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Authors
Affiliations
1 Centre for Earth Science Studies, P.B. 7250, Akkulam, Thuruvikkal Post, Trivandrum 695 031, IN
2 Department of Chemistry, College of Arts & Science, University of Tokyo, Komaba, Meguro, Tokyo 153, JP
3 Department of Chemistry, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182, JP
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 5 (1994), Pagination: 585-590
Abstract
Rhenium-Osmium (Re-Os) dating of two molybdenite samples from the alkali granite and pegmatite of Ambalavayal in northern Kerala (S. India) yielded ages of 567±28 Ma and 566±77 Ma, respectively. These ages closely compare with the previously determined Rb-Sr whole rock age of 595±20 Ma Rb-Sr for granite, and K-Ar biotite age of 560±30 Ma for the pegmatite.
Our study provides the first direct determination of the timing of ore mineralization associated with felsic magmatism in southern India, and reveals the fingerprints of a prominent Pan-African metallogenic event. This timing coincides with the formation of rare metal and gemstone-bearing pegmatites in different parts of southern India, Sri Lanka, Madagascar and East Antarctica. In most cases, the mineralizations are genetically related to felsic magmas emplaced along structural conduits, suggesting that the magmatism and metallogeny are related to deep-seated extension in the cratonized crustal segments of the Gondwana assembly.
Keywords
Geochronology, Molybdenite, Pan-African, Metallogeny, Southern India.
