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Mantle source characterization of Sylhet Traps, northeastern India: A petrological and geochemical study.

Authors :
Islam, Md
Meshesha, Daniel
Shinjo, Ryuichi
Source :
Journal of Earth System Science. Dec2014, Vol. 123 Issue 8, p1839-1855. 17p.
Publication Year :
2014

Abstract

In this study, mineralogical, geochemical, and isotopic data are presented for the Sylhet Trap at the southern flank of the eastern Shillong Plateau, northeastern India, to determine the magma genesis in relation to the Kerguelen plume mantle source. Sylhet Trap rocks are porphyritic tholeiite and have diverse chemical compositions from picro-basalt, basalt, andesite to dacite, but mostly are within the subalkaline field. Major and trace element data were used to identify two distinct magma fractionation trends, a low and medium K series, characterized by relatively flat MORB-like (analogous to Rajmahal Traps (II)) and enriched OIB chondrite-normalized Rare Earth Element (REE) patterns. Initial Sr/Sr, Nd/Nd, and Pb/Pb isotope compositions were widely varied, ranging from 0.70435-0.71357, 0.51196-0.51266, and 17.92-19.72, respectively, when compared with basalts from the West Bengal, the Rajmahal Traps and the Kerguelen plume. Correlations among isotopic and trace element ratios of the Sylhet Traps provide evidence for the involvement of (1) HIMU-like mantle component, (2) the Kerguelen plume-like component, and (3) EMII-like crustal component. Magma from the Sylhet Traps was originated from a melting that derived directly from the heterogeneous Kerguelen mantle plume (components 1 and 2), which strongly suggests the presence of the Kerguelen plume-head in the Bengal basin. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02534126
Volume :
123
Issue :
8
Database :
Academic Search Index
Journal :
Journal of Earth System Science
Publication Type :
Academic Journal
Accession number :
100064453
Full Text :
https://doi.org/10.1007/s12040-014-0512-2