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

B. R. G. Reddy ¹, A. Sriramadas ¹

Affiliations
1 Department of Geology, Andhra University, Waltair, IN

Abstract

Deposits of barytes, east of Khammam, Andhra Pradesh, are associated with early and late Precambrian formations. The barytes in association with chert occurs in the form of irregular veins and lenses along and across the bedding and foliation planes and along axial plane traces of the folds, in several lithological units indicating structural controls. Optical, chemical, X-ray and spectrochemical studies of four different types of barytes have been made in detail. The mineralogical studies and the mode of occurrence indicate that the barytes mineralisation resulted from residual solutions.

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A. Sriramadas ¹, M. S. Murty ¹

Affiliations
1 Department of Geology, Andhra University, Waltair, IN

Abstract

An area of about four hundred and eighty square kilometres in Visakhapatnam, consisting of khondalites, charnockites and granites, was geologically mapped. The trend of the formations varies from NE-SW through E-W to NW-SE. This trend neither conforms with NE-SW trend of the Eastern Ghats nor with the NW-SE trend of the hinterland of the Eastern Ghats between the Godavari and Mahanadi rivers. The change in the trend pattern is inferred to be due to the area being located in an intensely folded and faulted region in the eastern margin of the Eastern Ghats.

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A. Sriramadas ¹, A. T. Rao ¹

Affiliations
1 Department of Geology, Andhra University, Waltair 530003, IN

Abstract

The tonalitic charnockites from Visakhapatnam, Andhra Pradesh, belong to 2,600 m y. age. They were structurally emplaced along the axes of NE and E plunging overturned isoclinal synclines exhibited by khondalites. The palingenetic charnockites of granodioritic composition have indicated an age of 2,000 m.y., which corresponds to the age of NW-SE cross-folds in the Eastern Ghats of Andhra Pradesh.

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