Thurston Island is a largely ice-covered, glacially dissected island, 135 nautical miles long and 55 nautical miles wide, lying between Amundsen Sea and Bellingshausen Sea a short way off the northwest end of Ellsworth Land, Antarctica. The island is separated from the mainland by Peacock Sound, which is occupied by the west portion of Abbot Ice S…Thurston Island is a largely ice-covered, glacially dissected island, 135 nautical miles long and 55 nautical miles wide, lying between Amundsen Sea and Bellingshausen Sea a short way off the northwest end of Ellsworth Land, Antarctica. The island is separated from the mainland by Peacock Sound, which is occupied by the west portion of Abbot Ice Shelf.