Thermotectonic History of the Kluane Ranges and Evolution of the Eastern Denali Fault Zone in Southwestern Yukon, Canada
AffiliationUniv Arizona, Dept Geosci
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationMcDermott, R. G., Ault, A. K., Caine, J.S., & Thomson, S. N. (2019). Thermotectonic history of the Kluane Ranges and evolution of the eastern Denali fault zone in southwestern Yukon, Canada. Tectonics, 38, 2983–3010. https://doi.org/10.1029/2019TC005545
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AbstractExhumation and landscape evolution along strike-slip fault systems reflect tectonic processes that accommodate and partition deformation in orogenic settings. We present 17 new apatite (U-Th)/He (He), zircon He, apatite fission-track (FT), and zircon FT dates from the eastern Denali fault zone (EDFZ) that bounds the Kluane Ranges in Yukon, Canada. The dates elucidate patterns of deformation along the EDFZ. Mean apatite He, apatite FT, zircon He, and zircon FT sample dates range within similar to 26-4, similar to 110-12, similar to 94-28, and similar to 137-83 Ma, respectively. A new zircon U-Pb date of 113.9 +/- 1.7 Ma (2 sigma) complements existing geochronology and aids in interpretation of low-temperature thermochronometry data patterns. Samples <= 2 km southwest of the EDFZ trace yield the youngest thermochronometry dates. Multimethod thermochronometry, zircon He date-effective U patterns, and thermal history modeling reveal rapid cooling similar to 95-75 Ma, slow cooling similar to 75-30 Ma, and renewed rapid cooling similar to 30 Ma to present. The magnitude of net surface uplift constrained by published paleobotanical data, exhumation, and total surface uplift from similar to 30 Ma to present are similar to 1, similar to 2-6, and similar to 1-7 km, respectively. Exhumation is highest closest to the EDFZ trace but substantially lower than reported for the central Denali fault zone. We infer exhumation and elevation changes associated with similar to 95-75 Ma terrane accretion and EDFZ activity, relief degradation from similar to 75-30 Ma, and similar to 30 Ma to present exhumation and surface uplift as a response to flat-slab subduction and transpressional deformation. Integrated results reveal new constraints on landscape evolution within the Kluane Ranges directly tied to the EDFZ during the last similar to 100 Myr.
Note6 month embargo; published online: 15 August 2019
VersionFinal published version
SponsorsNSF-EAR National Science Foundation (NSF) ; Geological Society of America graduate student research grant; Mineral Resources Program of the U.S. Geological Survey