Summary of Abstract Submission

Abstract Submission No. IO50-08-0012PresentationPoster


Dr. Firoz Badesab*1, Dr. Pawan Dewangan1, Asha Usapkar1, T. Ramprasad1, Aditya Peketi1, Aninda Mazumdar1, Muralidhar Kocherla1

1 CSIR- National Institute of Oceanography, Goa, India


Magnetic minerals are helpful in understanding the primary depositional and secondary diagenetic processes in the marine sediments. Bio-geochemical processes associated with gas hydrate formation leads to the growth and preservation of iron oxides and sulphides which can be easily detected using magnetic measurements. The migration of SMTZ boundaries within sediment column is controlled by sedimentation rates,availability of sulfate, intensity of methane fluxes sourced from deeper sediment layers through episodic methane venting. Hence magnetic enhancement and depletion caused by the detrital and diagenetically altered minerals could provides important clues on paleo-SMTZ boundaries and methane venting events at cold seep sites. The rockmagnetic analysis along with geochemistry and sedimentological analyses were carried out on nearby sediment cores (MD161/8 & NGHP-01-10D) retrieved from a proven cold seep environment in Bay of Bengal. We identified two distinct zones of magnetite enrichments (Zone 1: 30.6 - 45.7 mbsf, Zone-2: 52.2 - 160.4 mbsf). SEM - EDS analysis of the magnetic extracts from this zones shows pyrite coated grains with a possible core of magnetite/greigite in Zone 1 while well preserved Fe- Ti rich oxides are observed in Zone ż 2. The higher susceptibility caused by well preserved detrital Fe- Ti rich minerals within the zone of gas hydrate (Zone ż 2) needs to be investigated further to understand the relationship between the preservation of magnetic minerals in a gas hydrates depositional environment.