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@article{2247305,
author = {Abdale, Lindsey and Belley, Philippe M. and Groat, Lee A. and Cempírek, Jan and Škoda, Radek and Wall, Corey},
article_number = {February},
doi = {http://dx.doi.org/10.1016/j.lithos.2022.106992},
keywords = {Corundum; Muscovite; Leucosome; Metamorphic core complex; Partial melting; Metamorphism},
language = {eng},
issn = {0024-4937},
journal = {Lithos},
title = {Corundum genesis at the Blue Jay Sapphire occurrence (British Columbia, Canada) as a record of metamorphism and partial melting in the Monashee Complex},
url = {https://doi.org/10.1016/j.lithos.2022.106992},
volume = {438-439},
year = {2023}
}
TY - JOUR
ID - 2247305
AU - Abdale, Lindsey - Belley, Philippe M. - Groat, Lee A. - Cempírek, Jan - Škoda, Radek - Wall, Corey
PY - 2023
TI - Corundum genesis at the Blue Jay Sapphire occurrence (British Columbia, Canada) as a record of metamorphism and partial melting in the Monashee Complex
JF - Lithos
VL - 438-439
IS - February
SP - 1-23
EP - 1-23
PB - Elsevier B.V.
SN - 00244937
KW - Corundum
KW - Muscovite
KW - Leucosome
KW - Metamorphic core complex
KW - Partial melting
KW - Metamorphism
UR - https://doi.org/10.1016/j.lithos.2022.106992
N2 - The sapphire (corundum) occurrence near Revelstoke, British Columbia, Canada, occurs in the Monashee Complex of the Omineca Belt of the Canadian Cordillera. Corundum occurs in boudins or pod-like zones of restite within a garnet-bearing leucosome. Both zones are peraluminous and contain plagioclase, K-feldspar, and biotite and muscovite as the dominant mineral phases. Relative to the leucosome, the corundum-pods are slightly depleted in SiO2 (55.28 wt% in corundum-pods vs. 62.7 wt% in leucosome) and K2O (4.74/7.05 wt%) and enriched in Al2O3 (22.57/21.97 wt%), Fe2O3 (5.96/2.11 wt%), TiO2 (0.71/0.21 wt%), CaO (0.68/0.60 wt%), and MgO (0.59/0.28 wt%). The peraluminous nature of the corundum-bearing pods is consistent with partial melting of a metapelitic protolith. Similar chemical compositions between the corundum-pods and garnet-leucosome are interpreted to infer a single, in situ partial melting event. Coinciding melt-compatible and incompatible elements suggest a closed system. Igneous textures in thin section (coarse-grained, euhedral corundum; twinning in plagioclase; small cuspate-shaped biotite, and myrmekitic intergrowths of feldspars) confirm a partial melt origin. Petrography and thermodynamic models reveal that corundum growth and partial melting was fueled by the breakdown of muscovite along the prograde P-T path. Whole-rock geochemistry of the leucosome groundmass devoid of garnet shows high Sr/Y and La/Yb ratios indicative of garnet fractionation, and garnet mineral chemistry are Ca-poor indicating garnets crystallized from the peraluminous partial melts at peak P-T conditions. 206Pb/238U ages of garnet-equilibrated zircon indicate that peak metamorphic conditions occurred at or before ∼60.69 Ma. Continued zircon growth until 50.22 Ma tracks the presence of continued partial melt following peak metamorphism during nearly-isothermal decompression. A resulting P-T-t path for basement rocks form the Thor-Odin dome constrains the timing of peak metamorphism and ensuing partial melting events during Cordilleran orogenesis.
ER -
ABDALE, Lindsey, Philippe M. BELLEY, Lee A. GROAT, Jan CEMPÍREK, Radek ŠKODA a Corey WALL. Corundum genesis at the Blue Jay Sapphire occurrence (British Columbia, Canada) as a record of metamorphism and partial melting in the Monashee Complex. \textit{Lithos}. Elsevier B.V., 2023, roč.~438-439, February, s.~1-23. ISSN~0024-4937. Dostupné z: https://dx.doi.org/10.1016/j.lithos.2022.106992.
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