Evidence and models

Professor Tim Naish and the multinational ANDRILL operation team drilled nearly 1,300 m below the Ross Ice Shelf. He explains how examining a sediment core is like pages in a history book.

ANDRILL (Antarctic Geological Drilling) is a multinational collaboration to obtain sediment cores. Drilling back through time can help guide our understanding of future changes.

Transcript

Professor Tim Naish

So, here we have the ANDRILL drill system sitting here on the Ross Ice Shelf. We made a hole 84 metres deep, then we lowered our pipe through the ice shelf and a further 850 metres down to the seafloor. And from there, we drilled back in time – we recovered a geological record 14 million years through sedimentary layers of rock. We got to the bottom of the hole. We had drilled 1,284 metres of core.

The sort of world, if you like the environment, the climate we are moving into, we’ve almost certainly experienced some aspects of before. And that’s captured, if you like, as layers in the sediments that sit under our ocean – that form geological strata – it’s captured in there, and what we are essentially doing with drilling is we are burrowing in, we are burrowing back through time, and you can think of these sedimentary layers like pages of a book. We are turning back the pages of Earth’s history as we burrow back to a window in the past that might represent where we are heading in the next 100, 200, 300 years.

Alex Pyne

We drill 6 metres at a time, and when we’ve drilled 6 metres, we stop, we break the drill string up at the surface, and we run a wire line down with a tool that goes down and picks up another tube inside that’s collected the core, bring that up to the surface.

Professor Tim Naish

We bring up these layers core barrel by core barrel – very laborious. We are bringing back a wealth of information on what the environment was like. How warm the ocean was. What was living in the ocean? What was living on land that got washed into the ocean, like pollen? Where were the ice sheets? Were they grounded on the seafloor? Was there sea ice? Wasn’t there sea ice? All this information is absolutely vital to reconstructing a picture of what our planet looked like at a time, which is probably a very good example of where we are heading to.

Acknowledgements

This video is an extract from Thin Ice – The Inside Story of Climate Science, a David Sington/Simon Lamb film.

The full documentary film is available by emailing thiniceclimate@vuw.ac.nz. The link for streaming is available free of charge. The DVD is also available to New Zealand schools for $20 to cover costs.