yrs BP), bedrock control points at the position of the present delta apex prevented the river channel from incising as deeply as many other major river systems. Shallow seismic data indicate that the late Pleistocene Orinoco incised into the present continental shelf, where it formed a braided-river complex that transported sediment to a series of shelf-edge deltas. As sea level rose from 16,000 to 9,500 yrs BP, the Orinoco shoreline shifted rapidly landward, causing shallow-marine waves and currents to form a widespread transgressive sand unit. Decelerating sea-level rise and a warmer, wetter climate during the early Holocene (9,500 to 6,000 yrs BP) induced delta development within the relatively quiet-water environment of the EVB embayment. Sea level approached its present stand in the middle Holocene (6,000 to 3,000 yrs BP), and the Orinoco coast prograded, broadening the delta plain and infilling the EVB embayment. Significant quantities of Amazon sediment began to be transported to the Orinoco coast by littoral currents. Continued progradation in the late Holocene caused the constriction at Boca de Serpientes to alter nearshore and shelf hydrodynamics and subdivide the submarine delta into two distinct areas: the Atlantic shelf and the Gulf of Paria. The increased influence of littoral currents along the coast promoted mudcape development. Because most of the water and sediment were transported across the delta plain through the Rio Grande distributary in the southern delta, much of the central and northwestern delta plain became sediment starved, promoting widespread accumulation of peat deposits. Human impacts on the delta are mostly associated with the Volcan Dam on Cano Manamo. However, human activities have had relatively little effect on the delta processes and environments.

Williams, H. F. L. and M. C. Roberts (1989). "Holocene Sea-Level Change and Delta Growth - Fraser-River Delta, British-Columbia." Canadian Journal of Earth Sciences 26(9): 1657-1666.

Williams, H. F. L. and R. J. Hebda (1991). "Palynology of Holocene Top-Set Aggradational Sediments of the Fraser-River Delta, British-Columbia." Palaeogeography Palaeoclimatology Palaeoecology 86(3-4): 297-311.

Palynological study of radiocarbon-aged top-set Holocene sediments of the Fraser Delta, British Columbia, reveals a record of tidal marsh, river marsh and river swamp environments which indicate former sea-level positions and rates of sea-level change. Interbedded silts and fine sands, containing Pinus and Cyperaceae pollen and monolete fern spores, occur between 15.1 and 14.2 m depth and are interpreted as freshwater-dominated delta-front marsh deposits. Organic-rich silts, containing grass and skunk cabbage pollen and horsetail spores, between 14.2-7.8 m depth, represent an emergent delta-top marsh environment, regularly flooded by the Fraser River. Arboreal pollen types pine, spruce and alder dominate organic-rich silts between 7.8 and 5.8 m, but Rosaceae pollen rises to dominance in peatier sediments between 5.8-4.7 m. These two zones record natural vegetation succession from marsh to swamp, due to increased relative elevation of the site. An increase in arboreal pollen in organic-rich silts between 4.7 and 2.3 m, signals a drop in relative elevation and return to regular flooding. Declines in percentages of arboreal pollen and increases in Rosaceae and skunk cabbage pollen, indicate preliminary stages of bog development and disappearance of fluvial influence above 2.3 m. Organic-rich silts formed mainly in a fluvially-dominated marsh setting, as top-set aggradation kept pace with sea-level rise between approximately 7960 and 4410 yr B.P. An apparent slowing or cessation in sea-level rise allowed peaty sediments to form around 6000 yr B.P. The rate of sea-level rise again declined at 4410 yr B.P., causing organic-rich silts to be replaced by peat deposition. The study provides insights into the history of sea-level change and aggradation in the Fraser River Delta.

Williams, H. F. L. (1994). "Intertidal Benthic Foraminiferal Biofacies on the Central Gulf-Coast of Texas - Modern Distribution and Application to Sea-Level Reconstruction." Micropaleontology 40(2): 169-183.

Six foraminiferal biofacies are defined for three tidal marshes on the central Gulf Coast of Texas. The Aransas River estuary and Port Bay marshes each contain four biofacies which occupy distinct elevational zones. Zonal definition at the Mustang Island marsh is less distinct due to the dominance of one biofacies. Analysis of core samples from the Port Bay marsh site enables reconstruction of Late Holocene sea levels and sedimentation rates. The resulting relative sea level curve contains evidence of a Late Holocene stillstand or highstand and shows that Late Holocene sea level rise continued to the present at this location.

