Archean granitoids of the Aravalli Craton, northwest India

Published on 2020-02-07T14:33:35Z (GMT) by
The Archean granitoids of the Aravalli Craton are represented by granitoid-gneisses (3.3–2.7 Ga and <i>c.</i> 1.7 Ga) and undeformed granitoids (<i>c.</i> 2.5 Ga). These granitoids have been classified into four compositional groups: (1) TTG; (2) t-TTG, low-Mg potassic gneisses and undeformed potassic granitoids; (3) sanukitoids (undeformed magnesio-potassic granitoids and high-Mg potassic gneisses); and (4) undeformed sodic gneisses. Based on the geochemical characteristics it is proposed that the TTG gneisses have formed from the partial melting of subducting oceanic plateau. The t-TTG, the undeformed potassic granitoids and the low-Mg potassic (LMP) gneisses formed due to reworking of an older continental crust (<i>c.</i> TTG composition) in response to tectonothermal events in the craton. For the formation of the sanukitoid group, a 2-stage petrogenetic model is invoked which involves metasomatization of the mantle-wedge, followed by slab-breakoff and asthenospheric upwelling which lead to the melting of the asthenosphere and the metasomatized mantle-wedge. It is proposed that subducted-sediments also contributed in the genesis of sanukitoid magma. The undeformed sodic granitoids are suggested to have formed by the partial melting of subducting basaltic slab whose parental magma did not interact with the overlying mantle-wedge.

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Mondal, M.A.E.; Ahmad, Iftikhar; Rahaman, Md Sayad; Bhutani, Rajneesh; Satyanarayanan, M. (2020): Archean granitoids of the Aravalli Craton, northwest India. Geological Society of London. Collection. https://doi.org/10.6084/m9.figshare.c.4848042.v1