Mosaic of Deformed Tectonic Blocks in the Central Basin of the Indian Ocean

A detailed map of the seafloor relief of a unique area of the intraplate lithosphere deformation in the Central Basin of the Indian Ocean was constructed for the first time. The data were obtained by a bathymetric survey with the use of a multibeam echosounder during the 42nd cruise of R/V Akademik Boris Petrov and cruise SO258 of R/V Sonne in 2017. The chaotic distribution of deformed hilly rises of an isometric shape and the significant difference in the morphology of all these rises are clearly shown. The new map did not confirm the existing concepts about the corrugated structure of the deformation area as a series of extended E–W undulations (linear ridges and troughs), which were considered to be formed by warping of the lithosphere by the N–S compression of the Indian Plate. The revealed morphology of the seafloor relief testifies to the mosaic-block pattern of the deformation area. This structure is formed by isometric deformed tectonic blocks, the different structure of which is determined by inhomogeneities in the lithosphere of the plate that existed at the time of the deformation.