• Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/jess/128/06/0158

    • Keywords

       

      Cinder cone morphometry; Harrat al Birk; Asir foreland; DEM; TGDZ; root-plumbing system.

    • Abstract

       

      The Harrat al Birk (HAB) of the alkali basalts of the post-Miocene age erupted through a thick Precambrian crust along the Red Sea coast. The 200 cinder cones scatter within HAB and three distinct Bouguer anomaly zones are identified as the coastal gravity high (CGH), axial gravity low (AGL) and a gravity high further east Jabal As-Sawda gravity high (JSGH). Interpreted satellite imagery for 150 sizeable cinder cones in three gravity anomaly zones (134 (90%) in CGH, 10 (6%) in AGL and 6 (4%) in JSGH) are morphologically analysed. The juvenile cinder cones (age <1 Ma) are characterised by sub-vertical slope angles (<40$^{\circ}$) with a variable average geomorphic slope, 27$^{\circ}$–40$^{\circ}$ in JSGH, 25$^{\circ}$ in AGL and 2$^{\circ}$–15$^{\circ}$ in CGH. The oldest cones of JSGH display a high $H_{\rm{co}}$/$W_{\rm{co}}$ ratio with angular asymmetry at their base angles. The major feeder lineaments/faults are oriented NNW–SSE to NW–SE, and they supply volcanic material to cinder cones within a distance of 2 km. The results, when integrated with geological maps and gravity profiles, provide a probable root-plumbing system of the volcano edifice. HAB is the produce of the volcanic process from the source area in JSGH that hosts the major cinders, where the tertiary gabbroic dyke zone acts as a vertical magma sheet for the cinders.

    • Author Affiliations

       

      Basab Mukhopadhyay1 Manoj Mukhopadhyay2 Eslam Elawadi3 Uday Kumar Ghosh4 Kaushik Pramanik4

      1. Map and Cartography Division, Geological Survey of India, 29 J.L. Nehru Road, Kolkata 700 016, India.
      2. Department of Applied Physics, University of Technology, Lae, Morobe Province, Papua New Guinea.
      3. Deanship of Scientific Research, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia.
      4. PGRS Division, Geological Survey of India, 29 J.L., Nehru Road, Kolkata 700 016, India.
    • Dates

       
  • Journal of Earth System Science | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.