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C. Rajshekhar ¹, P. P. Reddy ¹

Affiliations
1 Geology and Palaeontology Group, Agharkar Research Institute, G.G. Agarkar Road, Pune - 411 004, IN

Abstract

Pleistocene and Holocene formations in Andaman including the Ritchie's Archipelago were examined. Based on hthology and age the Neill West Coast Formation is emended and redesignated as Neill Formation. A new lithounit, the Chidyatapu Member is proposed here with its type locality and relationship with the underlying Limestone Member. Preliminary Petrographic observations assign biocalcarenite facies to the Chidyatapu Member.

Keywords

Quaternary Stratigraphy, Chidyatapu Member, Neill Formation, Andaman-Nicobar Islands.

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C. Rajshekhar ¹, P. P. Reddy ¹

Affiliations
1 Geology and Palaeontology Group, Agharkar Research Institute, G.G. Agarkar Road, Pune 411 004, IN

Abstract

The beach rock formations of south Andaman island are characterised by moderately soft to hard, fine to coarse grained/gritty, yellow to light buff coloured calcareous rocks. These rocks contain minute shells of gastropods and bivalves. The foraminifera are common and are dominantly represented by the species of the genus Pararotalia. The ¹⁴C dates of the beach rocks range from 4410- 1540 years B .P. The Wandoor beach rock with 1540- 1350 years B.P. is younger to the Chidyatapu beach rocks which have been dated 4410-3900 years B.P. PetrographicaIly, the Andaman beach rocks belong to algal biocalcarenite facies. The carbon isotope ages of the beach rock formations of the Indian Peninsula including Andaman indicate Late Holocene as a major transgressional event.

Keywords

Holocene, Beach Rock, Foraminifera, Biocalcarenite, Andamans.

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