Some recent studies have suggested that the phenomenon of Rock Melt Extrusion (RME) observed in the southern part of Peninsular India could be considered as evidence of volcanism. This suggestion raised major concern for the safety of the southernmost nuclear power plant of India located at Kudankulam, Tamil Nadu. As per IAEA guidelines for siting a nuclear facility, the behaviour of volcanic activity, if identified, needs to be considered for an area of 100 km radius. Hence an investigation was carried out to understand the genesis of the RME phenomena in this region. Review of earlier studies indicates that no volcanic rock younger than Deccan Trap volcanism (70–63 Ma) has been reported in the area and also that the area is undergoing compression in the present tectonic set-up. The physical observations support the suggestion that the RME phenomena has resulted from lightning and electrical discharge. For further ascertaining the characteristics of the RME, detailed analyses were carried out on the RME samples. Petrographical observations on the RME samples from Abhishekapatti suggest instant melting and consolidation in soil where bigger grains of quartz were not melted. Geochemical analysis of different portions of RME and the surrounding soil suggests that there is no variation between the two and both are of comparable compositions. The results suggest that the melt was produced instantaneously and has resulted from the superficial melting of soil. The purpose of this article is to make the public aware that the reported incidence of RME in Southern Peninsular India has nothing to do with volcanic activity and is related to lightning and electrical discharge.
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We thank the Director NIRM for his support and encouragement. The authors thank the financial assistance from NPCIL, Mumbai and Director AMD, Hyderabad for conducting sample analysis. Shri Muralidharan, AMD involved in the initial field work for identifying the locations. Shri V. Rajesh, NPCIL assisted the team during field visit.
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John, B., Singh, Y., Rao, D.T. et al. Observation on Rock Melt Extrusion Occurrence in Southern Part of Tamil Nadu. J Geol Soc India 97, 119–124 (2021). https://doi.org/10.1007/s12594-021-1641-2