Aims

Jo in Antarctica in 2006

Today I thought I would write a few words about what science I will be doing when I go to the Lassiter Coast. The essence of my project is to understand how the Antarctic ice sheet has changed in thickness and extent since the Last Glacial Period, which was around 20,000 years ago. That was the peak of the last ice age. We need to know how the ice sheet has changed so that we can make better ice sheet models - they will give us an indication of what the future holds in terms of how much water the Antarctic ice sheet will contribute to global sea level rise over the next 50-100 years. And that will help governments to prepare better for flooding etc.

I will be working along the eastern coast of the Antarctic Peninsula, next to the Ronne Ice Shelf (located where the 'A' of PENINSULA is on this map). Thanks to my colleague, James Smith for this map!

The part of Antarctica I am visiting has rarely been visited, and we know nothing about how thick the ice sheet was in that area in the past. However, we do know how thick the ice is there now, because we have very clever satellites that have collected all this information already. But satellite measurements cannot tell us about the past, and they only began in the 1970s....which is why I am going to look at the rocks!

I am using a technique called 'surface exposure dating' for my work. I have to collect rocks called 'erratics' which have been transported within glaciers and deposited on mountainsides as the ice sheet has thinned and retreated. These are usually easy to spot because they are of a different rock type from the mountain they are lying on (because they have been plucked off mountains much further away and transported in the ice). The picture opposite shows an erratic. Once I have the rocks back in Cambridge, I will do lots of chemistry on them to get out very small amounts of the isotope Beryllium 10. This builds up in the rocks when they are exposed to cosmic radiation (in effect, sunlight), but stops being produced when ice covers them. So the amount of the isotope tells us how long ago the rock was last covered by ice. If we collect rocks from different heights on the mountainside, and measure the amount of the isotope in each of them, we can see how rapidly the ice sheet has thinned through time.

An erratic cobble - the rounded shape shows it has been transported within ice.

This all sounds quite easy, but it is actually very time consuming to do the labwork. And it relies on finding the right kind of rocks in the first place....considering I know very little about my field area, apart from what I can 'see' on satellite images, I have no idea if I will find what I need! We shall see.....this is what being at the cutting-edge of science means!