Williams, H. F. L. (1999). "Foraminiferal distributions in tidal marshes bordering the Strait of Juan de Fuca: Implications for paleoseismicity studies." Journal of Foraminiferal Research 29(3): 196-208.

Foraminiferal distributions are reported for three marshes bordering the Strait of Juan de Fuca-the Sooke River marsh on Vancouver Island, Canada and the Discovery Bay and Gibson Spit marshes on the north shore of Washington State. Cluster analysis was used to define foraminiferal biofacies with distinct elevation ranges for each marsh. Comparison of these biofacies to foraminiferal zonations on other marshes in the Pacific Northwest suggests some broad similarities in foraminiferal distributions, but also reveals some important contrasts. Variations in marsh zone foraminiferal assemblages and position relative to mean tide level are presumably due to differences in marsh characteristics, including freshwater influence, sedimentation rates and substrate texture, and to differences in the sampling and statistical techniques used to define biofacies. On the marshes included in this study, foraminiferal biofacies analysis has the potential to estimate paleoelevations of subsurface deposits with an accuracy ranging from 0.05-0.45 m. Potential use of biofacies analysis to estimate coseismic subsidence on these marshes is more limited: Gibson Spit marsh lacks a sufficient number of biofacies and at Sooke River marsh, coseismic subsidence would had to have been unrealistically large for this technique to be applicable. Only at Discovery Bay does this approach have possible utility-here coseismic subsidence on the order 0.1-0.56 m could potentially be detected. A review of foraminiferal distributions in marshes of the Pacific Northwest suggests that foraminiferal analysis does have the potential to aid in identifying tsunami layers in high marsh deposits throughout the region.

Willis, J. M. and M. W. Hester (2004). "Interactive effects of salinity, flooding, and soil type on Panicum hemitomon." Wetlands 24(1): 43-50.

It is well documented that Louisiana is experiencing wetland loss at rates greater than any other locale in the world. High rates of relative sea-level rise, a combination of eustatic sea-level rise and subsidence, is anticipated to compound this problem further in the future through increased flooding and encroachment of saline water into freshwater wetlands. The research presented in this paper examines the interactive effect of increased salinity level, flooding depth, and soil type on the growth responses of a dominant Louisiana fresh-water marsh plant, Panicum hemitomon, whose prevalence in Louisiana is currently in decline. This study was conducted under greenhouse conditions and employed a factorial design consisting of three salinity-levels (0, 1.5, 3.0 ppt), three hydrologic regimes (0, 10, 20 cm), and two soil types (high organic content, low organic content). Panicum hemitomon productivity was significantly reduced even under the relatively small increases in salinity level (1.5 and 3.0 ppt) imposed in this study. Interestingly, moderate flooding tended to increase productivity, although this relationship was not statistically significant. Significantly greater productivity was observed for plants grown in mineral soil compared with organic soil. These results indicate that any degree of saline influx into P. hemitomon-dominated wetlands will result in decreased vigor and localized decline of this species. Moderate increases in the degree of freshwater inundation may not be as damaging as originally expected and, in fact, may actually stimulate production. However, if increased flooding is accompanied by increased salinity levels, which is anticipated to occur, then the overall effect on this species will be detrimental.

Winn, R. D., H. H. Roberts, et al. (1995). "Latest Quaternary Deposition on the Outer Shelf, Northern Gulf-of-Mexico - Facies and Sequence Stratigraphy from Main-Pass Block-303 Shallow Core." Geological Society of America Bulletin 107(7): 851-866.

Sedimentologic, biostratigraphic, and isotopic geochemical data from a nearly continuous 91.4 m core and high-resolution seismic-reflection data from the middle to outer shelf east of the Mississippi River delta document deposition during changes in latest Quaternary sea levels. The data suggest that the shelf edge of the northern Gulf of Mexico is constructed from deltas deposited during falling sea level and low-stands, from sediment deposited in valleys during rising sea level, and from highstand clay. The Main Pass Block 303 core records sedimentation from the late middle Pleistocene (before ca. 135 ka) to the present. A lower delta-front interval was sampled at the core base (78.5-91.4 m). Delta sediment is truncated by a sequence boundary probably eroded during maximum glaciation corresponding to oxygen isotope stage 6 (late Illinoian?) and then modified during the following transgression. Above the sequence boundary is a transgressive shelf sand (77.2-78.5 m), overlain by burrowed, hemipelagic clay (similar to 63.4-77.2 m). The sand and clay were deposited during postglacial sea-level rise and a highstand. The rise and highstand correspond to oxygen isotope stage 5 and Ericson zone X and part of Ericson zone Y (Sangamonian-''Eowisconsinan''). The clay interval from similar to 51.8 to 63.4 m depth, in turn, was likely deposited during oxygen isotope stages 3 and 4 during the early and middle Wisconsinan. Overlying, with a transitional contact, is a relatively thick mud and sand (16 to similar to 51.8 m) deposited during the subsequent sea-level fall to the maximum late Wisconsinan lowstand (oxygen isotope stage 2). The mud and sand interval correspond to steeply dipping clinoforms on seismic-reflection records. An interpreted sequence boundary, formed during fluvial incision of the shelf during the maximum late Wisconsinan lowstand, separates deltaic sediment from overlying fluvial, bay, and marsh deposits, which fill an incised valley. Thin, regressive delta and shelf facies overlie the valley fill. Sediment above the sequence boundary (above 16 m) was deposited during the rise in sea level from the maximum late Wisconsinan lowstand to the present. Late Wisconsinan deltaic acid overlying incised-valley-fill sediment was derived from an ancestral river system that drained the southeastern United States.

