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

Radha R. Das ¹, K. K. Dwivedy ¹, T. R. Mahalingam ², C. K. Mathews ²

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, Begumpet, Hyderabad - 500016, IN
2 Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu - 603 102, IN

Abstract

The relative abundance of radiogenic lead varies depending on the mineralogical characteristics of the ore. In high uranium containing coaly matter, radiogenic lead is > 80% of the total, whereas in a composite ore, as much as 60% of the total is of the initial common lead. The uranium-lead 'apparent ages' are in the range of 25 Ma to 95 Ma and are related to the mineralogical assemblage in the ore. The most recent of the uranium mineralization, of 'apparent age'-25Ma is with the coaly matter separates that contain considerable amount of pyrite. The variations in the abundance and distribution of radiogenic lead isotopes and the resultant orderly changes in 'apparent ages' of uranium mineralizations in different type of mineral separates are attributed to the existing favourable conditions in the ore for movement of uranium from the rock and preferential concentration and retention in the coaly matter, leading to more than one stage uranium mineralization.

Keywords

Geochemistry, Lead Isotope, U-Pb Apparent Ages, Meghalaya.

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R. Dhana Raju ¹, S. Vijayalakshmi ², T. R. Mahalingam ², C. R. M. Rao ³, Madhuparna Roy ⁴

Affiliations
1 Atomic Minerals Division, Dept. of Atomic Energy, Bangalore - 560 072, IN
2 Indira Gandhi Centre for Atomic Research, Dept. of Atomic Energy, Kalpakkam - 603 102, IN
3 Chemical Laboratory, Geological Survey of India, Madras - 600 032, IN
4 Atomic Minerals Division, Dept. of Atomic Energy, New Delhi - 110066, IN

Abstract

Platinum Group Elemental (PGEs-Pt, Ir, Pd, Rh and Ru) contents, determined by ICP-MS, are reported in a rare REE-Th-Zr-Ti-rich ultrabasic tremolite-actinolite rock from Vattalakki, Kerala. Data on PGE, together with unusually high contents of REE, Th, Zr and Ti at percent level, indicate this rock as 'anomalous'.

Keywords

Economic Geology, PGE, REE-Rich Metaultramafite, Kerala.

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