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

I. V. Radhakrishna Murthy ¹, B. Polinaidu ¹, A. T. Rao ²

Affiliations
1 Department of Geophysics, Andhra University, Visakhapatnam 530003, IN
2 Department of Geology, Andhra Univeristy, Visakhapatnam 530003, IN

Abstract

Magnetic anomalies in an area of about 1500 sq km around Vizianagaram town in Andhra Pradesh bring out a shallow magnetic basement of charnockitic rocks, which is highly faulted. The magnetic basement exhibits horst and graben-like structures and broadly maintains conformable relations with the antiformal and synformal structures of the overlying khondalite suite of rocks. The development of these faults is attributed to the earlier folding of the Eastern Ghats and their refolding about a N-S axis to change their initial NE-SW trend to E-W and NW-SE in the nonhern part of Andhra Pradesh. The development of the horst-graben type structure is explained by movements of the faulted blocks along the fault planes at different stages or tectonic activity.

Keywords

Geophysics. Magnetic anomalies, Vizianagaram, Andhra Pradesh, Basement Structure.

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