Leigh writes:
Daugaard-Jensen Gletscher
I was speechless and dumbfounded when we entered the northern part of Scoresby Sund. The fog lifted slowly, giving us spectacular views in incremental detail. I can hardly describe our surroundings except to say that it's the type of adrenaline-inducing landscape that simultaneously makes you want to laugh and do pushups and become a better person. Or maybe that's just me.
Studying geology shifts your sense of scale. We work in time scales of millions or billions of years; we calculate the forces needed to fold rocks and move tectonic plates; we detect cm-scale thickness changes in ice sheets that are up to 3 km thick. In a similar way, Scoresby Sund altered my sense of scale. Geology features that I'm used to observing in hand samples took up entire fjord walls. Chevron folds, hinge folds, unconformities, fault scarps, boudins, and anticlines of such grandeur I had only seen in textbooks. Moraines deposited from the Last Glacial Maximum ~20,000 years ago; enormous U-shaped valleys and steep-sided fjords; glacial striations, glacial polish, chattermarks, erratics, p-forms - all evidence of the ice that used to blanket the Greenland coast. We were sailing through textbooks of geological processes - geomorphology, glacial geology, structural geology, sedimentology and oceanography - and I could hardly contain my excitement.
Once anchored, Gordon and I made our first trip out to Daugaard-Jensen Gletscher. Having worked with satellite imagery of the glacier for months, I thought that the terrain would feel familiar to me. It was not at all. Unlike the slow-moving interior of West Antarctica, or the smaller glaciers that I've worked on in Sweden, Norway, Alaska and Washington, the glacier surface was like a sawtooth blade. Daugaard-Jensen Gletscher is one of the largest and fastest glaciers in Greenland. It drains approximately 4% of the ice sheet and moves ~9 m/day (~3.5 km/yr). When the ice moves faster than it can deform, crevasses form. In this case, the glacier surface was so jagged that it was hard to find places to land our small helicopter.
Setting up our first set of GPS units is a blur to me. We were so filled with adrenaline and purposefulness - so focused on safety and efficiency - that we were exhausted by the end of it. We were constantly double-checking things: for our own safety, for the safety of our (expensive) equipment, and for the value of our data. The less time we spent on the glacier surface, the safer we were. Getting out of the helicopter those first few times, I was focused on three things: crevasses, helicopter blades and the data. Crevasses and GPS data I'm accustomed to worrying about...helicopter blades were another thing. To the constant amusement of Huey (our helicopter pilot), I would crouch and run from those blades even when I was nowhere near them.
The hardest part was locating our stakes to resurvey them. In order to calculate the ice velocity, we need to determine the exact position of the stakes at least 20 hours apart. Even though we knew the GPS coordinate of the pole, they were hard to see on the glacier surface. We attached fluorescent green banners and neon orange flags to them, and still had trouble.
Having surveyed 3 glaciers now, Gordon and I are getting more efficient at setting up and taking down our GPS equipment, and I'm getting more used to the helicopter. We've had a number of spectacular days setting up GPS units near perfectly blue meltwater ponds and on seracs overlooking jaw-dropping fjords. Those are the days I've archived in my memory for when I'm back in my office in Maine, typing at 4 am.