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

R. K. Verma ¹, M. Mukhopadhyay ¹, M. H. Ashraf ¹

Affiliations
1 Indian School of Mines, Dhanbad 826004, IN

Abstract

Both coalfields are marked by significant gravity 'lows'. Maximum sedimentary thickness present is of the order of 1. 75km below the surface under the Karanpura and 0.8 km under the Daltonganj coalfields. The two coalfields, are characterized by prominent normal faults at their southern margin. The throw of the faults may be few hundred metres, Within the individual coalfields, basement faults appear to be associated with younger Gondwana sediments on the surface. The areas occupied by youngest Gondwanas do not necessarily represent the deepest part of the coalfields. This is noted, in general, for nearly all coalfields of the Damodar Valley. Differential movement appears to have occurred during Gondwana times under the coalfields resulting in either single-walled or double-walled grabens.

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R. K. Verma ¹, M. Mukhopadhyay ¹, P. B. V. Subba Rao ¹, Y. Satyanarayana ¹

Affiliations
1 Indian School of Mines, Dhanbad, IN

Abstract

A regional gravity survey has been carried out over the area lying between latitude 20°30' to 21°30'N, and longitude 85° to 86°15'E, forming a part of south Singhbhum geological province and northern part of the Eastern Ghats. The area is well-known for Sukinda ultramafic complex, Diateri and Malayagiri iron-ore deposits as well as Sukinda thrust.

Nearly 350 gravity stations were established along main roads, forest roads and cart tracks. Bouguer anomaly map of the area shows gravity highs over the Diated iron-ore group, the Malayagiri volcanics, the Sukinda ultramafic complex as well as over the Eastern Ghats province. Two-dimensional models. have been prepared to show the nature of the ultramafic complex, iron-ore group (lOG) of rocks and the Sukinda thrust. The lOG appear to form narrow but steeply dipping sedimentary troughs, while the Sukinda thrust appears to be steeply dipping to the south.

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