| Title | Cenozoic exhumation history of the eastern margin of the northern Canadian Cordillera |
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| Author | McKay, R; Enkelmann, E; Hadlari, T ; Matthews, W; Mouthereau, F |
| Source | Tectonics vol. 40, issue 4, e2020TC006582, 2021 p. 1-18, https://doi.org/10.1029/2020TC006582  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210041 |
| Publisher | Wiley |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Province | Yukon; British Columbia; Northwest Territories |
| NTS | 106M/09; 106M/10; 106M/11; 106M/12; 106M/13; 106M/14; 106M/15; 106M/16; 107B/03; 107B/04; 107B/05; 107B/06; 107B/11; 107B/12; 116P/09; 116P/10; 116P/11; 116P/12; 116P/13; 116P/14; 116P/15; 116P/16; 117A/01;
117A/02; 117A/07; 117A/08; 117A/09; 117A/10 |
| Area | Richardson Mountains |
| Lat/Long WENS | -138.0000 -134.0000 68.7500 67.5000 |
| Subjects | tectonics; geochronology; Science and Technology; Nature and Environment; Neogene; Paleogene; tectonic history; deformation; thermal history; burial history; bedrock geology; lithology; sedimentary
rocks; clastics; fission-track dates; zircon dates; apatite; modelling; structural trends; Canadian Cordillera; Phanerozoic; Cenozoic |
| Illustrations | location maps; stratigraphic columns; plots; diagrams; charts |
| Program | GEM2: Geo-mapping for Energy and Minerals Western Arctic-Beaufort-Northern Yukon |
| Released | 2021 02 18 |
| Abstract | New low-temperature thermochronology data from clastic sedimentary rocks in the northern Richardson Mountains, Canada, indicate significant exhumational cooling during late Eocene-early Oligocene time.
Apatite (U-Th-Sm)/He (AHe) data were collected from 19 Proterozoic-Paleocene rocks across a 115 km transect. Eighty-eight single-grain AHe dates range from 16-300 Ma and are generally younger than stratigraphic ages, indicative of thermal resetting
by burial. Additionally, zircon (U-Th)/He (ZHe) datesfrom two Proterozoic-Cambrian rocks range from 49-123 Ma and suggest burial to >160°C. In contrast, ZHe dates from Jurassic sandstones are older than the stratigraphic age, which limits maximum
burial to <160°C.Thermal history modeling reveals three phases of cooling, during the Paleocene-early Eocene (>65-50 Ma), late Eocene-early Oligocene (40-30 Ma), and late Oligocene-early Miocene (30-15 Ma). Most samples were sensitive to cooling
during the first and second phases, whereas the third phase is less well constrained. In general, most rocks were below the sensitivity of AHe analysis since the early-middle Miocene. The results suggest a previously unrecognized phase of inferred
deformation in the northern Richardson Mountains between 40-30 Ma. Our findings contribute to previous work that recognizes Late Cenozoic deformation along the eastern margin of the Northern Cordillera. We further investigated the potential
mechanisms of this widespread deformation and suggest exhumation may relate to kinematic changes of the North American plate relative to structural trends along the margin of the Northern Cordillera. |
| Summary | (Plain Language Summary, not published)
Rock samples from the Richardson Mountains were analysed for U-Th-He isotopes in order to develop a cooling model. The cooling model reconstructs when
the Richardson Mountains were uplifted from below sea level to form the present mountains, which occurred mainly in the Tertiary approximately 40-30 million years before present. |
| GEOSCAN ID | 328299 |
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