Odyssey of Archaean crustal evolution of the Southern Indian shield: An insight from petrogenesis of distinct Mesoarchaean and Neoarchaean trondhjemite to granite suites from the northwestern margin of the Dharwar Craton, India

• Published in: Lithos Vol. 454-455; p. 107280
• Main Authors: Hegde, Venkatraman S., Manikyamba, C., Basavaraj, K. Koti, Hulaji, Shivani, Korakoppa, Mahesh M, Shalini, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Crustalstabilization; Geodynamic setting; Granite; Neoarchaean; Trondhjemite; Western Dharwar Craton; Crustalstabilization; Western Dharwar Craton; Trondhjemite; Geodynamic setting; Neoarchaean; Granite
• ISSN: 0024-4937; 1872-6143
• DOI: 10.1016/j.lithos.2023.107280

Tectonic setting and crustal evolutionary processes recorded in the Meso–and Neoarchaean crust in the northwestern margin of the Dharwar Craton are discussed in this paper based on the geochemistry of 2.97 Ga granite from Kumta-Manjuguni-Kakkalli (KMK) and ≤ 2.65 Ga trondhjemite to granite near Ramnagar-Khanapur (RK). Both the plutonic suites are potassic (total alkalies∼8.9%), high in silica (SiO2 ∼ 71.9 wt%), and metaluminous to weakly peraluminous. The granite from KMK is characterized by moderately fractionated rare earth elements (REE) pattern (Lan/Ybn < 14), unfractionated heavy rare earth elements (HREE) and significant negative Eu/Eu* anomalies (0.2–0.7). The RK granite has fractionated LREE/HREE (20–41) with Eu/Eu* of 0.6–1.07 while the trondhjemite and granodiorite have LREE/HREE of 25–33 and Eu/Eu* between 0.67 and 0.74. The geochemical characteristics of KMK granite suggest derivation from intracrustal melting of TTG type crust and metasedimentary rocks whereas RK granite was derived predominantly from intracrustal melting of felsic crust and high -K basaltic rocks. While the RK trondhjemite was generated from the partial melting of metabasalt. Integration of the present data with those of other granitoids of the WDC indicates a five stage crustal growth, whereby K-rich KMK granite magmatism represented an early crust building cycle with crustal consolidation at ∼3.0 Ga, while the RK granitoids represent the younger and main orogenic cycle at 2.65–2.50 Ga. A similar style of episodic multi-stage crustal growth during the Archaean was common in major cratons globally involving plate convergence and accretion events and supercontinent amalgamation. [Display omitted] •The present data on granitoids of the Western Dharwar Craton (WDC) indicates a 5 stage crustal growth.•2.973 Ga K-rich magmatism in WDC concluded an early orogenic cycle with crustal consolidation.•2.65Ga magmatism represents the younger and main orogenic cycle at 2600-• 2500 Ma.•A thickened crust in WDC is indicated by the petrogenesis of 2.65Ga granitoids.