Episodes Vol. 44, No. 3 Discussion 349 by Kiran Shanker Misra Comment on “Emplacement history and evolution of the Deccan Volcanic Province, India” by Kale et al. (2020) University of Petroleum and Energy Studies, Dehradun, India; *Corresponding author, E-mail: drksmisra@gmail.com (Received: August 24, 2020; Revised accepted: September 1, 2020) https://doi.org/10.18814/epiiugs/2020/020082 This paper is most welcome as it reviews the chemo-stratigraphic work done in western part of Deccan volcanic province. Significantly it highlights the futility of establishing chemo-stratigraphic units and their long-distance correlation. The paper is also a step forward to remove certain misconceptions such as, the idea of hot spot related volcanism during northerly movement of Indian plate. Furthermore, the authors agree with the (unreferred) series of earlier publications (Misra, 1981, 1999, 2001a, 2004, 2005, 2007, 2008a, 2008c, 2009b, 2013, Misra and Misra, 2010, 2016b), that the volcanism seems to be related with the major rift and grabens. These publications, describe the geological details obtained by extensive field mapping, assisted by aerial photographs and high-resolution satellite images, integrate with the interpretation of aeromagnetic and seismic data sets along with the logs of several hun- dred drill holes. This comprehensive study has enumerated several manifestations of prolonged extensional tectonics in peninsular India. The significant ones are development of rift and grabens, formation of pull-apart sedimentary basins, decompression melting, magma gener- ation, widespread effusion and transportation of lava along with emplace- ment of dyke swarms and dykes. This has also brought out, that in time, the Cretaceous period is conspicuously marked by rampant and spasmodic volcanism in the entire Phanerozoic history of peninsular India. Most important information has come from the subsiding basins, where volcanic units are inter-layered with sediments and form unique volcano-sedimentary succession. This succession is represented by robust fossil record from the beginning to the end of Cretaceous. Since most of these basins are producing hydrocarbons and others have very high perspectivity, they have been explored in detail by innumer- able seismic profiles, profusely drilled and logged by dozens of well site geologists (Fig. 1). The details of these logs, geological interpreta- tions and compilations have been published and are available in public domain (Berger et al., 1983, Jagannathan et al., 1983, Roybarman, 1983, Misra, 2005, 2007, 2008c, 2018, Misra and Misra, 2010, 2013. Raju and Misra, 2009). These drill hole logs have played very significant role in establish- ing the volcanic stratigraphy. Total thickness of volcano-sedimentary sequence, ranges between 250 to 350 m in different basins. Individual volcanic units are 20 to 35 m thick. however, the top most unit, before the end of Cretaceous is thickest and is best exposed in western India and is generally described as Deccan Traps. Since all the units are part of the same package of Cretaceous period, (Misra, 2001a, 2004, 2004b, 2005, 2007, 2008a, 2008b, 2008c) grouped all the units in time and space and described them as Cretaceous volcanics. (Valdiya, 2010) also included all the volcanic outcrops exposed in different regions as Cre- taceous volcanism. Evidences suggest that the lava forming the volcanic units was gen- erated due to successive decompression melting due to down ward propagation of vertical faults and eruption along developing rift and grabens. Room created by effusion of lava caused repeated subsidence and accompanying sedimentation. Cessation of profound extensional tectonics terminated rampant volcanism just before K-T boundary. In sedimentary basins and oceanic regions, the volcano-sedimentary sequence is well recognized by very prominent seismic signatures. Interpreta- tion of innumerable seismic profiles demonstrated not only invariable presence of this sequence (Misra, 2016a, 2018) but also it forms the subsiding re-laid floor over which complete succession of Tertiary rocks has been deposited (Fig. 2). Apart from this, detailed work (Misra, 2008c, Misra and Misra, 2010, 2016b, 2018) has highlighted the significant role played by the volcanism in formation, migration and preferential accumulation of hydrocarbons. During pre-eruption stage the upwelling heat distilled the source sediments, later developing cracks, fractures and inter-con- nected vesicles provided required porosity and permeability for migra- tion and subsequent flows acted as important trapping mechanism by sealing the joints and fractures. Furthermore, these units have gener- ated lot of interest, as they are themselves very good reservoir rocks and prolific producers of hydrocarbons. Padhra and Ingoli fields in Cambay, Raggeshwari in Barmer and Mandapetta in K-G basin are some of the best examples. The other important basins underlain by volcanic units and have giant oil and gas fields, are Barmer on land and Bombay High in offshore region. On land, apart from the Deccan region of Maharashtra, prominent Cretaceous lava units are located in far off regions such as Saurashtra, Kutch and other parts of Gujarat; Malwa and Mandla regions of Mad- hya Pradesh; Rajmahal in West Bengal, Sylhet in Meghalaya, Rajah- mundry in Andhra Pradesh and St. Mary’s island in Karnataka, (Fig. 3). From this distribution pattern it is clear that all these occurrences cannot be explained by the presence of a single hot spot, supposed to have moved linearly from north to south along the west coast of India, crossed over to Arabian Sea and passed through Maldives and Chagos group of islands, jumped over diverging Carlsberg ridge to Reunion island in southern Indian Ocean. Furthermore, to explain the Rajma- hal and volcanic units on the eastern side of Peninsular India, one more