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

Utpal Bose ¹, A. K. Mathur ¹, K. C. Sahoo ², S. Bhattacharya ¹, Krishan Dutt ¹, V. Aneel Kumar ³, S. S. Sarkar ¹, S. Chowdhury ¹, I. Chowdhury ¹

Affiliations
1 Geological Survey of India, Jhalana Dungri, Jaipur - 302 004, IN
2 Geological Survey of India, Bhubaneswar - 751 012, IN
3 Geological Survey of India, Hyderabad - 500 660, IN

Abstract

The oldest cratonic nucleus pf the Western Indian shield, familiarly known as the Banded Gneissic Complex (BGC), occupies a large tract in the Mcwar plains of South Rajasthan. It has essentially an old gneissic component (3.3 Ga) and a host of mafic bodies associated with detrital and chemogenic sediments which have been subjected to multiple phases of anatexis and granite intrusions (2.9 Ga and later events). The emplacement of Berach granite and succeeding dolerite dyke swarms mark the end-Archaean cratonization process. This also initiated intracratonic and cratonmarginal basin formation.

Later magmatism, especially along the basement-cover interface. is due to local remobilisation of the basement at the time of Proterozoic orogeny.

Keywords

Banded Gneissic Complex, Stratigraphy, Petrochemistry, Rajasthan.

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S. Ananda Murthy ¹, V. Aneel Kumar ¹, P. V. Krishna Rao ¹, Sekhar Mallick ²

Affiliations
1 Project Gold, Operations Andhra Pradesh, Geological Survey of India, Southern Region, Hyderabad - 500 068, IN
2 Chemical Division, Southern Region, Geological Survey of India, Hyderabad-500 068, IN

Abstract

Heavy-concentrate has been found to be the most suitable sampling medium in geochemical exploration for gold in Atkur area of Gadwal schist belt, Mahabubnagar district, Andhra Pradesh. Au-contents in panned heavy concentrates of soil samples from B-horizon and termite mounds helped in improving gold anomaly contrast. SEM and heavy-concentrate analyses of termite samples reaffirm their utility in exploration for gold. Hence, the study of heavy fraction of soil and termite mound can be used as an important tool to reveal the subtle anomaly present in the conventional samples.

Keywords

Economic Geology, Termite Mound, Soil, Heavy Concentrate, Au-Anomaly, Gadwal Schist Belt, Andhra Pradesh.

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