Kaempf, Jonas and Clark, Chris and Johnson, Tim E. and Jayananda, Mudlappa and Hand, Martin and Sajeev, Krishnan
(2025)
Garnet as a reliable timekeeper in Archean polymetamorphic terranes.
Earth and Planetary Science Letters, 668 (119545).
ISSN 0012-821X; 1385-013X
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Garnet as a reliable timekeeper in Archean polymetamorphic terranes.pdf
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| Abstract: |
Reliably reconstructing the pressure–temperature–time (P–T–t) history of Archean polymetamorphic terranes is
key to gaining insight into the tectonic processes operating on the early Earth. In this regard, garnet is arguably
the most important mineral. Not only does it capture information about both the timing and the conditions of
metamorphism, but can also preserve this record through multiple tectonic cycles. Here, we used in situ Lu–Hf
dating of garnet from two greenstone belts in the Western Dharwar Craton (WDC) in southern India to investigate
their tectono-metamorphic evolution. Garnet ages reveal a record of two distinct medium- to high-pressure
tectono-metamorphic events during the Archean eon. Whereas garnet from the Holenarsipur Greenstone Belt
grew during late Neoarchean metamorphism at 2.53 Ga, garnet from the Kalyadi Greenstone Belt records a 2.96
Ga regional metamorphic episode that has not previously been recognized. Coupled with results from in situ
monazite U–Pb dating and thermodynamic modelling, our data suggest that the two neighboring greenstone
belts, which were previously thought to share a common tectonothermal history, underwent contrasting P–T–t
evolutions throughout the Mesoarchean and Neoarchean, challenging existing models for the tectonic evolution
of the WDC. Obtaining reliable age constraints in polymetamorphic terranes via in situ Lu–Hf dating of garnet
that can be directly linked to P–T information represents a key advance in deciphering the cryptic record of
crustal metamorphism throughout Earth history |
| Item Type: |
Journal Paper
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| Keywords: |
Archean metamorphism;Dharwar Craton; P–T–t;Lu–Hf garnet dating; Petrochronology; Phase equilibrium modelling |
| Subjects: |
School of Natural and Engineering Sciences > Geology |
| Divisions: |
Schools > Natural Sciences and Engineering |
| Date Deposited: |
20 May 2026 09:54 |
| Last Modified: |
20 May 2026 09:54 |
| Official URL: |
https://www.sciencedirect.com/science/article/pii/... |
| Related URLs: |
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| Funders: |
J.C. Bose National Fellowship grant for fieldwork and sample processing, Australian Research Council (ARC) grant DP200101104 |
| Projects: |
* |
| DOI: |
https://doi.org/10.1016/j.epsl.2025.119545 |
| URI: |
http://eprints.nias.res.in/id/eprint/3339 |
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