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Physicochemical conditions of crystallization of dunites of the Nizhnii Tagil Pt-bearing massif (Middle Urals)

Citation

Simonov, VA and Puchkov, VN and Prikhod'ko, VS and Stupakov, SI and Kotlyarov, AV and Karmanov, NS and Stepanov, AS, Physicochemical conditions of crystallization of dunites of the Nizhnii Tagil Pt-bearing massif (Middle Urals), Russian Geology and Geophysics, 57, (6) pp. 868-890. ISSN 1068-7971 (2016) [Refereed Article]

Copyright Statement

Copyright 2016, V.S. Sobolev IGM, Siberian Branch of the RAS

DOI: doi:10.1016/j.rgg.2015.05.015

Abstract

Studies of primary multiphase silicate inclusions in accessory Cr-spinels from the fine-grained dunites of the Nizhnii Tagil Pt-bearing massif reveal their similarity to melt inclusions trapped by chromite during its growth. The analyzed Cr-spinels with multiphase silicate inclusions differ in composition from ore chromites of the same massif and from chromites (with melt inclusions) from ultramafic oceanic complexes but are similar to Cr-spinels in dunites from Pt-bearing alkaline ultramafic massifs (Konder and Inagli). According to petro- and geochemical data on heated multiphase silicate inclusions, the studied Cr-spinels crystallized with the participation of subalkalic picrobasaltic melts similar to the magmas of the Konder Pt-bearing massif and having almost the same chemical composition as tylaites. The differences between the compositions of olivines formed within the multiphase silicate inclusions and of the rock-forming minerals show that the studied Cr-spinels formed from an intercumulus liquid melt in the olivine crystal interstices during the cumulate crystallization of most of the Nizhnii Tagil massif dunites in the intrusive chamber. Numerical modeling based on the compositions of heated multiphase silicate inclusions in accessory Cr-spinels demonstrates that olivines and Cr-spinels from the studied dunites crystallized at 1430 to 1310 C and then olivine formation continued to 1280 C during the evolution of melts.

Item Details

Item Type:Refereed Article
Keywords:Nizhnii Tagil, dunites, Middle Urals
Research Division:Earth Sciences
Research Group:Geology
Research Field:Mineralogy and Crystallography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Stepanov, AS (Mr Sasha Stepanov)
ID Code:116883
Year Published:2016
Web of Science® Times Cited:1
Deposited By:CODES ARC
Deposited On:2017-05-24
Last Modified:2017-11-08
Downloads:0

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