DOI: 10.1016/j.epsl.2021.116872
论文题名: Dating fault damage along the eastern Denali fault zone with hematite (U-Th)/He thermochronometry
作者: McDermott R.G. ; Ault A.K. ; Caine J.S.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 563 语种: 英语
中文关键词: aseismic slip
; Denali fault
; hematite (U-Th)/He thermochronometry
; hematite microtextures
; surface uplift
英文关键词: Aspect ratio
; Clay alteration
; Deformation
; Earthquakes
; Fault slips
; Phosphate minerals
; Population statistics
; Scanning electron microscopy
; Strike-slip faults
; Aseismic slip
; Denali fault
; Denali fault zone
; Fault damage zone
; Haematite
; Hematite (U-th)/he thermochronometry
; Hematite microtexture
; Hydrothermal alterations
; Surface uplift
; Thermochronometry
; Hematite
; deformation
; fault zone
; hematite
; plate boundary
; slip
; texture
; thermochronology
; uplift
; uranium series dating
; Alaska
; Denali Fault Zone
; United States
英文摘要: Unraveling complex slip histories in fault damage zones to understand relations among deformation, hydrothermal alteration, and surface uplift remains a challenge. The dextral eastern Denali fault zone (EDFZ; southwest Yukon, Canada) bounds the Kluane Ranges and hosts a variety of fault-related rocks, including hematite fault surfaces, which have been exhumed through the brittle regime over a protracted period of geologic time. Scanning electron microscopy-based microtextural observations and hematite (U-Th)/He (hematite He) thermochronometry from these surfaces indicate multiple generations of foliated, high-aspect ratio hematite plates. Single-aliquot hematite He dates (n=38) from 11 samples range from 11.5 ± 3.2 Ma (2σ) to 3.4 ± 2.1 Ma and exhibit moderate inter- and intrasample dispersion. A subset of dates is 15-20 Myr younger than previously published apatite (U-Th)/He dates from collocated host rocks, despite similar closure temperatures, precluding a simple ambient cooling interpretation for our hematite He data. Mixture modeling defines hematite He date populations at ∼8 Ma, ∼6 Ma, and ∼4 Ma, and when combined with microtextural observations, supports episodes of hydrothermal alteration and fault reactivation at aseismic to subseismic slip rates. There is no evidence that hematite experienced deformation- or hydrothermal fluid-related He loss. Hematite He dates overlap previously documented Kluane Ranges surface uplift and shifting dynamics of the Yakutat microplate, pinpointing fault networks and deformation processes that accommodate regional deformation in response to far-field plate boundary processes. © 2021 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165597
Appears in Collections: 气候变化与战略
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作者单位: U.S. Geological Survey, Anchorage, AK, United States; Department of Geosciences, Utah State University, Logan, UT, United States; U.S. Geological Survey, Denver, CO, United States
Recommended Citation:
McDermott R.G.,Ault A.K.,Caine J.S.. Dating fault damage along the eastern Denali fault zone with hematite (U-Th)/He thermochronometry[J]. Earth and Planetary Science Letters,2021-01-01,563