Woodroffe, C. D. and J. Chappell (1993). "Holocene Emergence and Evolution of the Mcarthur River Delta, Southwestern Gulf of Carpentaria, Australia." Sedimentary Geology 83(3-4): 303-317.

The McArthur River drains from a semiarid, sandstone catchment into a shallow embayment behind the Sir Edward Pellew Group of islands in the southwestern Gulf of Carpentaria. It has built a broad Holocene delta, present wit two active distributaries and several abandoned, mangrove-lined, former distributaries. Augering indicates that much of the delta is underlain by shelly sands which contain distinct shell beds in their position of growth. These are interpreted as delta front deposits, and the elevation of the landwardmost beds above high tide level implies emergence of 1-2 m over the last 4000 years. This relative sea-level fall appears to have been a major cause of rapid mid-Holocene delta progradation. The eastern margin of the delta has undergone little net progradation over the last 2000 years, though there has been accretion of small mangrove-covered islands to the northwest of the delta. Distributaries have migrated across the upper deltaic plain by lateral migration, leaving nested sequences of fluvial ridges. In the lower deltaic plain, channel migration appears to have occurred mainly by avulsion; former distributaries have been infilled with fluvial sands and are now tidally dominated.

Wu, C. Y. (1991). "Response of the Pearl River Estuarine Complex to the Meteorological Forcing and River Inflow - a Cybernetics Approach." Journal of Coastal Research 7(4): 1153-1167.

The present paper is a study on the sub-tidal sea level dynamic system from an extensive investigation on the "sea-river-atmosphere" system in the Pearl River Delta, Guangdong, China. The two-year long continuous time series records of sea level and meteorological forcing collected from more than 18 stations in the Pearl River Delta area reveal large amplitude fluctuations within the sub-tidal range 0.01-0.5 cpd. These fluctuations, according to power spectrum and coherence spectrum analysis, represent direct or indirect response of the estuary to variations in river inflow, wind stress and atmospheric pressure. MISO CAR model for each station is identified based on 1982 time series records. The system output is sub-tidal sea level, system inputs are river discharge, wind stress and atmospheric pressure. Models obtained and validated are used to conduct multistep prediction of 1983 sub-tidal sea level with good agreement. Frequency response analysis based on the models provides some important insights into the system. It is found that the maximum response of the estuary occurs at the frequencies 0.025-0.07 cpd. System simulations reveal, quantitatively, the relative importance and variations of the control variables on sea level in the estuarine complex. Response analyses in both frequency and time domains indicate that the nontidal sea level system is an oscillatory system. Its effects on estuarine circulation, volume, salt and sediment transport, and the formation of turbidity maximum need further study.

Wu, C. Y. and D. Zhou (2001). "Long-term morpho-dynamics in special type of estuary." Science in China Series B-Chemistry 44: 112-125.

Thousands of rocky hills and islands scattered in the Pearl River delta plain and the adjacent coastal waters in South China have been or will be acted as deposition nucleus during the evolution process of the delta. The Huangmaohai estuarine complex consists of two of the eight major outlets of the Pearl River estuarine system. Since sea level reached the present level approximately 6000 years ago, especially in the last 250 years, the Huangmaohai estuarine complex has progressed to the sea by filling up the sea inlets formed between these rocky islands and between mainland and islands. This 'filling up' process left deep imprints on the long-term morpho-dynamic equilibrium in the estuaries. The present paper reveals that the long-term morpho-dynamic relation originating from this 'filling up' process in the Huangmaohai estuarine complex is different from that in many coastal plain estuaries in several aspects: (1) longitudinal variation of estuary width, (2) longitudinal variation of tidal range, (3) unique combination of small-scale dynamic structures, (4) bidirectional jet systems, and (5) velocity field and turbidity maximum.

