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    • Keywords


      Deccan Volcanic Province; Malwa Traps; basaltic dyke; $^{40}$Ar/$^{39}$Ar geochronology; fissure fed eruption.

    • Abstract


      The Bhetkheda–Mohana Lineament is traced as a continuous lineament across nearly 100 km in the central Narmada valley across the Deccan Trap basalts and their basement of Proterozoic sediments. While a major length of this lineament is occupied by a basaltic dyke, there are segments where the dyke is completely absent, and the lineament is represented by a regional fracture/shear/fault zone. At its eastern extremity, this dyke is exposed intruding along the axis of a synclinorium of the Vindhyan Supergroup sediments, as a 4-km long string of hillocks of picturesque columnar jointed basalt. It has the presence of ignimbrites and a thin basaltic flow (resting on the sediments) surrounding it, suggesting the presence of an eruptive vent. This dyke intrudes the Mandleshwar Formation lava flows dated at 67–66 Ma and is associated with the Narmada dyke swarm. It has given $^{40}$Ar/$^{39}$Ar age of 66.6±0.5 Ma. Its chemical characters conform to those of the basaltic flows of the Malwa Traps, indicating a common source and emplacement history. This is a unique example of a dyke that was emplaced along a preexisting fracture zone cutting through the Proterozoic basement as well as the Deccan Trap lavas, with a distinct petrological identity with the host lava flows, indicating its feeder relation. It endorses the comparison of the Icelandic mode of fissure-fed flood basalts with the eruptive history of the Deccan Volcanic Province.

    • Author Affiliations



      1. Department of Environmental Science, Savitribai Phule Pune University, Pune 411 007, India.
      2. Department of Earth Sciences, Indian Institute of Technology (B), Powai, Mumbai 400 076, India.
      3. Department of Geology, Fergusson College, Pune 411 004, India.
      4. Advanced Center for Water Resources Development and Management (ACWADAM), Kshipra Society, Pune 411 058, India.
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    • Supplementary Material

  • Journal of Earth System Science | News

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