Antarctica is a long way to go to collect a bag of rocks.
But that’s exactly what Australian scientists have done in a bid to measure the impact of climate change on a glacier in East Antarctica.
As part of research partnership Securing Antarctica’s Environmental Future (SAEF), the team from Monash University took their tools to the Browning Peninsula, home of the Vanderford Glacier.
Dr Felicity McCormack said the region which feeds the Vanderford Glacier, known as the Aurora Subglacial Basin, was rapidly thinning and contributing to sea level rise.
“Vanderford Glacier is at substantial risk of rapid retreat as the ocean warms in response to climate change,” Dr McCormack explained.
“A recent study has shown that deep, warm ocean water parcels are making their way into the cavity beneath Vanderford ice shelf, and this could lead to ice shelf thinning as the climate warms.”
This change has scientists wanting to know more about the history of the Vanderford Glacier, but it is rocks, rather than ice that could hold the key.
Stone secrets
Rocks can hitch a lift on glaciers as they move slowly from the interior towards the coast, ripping up the rock beneath.
Glaciers can retreat but they leave the rocks they’ve pushed forward.
Dr Richard Jones said rocks contain chemical isotopes-special types of atoms that are produced in rocks when exposed to the sky and bombarded by cosmic radiation.
“By analysing these isotopes, we can build up a picture of how the Vanderford Glacier has retreated and advanced during past episodes of climate change over the last few thousand years,” Dr Jones said.
This information will help researchers better predict how the Vanderford Glacier will behave in future climates.
Here’s the drill
To seek out the geological clues required, the team used a special ‘rock corer’ to drill into bedrock.
Looking and sounding a little like a jack hammer, it allowed the group to drill into the bedrock to plot the previous path of the Glacier.
The rest of the mission was spent locating the perfect outcrop.
“After taking a few observational measurements, we used an angle grinder and chisels to collect Snickers-bar sized samples of the rocks for analysis,” Dr Jones said.
All up, the haul totalled 130 kilograms from 30 separate sites around the peninsula.
“We occasionally had to carry samples in our backpacks or drag them in sleds, but there was nothing too strenuous!”
Rock review
With the collection complete, the team now has the task of processing the samples in the laboratory.
“First we crush the rock, then we dissolve it, and finally we use some geochemistry wizardry to extract specific isotopes,” Dr Jones said.
“The isotopes measured from these rock samples will be used to determine when Vanderford Glacier retreated and thinned, prior to modern observations, and whether it ever re-advanced over the last few millennia.”
Observations from the field, satellite remote sensing, and ice sheet models will also be used.
This season was the first year of field work for the team, supported by nearby Casey research station and unusually kind Antarctic weather.
“Importantly, we had time to enjoy the breathtaking scenery, beautiful wildlife and stunning views of the incredible Vanderford Glacier,” Dr McCormack said.
SAEF is an Australian Research Council Special Research Initiative.