Xue, C. T., X. H. Zhu, et al. (1995). "Holocene Sedimentary Sequence, Foraminifera and Ostracoda in West Coastal Lowland of Bohai Sea, China." Quaternary Science Reviews 14(5): 521-530.

The Holocene sedimentary sequences in the west coastal lowland of the Bohai Sea consists in ascending order of: pre-transgression river and lake sediments, transgressive tidal flat and estuarine sediments, shelf sediments, and prograding delta and river deposits. The delta deposits are the thickest and are typically composed of two imbricating Yellow River delta super-lobes that acted at different periods. There are three marker horizons in the sequence at: (1) the bottom of marine sediments; (2) the bottom of shelf deposits; and (3) the boundary between two imbricating delta superlobes. Environmental changes were mainly controlled by a rising sea level prior to 6000 BP and by delta progradation after 6000 BP. Stratigraphic distribution of foraminifera and ostracoda vary according to variations in salinity and sedimentation rate. There is no evidence that the Yellow River delta developed during the Holocene transgression but rather during a later prograding phase. An understanding of the shelly ridges in the coastal lowland indicates that the ridges were formed at a similar level to the present and there is no evidence for Holocene sea levels 1-2 m higher than the present sea level.

Yang, S. L., Q. Y. Zhao, et al. (2001). "Seasonal changes in coastal dynamics and morphological behavior of the central and southern Changjiang River delta." Science in China Series B-Chemistry 44: 72-79.

Seasonal changes in sea level, tidal range, wind, riverine discharges, nearshore SSC (suspended sediment concentration) and bed-level of intertidal flat at 4 different sites were shown. In addition, the statistical relationships between the dynamics and the behavior of the sediment surface were examined. The average intertidal elevation seems negatively correlated to sea level while positively correlated to nearshore SSC. The effect of wind on seasonal cycle of average intertidal elevation is not evident although wind is an important factor governing short-term erosion/accretion events. The influence of riverine discharges on seasonal cycle of deltaic intertidal flats is masked by other factors. It is concluded that seasonality on mudflats is more complicated than on beaches.

Yum, J. G., K. Takemura, et al. (2003). "Holocene environmental changes of the Hwajinpo Lagoon on the eastern coast of Korea." Journal of Paleolimnology 29(2): 155-166.

Lithologic and geochemical data of a core from the Hwajinpo Lagoon, located on the eastern coast of Korea, provided the evolutionary history of the lagoon related to Holocene sea- level changes of the East Sea ( Sea of Japan). Grain size analysis, water content analysis, and soft X- ray analysis of core samples were used to reconstruct sedimentary environments, as were total organic carbon, C/ N, S and C/ S chemical records. Assemblages of mollusc and diatom remains also provided paleoenvironmental information. The reconstruction of paleoenvironments from these multi- proxy data allows the establishment of an evolutionary model of the Hwajinpo Lagoon. The environmental changes of the Hwajinpo Lagoon can be divided into seven different depositional facies: ( l) Exposed basement rock; ( 2) Estuarine; ( 3) Stagnant brackish lagoon ( isolated); ( 4) Oxic condition lagoon ( organic activity); ( 5) Fresh water lake; ( 6) Oxic brackish lagoon ( recent condition); ( 7) Prograding river delta. These environmental changes can be related to sea- level change during the Holocene. The trends of sea- level change in the Hwajinpo Lagoon from this study can be compared to those of the Japanese coastal areas located on the other side of the East Sea such as Lakes Shinji and Nakaumi.

Zong, Y. Q. (1992). "Postglacial Stratigraphy and Sea-Level Changes in the Han River Delta, China." Journal of Coastal Research 8(1): 1-28.

The Han River Delta has resulted from the postglacial marine transgression since 12,310 +/- 370 BP. Postglacial stratigraphy and sedimentary facies were recently investigated, with detailed analyses of borehole records and examination of sediment samples. From interpretation of the stratigraphic data and analysis of historical documentary data, three periods of marine transgression followed by regression in the delta during postglacial time were identified and described. The three periods of transgression are dated from 12,310 to 6320 BP, from 5380 to 3590 BP and from 2630 to 1840 BP. It is summarised that the stratigraphy is composed of three fining-upwards sequences which coincide with increase in marine action, resulting from three periods of marine transgression or rises in sea level.