Evidence for the Neoproterozoic Phulad Suture Zone and Genesis of Malani magmatism in the NW India from deep seismic images: Implications for assembly and breakup of the Rodinia

Abstract

Deep seismic reflection images across the late Mesoproterozoic South Delhi Fold Belt (SDFB), NW India, provide evidence for crustal-scale tectonic imbrication and collisional tectonism. An Andean-type margin with eastward subduction of oceanic lithosphere and subsequent collision of volcanic arc with Mewar craton is responsible for the evolution of the SDFB. Contrasting geophysical (particularly the deep seismic and gravity models) and geological signatures found across the SDFB suggest this as a suture, the Phulad Suture Zone (PSZ) with its extension into the Himalaya. Post-collisional delamination and orogenic collapse are responsible for the equilibrated younger Moho and evolution of Malani magmatism in the region. The present study envisages an evolutionary model for the Malani volcanics, unambiguously identifying for the first time the SDFB rocks as their basement. This model successfully resolves the ambiguity by correlating the Marwar Terrain with the Rodinia assembly rather than later Pan-African orogeny located further west. Evolution of the SDFB and Malani magmatism are coeval with the Rodinia assembly and breakup. The South Delhi orogeny, located between the east- and the west-Gondwana fragments, plays an important role for reconstruction of the Gondwana.