Title | Post-accretionary fault deformation of the Intermontane region, southern Yukon and northern British Columbia, Canadian Cordillera |
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Author | Kellett, D A ;
Ryan, J J; Zagorevski, A ; Colpron, M; Joyce, N |
Source | Cordilleran Tectonic Workshop, 2018; 2018 p. 40 Open
Access |
Links | Online - En ligne (PDF,
complete volume - volume complet, PDF, 4.80 MB)
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Image |  |
Year | 2018 |
Alt Series | Natural Resources Canada, Contribution Series 20190220 |
Meeting | Cordilleran Tectonic Workshop; Whitehorse, YT; CA; March 2-4, 2018 |
Document | book |
Lang. | English |
Media | on-line; digital |
File format | pdf |
Province | Yukon; British Columbia |
NTS | 104J; 104K; 104L; 104M; 104N; 104O; 105B; 105C; 105D; 105E; 105F; 105G; 105L; 115A; 115G; 115H; 115I; 115J |
Area | Whitehorse; Atlin Lake; Dawson |
Lat/Long WENS | -139.5000 -130.0000 65.0000 58.5000 |
Subjects | tectonics; structural geology; geochronology; Science and Technology; Nature and Environment; tectonic history; faulting; deformation; burial history; thermal history; volcanism; bedrock geology;
basement geology; structural features; faults; plate motions; kinematic analysis; thermal analyses; temperature; radiometric dating; uranium lead dating; zircon dates; fission-track dates; argon argon dating; potassium argon dating; muscovite;
modelling; models; illite; calcite; Paleogene; Intermontane Belt; Canadian Cordillera; King Salmon Fault; Laberge Group; Phanerozoic; Cenozoic; Tertiary; Mesozoic; Cretaceous; Jurassic |
Program | GEM2: Geo-mapping for Energy and Minerals Western Cordillera, Yukon Tectonic Evolution - late Mesozoic to Tertiary |
Released | 2018 03 01 |
Abstract | Jurassic and later post-accretionary structures in the northern Canadian Cordillera generally lack absolute timing constraints and their kinematics are only broadly understood. This is largely due to
the challenges in directly dating motion on brittle faults, as well as the recessive nature of brittle faults which often form linear topographic lows in the landscape. Low temperature multi-thermochronology can provide constraints on timing and
kinematics of brittle faults. Apatite and zircon U-Th/He and fission track dating methods are used to develop footwall and hanging wall temperature-time models for Jurassic to Paleogene faults in the Intermontane region of southern Yukon and northern
British Columbia. Preliminary results, which also incorporate complementary detrital zircon U-Pb and detrital muscovite Ar/Ar age data, illustrate the potential of these methods for reconstructing the post-accretionary structural history of the
Intermontane region. For example, multi-geo- and thermochronological results across the King Salmon fault in northern British Columbia demonstrate contrasting burial/heating and cooling histories for footwall and hanging wall Laberge Group units of
the Whitehorse trough. Detrital zircon U-Pb data constrain comparable Pliensbachian to Toarcian depositional ages for Laberge Group samples from both structural positions and zircon double dating results (U-Pb and U-Th/He ages from individual
crystals) confirm their volcanic source. Muscovite in footwall Laberge Group rocks preserve undisturbed Early Jurassic detrital ages, while zircon U-Th/He yields reset Early Cretaceous ages. Thus footwall Laberge Group and older basement rocks were
buried and heated to between 400-180 °C during Late Jurassic (Oxfordian) to Early Cretaceous (Albian) while hanging wall Laberge Group rocks remained above ~180 °C. Both footwall and hanging wall Laberge Group rocks exhibit cooling through ~40 °C at
ca. 40 Ma suggesting a common late exhumation history. These temperature-time models will be compared where possible against age constraints obtained by direct dating of fault materials: K-Ar dating of fault gouge illite and U-Pb dating of calcite
slickenfibres. |
GEOSCAN ID | 321385 |
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