Abstract
Abstract Granitoids form the dominant component of Archean cratons. They are generated by partial melting of diverse crustal and mantle sources and subsequent differentiation of the primary magmas, and are formed through a variety of geodynamic processes. Granitoids, therefore, are important archives for early Earth lithospheric evolution. Peninsular India comprises five cratonic blocks bordered by mobile belts. The cratons that stabilized during the Paleoarchean–Mesoarchean (Singhbhum and Western Dharwar) recorded mostly diapirism or sagduction tectonics. Conversely, cratons that stabilized during the late Neoarchean (Eastern Dharwar, Bundelkhand, Bastar and Aravalli) show evidence consistent with terrane accretion–collision in a convergent setting. Thus, the Indian cratons provide testimony to a transition from a dominantly pre-plate tectonic regime in the Paleoarchean–Mesoarchean to a plate-tectonic-like regime in the late Neoarchean. Despite this diversity, all five cratons had a similar petrological evolution with a long period (250–850 myr) of episodic tonalite–trondhjemite–granodiorite (TTG) magmatism followed by a shorter period (30–100 myr) of granitoid diversification (sanukitoid, K-rich anatectic granite and A-type granite) with signatures of input from both mantle and crust. The contributions of this Special Publication cover diverse granitoid-related themes, highlighting the potential of Indian cratons in addressing global issues of Archean crustal evolution.
Highlights
Granitoids constitute a major part of the Archean cratons, and originate from partial melting of a variety of crustal and mantle sources in a wide range of tectonic settings (Martin et al 2005; Halla et al 2017; Moyen 2020)
During the last few decades, a significant amount of structural, geochemical, isotope and geochronological data have been gathered on the diverse types of Archean granitoids occurring in the Indian cratons
The information is fragmentary, locality specific and often not readily accessible to international readers. The contributions of this Special Publication synthesize the available information on Archean granitoids from each Indian craton and highlight their potential in understanding evolution of early Earth
Summary
Peninsular India comprises five cratonic blocks (Dharwar, Singhbhum, Bastar, Bundelkhand and Aravalli) bordered by mobile belts (Eastern Ghats Mobile Belt, Southern Granulite Terrain and Central Indian Tectonic Zone) (Fig. 1) (Jain et al 2020; Jayananda et al 2020b). Greenstone belts containing mafic–ultramafic and felsic volcanic rocks, banded iron formations (BIFs) and quartzites, which range in age from the Mesoarchean to the Neoarchean, occur within the granitoids (Singh & Slabunov 2016). 3.5–3.2 Ga greenschist–amphibolite-facies metasediments (BIF, shale, chert) and mafic–ultramafic volcanic rocks (basalt, komatiite) which form synformal keels surrounding the domal Paleoarchean granitoid bodies These greenstone belts host Fe, Mn, Au and Cr deposits. The western block or Western Dharwar Craton (WDC) is composed of 3.42–3.2 Ga TTG gneisses, 3.35–3.15 Ga transitional TTGs and 3.20–3.00 Ga K-rich anatectic granites (Jayananda et al 2020b, c; Ranjan et al 2020a) (Fig. 3). The Neoarchean granitoids of the EDC have a wide range of compositions, including TTG, transitional TTG, sanukitoid (+Closepet-type granitoid), K-rich anatectic granite and A-type granite (+syenites) (Fig. 3) (Moyen et al 2003; Dey et al 2017a; Jayananda et al 2020a). The EDC stabilized at 2.5 Ga, concomitant with the formation of granulites in the lower crust and gold mineralization within the granite–greenstone belts (Peucat et al 2013; Pandit et al 2020)
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