The Cheyenne Belt

Dustin Ward
GEOL 5690, Tectonics of the Western United States, Spring 2010

The Cheyenne belt is interpreted as a Proterozoic suture between the Archean Wyoming craton and Proterozoic arc terrains of the southwestern United States. Exposed in the Medicine Bow and Sierra Madre mountains of southeastern Wyoming (figure 1), the Cheyenne belt consists of a series of  northeast-striking, steeply dipping shear zones (figure 2). This major structural boundary was initially recognized by Houston and McCallum (1961), however the interpretation of this region is a result of the work of many authors. Important studies in this area include stratigraphic and geochronologic investigations that have allowed authors to interpret the tectonic and accretionary history of the Cheyenne belt. An overview of the stratigraphy, geochronology and tectonic models are presented below. In addition, an overview of monazite geochronology is included, a method that could serve to better clarify the timing of deformational and metamorphic events within the Cheyenne belt.

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