Mangere Mountain

Mangere Mountain

We are on the rim of the main crater of Mangere Mountain (eruption about 20,000 years ago), and bang in the middle of the crater is a hump about 12 metres high — a plug of solidified magma (basalt) that was pushed out of the throat of the volcano after the main eruption by mounting pressure from below. Geologists call that a tholoid. The picture of the lagoon was taken from the opposite position on the rim.