ProfTalk: Kelly MacGregor on baby glaciers and looking back in time

By Lily Alexander

Kelly MacGregor is the current chair of the Geology Department. A geomorphologist, MacGregor has focused her work on glaciers and how they shape certain landscapes. She has also studied sediment patterns and dams and she has taught a variety of upper-level and introductory courses. In the past she has collaborated with students in Montana and along the St. Croix River. The Mac Weekly: What is glacial geomorphology? Kelly MacGregor: Geomorphology in general is the study of the evolution of landscapes—looking at and trying to understand the forces that shape the surface of our planet. Glacial geomorphology is basically trying to look at how glaciers and ice sheets erode mountain ranges and create deep valleys and how and why they leave the kind of deposits behind. A good and interesting question in geomorphology would be how were the land forms in Minnesota created and what kind of past climates were required to make Minnesota look the way it does? And how far back do you look in time? Some folks in geomorphology look at the last two million years. So you’re kind of looking at the time period when our planet was in glacial, inter-glacial cycles. That time period is realistic although my work really focuses on what’s going on in the daily to annual time scales. I have a recent project that’s looking at the last 15,000 years of environmental history. What is the focus of your current research? I have a couple of really fun projects right now. I have one project that is in Glacier National Park, Montana. I’ve been out there three times with students over the last several years. In 2010 I took seven students; two of them were Mac students and two of them were students from small liberal arts institutions around the country. I also went with Louisa Bradtmiller, a professor in the Environmental Studies department. And that’s the project where we’re using lake cores: the sediment that accumulates at the bottom of lakes, to look at changes in the environment essentially. The records that we collected are downstream from a glacier called Grinnell Glacier, a famous glacier in Glacier National Park that’s on the eastern side of the continental valley. We’re looking at the lakes that are downstream of this glacier to try to understand basically how the glaciers behaved over the last 15,000 years. We also had students looking at how has modern development in the park affected the lakes themselves. We had two students who completed senior honors theses. One student did a project on fire frequencies. Louisa’s student looked at pollen. She looked at what was the vegetation change in the park in the last thousand years and looked at the medieval warm period and the little ice age. I have a project with Dan Hornbach in the Biology Department and Environmental Studies. Dan has been looking at mussel population in the St. Croix river for the past 20 years. I got involved in this project five years ago because Dan was looking at the sediment, because mussels bury into the sediment. This area on the river below the big dam that has been there for over 100 years had a decline in the number of juvenile mussels of about 90 percent over a 20 year period. It used to be gravel and sand mix and over time it was transitioning to this silt. For me this was very interesting because usually below dams the opposite happens—the fine material actually gets sucked away and the course material is what’s left. [The silt] could be coming from natural variability in the system; it could be coming from development in the basin around the river. Increased construction could lead to increased sediment transport into the river. Or it could be that the dam is sort of filling up with sediment over time and it’s easy for that material to get over the dam. We know they’ve changed the way they operate the dam to be more ecologically friendly but it could mean that that change in operation has actually caused more material to come over. I also have finished a project but am still working on the papers. It’s a project looking at cirque glaciers. They’re these little baby glaciers, which is all that’s left of big glaciers. These are the glaciers that hang out at the tops of the mountain ranges in the US today. There’s a lot of evidence to suggest that they’re pretty important in shaping mountainous landscapes. Understanding how they behave is a really good way to understand how we might link climate and land forms. Is there a lot of mountain climbing and ice climbing involved in your research? It sort of depends on the project. Obviously on the St. Croix River, there’s not as much. But we do expect students to become scuba certified and we do some on-site training. But all of these projects require an incredible amount of physical exertion. We’re also dealing with analytical equipment and gear so they have to be creative in that side of things. We’ve gone over to Vertical Endeavors, the climbing gym, and worked on things like how you traverse a glacier. What are some of the tools you have to use in your research? When I do work on a glacier I bring a wide variety of tools. One thing I bring is GPS equipment. It’s kind of fancier GPS than what you have in your car or a handheld unit. There are these big stations with huge antennas the size of a huge dinner plate. We install a couple of those across the glacier to look at how fast the ice is moving and then we install one on solid rock. So what you’re doing is looking at how fast the ice is moving relative to that rock. I put weather stations up, so meteorological stations. Again there’s always a battery and a solar panel that’s charging the battery because we’ll leave it in the field for weeks or months at a time. I do a lot of monitoring of the streams. We mostly borrow or rent equipment from this laboratory from the University of Minnesota called LacCore. It’s a National Science Foundation sponsored laboratory. Where has your research taken you? The St. Croix River, for sure. The border between Minnesota and Wisconsin is probably the closest research site. I actually do some numerical modeling, so right in my office is where I’ve spent a lot of my time on my computer. That’s not so much the collaborative work with students, that’s more what I’ve done by myself. But Glacier National Park in Montana. British Columbia, so near Golden, British Columbia. It’s not too far from Banff and Jasper National Parks. So that’s where my recent research has been. I’ve worked in Alaska for my PhD. Do you have a favorite mountain range or geographic area? I have to admit I love Glacier National Park, the Northern Rockies. And it’s partly because it’s such a spectacular landscape. I have to admit I just love the mountains. I love alpine environments. Has this been a life-long interest? Yes. Part of the reason I love glaciers so much is that I actually grew up in St. Paul and as a kid our family vacations were always driving out to Montana. It’s a two-day drive through the flatlands of Minnesota and North Dakota and then you hit Montana and it starts to get pretty spectacular and then you hit the Rockies and out of nowhere they just kind of appear. I used to go there as a kid so it’s been a really a pleasure to go back there as a scientist. And also as a parent, I’ve brought my kids out there and had a babysitter help with them while we did research. It’s really been a full circle experience for me. I love those landscapes. Alaska was pretty spectacular too. Has your research revealed dramatic changes in glaciers and landscapes due to climate change? I think the most interesting thing from the college community’s perspective has been this work in Glacial National Park looking at environmental change, documenting that there appears to be evidence of pretty rapid environmental change in the park in certain time periods. There are time periods where it looks like these high alpine systems are immune to the changes we see in flatland environments but other times when it looks like those landscapes are very, very sensitive. It’s not clear exactly where and why that occurs. But just to have the documentati
on that those changes are happening is an interesting contribution. What classes are you teaching right now? So this is my first year as department chair, so I’m only teaching one class right now. And it’s my geomorphology class. It’s probably my favorite class to teach because it’s what I do. I have a geography major in there, a classics major, an environmental studies major, so it’s nice to see a cross-section of people that are interested in the environment of landscapes. Do you take your classes on a lot of field trips? Yeah, we do. And I think that’s kind of a traditional geology department thing. And you know a lot of geologists are really visual learners. There’s a lot of people who do geology that are really into art or are artists and love maps, much like geography. But even more just spending time out in the landscape is important to us. I do a lot of field trips for my lab periods, so we go out and monitor water discharge in Minnehaha creek and we went to a graveyard to look at weathering of rocks and stone, looking at the effect of different rocks on weathering rates. I love doing outings. It’s a great way to have the students see how research works and what kind of opportunities there are in geologic research. It is also a good bonding experience between me and the students. It’s a lot of fun.