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A better understanding of Archean crustal evolution: exploring the sedimentary archive of the Singhbhum Craton, eastern India.
- Source :
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Journal of Asian Earth Sciences . Aug2023, Vol. 251, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
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Abstract
- [Display omitted] • Juvenile crust in Singhbhum Craton formed at ∼3.51, ∼3.45, 3.38–3.25, 3.15–3.05 and ∼2.80–2.75 Ga. • Reworking of older crust in the craton occurred at ∼3.46, ∼3.3, ∼3.1 and ∼2.8 Ga. • Maximum crustal thickness was attained at ∼3.3 Ga followed by a possible reduction over ∼3.1–2.8 Ga. • Paleo-Meso–Archean continental growth occurred through episodic intraplate juvenile magmatism and resultant crustal reworking. The composition of continental crust and its temporal variation, the mechanism of crust-mantle interaction, and the degree of mantle depletion during the early Archean have been widely debated. To address these issues related to the Singhbhum Craton, we present whole-rock sediment geochemistry, detrital zircon U-Pb date, trace element and Hf isotope data from four Archean clastic sedimentary successions. The rocks have high whole-rock K 2 O/Na 2 O, relatively high La and Th compared to Ni and Sc, distinct negative Eu anomaly and flat HREE patterns, and high detrital zircon U/Yb ratios. These features suggest attainment of early crustal stability with the sediments derived from a strongly weathered basement dominated by granitoids formed through shallow intracrustal melting. Detrital zircon U-Pb and Hf isotope data indicate episodic crust formation at ∼3.51, ∼3.46, 3.38–3.25, 3.15–3.05 and ∼2.80–2.75 Ga. Each major crust formation event is marked by addition of depleted mantle-derived juvenile crust and its quick reworking. Besides, episodic tapping of older crust, as indicated by a wide range (both positive and negative) of zircon εHf t values, are evident at ∼ 3.46, ∼3.3, ∼3.1 and ∼2.8 Ga. Pressure-sensitive zircon trace element ratios suggest that the crust attained the maximum thickness at ∼3.3 Ga followed by a possible reduction in thickness over ∼3.1–2.8 Ga. In the absence of strong evidence of subduction, the rock association and their temporal distribution (coeval granitoid and mafic-ultramafic magmatism) suggest that the Paleoarchean-Mesoarchean crustal growth in the Singhbhum Craton was a result of episodic, depleted mantle-derived, intraplate magmatic injection and attendant crustal reworking. [ABSTRACT FROM AUTHOR]
- Subjects :
- *MAGMATISM
*ARCHAEAN
*CONTINENTAL crust
*GEOCHEMISTRY
*ZIRCON
*URANIUM-lead dating
Subjects
Details
- Language :
- English
- ISSN :
- 13679120
- Volume :
- 251
- Database :
- Academic Search Index
- Journal :
- Journal of Asian Earth Sciences
- Publication Type :
- Academic Journal
- Accession number :
- 163768196
- Full Text :
- https://doi.org/10.1016/j.jseaes.2023.105630