Stratigraphy of Colorado River deposits in lower Mohave Valley, Arizona and California

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Abstract

Deposits in lower Mohave Valley and upper Topock Gorge near Topock, Arizona and Park Moabi, California record a succession of depositional and erosional events since late Miocene time that relate to the development of the Colorado River. Upper Miocene alluvial fans were deposited toward a depocenter east of the present valley bottom, indicating there was no valley outlet then through the area of Topock Gorge. The lower Pliocene Bouse Formation subsequently accumulated to thicknesses of at least 330 m in ancestral Mohave Valley before most of it was incised by a Colorado River that carried clasts as large as 0.9 m and drained southward through ancestral Topock Gorge. Pliocene fluvial sandstone and conglomerate exposed in this area record 160 m of subsequent aggradation. One or more sedimentary sequences of varied fluvial, paludal, and alluvial fan environments accumulated on the margin of the floodplain in Pleistocene time, including during deposition of the upper Pleistocene Chemehuevi Formation of Longwell (1936). River boulders as large as 1.2 m derived from Pliocene gravel were deposited in terraces along the river during later incision. Vertebrate fossil finds and historical descriptions of the 19th century enrich the history of the area

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Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Stratigraphy of Colorado River deposits in lower Mohave Valley, Arizona and California
Year Published 2007
Language English
Publisher Northridge, California State University
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 7 p.
Larger Work Title Wild, Scenic and Rapid, a trip down the Colorado River trough: Field trip guide and abstracts from the 2007 Desert Symposium
First page 50
Last page 56
Country United States
State Arizona, California
Other Geospatial Mohave Valley