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    • Keywords


      Southwest continental margin of India; Laccadive Ridge; seaward dipping reflectors; SDRs; gravity model; continent–ocean transition.

    • Abstract


      Multi-channel seismic reflection profiles across the southwest continental margin of India (SWCMI) show presence of westerly dipping seismic reflectors beneath sedimentary strata along the western flank of the Laccadive Ridge –northernmost part of the Chagos –Laccadive Ridge system. Velocity structure, seismic character, 2D gravity model and geographic locations of the dipping reflectors suggest that these reflectors are volcanic in origin, which are interpreted as Seaward Dipping Reflectors (SDRs).

      The SDRs; 15 to 27 km wide overlain by ∼1 km thick sediment; are observed at three locations and characterized by stack of laterally continuous, divergent and off-lapping reflectors. Occurrence of SDRs along western flank of the Laccadive Ridge adjacent to oceanic crust of the Arabian Basin and 2D crustal model deduced from free-air gravity anomaly suggest that they are genetically related to incipient volcanism during separation of Madagascar from India.

      We suggest that (i)SWCMI is a volcanic passive margin developed during India –Madagascar breakup in the Late Cretaceous, and (ii)continent –ocean transition lies at western margin of the Laccadive Ridge, west of feather edge of the SDRs. Occurrence of SDRs on western flank of the Laccadive Ridge and inferred zone of transition from continent to ocean further suggest continental nature of crust of the Laccadive Ridge.

    • Author Affiliations


      K K Ajay1 2 A K Chaubey1 K S Krishna1 D Gopala Rao3 D Sar4

      1. National Institute of Oceanography (CSIR), Dona Paula, Goa 403 004, India.
      2. Present address: Department of Geology, Government College Kottayam, Nattakom 686 013, Kerala, India.
      3. Department of Geology, Osmania University, Hyderabad 500 007, India.
      4. KDMIPE, Oil and Natural Gas Corporation, 9 Kaulagarh Road, Dehradun 248 195, India.
    • Dates

  • Journal of Earth System Science | News

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