Geochemistry and petrogenesis of lava flows around Linga, Chhindwara area in the Eastern Deccan Volcanic Province (EDVP), India

Autor(en)

Sohini Ganguly, Jyotisankar Ray, Christian Koeberl, A. Saha, Martin Thoeni, V. Balaram

Abstrakt

Based on systematic three-tier arrangement of vesicles, entablature and columnar joints, three distinct quartz normative tholeiitic lava flows (I, II and III) were recognized in the area around Linga, in the Eastern Deccan Volcanic Province (EDVP). Each of the flows exhibits intraflow chemical variations marked by high Mg#-low Ti, and low Mg#-high Ti contents. The MgO (4.27-7.74wt.%), Mg# (23.45-41.89) and Zr (161.5-246.3ppm) of Linga flows suggest an evolved chemistry marked by fractional crystallization and crustal contamination processes. Positive Rb and Th anomalies, negative Nb anomalies, relative enrichment of LILE-LREE with respect to Nb, Nb/Th:3.71-6.77 indicate crustal contamination of magma by continental materials through magma-crust interaction during melt migration and contributions from sub-continental lithospheric mantle (SCLM). Negative K, Sr and Ti anomalies corroborate an intracontinental, rift-controlled tectonic setting for the genesis and evolution of Linga basalts. Chondrite-normalized REE patterns reflect low HREE abundances and prominent LREE/HREE, MREE/HREE fractionation thereby pointing towards partial melting of garnet peridotite mantle source. Nb, Zr, Y variations suggest 10-15% partial melting of mantle source for the derivation of parent tholeiitic melt that suffered crystal fractionation of phenocrystal phases and subsequent liquid immiscibility. Critical evaluation of Sr

_initial and Nd

_initial (65Ma) isotopic compositions (

⁸⁷Sr/

⁸⁶Sr

_initial between 0.705656 and 0.706980 and

¹⁴³Nd/

¹⁴⁴Nd

_initial between 0.512523 and 0.512598) suggests that these basalts were derived from an enriched mantle (~EM I-EM II) source. The ε

_Sr (21.84-41.27) and ε

_Nd (-0.28 to 1.10) isotopic signatures defined by higher ε

_Sr and lower ε

_Nd fingerprint a plume-related source. Positive and negative values of ε

_Nd indicate an isotopically heterogeneous mantle source marked by mixing of depleted (DM) and enriched mantle (EM I-EM II) components at the source region and together with

⁸⁷Sr/

⁸⁶Sr

_initial ranging from 0.705656 to 0.706980 suggest two stage contamination of parent magma which is much similar to that of Poladpur, Toranmal, Mhow, Chikaldara flows. Ba/Y versus

⁸⁷Sr/

⁸⁶Sr and Nb/Y versus Rb/Y variations show an Ambenali-Poladpur contamination trend for the Linga basalts thereby suggesting the role of upper continental granitic crust as the contaminant of these flows through magma-crust interaction during melt migration. The lava flows of Linga are geochemically correlatable with the Poladpur flows of southwestern and Toranmal flows of northern Deccan and show genetic coherence with the basalts of Jabalpur, Seoni, Chakhla-Delakhari of eastern Deccan.

Organisation(en)

Department für Lithosphärenforschung

Externe Organisation(en)

University of Calcutta, Council of Scientific & Industrial Research, Naturhistorisches Museum Wien (NHM)

Journal

Journal of Asian Earth Sciences

Band

91

Seiten

174-193

Anzahl der Seiten

20

ISSN

1367-9120

DOI

https://doi.org/10.1016/j.jseaes.2014.05.020

Publikationsdatum

2014

Peer-reviewed

Ja

ÖFOS 2012

105105 Geochemie, 105120 Petrologie

Schlagwörter

ASJC Scopus Sachgebiete

Earth-Surface Processes, Geology

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e40e22d8-88ce-4087-9427-aa5aacc79860