EARTH CRUST OF THE BRANSFIELD STRAIT BETWEEN ANTARCTIC PENINSULA AND KING GEORGE ISLAND

Abstract

Gravitational modeling along the DSS 1 profile was carried out, which made it possible to obtain the density structure of the lithosphere of Bransfield Strait between the Antarctic Peninsula and King George Island to a depth of 80 km, to clarify the geological structure of the upper part of the crust, obtained as a result of the interpretation of the seismic survey, and draw conclusions on the course of the evolution of the strait in the cross section of the profile. The identical structure of the bowels of King George Island and Trinity Peninsula, together with the inside of the Bransfield Platform, confirm the common origin of these formations. The crust under the Bransfield Trough has a distinct suboceanic type. The structure of the lithosphere of the Bransfield Strait allows us to distinguish three episodes of tectonic-magmatic activity, which manifested themselves in the introduction of the mantle substance into the crust followed by subsidence of the surface as a result of smelting crystallization. Asymmetric spreading can be explained by the fact that the crust growth to the southeast coincides with the rotational movement of the Antarctic Plate in the east direction, and the pressure from the Phoenix Plate prevents growth from the north-west side. The formation of the oceanic crust of the strait occurs in the areas of the crust that successively pass over the fixed mantle astenolite, i.e. the «hot spot» effect is evident.

Keywords

• bransfield strait
• dss-1 profile
• gravity modeling
• structure of the lithosphere