Compression srucures of different scales and strike slip faults within the intraplate deformation zone in the indian ocean lithosphere

摘要

A detailed tectonic map and a schematic of tectonic blocks in the equatorial part of the area of intraplae lithosphere deformations were compiled for the Mid-Indian Basin of the Indian Ocean in the region of the Indira Fracture Zone using the materials of continuous seismic profiling over test areas.A wide distribution of the shear displacements in the deformed sequence is typical of this region.The younger Late Miocene structures of different orders are superim posed on the ancient passive transform faults,locally shifting them.A new type of deformations ("sqeezed blocks") identified hereis represented by complicated folded-faulted linear structures of the east-west orientation ,located between listric faults.Theobserved superposition of large domeshaped rises over the ancient structural pattern may be related to the passibe transverse extensio nof the Indira Fracture Zone under the conditions of a submeridional compression and,partly,to the processes of serpentinization of ultramafic rocks in the lower curst and upper mantle due to the water supply over the faces of numerous faults.