- Dona Paula, Goa, India.
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Abstract Submission No. | ABS-2022-13-0276 |
Title of Abstract | Rock magnetic properties of short sediment cores from the Carlsberg Ridge. |
Authors | Sambhabana Lenka*, Dr Rajni Magotra, Dr Pratima M. Kessarkar, Dr Lina L. Fernandes |
Organisation | National Institute of Oceanography,Goa |
Address | At-SR/18 Hostel,Nio Colony,Dona Paula,Panjim, Goa,403004 Panjim, Goa, India Pincode: 403004 Mobile: 8917622026 E-mail: lenkasambhabana@gmail.com |
Country | India |
Presentation | Oral |
Abstract | The Carlsberg Ridge (CR) is located in the north-western Indian Ocean. It is a slow-spreading ridge, spreading along the northwest-southeast direction and separates the Indian plate from the Somalian plate. Three spade cores (SC), SC03 of 31 cm, SC04 and SC07 of 38 cm each were collected from the axis valley of the Carlsberg ridge. The sediments were analysed for rock magnetic parameters and CaCO3 content to study changes in the rock magnetic properties at the ridge axis. The colour of the sediment in core SC03 is pale yellowish brown to moderate yellowish brown, in core SC07 colour is dark yellowish brown to moderate yellowish brown whereas, in core SC04 colour is moderate brown throughout the core. The CaCO3 content in the cores ranges between 54.4 and 71.9% with relatively higher values in SC03 as compared to SC04 and SC07. Magnetic susceptibility (Xlf) ranges between 15.1 and 34.5 ÿ 108 m3 kg1 with relatively higher values observed in the core SC04. Down core variations in Xlf and CaCO3 does not show any correlation suggesting carbonate content may not be main controlling factor for changes in the magnetic susceptibility. Down core Xlf variations observed in the spade cores may be result of the changes in contribution of the magnetic minerals and/or the diagenetic processes. The magnetic concentration parameters in core SC03 show higher values between 10 and 20 cm whereas there are no variations in the magnetic grain size parameters. Core SC04 and SC07 exhibit decrease in magnetic concentration parameters down core and increase in the magnetic grain size parameters. The S-ratios are high (>95 %) in all the cores suggesting magnetite to be dominant mineral. |