Lithofacies and eruptive conditions of the southernmost volcanoes in the world (87° S)

Abstract Neogene volcanic centres are uncommon in the Transantarctic Mountains but at least three basaltic examples occur within 300 km of South Pole, above 2200 m asl and inland margin West Antarctic Rift System. They southernmost volcanoes on Earth have yielded Early—mid Miocene isotopic ages. Two centres, Mt Early Sheridan Bluff, been examined. The centre is unequivocally glaciovolcanic. It formed a tall monogenetic edifice 1 high > 1.5 diameter. erupted under significantly thicker-than-modern ice, which was probably fast-moving ice stream eruptive site resulted distinctive constructive architecture lithofacies. first described example glaciovolcano beneath an stream. characteristics second Bluff indicate that it also volcano with shield-like profile, originally c. 6 basal diameter just 400 high. substantial pluvial lake ice-poor or ice-free environment. strongly contrasting settings now identified by sequences both examined testify to highly dynamic Ice Sheet during Miocene.