Informatics Publishing Limited

S. Zakaulla ¹, H. S. Rajaraman ², A. P. Dhurandhar ³, R. Timothy ⁴, K. Umamaheswar ²

Affiliations
1 Atomic Minerals Directorate, Department of Atomic Energy, Bangalore, IN
2 Atomic Minerals Directorate, Department of Atomic Energy, Hyderabad, IN
3 Atomic Minerals Directorate, Department of Atomic Energy, Nagpur, IN
4 Atomic Minerals Directorate, Department of Atomic Energy, Shillong, IN

Abstract

In the Proterozoic Shillong Group, the Meso-Proterozoic arenaceous Barapani Formation, unconformably overlies the Paleo proterozoic Tyrsad Formation. Argillaceous quartz arenite, quartzite and quartz wacke are the constituents of Barapani Formation, in both Meghalaya plateau and Mikir Hilis in Assam. Samples from both the domains contain same type of detrital grains. Monocrystalline quartz forms about 70 to 90 % and feldspars and lithic fragments form minor part of the framework constituents. Sericite is the major mineral in matrix. Geochemical data (major and trace elements) of these arenites show overall similar elemental composition of all the samples from both Meghalaya plateau and Mikir Hills, Assam, indicating constancy of provenance. However, samples from the Mikir Hills as compared to that from Meghalaya Plateau show depletion in FeO(t), CaO, and MgO and enrichment in V, Cr, Co, Ni and Cu. Samples from both the Meghalaya plateau and Mikir Hills indicate a passive margin tectonic setting of sedimentation.

Keywords

Petrology, Geochemistry, Mid-Proterozoic, Barapani Arenite, Meghalaya, Mikir Hills, Assam.

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S. N. Chaturvedi ¹, S. Balasubramani ¹, H. S. Rajaraman ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research (AMD), NorthEasternRegion, Nongmynsong, Shillong - 793 01, IN

Abstract

No Abstract.

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H. S. Rajaraman ¹, S. K. Jain ¹, B. S. Bisht ¹, A. V. Jeyagopal ¹, M. B. Verma ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad 500 016, IN

Abstract

In the eastern Dharwar craton, the crescent- shaped Cuddapah Basin forms a large intracratonic basin, comprising Meso–Neoproterozoic sedimentary sequence with volcanic rock components. The sedimentary environment of the Cuddapah Basin, in general, is comparable with peri-tidal complex with shallow marine carbonate shelf and beach environment. Systematic geological studies of the Cuddapah Basin are well documented^1,2. The litho-units of the basin are mainly divided into older Cuddapah Supergroup and a younger Kurnool Group. The former is present throughout the basin, while the younger group is seen in its western and northeastern parts. The sediments of the basin overlie the Late Archaean–Lower Proterozoic granitoids intruded by basic and ultrapotassic dykes.

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