Crustal root of the Eastern Dharwar Craton: Zircon U–Pb age and Lu–Hf isotopic evolution of the East Salem Block, southeast India

摘要: Abstract The Salem Block represents the northern part of Southern Granulite Terrane in SE India, adjacent to southern Dharwar Craton. New zircon U–Pb and Lu–Hf results on charnockites, granitoids migmatites from eastern indicate that it mainly consists bimodal juvenile Neoarchaean – early Palaeoproterozoic (∼2.75–2.65 Ga ∼2.55–2.48 Ga) crust underwent peak metamorphism at ∼2.53 Ga. These ages isotopic signatures characterize as lower Eastern oldest (∼2.75–2.65 Ga) granulites can be traced along important shear zones (Salem-Attur Gangavalli Shear Zones), which may thus expose deeper levels crust, a way similar proposed for Nilgiri granulites. An additional (minor) contribution recycled Western Craton is suggested by presence limited ∼3.65–3.35 Ga ∼2.9–2.6 Ga detritus. Younger intrusions within include Cryogenian (∼820–800 Ma) Yelagiri alkaline complex Ediacaran (559.1 ± 3.5 Ma) Sankari-Tiruchengode granitoid complex. were sourced protoliths Block. Cryogenian-Tonian age magmatism widespread possibly related initial subduction Mozambique Ocean. A-type are thought have formed during Malagasy Orogeny with final consumption Ocean collision India Azania-East Africa.