Glaciers

Today we decided to take the opportunity to collect some ice samples from the Tasman Glacier Lake. This lake has been expanding rapidly over the last few years. I took the first photo in 2002. See how much it has changed between then and today! A few days ago there was a huge break-out of ice bergs from the end of the glacier. You can see them in the second photo. We were interested to get hold of some ice that would normally be out of reach deep below the surface, so we hired a boat with the Glacier Explorers and launched off with some insulated sample boxes and ice axes to go berg hunting… It was an eerie feeling chugging slowly amongst the ice bergs, knowing that for every cubic metre of ice that we could see, there was another 9 metres of it under the water, ready to pop up from beneath at any time. Sure enough as we moved past one of the bergs a large chunk peeled off and a huge whale of a lump came surging up from below. Needless to say we got away as fast as we could! When the small tsunami had passed and things looked calm again we went back for a close up look at the ‘deep ice’, and managed to collect a couple of nice chunks to send back to the ice core laboratory freezer. Check out my exciting video of our iceberg adventure! Home to Lower Hutt again tomorrow to start planning the logistics of our ice coring season. My next blog will be in March when I take some students on a glacier science tour of the South Island. I hope you will join me to find out how we get on!

As well as having detailed discussions and poring over maps and images today, we took a ski plane flight to get a close up look at the possibilities. I have flown over the mountains of Aoraki/ Mount Cook National Park many times, but they never fail to impress. Have a look at my Mount Cook Fly-by video that I took as a record for our discussions… You can see how dynamic the glaciers are – being very close to the Tasman Sea the mountains get huge quantities of snowfall. The glaciers cause rapid erosion of the shattered bedrock – hence the quantities of rock debris all over the place. Because of the fast ice movement down steep slopes there are lots of open crevasses – especially as we are at the end of the summer, where a lot of winter snow has melted back. Unfortunately these conditions make it very hard to find good ice core drilling sites which need to be high, stable, flat or dome shaped areas with no crevasses!