Early research indicated that most of Mount Takahe formed underneath the ice, but more detailed field studies concluded that most of the volcano developed above the ice surface. The ice surface has fluctuated over the life of Mount Takahe, explaining why units originally emplaced under ice or water now lie above the ice surface and alternate with lava flow deposits. These elevated deposits were emplaced about 29,000-12,000years ago while the lava delta-like deposits are between about 70,000and 15,000years old. After it grew out of the ice, Mount Takahe increased in size through the emission of lava flows with occasional pyroclastic eruptions. Outcrops in the summit region indicate that most eruptions were magmatic, but some hydromagmatic activity occurred. Cinder cones and tuff cones formed during the late stage of activity.