Analysis of an Exposed Portion of the Badwater Turtleback Shear-zone, Death Valley, California, USA
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Date
2018-04-10
Authors
Jarrett, Corey
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
The exposed shear zone within the footwall of the Badwater turtleback presents an excellent opportunity to explore the brittle-ductile transition. Within this shear zone, a variety of lithologies preserve the last stages of crystal-plastic deformation concurrent with exhumation of the turtleback. The included field study captures a snapshot of each lithologic element during the last stages of ductile deformation.
The exposed shear zone's journey through the brittle-ductile transition is analyzed using the deformation mechanisms of calcite and quartz. A history of strain partitioning is constructed through comparison of the strain and temperature environments needed to facilitate each mechanism of crystal-plastic deformation. As the shear zone cooled, strain was partitioned from quartz-rich mylonitic gneiss to the calcite-dominated marbles and mylonites. Correlation of deformation temperatures with previous studies further constrains the timing of the last stage of ductile deformation to between 13 and 6 Ma.
Description
Keywords
Calcite, Death Valley, Microtectonics, Mylonite, Shear zone, Structural geology