Chromite Paleoplacer in the Permian Sediments at the East Edge of the East European Platform: Composition and Potential Sources
| Autor: | Evgenii V. Pushkarev, Irina A. Gottman, Ildar R. Rakhimov |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Ural orogen
010504 meteorology & atmospheric sciences Permian Geochemistry 010502 geochemistry & geophysics Ophiolite melt inclusions 01 natural sciences Mantle (geology) chromite placer solid-state inclusions 0105 earth and related environmental sciences Melt inclusions Horizon (geology) geography geography.geographical_feature_category Subduction Geology Geotechnical Engineering and Engineering Geology Mineralogy Ural Foredeep Volcanic rock ophiolite composition of chromspinel Chromite provenance sources QE351-399.2 |
| Zdroj: | Minerals Volume 11 Issue 7 Minerals, Vol 11, Iss 691, p 691 (2021) |
| ISSN: | 2075-163X |
| DOI: | 10.3390/min11070691 |
| Popis: | A chromite occurrence called the Sabantuy paleoplacer was discovered in the Southern Pre-Ural region, at the east edge of the East-European Platform in the transitional zone to the Ural Foredeep. A ca. 1 m-thick chromite-bearing horizon is traced at a depth of 0.7–1.5 m from the earth’s surface for the area of ca. 15,000 m2. The chromspinel content in sandstones reaches 30%–35%, maximum values of Cr2O3 are 16–17 wt. %. The grain size of detrital chromspinel ranges from 0.15 to 0.25 mm. Subangular octahedral crystals dominate rounded grains and debris are rare. The composition of detrital chromspinel varies widely and is constrained by the substitution of Al3+ and Cr3+, Fe2+ and Mg2+ cations. Chemically, low-Al (Al2O3 = 12 wt. %) and high-Cr (Cr2O3 = 52–56 wt. %) chromspinel prevail. The compositional analysis using discrimination diagrams showed that most chromites correspond to mantle peridotites of subduction settings. Volcanic rocks could be an additional source for detrital chromites. It is confirmed by compositions of monomineralic, polymineralic and melt inclusions in chromspinels. The presented data indicates that ophiolite peridotites and related chromite ore associated with oceanic and island-arc volcanic rocks, widespread in the Ural orogen, could be the main sources of the detrital chromspinel of the Sabantuy paleoplacer. |
| Databáze: | OpenAIRE |
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