U-Pb And Lu-Hf Systematics Of Zircons From Sargur Metasediments, Dharwar Craton, Southern India: New Insights On The Provenance And Crustal Evolution

A study of U-Pb and Lu-Hf-Yb isotope data in zircons from metamorphosed psammopelite and quartzite from the type area of Archaean Sargur Group, Dharwar Craton, India is carried out. Two age populations are observed: an older population with concordant U-Pb ages between 2.7 and 2.8 Ga, and a younger population with ages in the 2.4-2.6 Ga age range. The. Hf values of 0 to +2.0 for the older zircon population suggest that they were derived from juvenile crust formed at 2.7-2.8 Ga. Sub-chondritic. Hf values for the younger population indicate metamorphism and/or crustal reworking at similar to 2.5 Ga. Meta-sedimentary enclaves in the Sargur type area are therefore part of the gneiss-supracrustal complex of different antiquities and may not have an independent stratigraphic status.