Columbia River Flood Basalt Province
By Heidi Reeg
This photo shows a thick section of Columbia River Flood Basalts (www.krsh.com)
Continental Flood Basalt provinces, which are found around the world, are voluminous lava outpourings associated with melting anomalies located in the upper mantle (Ernst and Buchan, 2003). Figure 2 shows the location and areal extent of main flood basalt provinces.
(Figure from Jerram and Widdowson, 2005)
The Columbia River Flood basalts are one of the youngest of the continental flood basalt provinces found around the world. They erupted between 17.5 and 6 Ma, with the bulk of the basalt eruption occurring in the first three million years (Hooper and Hawkesworth, 1993). The next figure shows the areal extent of the CRFB’s at the time they erupted
(From
www.volcano.und.edu).
The Columbia River Flood basalts are one of the smallest flood basalt provinces. 1.73 x 105 km3 of basalt erupted in this province, compared with 106 km3 of basalt in larger continental flood basalt provinces (Jerram and Widdowson, 2005).
There is controversy surrounding the cause of the initiation of the Columbia River Flood Basalts, as well as the source of the melted material.
For a brief overview of the controversy and conclusions, click
on summary page
To get more in-depth information about the controversy, including the geochemical
isotopic analyses involved, click here