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

Subrata Sarkar ¹, M. A. Khonglah ¹, M. A. Khan ², T. B. R. Kumar ³, J. .N Ray ⁴

Affiliations
1 North Eastern Region, Shillong - 793 003, IN
2 Northern Region, Lucknow-226 024, IN
3 Bangalore-560 078
4 Eastern Region, Kolkata -700 091, IN

Abstract

Early mafic differentiate of quartz diorite to quartz monzodiorite composition related to Mid-ProterozoIc, late to post-tectonic calc-alkaline (diorite-granodiorite) plutons in Meghalaya occur in three different modes, viz. (l)dykes in country rock gneisses along tectonic locales, (2) endogenous inclusions in the diorite-granodionte intrusive plutons, as early differentiated product through fractional crystallization or liquid immiscibility, and (3) xenohths in Upper Proterozoic-Early Palaeozoic granite plutons (Nonpoh granite). These appear to be basic precursors of thc granitoids. The mafic inclusions were subjected to metasomatism by granitoids over an extended period starting with the formation of the granitic differentiates of calc-alkaline intrusions and ending with the placement of the later granitic plutons. Petrology and chemistry of the mafic rocks suggest a possible basic parentage.

Keywords

Calc-Alkaline plutons, Mafic differentiates, Petrology, Meghalaya.

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M. A. Khan ¹, Mukesh Sharma ¹

Affiliations
1 Central Arid Zone Research Institute, Jodhpur - 342 003 Rajasthan, IN

Abstract

An approach for estimating groundwater potential in Luni block of Jodhpur district by isopach maps that were prepared based on electrical resistivity method are highlighted in this paper. Groundwater potential and quality of different aquifers are estimated based on the depth to bed rock, thickness of saturated zone and aquifer resistivity drop ratio. The total groundwater potential of suitable quality is estimated to be around 49 mem. The isopach maps prepared based on electrical resistivity survey to estimate the thickness of saturated zone are found fairly compatible with the ground conditions.

Keywords

Groundwater, Isopach, Water quality, Hydrogeology, Electrical sounding, Resistivity, Jodhpur District, Rajasthan.

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R. K. Ray ¹, D. S. Thambi ¹, M. A. Khan ², Mukesh Sharma ²

Affiliations
1 Central Ground Water Board, NCCR, 2nd Floor, Reena Apartments, Pachpedi Naka, Raipur - 492 001, IN
2 Central Arid Zone, Research Institute, Jodhpur - 342 003, IN

Abstract

No Abstract.

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M. A. Khan ¹, G. N. Dwivedi ¹

Affiliations
1 Geological Survey of India, Lucknow - 226 024, IN

Abstract

Preliminary sampling of banded iron formation (BIF) of Agori Formation in Goindari and Pararawa areas of Sonbhadra district, has indicated gold mineralisation. Samples of BIF analysed 0.2g/t to 0.96 g/t and a sheared quartz vein sample gave 5.46 g/t gold.

Keywords

Economic Geology, Gold, Scorodite, Mahakoshal Greenstone Belt, Sonbhadra, Uttar Pradesh.

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