Crust–Mantle Interactions and Granitoid Diversification: Insights from Archaean Cratons
This Special Publication sheds light on crust formation and tectonic processes in early Earth by focusing on Archaean granitoids and related rocks from West Greenland in the North Atlantic Craton, Karelia Province of the Fennoscandian Shield, Eastern Dharwar and Bundelkhand cratons in the Indian Shield and Bug Complex of the Ukrainian Shield. Resulting from the IGCP-SIDA 599 project ‘The Changing Early Earth’, this compilation of papers provides explanations on the nomenclature of Archaean granitoids and explores the petrology, element and isotope geochemistry, geochronology and metamorphism of granitoids and supracrustal rocks of variable metamorphic grade. This volume provides information on the increase and timing of crust-mantle interactions and granitoid diversification from early Archaean protoliths of island arc origin to the emergence of multi-source high-K calc-alkaline granitoid batholiths at convergent continental margins. The formation of abundant granitoid batholiths suggests a significant change in mantle dynamics and plate tectonics towards the end of the Archaean.
Geochronology of Neoarchaean granitoids of the NW eastern Dharwar craton: implications for crust formation
Published:January 01, 2017
Sukanta Dey, Jaana Halla, Matti Kurhila, Jinia Nandy, Esa Heilimo, Sayantan Pal, 2017. "Geochronology of Neoarchaean granitoids of the NW eastern Dharwar craton: implications for crust formation", Crust–Mantle Interactions and Granitoid Diversification: Insights from Archaean Cratons, J. Halla, M. J. Whitehouse, T. Ahmad, Z. Bagai
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The Neoarchaean Era is characterized by large preserved record of continental crust formation. Yet the actual mechanism(s) of Neoarchaean crustal growth remains controversial. In the northwestern part of the eastern Dharwar craton (EDC) granitoid magmatism started at 2.68 Ga with gneissic granodiorites showing intermediate character between sanukitoid and tonalite–trondhjemite–granodiorite (TTG). This was followed by intrusion of transitional (large-ion lithophile element-enriched) TTGs at 2.58 Ga. Finally 2.53–2.52 Ga sanukitoid and Closepet-type magmatism and intrusion of K-rich leucogranites mark the cratonization in the area. These granitoids mostly display initial negative εNd and Mesoarchaean depleted mantle model ages, suggesting presence of older...