New insights into migration of the Cretaceous Sierran arc using highprecision U-Pb geochronology Public Deposited

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Last Modified
  • March 22, 2019
Creator
  • Beck, Courtney
    • Affiliation: College of Arts and Sciences, Department of Geological Sciences
Abstract
  • A compilation of 254 U-Pb zircon and K-Ar and Ar-Ar biotite ages for the central Sierra Nevada batholith, CA, shows no record of monotonic west-to-east migration of magmatism during the Cretaceous. Rather, spatial age variation in the central Sierra Nevada batholith is dominated by 1) a stepwise shift of the locus of magmatism 2) a west-to-east migration to the end of magmatism and 3) patterns within intrusive suites that reflect local crustal deformation. The step in magmatism was contemporaneous with the beginning of the Sierra Crest magmatic event and beginning of deformation along ductile shear zones in the eastern Sierra. At ~102 Ma, a laterally extensive shear zone formed along the eastern margin of the Cretaceous batholith and was localized and dissected by Sierra Crest plutons. Central Sierran biotite ages cluster between ~78 and 90 Ma and may reflect batholith-wide exhumation or cooling related to waning of local magmatism.
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  • In Copyright
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  • Includes supplemental video.
Advisor
  • Coleman, Drew S.
Degree
  • Master of Science
Graduation year
  • 2013
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