DIRT-Lab: Earth Surface Processes Research
Geomorphology and Geochemistry research led by Dr. Jean Dixon
The Earth Surface Group studies the chemical and physical evolution of Earth's soils and surface, using a diverse range of geochemical, remote sensing, geophysical, and field methods. In addition to computing lab and field supply space, we have two major lab facilities at MSU.
- Cosmogenic-Radionuclide (CRN) Preparation Facility
- This facility is used to prepare soil and sediment samples for cosmogenic isotope analysis. These rare isotopes serve as clocks that record the time spent near the surface by Earth materials, and can be used to derive soil or landscape erosion rates that average over thousand to million year time scales. This facility includes two processing laboratories, which host acid digestion hoods, laminar flow clean benches, ultrapure water, centrifuges, and high-resolution analytical balance.
- Gamma-Spectroscopy Lab
- This facility includes two high-resolution, broad energy germanium (BEGe) detectors that measure gamma radiation of fallout radionuclides. These isotopes are produced in the atmosphere and deposited at the surface where they can be used to track soil and sediment movement. By measuring their natural radioactivity, we can record soil and sediment processes averaged over the scale of an individual storm event (7Be), a few decades (137Cs), or upwards of a hundred years (210Pb).
Earth Surface Research at Montana State University
Controls on soil formation and sediment movement
Glaciers leave a imprint on the landscape that lasts long after the ice recedes. This topographic forcing influences the erosion and weathering processes that alter bedrock to soil, transfer soils and solutes to stream channels, and transport these sediments and nutrients through the river system.
We are investigating how the topographic imprint of past glaciation drives later landscape evolution and soil formation. Our work studies landscapes at the margin of LGM ice extent to compare and contrast previously glaciated and unglaciated regions of the same mountain belt. Current work is funded by NSF to explore sediment connectivity in the Bitterrroot Basin of Montana.
The influence of climate on chemical weathering rates
Chemical weathering converts bedrock to soil, releases rock-derived nutrients to ecosystems, sequesters atmospheric carbon dioxide over geologic timescales, and plays an integral role in shaping Earth's surface. Understanding the influence of climate (both the magnitude and variability of available moisture and temperature) on chemical weathering remains a fundamental need for our science, but is limited by quantitative data.