Auckland – West                          Mainly West of Queen Street – seen through my lens

June 19, 2013

Tholoid

Filed under: Mangere,Volcanoes — paul @ 7:15 am
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.

1 Comment

  1. With all that greenery, I would never have thought that this was a crater. Scientists are just amazing.

    Comment by Hilda — June 19, 2013 @ 4:54 pm

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