Thanks to Ian and Farrell at Mangere Mountain Education Centre for sharing their knowledge with 3 parties of Green Bay High School students as they researched surface processes for science 1.13. Walk the present, discover the past.
Students focussed their research on:
- the shape of the scoria cone (steep sided compared with Rangitoto a shield volcano where the molten basalt flowed freely without a high gas content.)
- major landsape features and processes (explosion crater, large southern cone with a smaller cone to the north)
Other landscape features including a breach on the eastern side of the southern cone that allowed basalt to flow freely where the football fields are now. Another minor breach that local Maori had to fortify to prevent incursions by unwelcome guests - Assorted lava bombs and evidence of fire fountaining as volcanic activity waned
- Human impact through stone gardens, kumara pits. There was substantial quarying as durable basalt and scoria were removed for building purposes.
Watch out for some of the features in the video of the field trip.
Untitled from john west on Vimeo.
The basaltic magma is produced 70Km below the surface as the pacific plate is subducted beneath the Australian plate. It gradually makes it way to the surface and it is only a matter of time before another volcano joins 50 others dotted accross the Auckland landscape
Some more on Auckland volcanos
Maori Bay a 17 million year old Auckland volcano….. yep those plates were colliding then!
Lake Pupuke, one of the oldest volcanos in the Auckland field.
Te Henga Bethell’s Beach, evidence for a 20 million year old volcano
A look at the subduction zone responsible for all the volcanic activity in the North Island and the devastating earthquake in Christchurch. Why Tonga has a precarious existence
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