PRELIMINARY REPORT OF GEOPHYSICAL AND GEOLOGICAL SURVEYS OFF THE SOUTH ORKNEY ISLANDS, SCOTIA ARC REGION

• Main Authors: シミズ ショウシロウ, モリシマ ヒロシ, タムラ ヤスオ, Shoshiro SHIMIZU, Hiroshi MORISHIMA, Yasuo TAMURA
• Format: Report
• Language: English
• Published: Technology Research Center, Japan National Oil Corporation 1989
• Subjects: Antarctic; West Antarctica; Weddell; South Orkney Islands; Powell Basin; Weddell Basin; Jane Basin; Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2590; http://id.nii.ac.jp/1291/00002590/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2590&item_no=1&attribute_id=18&file_no=1

Geophysical and geological surveys off the South Orkney Islands, West Antarctica, were conducted in Antarctic summer season from 1987 to 1988. The survey area covers the continental shelf, continental rise and the abyssal plain. As a result of the surveys, the presence of four basins was confirmed. Two basins of them, namely, the Powell Basin lying west of the South Orkney Microcontinent, and the Jane Basin east of it, are considered northern extensions of the Weddell Basin. Other two basins are on the South Orkney Microcontinental Shelf. Two seismic depositional sequences and the acoustic basement are identified in seismic reflection patterns. Thickness of the sediment is evaluated as approximately 2km at a maximum. The age of these depositional sequences is estimated to range from Eocene to Quaternary, and the acoustic basement is considered to be pre-Paleogene.