Claim: Mount Haddington formed during the Miocene and Pliocene epochs and it has had subglacial eruptions which formed tuyas but recent eruptions produced tuff cones on its slopes.
Evidence: Haddington formed along the Larsen Rift dominantly during the Miocene and Pliocene epochs but more recent eruptions have produced tuff cones on its slopes. It is 60 km (37 mi) wide and has had numerous subglacial eruptions throughout its history, forming many tuyas. The youngest tuff cones and pyroclastic cones on the eastern slope are situated below the summit icecap and may have formed in the last few thousand years.