The Wayanad Schist Belt (WSB) located along the southern margin of the Western Dharwar Craton (WDC) is a small discontinuous schistose belt occur as pockets and patches within basement gneisses. WSB is oriented parallel to the E-W trending Moyar Shear Zone (MSZ) separating the WDC and Southern Granulite Terrane (SGT). The major rock types include metapelitic schists, metamafic schists, banded magnetite quartzite, pyroxene granulite, amphibolite, metapyroxenite, mylonite, hornblende-biotite schist/gneiss, micaceous quartzite etc. The fabrics in schistose rocks are defined mostly by the orientation of shape-preferred aggregates of biotite-chlorite-muscovite-sillimanite (in metapelites) and tremolite-talc-chlorite-actinolite (in metamafites). Whereas the gneissic fabric is defined by the quartz-plagioclase rich leucocratic layers and biotite-garnet-amphibole-pyroxene rich melanocratic layers. The WSB has undergone at least three phases of deformation. The most prominent fabric in WSB is the E-W to ESE-WNW trending sub-vertical foliations developed during the D3 deformation. Poles to the steep-dipping S3 foliations are WNW-ESE trending and the F3 folds are steeply plunging in nature. At the low strain domains of D3 deformation the early foliations are preserved. The N-S to NNW-SSE trending sub-vertical S2 fabric developed axial planar to moderately tight to open (F2) folds during D2 deformation. The early S1 foliations are rarely preserved in the interfolial domains of S2 foliation. In the regional scale, the poles to S1 fabrics lie on a well-defined girdle with NE-SW trending upright asymmetric folds. The U-Th-total Pb dating of texturally controlled monazites from WSB has yielded prominent age populations at around 700-850 Ma and 500-600 Ma with minor age peaks at 2.2-2.3 Ga, 2.4-2.6 Ga. The structural and chronological data suggest that, the deformation events in WSB are similar to that reported from the WDC. However, the D3 deformation is more prominent and all the earlier fabrics are truncated or brought into parallelism with the S3 fabric during D3 deformation. The 700-850 Ma and 500-600 Ma monazite growths post-tectonic with respect to the D3 deformation indicates that the Neoproterozoic accretionary events affected the whole SGT must have recrystallized the monazites present in the MSZ.

The Achankovil Shear Zone (AKSZ) is a NW-SE trending ductile shear zone passing through the Southern Granulite Terrain (SGT) has remained enigmatic among scientific community for the perspective of shear zone status and extension. While some consider the AKSZ to represent a Pan African terrain boundary between the Trivandrum block (TB) in the Kerala Khondalite Belt (KKB) and Madurai block (MB) of the SGT (Drury et al. 1984; Santosh, 1987; Harris and Santosh 1994; Santosh et al. 1992, 2005, 2006; Guru Rajesh and Chetty, 2006; Sreejith and Ravindra Kumar, 2013) that can be traced in to now- dispersed crustal fragments of Madagascar and Sri Lanka (Braun and Kriegsman, 2003; Guru Rajesh and Chetty, 2006; Santosh et al. 2009, Sreejith and Ravindra Kumar, 2013). Others consider MB and TB evolved coherently and AKSZ to be a high strain zone (MB is the continuation of TB) within the SGT (Ghosh et al 2004). Detailed structural field work across the SGT suggests that MB and TB are two different blocks and the lineament occurs between these two blocks is the Achankovil Shear Zone (AKSZ). Tracing the paleo-sutures across the rifted crustal fragments is an important method for the reconstruction of the pre-drift crustal assembly. For tracing paleo-sutures detailed structural evolutionary studies are necessary. Available data suggest that the middle and central crustal domains of the present day landmass of Madagascar was with India vis-à-vis East Gondwanaland (comprising India, Australia and Antarctica) that accreted with the West Gondwanaland (comprising Africa), during Late Neoproterozoic and Early Paleozoic (Tucker et al., 1999; Sommer et al., 2003; Collins, 2006). Geologists correlated the AKSZ of India with different major and minor shear zones present in the southern Madagascar, for example Ranotsara shear zone (RSZ), Tranomaro shear zone (TSZ), Angavo shear zone (ASZ) etc. (Tucker et al., 1999; Raharimahefa and Kusky, 2006, 2010; Sajeev et al., 2009; Tucker et al., 2011a, b). Monazites analyzed from the Antananarivo block maintained Neoproterozoic age of 796Ma (Cenki Tok et al, 2016) and also the Imorona–Itsindro Suite of central Madagascar represents 850–750 Ma magmatism (Zhou et al, 2015; Archibald et al, 2016) which is similar to the chronology of Madurai block, SGT. Age of Androyan group (Southern Madagascar) ranges from 560-530 Ma (Jons & Schenk, 2011) obtained from monazites which is similar to the chronology of Trivandrum block, SGT. Taking the arguments a step further, we argue the extension of AKSZ of SGT towards the RSZ of Madagascar which is consistant with the suggestion by Windley et al. 1994; Markl et al. 2000; Cenki et al. 2004; Jons & Schenk, 2011; Zhou et al, 2015; Archibald et al, 2016 based on structural studies and chronology.