Geochemistry of Greenstone Belt Rocks Around Kalikapur-Potka-Dabanka, Singbhum Craton, East Singbhum, Jharkhand

Reddy, Anvesh M (2013) Geochemistry of Greenstone Belt Rocks Around Kalikapur-Potka-Dabanka, Singbhum Craton, East Singbhum, Jharkhand. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS Dissertation of Anvesh M Reddy) Anvesh_M_Reddy-08Ms29-MSThesis.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

The recent geochronological data clearly brings out the Mesoarchean craton geological situation where the IOG greenstone rocks and the earliest TTG rocks have very similar ages of ~3.5 Ga and thus represent a case similar to those seen in the very ancient greenstone – TTG belts around the world including those in the Barberton greenstone belt of South Africa, Pilbara in Australia and probably the older Isua supracrustals of Greenland. Any study of these Mesoarchaen rocks in general would directly indicate petrogenesis of the TTG and thus geodynamic processes leading to craton formation, sedimentation and early life evolution in favourable marine conditions. In particular, we wanted to test the hypothesis proposed earlier on the equivalence of these small, disrupted greenstone belts occurring at places even as enclaves within the younger Singhbhum granite phases (both SBG-A and SBG-B) to the IOG, despite the fact that the interbedded cherts clearly are carbonaceous rather than typically iron bearing BIF as seen in both the Badampahar and the Daitari greenstone –BIF units. It appears that the basalt-komatiite-chert sequence of this greenstone developed as a supracrustal unit in a continental arc type setting where the shallow marine environment supported earliest life. The similar δ13C values from both the basalt and chert strongly suggest that these constituted a cogent depositional unit with a high degree of basaltseawater interaction in the marine environment.

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