Spreading rate dependent seafloor deformation in response to India-Eurasia collision: results of a hydrosweep survey in the Central Indian Ocean basin
Abstract
The nature of magnetic anomalies and associated ridge-parallel structural lineaments and topographic complexities from an area bounded by latitudes 9 degrees 45'S and 14 degrees 45'S in the Central Indian Ocean Basin (CIOB) suggest that the underlying crust was generated from the South East Indian Ridge (SEIR) between 60 and 50 Ma. The multibeam bathymetry reveals intense ridge-parallel flexuring and faulting of the seafloor. The nature and intensity of flexures (amplitude and wavelength), and fault scarps (their ridge-parallel orientation, variable length, and non-uniform spacing) implies a pronounced effect of regional tectonic disturbance. We attribute these variations to variation in the rates of spreading at th eridge crest. In particular, a decrease in the rate of plate accretion around magnetic anomalies 26 and 23 about the SEIR, are reflected in the morphology, distribution, and nature of fault scarps and flexures. These deformations seem to have been by two episodes of collision between India and Eurasia: an initial phase at A26 (approx 58.2 Ma) and a final phase at A23 (approx 51.6 Ma)
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