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Guadalupe pluton–Mariposa Formation age relationships in the southern Sierran Foothills: Onset of Mesozoic subduction in northern California?

Ernst, W. G. and Saleeby, Jason B. and Snow, Cameron A. (2009) Guadalupe pluton–Mariposa Formation age relationships in the southern Sierran Foothills: Onset of Mesozoic subduction in northern California? Journal of Geophysical Research B, 114 . Art. No. B11204. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20091207-093645860

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Abstract

We report a new 153 ± 2 Ma SIMS U-Pb date for zircons from the hypabyssal Guadalupe pluton which crosscuts and contact metamorphoses upper crustal Mariposa slates in the southern Sierra. A ~950 m thick section of dark metashales lies below sandstones from which clastic zircons were analyzed at 152 ± 2 Ma. Assuming a compacted depositional rate of ~120 m/Myr, accumulation of Mariposa volcanogenic sediments, which overlie previously stranded Middle Jurassic and older ophiolite + chert-argillite belts in the Sierran Foothills, began no later than ~160 Ma. Correlative Oxfordian-Kimmeridgian strata of the Galice Formation occupy a similar position in the Klamath Mountains. We speculate that the Late Jurassic was a time of transition from (1) a mid-Paleozoic–Middle Jurassic interval of mainly but not exclusively strike-slip and episodic docking of oceanic terranes; (2) to transpressive plate underflow, producing calcalkaline igneous arc rocks ± outboard blueschists at ~170–150 Ma, whose erosion promoted accumulation of the Mariposa-Galice overlap strata; (3) continued transpressive underflow attending ~200 km left-lateral displacement of the Klamath salient relative to the Sierran arc at ~150–140 Ma and development of the apparent polar wander path cusps for North and South America; and (4) then nearly orthogonal mid and Late Cretaceous convergence commencing at ~125–120 Ma, during reversal in tangential motion of the Pacific plate. After ~120 Ma, nearly head-on subduction involving minor dextral transpression gave rise to voluminous continent-building juvenile and recycled magmas of the Sierran arc, providing the erosional debris to the Great Valley fore arc and Franciscan trench.


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http://dx.doi.org/10.1029/2009JB006607 DOIUNSPECIFIED
http://www.agu.org/pubs/crossref/2009/2009JB006607.shtmlPublisherUNSPECIFIED
Additional Information:© 2009 American Geophysical Union. Received 11 May 2009; accepted 18 August 2009; published 12 November 2009. Stanford University and the Geological Society of America Graduate Student Research Grant Program supported this research. Joe Wooden, Chris Mattinson, and Uwe Martens helped with the SHRIMP-RG analyses and data reduction. Marty Grove and Trevor Dumitru provided constructive feedback on a draft version of the manuscript. Ray Ingersoll and an anonymous reviewer gave us useful criticism for the journal article. We thank the above institutions and scientists for support and advice.
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Stanford University UNSPECIFIED
Geological Society of America UNSPECIFIED
Subject Keywords:subduction; transpression; zircon age data
Record Number:CaltechAUTHORS:20091207-093645860
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20091207-093645860
Official Citation:Ernst, W. G., J. B. Saleeby, and C. A. Snow (2009), Guadalupe pluton–Mariposa Formation age relationships in the southern Sierran Foothills: Onset of Mesozoic subduction in northern California?, J. Geophys. Res., 114, B11204, doi:10.1029/2009JB006607.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16884
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Jan 2010 18:46
Last Modified:03 Oct 2019 01:18

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