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Geochemistry, Petrography and Rock Magnetism of the Basalts of Phek District, Nagaland


Affiliations
1 Geological Survey of India, Northeastern Region, Agartala 799 006, India
2 Dr K.S. Krishnan Geomagnetic Research Laboratory, Allahabad 221 505, India
3 Department of Geology, Nagaland University, Kohima Campus, Meriema, Kohima 797 004, India
 

Basalts occur as sub-alkaline tholeiites in the Naga ophiolite belt. They bear an E-MORB affinity ascribed to aqueous fluid addition from a dehydrating oceanic crust in a supra-subduction zone during the Indo-Burma plate collision. They are commonly altered to spilite. They exhibit relatively poor REE fractionation with almost flat chondrite-normalized patterns. Eu-anomalies are not prominent, indicating the negligible role of plagioclase fractionation in their petrogenesis. Rock magnetic studies suggest that magnetite is the major magnetic mineral in these Upper Cretaceous basalts.

Keywords

Basalt, Geochemistry, Petrography, Rock Magnetism.
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  • Geochemistry, Petrography and Rock Magnetism of the Basalts of Phek District, Nagaland

Abstract Views: 321  |  PDF Views: 143

Authors

Watitemsu Imchen
Geological Survey of India, Northeastern Region, Agartala 799 006, India
S. K. Patil
Dr K.S. Krishnan Geomagnetic Research Laboratory, Allahabad 221 505, India
V. Rino
Department of Geology, Nagaland University, Kohima Campus, Meriema, Kohima 797 004, India
Glenn T. Thong
Department of Geology, Nagaland University, Kohima Campus, Meriema, Kohima 797 004, India
Temjenrenla Pongen
Department of Geology, Nagaland University, Kohima Campus, Meriema, Kohima 797 004, India
B. V. Rao
Department of Geology, Nagaland University, Kohima Campus, Meriema, Kohima 797 004, India

Abstract


Basalts occur as sub-alkaline tholeiites in the Naga ophiolite belt. They bear an E-MORB affinity ascribed to aqueous fluid addition from a dehydrating oceanic crust in a supra-subduction zone during the Indo-Burma plate collision. They are commonly altered to spilite. They exhibit relatively poor REE fractionation with almost flat chondrite-normalized patterns. Eu-anomalies are not prominent, indicating the negligible role of plagioclase fractionation in their petrogenesis. Rock magnetic studies suggest that magnetite is the major magnetic mineral in these Upper Cretaceous basalts.

Keywords


Basalt, Geochemistry, Petrography, Rock Magnetism.



DOI: https://doi.org/10.18520/cs%2Fv108%2Fi12%2F2240-2249