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

Darshan Kumar ¹

Affiliations
1 Geological Survey of India, Agartala, IN

Abstract

Concretions of varying composition and nature occur in large numbers in the upper Tertiary rocks of North Tripura. The different types of concretions can be broadly grouped into three classes. The iron oxide concretions in the ferruginous Tipam sandstones, calcareous concretions in the Boka Bil shales and siltstones and the sand coated calcareous concretionary boulders of the Bhuban sandstones. Field observations indicate both syngenetic and epigenetic origin for calcareous concretions but the ovoidal iron oxide concretions appear to have originated by oxidation.

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P. M. Inamdar ¹, Darshan Kumar ²

Affiliations
1 A-9, Chaitanya Flats, Shivajinagar, Nagpur, 440010, IN
2 B-7 Qtrs, P.O. Kandelwalnagar-441402, IN

Abstract

The origin of red boles occurring between lava flows has been a subject of controversy though widely believed that it is a product of weathering of basalts and the term 'bole' meaning fossil laterite. A red to brown clay section of 7 .25 m thickness, sampled at every meter interval inclusive of the lower part of the overlying flow and the upper part of the underlying flow showed such marked physical and chemical changes which do not confirm to a weathered zone. This section forms a sample of the inumerabJe sections at flow contacts observed in parts of Akola, Nanded, Parbhani, Nagpur and Amaravati Districtcs in Deccan Traps during systematic geological mapping.

Keywords

Bole, Deccan Trap, Maharashtra.

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