Geophysical Journal | 2012 volume 34 5

Paleostructure of the northwestern end of Antarctica and the Bransfield strait evolution

© Yu.V. Kozlenko, M.V. Kozlenko

In order to study evolution of the Bransfield Straight, reconstruction of paleostructure of northwestern extremity of Antarctica has been conducted on the base of analysis of batimetric and seismologic data as well as results of mapping of DSS and GPS observations. As a result of conducted studies the limits of the Earth's crust blocks of the northern extremity of the Antarctic Peninsula, the North Shetland Islands and adjacent water area, which are different by their characteristics and history of development have been found. A scheme has been proposed for the mechanism of formation of up to-date structure of the region. It has been shown that earlier in this region a single geomorphologic mega-structure existed. Expansion of the Earth's crust in the central part of the rift resulted in creation of the passive rift in the western sub-depression. The results obtained testify to the fact that the leading role in formation of the North-Shetland trough was played by the thrust of the South-Shetland block to the Phenix Plate as a result of spreading in the Bransfield Straight. In such a way the concept of arising of this structure as a result of subduction of the Plate Phenix under the Antarctic Peninsula is denied.

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