| Abstract Submission No. | ABS-1.2-0066 |
| Title of Abstract | Overview of High-Resolution Marine Geophysical Investigations Along the Central Indian Ridge, Indian Ocean: Segmental Structure and Crustal Variability |
| Authors | KIRANMAI SAMUDRALA* |
| Organisation | CSIR-National Geophysical Research Institute |
| Address | Senior Technical Officer, CSS & Gas Hydrates Building, CSIR-NGRI, Uppal Road Hyderabad, Telangana, India Pincode: 500007 E-mail: kiranmai.ngri@csir.res.in |
| Country | India |
| Presentation | Oral |
| Abstract | A 750 km segment of the Central Indian Ridge (CIR) between 3oS and 11oS has been investigated to understand the processes driving oceanic crust formation and its subsequent evolution, using detailed marine geophysical data. High-resolution multibeam bathymetric mapping has revealed twelve ridge segments and seven distinct ridge-transform intersection (RTI) highs, located at inside-corner tectonic settings. Three of these RTI highs are interpreted as oceanic core complexes or megamullion structures. Magnetic modeling confirms that the CIR is a slow spreading ridge, with full spreading rates ranging from 27 to 38 mm/yr. Magnetic anomalies are traceable up to anomaly 3 across over the past 0-4 Million years. Additionally, gravity data have been analyzed to further characterize the underlying crustal structure. The computed mantle Bouguer anomalies (MBA) and the residual mantle Bouguer anomalies (RMBA) reveal significant variability along ridge segments, which are separated by both transform and non-transform discontinuities. Both transform faults and non-transform discontinuities are characterized by thinner crust. Crustal thickness along the ridge axis, estimated from RMBA, average around 5.23 km. Notably, the longer linear segments L and N exhibit up to crustal thickening of up to 7.8 km towards their centers. Diffuse plate boundaries are broad zones where the effects of plate interaction are complex and the boundaries are not clearly defined. At several locations on the northeastern flank of CIR, deviations from the typical ridge-parallel seafloor fabric have been observed. These anomalies are interpreted as potential indicators of a diffuse plate boundary zone between the India and Capricorn plates, affecting the newly formed ocean floor. Additionally, clusters of higher-magnitude earthquake events (Mw 5 to 9) have been recorded within this divergent deformation zone, further supporting the presence of active tectonic processes in the region. |
| Keywords | Central Indian Ridge; Indian Ocean; Magmatic; Tectonic; Gravity; Magnetics; Multibeam bathymetry; Seismicity |