Brittle regime slip partitioned damage and deformation mechanisms along the eastern Denali fault zone in southwestern, Yukon

Journal of Geophysical Research: Solid Earth
By: , and 

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Abstract

Rare bedrock exposures of the eastern Denali fault zone in southwestern Yukon allow for the measurement, sampling, and analyses of brittle regime fault slip data and deformation mechanisms to explore relations to far field, oblique plate motions. Host rock lithologies and associated slip surfaces show episodic damage zone‐related deformation and calcite ± hematite ± chlorite related hydrothermal fluid flow. This regional scale network of asymmetric fault damage is spatially and kinematically linked to a discrete and narrow fault core. Fault network observations, orientations, slip data, and strain inversions document a slip partitioned strike‐slip fault system with locally and mutually overprinting strike‐, oblique‐, and dip‐slip components. Microstructural analyses reveal crystal plastic and co‐seismic brittle deformation mechanisms active in a narrow range of upper crustal temperature, pressure, fluid, and chemical conditions. The net damage related slip is not exclusively formed by a single kinematic system, but rather a fully partitioned, time integrated system likely operative for much of the fault's brittle regime evolution temporally constrained by previously published thermochronometric data. Although the fault slip data was collected from outcrop‐scale exposures at sites tens of kilometers apart, results show remarkable correlation between fault kinematics and plate motions along the ∼580 km long eastern Denali fault segment. End member, subhorizontal, northeast directed reverse and north directed dextral strike slip fault strain axes closely reflect relative plate motion interactions over at least the last 30 m.y. and act as a proxy for far‐field stresses compatible with the kinematics of the damage zone network.

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Publication type Article
Publication Subtype Journal Article
Title Brittle regime slip partitioned damage and deformation mechanisms along the eastern Denali fault zone in southwestern, Yukon
Series title Journal of Geophysical Research: Solid Earth
DOI 10.1029/2024JB029506
Volume 129
Issue 11
Year Published 2024
Language English
Publisher American Geophysical Union
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description e2024JB029506, 35 p.
Country Canada, United States
State Alaska
Other Geospatial British Columbia, southwest Yukon
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