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Contrasting thermal and melting histories for segments of mantle lithosphere in the Nahlin ophiolite, British Columbia, Canada

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dc.contributor.author McGoldrick, Siobhan
dc.contributor.author Canil, Dante
dc.contributor.author Zagorevski, Alex
dc.date.accessioned 2018-09-27T18:57:04Z
dc.date.copyright 2018 en_US
dc.date.issued 2018-03
dc.identifier.citation McGoldrick, S., Canil, D. & Zagorevski, A. (2018). Contrasting thermal and melting histories for segments of mantle lithosphere in the Nahlin ophiolite, British Columbia, Canada. Contributions to Mineralogy and Petrology, 173, 25. https://doi.org/10.1007/s00410-018-1450-9 en_US
dc.identifier.uri https://doi.org/10.1007/s00410-018-1450-9
dc.identifier.uri https://dspace.library.uvic.ca//handle/1828/10109
dc.description.abstract The Permo-Triassic Nahlin ophiolite is the largest and best-preserved ophiolite in the Canadian Cordillera of British Columbia and Yukon, Canada. The ophiolite is well-exposed along its ~ 150 km length with mantle segments divisible into the Hardluck and Menatatuline massifs. Both massifs comprise mostly depleted spinel harzburgite (< 2 wt% Al2O3 and ~ 45 wt% MgO). Chondrite normalized REE abundances in clinopyroxene vary in (Gd/Yb)N from 0.2 to 1.1. Inversion modelling of clinopyroxene REE abundances requires 10–16% and 16–20% partial melting in the Hardluck and Menatatuline massifs, respectively. The two-pyroxene and Fe–Mg exchange temperatures in the mantle of the ophiolite also change systematically along strike with the degree of partial melt depletion. The temperatures recorded by REE and Ca-Mg exchange between coexisting pyroxenes require markedly higher peak temperatures and cooling rates for the Menatatuline massif (1250 °C, 0.1–0.01 °C/year) compared to the Hardluck massif (< 1100 °C, ~ 10− 4 °C/year). The differences between these two contiguous massifs can be reconciled by their evolution as two separate segments along a ridge system having varying melt depletion, with contrasting cooling rates controlled by presence or absence of a crustal section above the mantle lithosphere, or by rapid exhumation along a detachment. en_US
dc.description.sponsorship This research was supported by scholarships from Natural Sciences and Engineering Research Council of Canada (NSERC) and Geoscience BC to S. McGoldrick, by a NSERC of Canada Discovery Grant to D. Canil, and by funds from the Geological Survey of Canada’s Geomapping for Energy and Minerals program (GEM2-Cordillera) to A. Zagorevski. en_US
dc.language.iso en en_US
dc.publisher Contributions to Mineralogy and Petrology en_US
dc.subject Mantle en_US
dc.subject Thermometry en_US
dc.subject Melting en_US
dc.subject Geochemistry en_US
dc.subject Ophiolite en_US
dc.subject Arc en_US
dc.subject Cordillera en_US
dc.title Contrasting thermal and melting histories for segments of mantle lithosphere in the Nahlin ophiolite, British Columbia, Canada en_US
dc.type Postprint en_US
dc.description.scholarlevel Faculty en_US
dc.description.reviewstatus Reviewed en_US
dc.description.embargo 2019-04-01


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