20 Mar 2014

Drilling on Rangitoto Island

From Our Changing World, 9:06 pm on 20 March 2014

Drilling into the lava on Rangitoto Island and checking the cores

The drill rig in place in Rangitoto Island’s southwest, and the drilling team carefully removing a core sample from the drill barrel (images: University of Auckland)

In June last year, University of Auckland geologists Phil Shane and Paul Augustinus told Our Changing World about their research into the volcanic history of Rangitoto Island in the Hauraki Gulf. After analysing sediments from nearby Lake Pupuke, a picture emerged of Rangitoto as both older and far more active than previously believed. It had previously been thought that Rangitoto had emerged only about 500 years ago and had been intermittently active. The lake sediments suggest an age closer to 1500 years with frequent small eruptions and two quite violent eruptions about 500 years ago.

To test this further, this summer the team launched a drilling project on the island to remove and examine core samples. After a week of drilling and at a depth of 110 metres they were just above sea level. Justin Gregory joined them on the island and talked with Phil Shane, Masters student Tamzin Linnell, Elaine Smid and ProDrill’s Chris Hine who was running the drilling operation.

Click here to listen to an Our Changing World interview with Bruce Hayward about his book ‘Volcanoes of Auckland – an essential guide’.

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