Contribution to the Mineral Chemistry of the Proterozoic Aravalli Mafic Meta-Volcanic Rocks from Rajasthan, NW India

Autor:	Talat Ahmad, Janina Wiszniewska, Anna Grabarczyk, Ewa Krzemińska
Jazyk:	angličtina
Rok vydání:	2020
Předmět:	Basalt geography basaltic komatiite geography.geographical_feature_category Pillow lava lcsh:Mineralogy lcsh:QE351-399.2 010504 meteorology & atmospheric sciences Lava Greenschist Fe-tholeiite Geochemistry Metamorphism Geology 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology 01 natural sciences pillow lava Volcanic rock Aravalli craton Mafic Metamorphic facies 0105 earth and related environmental sciences
Zdroj:	Minerals Volume 10 Issue 7 Minerals, Vol 10, Iss 638, p 638 (2020)
ISSN:	2075-163X
DOI:	10.3390/min10070638
Popis:	Field, petrological and mineral chemistry for meta-volcanic rocks from the Aravalli sequence (Aravalli Craton, India) are presented. Field evidence such as volcanic flows and suspect pillow lava structures, dominant Fe-tholeiite lava flows intercalated with quartzites and argillaceous sediments, indicate rift tectonic environment. Primary mineralogy was obliterated during post-magmatic processes such as metamorphism corresponding to the greenschist to lower amphibolite facies conditions. The rock&rsquo s mineral composition was overprinted by plagioclase&ndash chlorite&ndash amphibole&ndash epidote assemblage. The relicts of clinopyroxene were observed. The P-T estimation indicates a temperature of 550&ndash 600 ° C for the pressure ranging from 3.0 to 7.0 kbar for the majority of amphiboles and 8.0&ndash 10.7 kbar for the minority. Geochemically, these rocks are komatiitic (picritic) and high-Fe tholeiitic basalts with 45.06&minus 59.2 wt.% SiO2 and MgO content from 5 to 22.4 wt.% and Mg# of 17 to 71. They show large-ion lithophile elements (LILE) and light rare-earth elements (LREE) enrichment. Chondrite normalized rare-earth elements (REE) patterns for the Aravalli lava are moderately enriched with (La/Sm)N = 1.1&minus 3.85, (La/Yb)N from 1.49 (komatiites) to 14.91 (komatiitic basalts). The trace element systematics with the negative Nb, P and Zr anomalies reflect their derivation from enriched sub-continental lithospheric sources, although minor crustal contamination cannot be ruled out. Aravalli rocks are considered to represent the transition from continental rift magmatism to shallow submarine eruption.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0f50831ffea9b73014b93c5a69c2f852 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
Nepřihlášeným uživatelům se plný text nezobrazuje	K zobrazení výsledku je třeba se přihlásit.