J 2017

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

BELLEY, P.M., T.J. DZIKOWSKI, A. FAGAN, Jan CEMPÍREK, L.A. GROAT et. al.

Basic information

Original name

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

Authors

BELLEY, P.M. (124 Canada), T.J. DZIKOWSKI (124 Canada), A. FAGAN (124 Canada), Jan CEMPÍREK (203 Czech Republic, belonging to the institution), L.A. GROAT (124 Canada), J.K. MORTENSEN (124 Canada), M. FAYEK (124 Canada), G. GIULIANI (250 France), A.E. FALLICK (826 United Kingdom of Great Britain and Northern Ireland) and P. GERTZBEIN (124 Canada)

Edition

Canadian Mineralogist, QUEBEC, MINERALOGICAL ASSOC CANADA, 2017, 0008-4476

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10500 1.5. Earth and related environmental sciences

Country of publisher

Canada

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 0.945

RIV identification code

RIV/00216224:14310/17:00095032

Organization unit

Faculty of Science

UT WoS

000406369600008

Keywords in English

sapphire; corundum; marble; calc-silicate rock; scapolite; gem deposits; metamarl; nepheline; proterozoic

Tags

Tags

International impact, Reviewed
Změněno: 10/4/2018 12:05, Ing. Nicole Zrilić

Abstract

V originále

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.

Links

GA17-17276S, research and development project
Name: Turmalín - indikátor geologických procesů
Investor: Czech Science Foundation