Mount Steere

Crary Mountains (76°48′S 117°40′W) are a group of ice-covered volcanoes in Marie Byrd Land, Antarctica. They consist of two or three shield volcanoes, named Mount Rees, Mount Steere and Mount Frakes, which developed during the course of the Miocene and Pliocene and last erupted about 30,000-40,000 years ago. The first two volcanoes are both heavily incised by cirques, while Mount Frakes is better preserved and has a 4 kilometres (2.5 mi) wide caldera at its summit. Boyd Ridge is another part of the mountain range and lies southeast of Mount Frakes; it might be the emergent part of a platform that underlies the mountain range. The volcanoes consist mainly of basalt, trachyte and phonolite in the form of lava flows, scoria and hydrovolcanic formations. Volcanic activity here is linked to the West Antarctic Rift system, which is responsible for the formation of a number of volcanoes in the region. During their existence, the range was affected by glaciation and glacial-volcanic interactions.