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

Deshbandhu Sikka ¹, C. E. Nehru ²

Affiliations
1 Cabinet-Conseil En Geologie Miniere Sikka ENR. 2108, 3463 Rue Ste Famille, Montreal, H2X 2K7, CA
2 Department of Geology, Brooklyn College, City University of New York, Brooklyn, NY 11210, US

Abstract

Precambrian porphyry type Cu±Mo±Au deposits are present in many parts of the world including Australia, Brazil, Canada, China, Finland, India, Namibia, Russia, Sweden, and Zambia. Most of them are associated with calc-alkaline or alkaline subduction zone volcanics or granitoids of the I-type. Precambrian deposits range in age from 33l4±6 Ma to 561±9 Ma. The majority of the deposits fall into four age groupings with peaks around 3300±100Ma, 2700±100Ma, 1900±100 Ma. and 1100 ± 100 Ma which are indicative of major tectonic and magmatic episodes in different parts of the world. Precambrian deposits have many similarities with the younger porphyry copper deposits in the Phanerozoic. Some outstanding examples include Malanjkhand deposit (789 Mt x 0.83% Cu; 0.004% Mo: 0.2 gm/T Au; 6 gm/T Ag) and Tongkuangyu, China (380 Mt x 0.67% Cu) are in production. The Troilus Lake deposit, Quebec, Canada (42.9 Mt x 0.12% Cu; 1.4 gm/t Au; 1.4 gm/ t Ag) and Haib River, Namibia (600 Mt x 0.3% Cu) are being considered for exploitation.

After a review of the salient features of porphyry Cu±Mo±Au deposits in general and those of the Precambrian porphyry Cu±Mo±Au age in particular, it is suggested that Precambrian terrains should be good targets for exploration.

Keywords

Economic Geology, Porphyry Cn±Mo±Au Deposits, Malanjkhand, Madhya Pradesh.

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D. B. Sikka ¹, C. E. Nehru ²

Affiliations
1 Cabinet-Conseil en Geologie Miniere Sikka ENR, 2108, 3463 Rue Ste. Famille, Montreal, H2X 2K7, CA
2 Department of Geology, Brooklyn College of the City University of New York, Brooklyn, NY 11 210, US

Abstract

The classification of the Malanjkhand as a porphyry type copper deposit is still being debated by some, despite the documentation of all the classic characteristics of the porphyry type deposit. A careful analyses and review of the available data, from many papers, unpublished theses and our own work on Malanjkhand, clearly documents it as a porphyry type copper deposit. Some of the salient factors in arriving at this conclusion are: (1) low grade ore coupled with large tonnage, (2) regional geologic and tectonic setting: Proterozoic host rocks of the Malanjkhand deposit belong to a subduction zone calc-alkaline volcanic arc category, (3) presence of stockwork type control, (4) the genesis of mineralized quartz spatially related to the mineralized zone, (5) zonation of the alteration products in the deposit, (6) diverse ore mineral associations, and (7) sulphur isotope data that are within the range of values expected for porphyry copper deposits.

Keywords

Porphyry Type, Copper, Malanjkhand, Madhya Pradesh.

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Rajesh K. Vishwakarma ¹, D. B. Sikka ², C. E. Nehru ³

Affiliations
1 Investigation Division, NMDC Ltd., Masab Tank, Hyderabad - 500 028, IN
2 Cabinet-Conseil en Geologic Miniere Sikka ENR, 2108, 3463 Rue Ste. Famille, Montreal Canada, H@x 2k7, CA
3 Department of Geology, Brooklyn College of the City University of New York, Brooklyn, NY -11210, US

Abstract

No Abstract.

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