Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Tapan pal ¹, T. Dutta Gupta ¹, S. C. Das Gupta ¹

Affiliations
1 Project: Andaman, Op: WSA, ER, GSI, GSI Complex, Karunamoyee, DK Block, Salt Lake, Kolkata - 700 091, IN

Abstract

Vitric tuff is being reported from Archipelago Group of South Andaman. The tuff is composed of delicately shaped glass shards with variable amount of microlites and broken phenocrysts of quartz, plagioclase and mica. Major oxide analyses show dacitic composition of the tuff. Petrographic and XRD studies show that the glass is altered to clinoptilolite and analcime. The sedimentary structures in tuff beds suggest these as products of ash turbidite.

Keywords

Vitric tuff (dacitic), Mio-Pliocene, South Andaman.

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