Origin of scapolite-hosted sapphire (corundum) near Kimmirut, Baffin Island, Nunavut, Canada

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00095032" target="_blank" >RIV/00216224:14310/17:00095032 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.3749/canmin.1700018" target="_blank" >http://dx.doi.org/10.3749/canmin.1700018</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3749/canmin.1700018" target="_blank" >10.3749/canmin.1700018</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Origin of scapolite-hosted sapphire (corundum) near Kimmirut, Baffin Island, Nunavut, Canada

Popis výsledku v původním jazyce

Gem-quality corundum (sapphire) occurs in scapolite-rich calc-silicate rock hosted in marble of the Lake Harbour Group near Kimmirut, southern Baffin Island. A deposit of blue and colorless gem corundum (Beluga occurrence) is compared to a similar calc-silicate pod generally lacking corundum but containing nepheline (Bowhead occurrence) and located 170 m to the SSW. Corundum formation was made possible by three equally important sequential metamorphic reactions: (1) formation of nepheline, diopside, and K-feldspar (inferred) at granulite facies peak metamorphic conditions; (2) partial retrograde replacement of the peak assemblage by phlogopite, oligoclase, calcite, and scapolite (Me-50-Me-67) as a result of CO2-, H2O-, Cl-, F-bearing fluid influx at 1782.5 +/- 3.7 Ma (P-T 720 degrees C, 6.2 kbar); and (3) retrograde breakdown of scapolite + nepheline (with CO2-and H2O-bearing fluid) to form albite, muscovite, corundum, and calcite. Late, low-temperature zeolite mineralization is common in corundum-bearing zones. Based on thermodynamic models, the corundum-forming reaction only occurs in a 100 degrees C window with an upper limit determined by scapolite-nepheline stability, and a lower limit determined by the formation of Al-silicate rather than corundum. The protolith is inferred to be dolomitic argillaceous marl with no evidence to suggest the initial presence of evaporites. The enrichment of trace metals V and Cr, and the depletion of Co, Ni, and Mn, suggest reducing diagenetic conditions in the initial sediment. Beluga calc-silicate rock is strongly depleted in REE. Oxy-dravite delta B-11 (+3.9 +/- 0.7%) is consistent with a marine boron source. The oxygen isotope composition of corundum (delta O-18(VSMOW) = 16.4 +/- 0.1%) is comparable to that of corundum in marble or desilicated pegmatite associated with marble.

Název v anglickém jazyce

Origin of scapolite-hosted sapphire (corundum) near Kimmirut, Baffin Island, Nunavut, Canada

Popis výsledku anglicky

Gem-quality corundum (sapphire) occurs in scapolite-rich calc-silicate rock hosted in marble of the Lake Harbour Group near Kimmirut, southern Baffin Island. A deposit of blue and colorless gem corundum (Beluga occurrence) is compared to a similar calc-silicate pod generally lacking corundum but containing nepheline (Bowhead occurrence) and located 170 m to the SSW. Corundum formation was made possible by three equally important sequential metamorphic reactions: (1) formation of nepheline, diopside, and K-feldspar (inferred) at granulite facies peak metamorphic conditions; (2) partial retrograde replacement of the peak assemblage by phlogopite, oligoclase, calcite, and scapolite (Me-50-Me-67) as a result of CO2-, H2O-, Cl-, F-bearing fluid influx at 1782.5 +/- 3.7 Ma (P-T 720 degrees C, 6.2 kbar); and (3) retrograde breakdown of scapolite + nepheline (with CO2-and H2O-bearing fluid) to form albite, muscovite, corundum, and calcite. Late, low-temperature zeolite mineralization is common in corundum-bearing zones. Based on thermodynamic models, the corundum-forming reaction only occurs in a 100 degrees C window with an upper limit determined by scapolite-nepheline stability, and a lower limit determined by the formation of Al-silicate rather than corundum. The protolith is inferred to be dolomitic argillaceous marl with no evidence to suggest the initial presence of evaporites. The enrichment of trace metals V and Cr, and the depletion of Co, Ni, and Mn, suggest reducing diagenetic conditions in the initial sediment. Beluga calc-silicate rock is strongly depleted in REE. Oxy-dravite delta B-11 (+3.9 +/- 0.7%) is consistent with a marine boron source. The oxygen isotope composition of corundum (delta O-18(VSMOW) = 16.4 +/- 0.1%) is comparable to that of corundum in marble or desilicated pegmatite associated with marble.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10500 - Earth and related environmental sciences

Projekt

<a href="/cs/project/GA17-17276S" target="_blank" >GA17-17276S: Turmalín - indikátor geologických procesů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Canadian Mineralogist

ISSN

0008-4476

e-ISSN

—

Svazek periodika

55

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

CA - Kanada

Počet stran výsledku

31

Strana od-do

669-699

Kód UT WoS článku

000406369600008

EID výsledku v databázi Scopus

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