Memeti, V. and Gehrels, G. E. and Paterson, S. R. and Thompson, J. M. and Mueller, R. M. and Pignotta, G. S. (2010) Evaluating the Mojave–Snow Lake fault hypothesis and origins of central Sierran metasedimentary pendant strata using detrital zircon provenance analyses. Lithosphere, 2 (5). pp. 341-360. ISSN 1941-8264 http://resolver.caltech.edu/CaltechAUTHORS:20101011-133936215
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Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) detrital zircon age data and detailed mapping of metasedimentary and metavolcanic pendants in the central Sierra Nevada are used to examine the age and origin of the metasediments, and to search for evidence of the location and history of the Cretaceous Mojave–Snow Lake fault. Quartzites from the Snow Lake, Benson Lake, May Lake, and Quartzite Peak pendants yield age spectra that best match Neoproterozoic to Ordovician passive-margin strata, thus supporting the presence of displaced passive-margin strata now preserved in Sierran pendants. Sediments at Cinko Lake, Strawberry Mine, and NE of Snow Lake are interpreted to be Early Jurassic to Early Cretaceous and marine, and probably not equivalents of the Fairview Valley Formation at Black Mountain as previously interpreted. Without this correlation, the suggested 400 km of displacement along the Mojave–Snow Lake fault is unconstrained, the exact location of origin for these passive-margin and Jurassic marine metasediments is uncertain, and the nature of the contact between these two sediment packages, which has been suggested to be an angular unconformity, is speculative and deserving of a more detailed evaluation. The timing of displacement along the inferred dextral Snow Lake fault is constrained to be between ca. 145 Ma, the maximum depositional age of Jurassic strata at Cinko Lake, and 102 Ma and 103–108 Ma, the age of the oldest intruding pluton and the youngest volcanic rocks juxtaposed along the stratigraphic break with adjacent eugeoclinal rocks.
|Additional Information:||© 2010 Geological Society of America. Manuscript received 8 May 2009; Revised manuscript received 10 June 2010; Manuscript accepted 16 June 2010. This project was supported by National Science Foundation grant EAR-0537892 and U.S. Geological Survey EDMAP grants to Paterson, and the Department of Earth Sciences at the University of Southern California. Many thanks are due to Bob Miller for providing the quartzite sample from Quartzite Peak and information about the pendant, and the Arizona LaserChron Center, especially Victor Valencia and Alex Pullen, University of Arizona, for use of the LA-ICP-MS facilities and help in conducting the analyses. Roland Mundil and Jenny Matzel greatly contributed to this study financially and by providing laboratory facilities at the Berkeley Geochronology Center for obtaining precise U/Pb zircon CA-TIMS ages for the Cinko Lake quartz diorite and the Harriet Lake pluton. We thank Kathleen Ritterbusch and David Bottjer, University of Southern California, for providing a fossil identification and age estimate for the fossils found at Snow Lake. The detailed geologic mapping of the Benson Lake and May Lake pendants could not have been realized without the help of Rita Economos, Saskia Erdmann, Robert Miller, and field assistants Gayle Hough and Claire Wilke. University of Southern California undergraduate team research students, under the supervision of Scott Paterson, Lawford Anderson, and Geoff Pignotta, helped greatly in our “search for the Mojave– Snow Lake fault” during field mapping of the Cinko Lake area in summer of 2006, producing the geologic map in Figure 5. We thank Paul Stone and an anonymous reviewer for detailed reviews on the manuscript, and Jason Saleeby, Jim Wright, and Rich Schweickert for reviews of an earlier version of this paper. Andy Barth, Cal Stevens, Frank Corsetti, Greg Davis, and Marty Grove are thanked for stimulating discussions about detrital zircon provenance analyses, passive-margin strata in the Mojave Desert, and the Mojave–Snow Lake fault.|
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|Deposited By:||Tony Diaz|
|Deposited On:||29 Nov 2010 23:54|
|Last Modified:||26 Dec 2012 12:31|
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