Chrome Spinels in Carbonate Veins of the Onguren Complex, Western Baikal Region
| Autor: | E. P. Bazarova, V. B. Savelyeva, E. A. Khromova |
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| Rok vydání: | 2020 |
| Předmět: |
Calcite
Greenschist Dolomite Geology engineering.material 010502 geochemistry & geophysics 01 natural sciences Crystallography chemistry.chemical_compound chemistry Geochemistry and Petrology Content (measure theory) engineering Carbonate Economic Geology 010503 geology Vein (geology) Ilmenite 0105 earth and related environmental sciences Magnetite |
| Zdroj: | Geology of Ore Deposits. 62:652-668 |
| ISSN: | 1555-6476 1075-7015 |
| DOI: | 10.1134/s1075701520070107 |
| Popis: | Chrome spinels in carbonate veins of the Onguren Complex, East Siberia, Western Baikal region are predominantly ferrichromite and chrommagnetite (MgO ≤ 0.3 wt %, Mg# ≤ 0.04, Al2O3 ≤ 2.5 wt %; Cr# 0.91–1.00, Fe2+/Fe3+ 0.8–1.4) with a high ZnO content (0.9–4.6 wt %). In the calcite vein, titanian chrome-magnetite is transformed into Cr-bearing titanomagnetite, which decomposes into Ti-depleted magnetite and ilmenite at temperature of 970–1000°С and $${{f}_{{{{{\text{O}}}_{{\text{2}}}}}}}$$ approximately of +0.5…+0.7 QFM. In the dolomite vein, ferrichromite and chrome-magnetite grains contain relict cores of subferrialumochromite (Al2O3 10.6–14.4 wt %, Cr# 0.63–0.73, Fe2+/Fe3+ 4.1–5.2, MgO ≤ 0.52 wt %) with elevated ZnO (3.7–5.1 wt %), TiO2 (3.2–4.1 wt %), and MnO (0.6–1.1 wt %). Ferrichromite and chrome-magnetite are formed during the high-temperature (>600°C) metamorphism of the vein. Superimposed deformations under greenschist facies conditions lead to the formation of magnetite rims around chrome-magnetite grains. |
| Databáze: | OpenAIRE |
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