Hello from the land of perpetual winter! We’ve been in Thule, NW Greenland for about a week and have had a highly successful field season so far. That said, we were also quite surprised by the weather conditions when we arrived: it’s still so wintry! When we landed, we were greeted with snow on the ground, ice on the lakes, and a fjord still filled with sea ice. We’ve had a few spectacular days, but have also seen falling snow several times, including the first two days of July. We even tried to sample rocks in 60-knot winds and horizontal sleet. This is my third trip up to Thule, and is by far the latest spring I’ve seen.
Most of the work we’ve been doing this week has involved looking closely at the landscape for clues about the past. Much of our time has been spent around a lake near Thule Air Base, which has a beautiful series of glacial moraines on one side and a nice set of wave-cut benches on the other. I hypothesize that the glacial moraines were deposited ~10,000-12,000 years ago, during a cold period when fjord-based glaciers re-advanced and covered part of the landscape. The wave-cut benches, on the other hand, likely formed after the last glacial period when the land surface was still depressed from the weight of the over-lying ice sheet and relative sea level was higher. By reading the landscape, mapping interesting features, and examining these features closely, we attempt to reconstruct a sequence of events that happened thousands of years ago!
View of the landscape near Thule, where we’ve spent most of the past week.
In addition to studying landscape features, we also try to determine how old these features are. This helps us to link them with climate events that may have led to their formation. The method I specialize in is called cosmogenic dating, which allows me to determine how long a rock has been exposed since it was last covered by ice. This method makes use of the rare isotope beryllium-10, which builds up slowly in a rock’s surface due to bombardment by cosmic rays. This week we have already collected about 25 boulder samples that will allow us to date the glacial moraines near Thule.
All-star field assistant Everett Lasher (PhD student, Northwestern University) stands with a boulder sample on a glacial moraine.
Since today is the fourth of July, we took the afternoon off and celebrated in true Greenland style. Along with some of the other scientists staying at Thule Air Base, we took a trip to an overlook that provides amazing views of the fjord and the glaciers north of Thule. The aptly named “Secret Place” is a secret worth sharing with friends! Despite the fact that this is my fifth trip to Greenland and my third trip to Thule, I was just as awestruck this afternoon as I ever have been on this very special, icy island.
View from “Secret Place” north of Thule Air Base into Wolstenholme Fjord and towards the Harald Moltke Brae glacier.