An exotic Mesoarchean microcontinent: The Coorg Block, southern India

Crustal assembly of the Antananarivo and Masora domains, central–eastern Madagascar: constraints from U–Pb zircon geochronology and whole–rock geochemistry of meta–granitoids

“…Granitoids older than~2500 Ma have also been reported in the Coorg and Madurai Blocks and within the Central Dharwar Craton of India. The Coorg Block and the Madurai Block are dominated by~2900-3100 and 2500-2600 Ma charnockites, respectively (Plavsa et al, 2012;Peucat et al, 2013;Santosh et al, 2013). In addition, the igneous ages of the main protolith lithologies differ between the Coorg Block (Peucat et al, 2013;Santosh et al, 2013) and the Antananarivo domain.…”

“…The Coorg Block and the Madurai Block are dominated by~2900-3100 and 2500-2600 Ma charnockites, respectively (Plavsa et al, 2012;Peucat et al, 2013;Santosh et al, 2013). In addition, the igneous ages of the main protolith lithologies differ between the Coorg Block (Peucat et al, 2013;Santosh et al, 2013) and the Antananarivo domain. Thẽ 2600 Ma felsic granulites in the Central Dharwar Craton have chondrite-normalized REE patterns similar to those of the tonalitic gneisses in the southeastern part of the Antananarivo domain, and both units are characterized by positive Eu anomalies and relatively fractionated REE patterns ( Fig.…”

Geochronology and geochemistry of igneous rocks in the Bailingshan area: Implications for the tectonic setting of late Paleozoic magmatism and iron skarn mineralization in the eastern Tianshan, NW China

“…The in-situ Hf isotopic analysis of zircons, combined with their U-Pb ages, provides a robust method to trace the source and petrogenesis of magmas, and to constrain the crustal evolution history (Woodhead et al, 2001;Kinny and Maas, 2003;F.Y. Wu et al, 2006;Kemp et al, 2007;Santosh et al, 2015). Kinny and Maas (2003) have shown that negative ε Hf (t) values indicate source materials derived from partial melting of older crust and positive ε Hf (t) values indicate derivation from juvenile magmas.…”

Physical volcanology and geochemistry of Palaeoarchaean komatiite lava flows from the western Dharwar craton, southern India: implications for Archaean mantle evolution and crustal growth

“…2.5 Ga (Peucat et al 2013;Jayananda et al 2013a;Santosh et al 2015). The craton exposes a large tilted section of continental crust offering excellent opportunities to study crustal accretion patterns along different crustal levels in three dimensions (Chardon et al , 2011.…”

“…3.8 Ga) crustal record have not been documented for the Dharwar craton, Nd model ages (Jayananda et al 2015) and a single zircon grain age of ca. 4.0 Ga (Santosh et al 2015) suggest remnants of Eoarchaean-Headen crust. Alternatively, such highly depleted mantle reservoirs were attributed to early global differentiation of silicate earth by Boyet and Carlson (2005).…”