Geomorphologic and paleoenvironmental change in Glacier National Park, Montana
What: We will be working on reconstructing past environmental and geomorphic conditions in Glacier National Park through collection and analysis of lake sediment cores. There is broad interest in the future of our National Park system, particularly Glacier National Park, which is sensitive to climate change through glacial retreat and ecosystem adjustments. This research project is aimed at understanding environmental and climate change in a near-pristine alpine basin in North America, and we will collect data that is very relevant to the debate about climate change in the northern Rockies since the Last Glacial Maximum.
When: approximately June 29-July 27 (arrive on June 29, travel July 1-2, GNP reservations July 2-11, travel July 12-13, LacCore labwork July 14-27)
Where: 10-days of fieldwork in Glacier National Park, Montana, plus 2 weeks of labwork at the LacCore lab/Limnological Research Center at the University of Minnesota, Minneapolis. Students will live in the dorms at Macalester College during the lab work portion of the project.
Who: A team of 6 students, Professor Kelly MacGregor from Macalester College, Professor Catherine Riihimaki from Drew University, and 2 lake-coring experts from the Limnological Research Center
Project description and goals
Understanding controls on past climate variability is key to assessing potential future environmental change. There are few lake records from the northern Rockies spanning the entire Holocene and therefore our knowledge of the timing of major climate shifts in the northern Rockies is incomplete. In 2005, we collected several lake cores in Swiftcurrent Lake, and one core from Lake Josephine, lakes that are located downstream of Grinnell Glacier in the Many Glacier region of Glacier National Park, Montana.
In summer 2010, the collection of a series of new cores from Lake Josephine, Lower Grinnell Lake (just upstream), and Fishercap Lake (in the adjacent valley) will help us meet three research goals: 1) test the relationship between climate fluctuations and lake sediment variables, like organic carbon content and charcoal concentrations; 2) enhance our understanding of the connections between lakes within the Grinnell Glacier watershed, and between glacial erosion and downstream lake sedimentation; and 3) assess the human impacts on the watershed through collection and dating of near-surface sediments.
In addition to the millennial timescale questions that can be addressed through lake cores, we are interested in examining recent environmental change in the Many Glacier area. Changes in glacier size, hydrology, ecology, and the human footprint in the Park is relatively well documented, and surface cores (which are easy to collect across a wide area of Swiftcurrent Lake) would provide excellent spatial controls on changing sedimentation in the basin. Coupled with 210Pb dating, this project could offer insights into environmental change in the basin over the last several hundred years.
There are a wide range of possible student projects, depending on the expertise of the students and the lab facilities at their home institutions. Possible projects include:
Lake core analyses
- Several projects could be done on the ~30 meters of core we collected from Swiftcurrent Lake and Lake Josephine in 2005, in the event few cores can be collected during the field season (or if a student or two is interested in the entire Holocene record). Charcoal analysis to constrain fire frequency and history could be done, along with pollen studies and diatom analysis.
- Carbon/Nitrogen ratios: C/N analyses document the source of organic material in lake sediments. A study could build on some analyses done on the 2005 cores to look at the relative importance of algae to terrestrial carbon in the various lakes. Collections of vegetative material (rooted aquatic plants, terrestrial plant, algal aquatic material) would be sampled and analyzed to better constrain the C/N data.
- Analysis of near-surface cores (the top 20-70 cm of sediment) to examine evidence of human impacts on the basin (including the building and renovation of the Many Glacier Hotel), changes in modern/historical sediment transport in a given lake, and/or sedimentation rates and erosional patterns in previously unsampled parts of the Many Glacier region
- Core analyses that would provide key information regarding changes in the lake environments: age models (sampling and analysis using cesium-137 and/or lead-210), color analysis (we have demonstrated this has great potential for quantifying dolomite concentration in Swiftcurrent Lake), grain size analyses, coulometry, and XRD.
GIS bathymetry project
Swiftcurrent and Josephine lakes have not yet been mapped! We will have the equipment (raft and depth sounder) to produce maps of each lake. With bathymetry maps, a student could calculate residence times of water in the system, model sedimentation patterns, model sensitivity of lake level to changing amounts of precipitation, and/or compare lake morphology with other glacial lakes.
We intend to borrow ground-penetrating radar, or more likely near-surface seismic instruments to examine the underlying bedrock morphology in the valley. A project could focus on gathering and interpreting seismic data to map bedrock topography and constrain the thickness of till cover in the area. This data could also help to focus future coring efforts, particularly in Lower Grinnell Lake.
July weather conditions in Glacier National Park can vary dramatically, from near freezing conditions to highs in the 90s, and from sunny weather to downpours. Bringing layers of clothing is key! We will be staying in cabins near our field sites. Wildlife sightings are common, including bears. During lake coring, teams of 3-4 will be on the water for several hours at a time.
Prerequisites are sedimentology and/or geomorphology, with GIS expertise a plus. In addition, the students should have some outdoor experience, comfort with boating, the ability to swim, and the willingness and ability to live in close quarters while we are staying at Glacier National Park. We will be interacting with Park visitors and staff (both formally and informally) during the trip, and will be the ‘face’ of the Keck Consortium in the Park. Maturity and independence, as well as strong oral communication skills are necessary!