Chronology of Miocene-Pliocene deposits at SplitMountain Gorge, southern California
Document Type
Article
Journal/Book Title/Conference
Geology
Volume
35
Publisher
Geological Society of America
Publication Date
2007
First Page
57
Last Page
60
Recommended Citation
Dorsey, R. J., Fluette, A., McDougall, K. A., Housen, B. A., Janecke, S. U., Axen, G. A., and Shirvell, C. R., 2007, Chronology of Miocene-Pliocene deposits at Split Mountain Gorge, southern California: A record of regional tectonics and Colorado River evolution: Geology, v. 35, p. 57-60.
COinS
Comments
Late Miocene to early Pliocene deposits at Split Mountain Gorge, California, preserve a record of basinal response to changes in regional tectonics, paleogeography, and evolution of the Colorado River. The base of the Elephant Trees Formation, magnetostratigraphically dated as 8.1 ± 0.4 Ma, provides the earliest well-dated record of extension in the southwestern Salton Trough. The oldest marine sediments are ca. 6.3 Ma. The nearly synchronous timing of marine incursion in the Salton Trough and northern Gulf of California region supports a model for localization of Pacific–North America plate motion in the Gulf ca. 6 Ma. The first appearance of Colorado River sand at the Miocene-Pliocene boundary (5.33 Ma) suggests rapid propagation of the river to the Salton Trough, and supports a lake-spillover hypothesis for initiation of the lower Colorado River.