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Chronology of Miocene-Pliocene deposits at Split Mountain Gorge, southern California
Geology (2007)
  • R. J. Dorsey
  • A. Fluette
  • K. A. McDougall
  • B. A. Housen
  • Susanne U. Janecke, Utah State University
  • G. A. Axen
  • C. R. Shirvell
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.
  • Chronology,
  • fault split,
  • Southern california
Publication Date
January 1, 2007
Citation Information
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.