Glacial Weathering
Glaciers and ice sheets are powerful agents of physical erosion that create environmental conditions conducive for chemical weathering of bedrock. Consequently, glacial waters can strongly influence geochemical cycles and nutrient availability as they flow into downstream ecosystems. My research focuses on identifying the dominant chemical weathering reactions beneath ice sheets, assessing the biogeochemical impact of glacial chemical weathering in glacial environments, and searching for records of ice-sheet related chemical weathering in the rock record.
Blood Falls in Taylor Valley, Antarctica, is an example of a highly evolved subglacial water that is rich in rock derived nutrients, most notably iron, which gives it its red color.
Ice Sheets as Weathering Agents
I am working on projects aimed at characterizing the physical and chemical weathering processes in Antarctica. In one effort, we analysed the carbon and oxygen isotopic composition of a large suite (n = 49) of carbonate rocks that formed in Antarctic subglacial waters. These results describe widespread microbial carbon cycling in Antarctic basal waters, which drives both carbonate and silicate weathering beneath the ice sheet. The intensity of this subglacial weathering depends primarily on bedrock type. Read more about this work in our preprint here.
I am also interested in the timescales of ice sheet weathering, and have used uranium-series isotopes as a tracer of physical and chemical weathering in glacial environments. In a project studying sediment from Taylor Valley, Antarctica, we found evidence for active incision of upper Taylor Valley by Taylor Glacier, and extensive chemical weathering of sediment in Taylor Valley. You can read more about this in our recent publication here.