Land-Based Ice Retreat

The Boulder Team

The “Boulder Team” consists of Dr. Shaun Marcott, PhD student Elizabeth Ceperley, and Masters student Melissa Reusche all from the University of Wisconsin­Madison, as well as science journalist/mountaineer Dr. Julia Rosen.

hammertime shaun

Early in the trip, we will leave our colleagues on the ship and set up camp on land. The aim of our work is to understand the history of the Petermann Glacier. To do this, the team will sample so-called erratic boulders within the study area for cosmogenic exposure dating. As glaciers advance towards the ocean, the ice engulfs boulders, rock fragments, and sediment that then travel along with it. These fragments melt out of the ice and are left behind as erratics when the glacier retreats. Cosmogenic exposure dating helps us determine when that happened.

Cosmic rays are charged particles from outer space that have enough energy to fragment the nucleus of an atom, which causes rare nuclides to form within the exposed substance. In our case, this substance is rock and the nuclide of interest is beryllium­10.

By measuring the amount of beryllium­10 within a sample, scientists can calculate how long that boulder was exposed to cosmic rays and therefore when it was left behind by the retreating glacier. The Boulder Team can reconstruct the history of ice retreat in this area using these ages, which will give the project scientists a better understanding of how Petermann Glacier reacted to past changes in climate.

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