@article{fdi:010062307, title = {{O}rigin of gem corundum in calcite marble : the {R}evelstoke occurrence in the {C}anadian {C}ordillera of {B}ritish {C}olumbia}, author = {{D}zikowski, {T}. {J}. and {C}empirek, {J}. and {G}roat, {L}. {A}. and {D}ipple, {G}. {M}. and {G}iuliani, {G}aston}, editor = {}, language = {{ENG}}, abstract = {{T}he calcite marble-hosted gem corundum (ruby, sapphire) occurrence near {R}evelstoke, {B}ritish {C}olumbia, {C}anada, occurs in the {M}onashee {C}omplex of the {O}mineca {B}elt of the {C}anadian {C}ordillera. {C}orundum occurs in thin, folded and stretched layers with green muscovite + {B}a-bearing {K}-feldspar + anorthite ({A}n(0.85-1)) +/- phlogopite +/- {N}a-poor scapolite. {O}ther silicate layers within the marble are composed of: (1) diopside + tremolite quartz and (2) garnet ({A}lm(0.7-05){G}rs(0.2-0.4)) + {N}a-rich scapolite + diopside + tremolite + {N}a,{K}-amphiboles. {N}on-silicate layers in the marble are either magnetite- or graphite-bearing. {P}redominantly pink (locally red or purple) opaque to transparent corundum crystals have elevated {C}r2{O}3 (<= 0.21 wt.%) and variable amounts of {T}i{O}2; rare blue rims on the corundum crystals contain higher amounts of {T}i{O}2 (<= 0.53 wt.%) and {F}e2{O}3 (<= 0.07 wt.%). {T}he associated micas have elevated {C}r, {V}, {T}i, and {B}a contents. {P}etrography of the silicate layers show that corundum formed from muscovite at the peak of metamorphism (similar to 650-700 degrees {C} at 8.5-9 kbar). {B}ecause the marble is almost pure calcite (dolomite is very rare), the corundum was preserved because it did not react with dolomite to spinel + calcite during decompression. {T}he scapolite-bearing assemblages formed during or after decompression of the rock at similar to 650 degrees {C} and 4-6 kbar. {G}em-quality corundum crystals formed especially on borders of the mica-feldspar layers in an assemblage with calcite. {W}hole rock geochemistry data show that the corundum-bearing silicate (mica-feldspar) layers formed by mechanical mixing of carbonate with the host gneiss protolith; the bulk composition of the silicate layers was modified by {S}i and {F}e depletion during prograde metamorphism. {H}igh element mobility is supported by the homogenization of delta {O}-18 and delta {C}-13 values in carbonates and silicates for the marble and silicate layers. {T}he silicate layers and the gneiss contain elevated contents of {C}r and {V} due to the volcanoclastic component of their protolith.}, keywords = {{C}orundum ; {M}uscovite ; {C}alcite marble ; {O}xygen isotopes ; {G}eochemistry ; {M}etamorphism ; {CANADA}}, booktitle = {}, journal = {{L}ithos}, volume = {198}, numero = {}, pages = {281--297}, ISSN = {0024-4937}, year = {2014}, DOI = {10.1016/j.lithos.2014.03.030}, URL = {https://www.documentation.ird.fr/hor/fdi:010062307}, }