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

P. V. Sunder Raju ¹, R. K. W. Merkle ²

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500007, IN
2 Department of Geology, University of Pretoria, ZA

Abstract

No Abstract.

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P. V. Sunder Raju ¹, S. Nirmal Charan ¹, D. V. Subba Rao ¹, B. Uday Raj ¹, S. M. Naqvi ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

Gold mineralisation occurs at Chikkasiddavanahalli (C S Hall!) in Archaean volcano-Sedimentary sequence of the Ingaldhal Formation, in Chiradurga Group, Dharwar craton. The C S Hal1i ridges and low mounds are about 1 2 km long and 100 in wide with N-S strike and vertical to steep easterly dips comprising mixed sulphide/oxide facies banded iron formations (MSOBIF) and associated ferruginous phyllites, metavolcanics and minor carbonates. Several horizons of BIF's occur as parallel to subparallel linear brands and extend over a strike length of 20-40 km with widths ranging from 2-25 m. These BIF s are highly sheared, deformed and metamorphosed to upper greenschist facies. The shears in BIF's are occupied by several syn-Tectonic quartz carbonate veins of various dimensions and found to be favourable loci for Gold-Sulphide mineralisation. Petrological studies show major mineral constituents with pyrite, arsenopyrite and subordinate grunerite, hornblende, chlorite, muscovite, ankerite, calcite, magnesian siderite and quartz. Most gold deposits world over are hosted in second order and subsidiary shear zones. The primary gold in BIFs is enriched with intense fracturing controlled by major shear systems extending from Gadag in the north and Doduguni in the south Active convergent margin settings related to accretionary processes and fluid activity are suggested to have led to Epigenetic gold mineralisation in BIFs at C S Halli area with an average gold grade of 2 08 g/t.

Keywords

Au Mineralisation, Structural Controls, Shear Zones, C S Halli, Chitradurga Schist Belt, Karnataka.

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S. M. Hussain ¹, P. V. Sunder Raju ¹

Affiliations
1 National Geophysical Research Institute. Hyderabad - 500 007, IN

Abstract

No Abstract.

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P. V. Sunder Raju ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

A preliminary report on the ocelli-Bearing mafic-Ultramafic rock from Honnavalli village near Arsikere in Hassan district of Karnataka is presented in this note.

Keywords

Ocellar Texture, Ultramafics, Hassan District, Karnataka.

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P. V. Sunder Raju ¹, Rajeev Menon ¹

Affiliations
1 NGRI, Hyderabad, IN

Abstract

No Abstract.

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Rajeev Menon ¹, P. V. Sunder Raju ¹, G. K. Reddy ¹

Affiliations
1 National Geophysical Research Institute, (Council of Scientific and Industrial Research), Hyderabad - 500 007, IN

Abstract

A geochemical soil sampling survey undertaken at Tumallpalle uranium mineralized zone Cuddapah district, has confirmed the presence of uranium anomalies in soils. Bulk soil samples were collected at every 20 m along the traverse from approximately 30 cm below the surface and were assayed for uranium by x-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). The uranium anomalies detected by the insitu radiometric survey show a correlation with the helium highs. The soil gas helium studies have aided in delineating the subsurface extension of the deposit. This study endeavors for an integration of different techniques in a known area which could probably aid in delineating uranium zones for optimal exploitation in the future exploration programmes.

Keywords

Geochemistry, Radiometry, Uranium, Cuddapah Basin, Andhra Pradesh.

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P. V. Sunder Raju ¹

Affiliations
1 NGRI, Hyderabad, IN

Abstract

No Abstract.

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P. V. Sunder Raju ¹

Affiliations
1 CSIR-NGRI, Hyderabad, IN

Abstract

No Abstract.

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