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Published April 1993 | public
Journal Article

Thermochronologic record of pluton emplacement, deformation, and exhumation at Courtright shear zone, central Sierra Nevada, California

Abstract

Thermochronology and thermobarometry of two plutons and a ductile shear zone at their contact in the central Sierra Nevada, California, as defined over the range 700 to 300 °C by ^(40)Ar/^(39)Ar dating of hornblende and biotite and U-Pb dating of zircon, indicate that ductile shear coincided closely with dramatically increased cooling and possible decompression of both plutons. Deformation occurred as the younger (∼90 Ma) Mount Givens pluton was emplaced against the older (∼102 Ma) Dinkey Creek pluton, which was softened by conductive heating, during extension. These events coincided with significant regional exhumation, possibly a result of crustal inflation, recorded by a major pulse of rapid sediment accumulation in contemporaneous fore-arc strata of the Great Valley sequence.

Additional Information

© 1993 Geological Society of America. Manuscript received July 8, 1992. Revised manuscript received November 6, 1992. Manuscript accepted November 13, 1992. Supported by the Institute of Human Origins (Renne) and National Science Foundation grants EAR-9002672 (to Tobisch) and EAR-9105692 (to Saleeby). We thank A. Jaouni and F. Drayer for preparing samples for ^(40)Ar/^(39)Ar analysis; D. Beckner for preparing Figures 1 and 2; W. Sharp for discussion; and L. Hollister, J. Wooden, and two anonymous referees for reviewing the manuscript.

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023