Petrogenesis of the late Archean Pillow Basalts from the Chitradurga greenstone belt, Western Dharwar Craton (southern India)
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The well-preserved exposures of pillow basalts from the late Archean (2.7 Ga) Chitradurga greenstone belt (Western Dharwar Craton) have been studied in detail using petrological, bulk-rock geochemical and isotope data. The pillows are compositionally basalts to basaltic andesites, and constituted of actinolite and plagioclase. The pillows show slight to moderately depleted LREE (La/SmN = 0.6−1.03), and nearly flat HREE patterns (Gd/YbN = 1.03−1.17) that are comparable with MORBs, but have an overall depletion in REEs relative to the latter. The trace-element patterns of the pillows on an N-MORB normalized multi-element diagram, however, are broadly comparable with that of Island Arc Basalts. The pillows were perhaps generated during the initiation of an intra-oceanic subduction zone where a depleted upper mantle (MORB-source) was metasomatized with slab-derived aqueous fluids. The pillows show a whole-rock Sm–Nd errorchron age of 2433 ± 400 Ma, which is within error of the previously reported Sm–Nd age of 2747 ± 15 Ma. The Pb–Pb isochron age (2627 ± 82 Ma) of the pillows is much closer to the previously reported Sm–Nd age, and it may also indicate the 2.62 Ga thermal event associated with felsic magmatism in the Western Dharwar Craton.
| Original language | English |
|---|---|
| Article number | 95 |
| Journal | Journal of Earth System Science |
| Volume | 131 |
| Issue number | 2 |
| Number of pages | 26 |
| ISSN | 2347-4327 |
| DOIs | |
| Publication status | Published - 2022 |
Bibliographical note
Funding Information:
Ria Mukherjee wishes to acknowledge IISER Bhopal for financial support to conduct fieldwork and analytical work for this study through an Initiation Research Grant Inst/EES/2018010. The Isotope Geochemistry Lab, University of Copenhagen is acknowledged for analytical support. Sisir Mondal wishes to acknowledge the CEFIPRA Project 6007-1. Lewis Ashwal and William L Griffin are kindly acknowledged for reading the initial draft and providing useful suggestions for significantly improving the manuscript. Two anonymous reviewers are acknowledged for providing constructive criticism that helped to improve the manuscript appreciably.
Funding Information:
Ria Mukherjee wishes to acknowledge IISER Bhopal for financial support to conduct fieldwork and analytical work for this study through an Initiation Research Grant Inst/EES/2018010. The Isotope Geochemistry Lab, University of Copenhagen is acknowledged for analytical support. Sisir Mondal wishes to acknowledge the CEFIPRA Project 6007-1. Lewis Ashwal and William L Griffin are kindly acknowledged for reading the initial draft and providing useful suggestions for significantly improving the manuscript. Two anonymous reviewers are acknowledged for providing constructive criticism that helped to improve the manuscript appreciably.
Publisher Copyright:
© 2022, Indian Academy of Sciences.
- Chitradurga greenstone belt, Late Archean, metasomatism, pillow basalt, subduction zone
Research areas
ID: 305174675