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U–Pb and Lu–Hf Systematics of Zircons from Sargur Metasediments, Dharwar Craton, Southern India:New Insights on the Provenance and Crustal Evolution


Affiliations
1 Department of Earth Sciences, Manipur University, Imphal 795 003, India
2 Institute of Geosciences, Mineralogy, J.W. Goethe University, Frankfurt 60438, Germany
3 Centre for Atmospheric and Ocean Sciences, Indian Institute of Science, Bengaluru 560 012, India
4 Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, India
 

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 εHf 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 εHf values for the younger population indicate metamorphism and/or crustal reworking at ~2.5 Ga. Metasedimentary 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.

Keywords

Detrital Zircon, High- and Low-Grade Metamorphism, Isotope Analysis, Supracrustal Rocks.
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  • U–Pb and Lu–Hf Systematics of Zircons from Sargur Metasediments, Dharwar Craton, Southern India:New Insights on the Provenance and Crustal Evolution

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Authors

Bidyananda Maibam
Department of Earth Sciences, Manipur University, Imphal 795 003, India
Axel Gerdes
Institute of Geosciences, Mineralogy, J.W. Goethe University, Frankfurt 60438, Germany
R. Srinivasan
Centre for Atmospheric and Ocean Sciences, Indian Institute of Science, Bengaluru 560 012, India
J. N. Goswami
Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, India

Abstract


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 εHf 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 εHf values for the younger population indicate metamorphism and/or crustal reworking at ~2.5 Ga. Metasedimentary 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.

Keywords


Detrital Zircon, High- and Low-Grade Metamorphism, Isotope Analysis, Supracrustal Rocks.

References





DOI: https://doi.org/10.18520/cs%2Fv113%2Fi07%2F1394-1402