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 V. Vijaya Rao a, ⁎, V.G. Krishna b a CSIR-National Geophysical Research Institute, Hyderabad-500007, India b Fashions' Apts., 10-2-267/2, West Marredpally, Secunderabad-500026, India abstract article info Article history: Received 24 August 2012 Received in revised form 7 November 2012 Accepted 30 December 2012 Available online 12 January 2013 Keywords: Deep seismic images South Delhi fold belt Marwar Terrain Collision boundary Phulad Suture Zone Malani magmatism 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. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Convergence of two cratonic blocks (continents or island arcs) leads to subduction of the oceanic crust and its subsequent closing and finally a collision of these cratonic blocks with the formation of an orogenic belt between them. During the process of convergence, Alpine– Himalayan-type collisional orogens or the Pacific-type or Andean-type island arc accretionary orogens are evolved depending on the nature of the lithospheric plates. Convergence and collision of a large number of continental blocks carrying ancient cratons together with accreted terrains have created a single larg3e landmass termed as superconti- nent (Rogers and Santosh, 2004). Collision and accretion of crustal blocks with formation of supercontinent and its subsequent breakup is a fundamental process of continental evolution and occupies a central position in terms of processes of Earth system. A number of superconti- nents are believed to have existed since Paleoproterozoic/Archean. A collisional boundary where the cratonic blocks of independent evolutionary history are stitched together represents the suture. A number of anomalous features exhibiting different physico-chemical and thermo-mechanical properties are developed at the suture zones during the orogenic process. Therefore, various geological/geochemical and geophysical methods are employed to identify the suture zones by mapping their diagnostic properties. Among various geophysical methods, seismic methods are the most effective as they provide high-resolution structural images of the deep crust. Study of the suture zones plays an important role in identifying the metallogenic provinces and seismicity, besides revealing the evolutionary history of a region. The Indian shield consisting of five Archean cratonic blocks with 3.6 Ga age rocks represents one of the oldest parts of the Earth (Fig. 1a). The lithospheric evolution of the Indian shield is intimately related to a large number of orogenic episodes involving these cratonic blocks since the late Archean, and the associated suture zones are now located in the continental interior (Vijaya Rao, 2008). The late Mesoproterozoic oro- genic belts and the associated suture zones of the Indian shield, related to the Rodinia assembly, are shown in Fig. 1a. The orogenic cycle is a two- stage process involving both evolution of collisional orogeny and its sub- sequent collapse due to extension (Dewey, 1988). Collisional suturing is thus usually followed by addition of various types of magma in the form of volcano-plutonic sequences. Thus, a model involving both colli- sional and post-collisional activities provides better constraints to under- stand the lithospheric evolution of a region. In this context, the present study examines both the collisional and post-collisional tectonic features of an orogenic cycle related to the crustal evolution of one of the orogenic belts of the Indian shield, namely the South Delhi Fold Belt (SDFB). Tectonophysics 589 (2013) 172–185 ⁎ Corresponding author. Tel.: +91 40 23434686. E-mail addresses: vijayraov@yahoo.co.in (V. Vijaya Rao), v_gopalak@yahoo.com (V.G. Krishna). 0040-1951/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.tecto.2012.12.041 Contents lists available at SciVerse ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto