Monday, November 5, 2007

Field trip to the Mackay Glacier

A couple of days ago we completed our tasks for the day a little early so our chief scientist, Dr. Ross Powell, took us on a field trip out to see the Mackay Glacier up close. Our seismic survey is mapping sediment deposited by the Mackay and this was a great opportunity to understand the depositional process better. To get there from our camp we had to take a very bumpy, 45 min. Pisten Bully ride over multi-year ice. Our camp and survey line are located on single season ice, which means the ice breaks up and flows out to sea every season. That can be a little dangerous as the season goes on, but the ice is fairly smooth and easy to travel over. The multi-season ice is not smooth, at all!!!!

[Note that there was a movie that should be inserted here, but it is too large to insert - Ed.)

Once we had our brains unrattled (which isn’t really a word, but I’m exercising artistic license) we were amazed to find ourselves dwarfed by ice.The Mackay is an outlet glacier from the east Antarctic ice sheet flowing from a high mountain plateau. It ends as a tongue that sticks out onto the sea ice. The forward edge of the tongue shoves the sea ice ahead of it, creating sea ice chunks that often stand vertically reminding me of sculptural works.
In those areas melt pools form this time of year and are great places to find seals. Around the edges of the melt pools delicate ice crystals form. You do have to watch where you step in these areas to make sure you don’t fall into a crack. Some can be fairly deep,but Galen the mountaineer/field safety specialist makes sure we don’t get into trouble.
As the glacier makes its way to the sea, it flows over and through granite and dolerite formations. The sea ice gets shoved up against the cliff sides causing great undulations.
The younger, darker dolerite sits on top of the older, lighter color granite.
Jacob, a student from University of Nebraska, was very excited to examine the crystalline structure of this boulder up close.
As we walked through one of the glaciers canyons, we spotted pockets of clear ice that form when melt water within the glacier refreezes.
If you look closely you can see some sediment trapped in the clear ice. These sediments are carried out to sea and as the glacier melts, drop to the sea floor creating sediment layers that show up in the seismic survey data.
Some members of our party in the distance behind me were trying to find clear ice without sediment to bring back to camp to cool their beverages. I’m not sure why they need ice when you can just stick drinks outside for a couple of minutes! But then, how many times in your life can you say you’ve eaten ice that’s thousands of years old.

1 comment:

Laurie said...

Hey J Dooley! Saw your class notes post on RIT newsletter and thought I would check out what you are up too. This is the opposite weather of where I now live [Ft Lauderdale FL] but seems like what we endured at RIT in the early 80's...LOL

Stay safe and warm...I will be checking out you blog regularly

Laurie Davis
RIT Class of 83