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Crust structure and features of the geodynamic evolution of the South Shetland trough and Bransfield Strait (West Antarctica) by geophysical data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 14th EAGE International Conference on Geoinformatics - Theoretical and Applied Aspects, May 2015, Volume 2015, p.1 - 6
Abstract
During Ukrainian Antarctic Expeditions (2006, 2012) new geophysical data for the West Antarctica bottom structures were obtained. The geophysical investigations included the geoelectric methods of forming a short-pulsed electromagnetic field (FSPEF) and vertical electric-resonance sounding (VERS). These methods were used for the crustal structure studying. Detailed geoelectric sections (with depth up to 24–32 km) were constructed for Drake Passage, Scotia Sea and Bransfield Strait tectonic structures as a result of these seasonal works. On the geoelectric models there are the major crustal boundaries and deep crustal heterogeneities. Some specific geoelectric boundaries below the Moho in Drake Passage are given. The occurrence of possible deep high-temperature zones of rocks may reflect the heterogeneity of Passage bottom structures and available processes of tectonic and magmatic activity with the local areas of modern rifting in Bransfield Basin. New hypothesis for geodynamical and evolution processes in Drake Passage and the Bransfield Strait forming is proposed. Data obtained showed that evolution of this region was determined as a result of a hot upper mantle plume upward into the Bransfield Strait crust. The VERS data obtained not confirm the presence of clearly expressed subduction zone at the continental margin of the South Shetland Islands, indicating the important role of thrust movements and extension of Bransfield Basin in the South Shetland Trench forming.