“…Southern Kerala region at the southern tip of Peninsular India (Figure 1a) forms part of the Southern Granulite Terrane (SGT) and incorporates Palaeo-to Neoproterozoic basement rocks belonging to the Trivandrum and Nagercoil blocks amalgamated to the Madurai Block along the Achankovil Suture Zone (ACSZ) (Clark et al, 2015;Collins et al, , b, 2014Liu et al, 2016;Rajesh et al, 2004;Rajesh & Arai, 2006;Rajesh, Arai, & Satish-Kumar, 2009;Santosh et al, 2006,b;Santosh et al, ,b, 2015Santosh et al, , 2017Taylor et al, 2014;Zhang & Santosh, 2019). The SGT is a collage of crustal blocks ranging in age from Mesoarchean to Neoproterozoic (Santosh, 2020;Yu, Santosh, Amaldev, & Palin, 2020), and the latest granulite-facies metamorphism ranged up to ultrahigh temperatures at P-T conditions of 6-8 kbar and up to 950 C during Late Neoproterozoic-Cambrian, associated with the final assembly of the Gondwana supercontinent (Geological Survey of India, 1995;Harley & Nandakumar, 2014;Harley & Santosh, 1995;Rajesh et al, 2004;Rajesh & Arai, 2006, Rajesh et al, 2009Santosh, Yokoyama, Biju-Sekhar, & Rogers, 2003;Santosh, Collins, Morimoto, & Yokoyama, 2005;Santosh et al, ,b, 2015Santosh et al, , 2017.…”