Out on the ice

Out on the ice

While the rest of us were enjoying a Kiwi summer, Summer Research Scholarship student Theo Calkin was out on the Ross Ice Shelf investigating the Antarctic ice for clues about the frozen continent’s past. 

Theo Calkin and thesis supervisor DR Gavin Dunbar are all smiles after a successful mission.

“You won’t shower for a month. You’ll be living in a tent, peeing into a bottle, and crapping in a bucket the entire time. And you might not see a single penguin!” My Antarctic experience began with that brutal introduction to the realities of Antarctica fieldwork from three experienced scientists from Te Herenga Waka—Victoria University of Wellington’s world-leading Antarctic Research Centre. Luckily, the fear-mongering chat only put me off the idea of spending my summer on the ice for about five minutes…

In late 2019 I was fortunate enough to spend a month down in Antarctica, mostly operating out of a remote field camp at Kamb Ice Stream, 850 kilometres from Scott Base. We were working to recover cores of soft sediment from the seafloor beneath the Ross Ice Shelf. Alongside sedimentology, the wider field programme incorporated studies of oceanography, microbiology, geothermal heat flux, and the structure of the ice shelf and the rocks beneath it. The hole was also used by a NASA-funded team to deploy an unmanned submarine beneath the ice shelf, which is part of their preparation for developing a robot intended for deployment to Europa, Jupiter’s icy moon.

The hole drilled during fieldwork on the Ross Ice Shelf. It goes down 600 metres!

While any fieldwork in Antarctica is challenging, our main obstacle in recovering seafloor sediments was the physical barrier separating our field camp on the surface, from the seafloor below—about 600 metres of ice, and a further 30 metres of ocean water beneath that. To access the sediments, our drill team melted a hole through the ice shelf with a hot water drilling system.

Once the hole was open, the environment caused several complications. Instruments froze to the side of the hole, and pumps and mechanisms within the instruments also froze in the -2.8°C water and therefore failed to collect data. Fortunately we managed to achieve our sedimentary scientific objective by recovering one lovely 61-cm-long core, along with some other shorter cores.

Field accommodation on a good day. The flat topography extends in every direction.

Once back in New Zealand, we intend to scan the cores to determine the structure of the sediment, which will indicate what the environmental conditions were when it was deposited. We’ll also analyse the geochemistry, microfossil content, and organic content of the core to find out where the sediments come from and how old they are. The results should improve our understanding of how the West Antarctic Ice Sheet has responded to global warming in the past, and may be used to tune computer simulations, which predict how the West Antarctic Ice Sheet will respond to human-caused climate change in the future.

As I sit in Scott Base reflecting on my time and writing this blog, I can’t stop thinking about how lucky I’ve been. It’s been a whale of a time, and though I’ve seen and experienced a lot, I might have to come back again. As predicted, I didn’t manage to see any penguins!

Theo Calkin is studying for a Master’s in Geology with the support of supervisor Dr Gavin Dunbar.

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