[IIOE2-EP35] The origin of 85 °E Ridge and its role in the Plate tectonic history of the bay of Bengal

Lead Investigator :

  1. Maria Desa,CSIR-National Institute of Oceanography, Goa, India
     mdesa@nio.org / mdesa939@gmail.com

Other Key participants (s):

  1. Kolluru Krishna, University of Hyderabad,Gachibowli, Hyderabad, India
  2. Manik Talwani, Rice University, USA
  3. Oleg Levchenko ,PP Shirshov Institute of Oceanology, Russian Academy of Sciences, Russia
  4. M Radhakrishna Indian Institute of Technology, Mumbai, India
  5. M IsmaielUniversity of Hyderabad, Gachibowli, Hyderabad,India
  6. G Srinivas Rao Indian School of Mines, Dhanbad

Period of Project: October 2019 to September 2023

Brief description of the Project:

The 85 °E Ridge is a prominent aseismic buried ridge in the Bay of Bengal, Northeastern Indian Ocean possessing a negative gravity anomaly. Several hypothesis have been proposed for the origin of the ridge ranging from continental sliver to abandoned spreading center, volcanic trace etc. The latest explanation by Talwani et al (2016) suggests it is largely a transform fault (fracture zone), but does not explain its extraordinary width nor associated negative gravity anomaly. Further their study is able to characterize the nature of the crust in the Bay of Bengal and onshore Bangladesh. At the same time, Sibuet et al (2016) have offered diverging views about the nature of the crust beneath the northern Bay of Bengal. A major challenge for the plate model that honours thinned continental crust in the Bengal Basin is to provide enough space for the production of ocean floor in the northern Bay of Bengal for the period 123 - 84 Ma whilst keeping other boundary conditions unchanged. To resolve these issues, it is necessary to conduct new seismic refraction and reflection experiments as available refraction/sonobuoy data collected in the 1960s and 70s (Curray et al., 1982) are inadequate to resolve the questions. Solutions for relatively small scale regional tectonic problems like this must be incorporated into the complete plate circuit in order to fully assess their impact.

Region of study:

The region of study is the northern Bay of Bengal, off the East Coast of India.Between 84 °E to 92 °E longitudes and 8 °N to 20 °N latitudes.