Abstract
Archean-Proterozoic boundary represents a significant transitional phase in the Earth’s history. Bastar Craton is one of the major Archean cratons in the Indian subcontinent with voluminous granites, supracrustal rocks and tectonic belts. Malanjkhand, Dongargarh, and Kanker are the three major granitic plutons emplaced during the Archean-Proterozoic transition in the Bastar Craton, and this study is confined to the granites of Kanker pluton. Based on geochemical systematics, the Kanker granites are classified into sanukitoids, biotite and two-mica granites and hybrid granites. The compositional diversity of the Kanker granites is attributed to two end-member sources, i.e., the enriched mantle and an older felsic crust, and the interactions between them. The sanukitoids were derived from an enriched mantle source that was metasomatized by the subducted sediments. Heat supplied by the sanukitoid magmas induced the crustal melting to form the biotite and two-mica granites. The interaction between these two mutually end-member sources, i.e., the enriched mantle and an older felsic crust, resulted in the formation of hybrid granites. The evolution of the Kanker granites can be accounted for a transitional geodynamic environment, involving subduction and collisional tectonics during the Archean-Proterozoic transition.
Highlights
The Archean-Proterozoic boundary witnessed critical changes in the Earth’s history, such as the increase in the crustal thickness, decrease in the rate of continental crustal growth, oxygenation of the atmosphere, widespread occurrences of plate tectonic indicators and the formation of supercontinental assemblages (Durrheim and Mooney, 1991; Condie and Kröner, 2008; Keller and Schoene, 2012; Cawood et al, 2013; Lee et al, 2016)
Based on the source and petrogenetic mechanism, the Neoarchean granitoids have been classified into Tonalite Trondhjemite Granodiorites (TTGs), sanukitoids s.l., biotite and two-mica granites and hybrid granites (Laurent et al, 2014)
The TTGs are sourced from the partial melting of metabasalts, sanukitoids are derived from an enriched mantle, and the biotite and two-mica granites are purely crustal-derived
Summary
The Archean-Proterozoic boundary witnessed critical changes in the Earth’s history, such as the increase in the crustal thickness, decrease in the rate of continental crustal growth, oxygenation of the atmosphere, widespread occurrences of plate tectonic indicators and the formation of supercontinental assemblages (Durrheim and Mooney, 1991; Condie and Kröner, 2008; Keller and Schoene, 2012; Cawood et al, 2013; Lee et al, 2016). The essential minerals that constitute biotite and two-mica granites are alkali feldspar, plagioclase, and quartz, with biotite and muscovite forming the accessory phases (Figures 3A,B). This classification scheme enables us to characterize these rocks for the petrogenetic evolution and sources, apart from being consistent with the global adaptability of Neoarchean granitoids (Laurent et al, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
