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Hot-side-up aureole in southwest Yukon and limits on terrane assembly of the northern Canadian Cordillera

1995; Geological Society of America; Volume: 23; Issue: 5 Linguagem: Inglês

10.1130/0091-7613(1995)023 2.3.co;2

1943-2682

Stephen T. Johnston, Philippe Erdmer,

Geochemistry and Geologic Mapping

Research Article| May 01, 1995 Hot-side-up aureole in southwest Yukon and limits on terrane assembly of the northern Canadian Cordillera Stephen T. Johnston; Stephen T. Johnston 1Canada-Yukon Geoscience Office, Box 2703 (F-3), Whitehorse, Yukon Y1A 2C6, Canada Search for other works by this author on: GSW Google Scholar Philippe Erdmer Philippe Erdmer 2Department of Geology, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen T. Johnston 1Canada-Yukon Geoscience Office, Box 2703 (F-3), Whitehorse, Yukon Y1A 2C6, Canada Philippe Erdmer 2Department of Geology, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (5): 419–422. https://doi.org/10.1130/0091-7613(1995)023 2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Stephen T. Johnston, Philippe Erdmer; Hot-side-up aureole in southwest Yukon and limits on terrane assembly of the northern Canadian Cordillera. Geology 1995;; 23 (5): 419–422. doi: https://doi.org/10.1130/0091-7613(1995)023 2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Near Aishihik Lake in southwest Yukon, Canada, Paleozoic and older pericratonic metamorphic rocks of the Nisling terrane are overlain by foliated granodiorite of the Aishihik batholith (186.0 ± 2.8 Ma), part of the Lower Jurassic Aishihik plutonic suite. Isograd geometry in the Nisling rocks indicates that metamorphism resulted from intrusion of the batholith. Metamorphic minerals define a series of zones, including staurolite, staurolite-kyanite, kyanite, and sillimanite, which are parallel to schistosity and dip beneath the batholith. They form a hot-side-up aureole in which metamorphic grade increases upward. Petrogenetic relations and geothermobarometry indicate peak metamorphism at pressures of 8 to 10 kbar and temperatures in excess of 720° C in the sillimanite zone. A U-Pb age determination on titanite from the aureole indicates cooling through 600° C at 184 ± 2 Ma, soon after crystallization of the batholith, consistent with emplacement of the Aishihik batholith into the Nisling terrane. Early Jurassic arc magmatism is therefore a characteristic of Nisling and Stikinia. Isotopic and stratigraphic data point to the construction of a single arc across these previously juxtaposed terranes, although it is possible that coeval Lower Jurassic arcs may have developed on both terranes in response to the closure of intervening basins. This magmatism distinguishes Nisling from conterminous North America, which lacks significant Lower Jurassic igneous rocks. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.