How do solifluction patterns form? A journey through icy, drippy, wavy Arctic hillslopes

 Presented by Dr. Rachel Glade | Assistant Professor of Earth and Environmental Sciences and Assistant Professor of Mechanical Engineering, University of Rochester

Talk Abstract:

Slowly flowing soil in some of the coldest places on Earth produces large scale features called solifluction patterns that strongly resemble a variety of different fluid patterns, like rainwater flowing down window glass or icing dripping down a cake. We found that despite their striking similarity, the physical ingredients needed to form solifluction patterns are distinct from those found in everyday fluids. Perhaps the closest analogous fluid pattern was only recently discovered—waves formed in oobleck (cornstarch mixed with water). This requires unique behavior in which the flow stiffens at the downhill side of bumps, causing a buildup of material behind it and the ultimate formation of waves. Our work, which includes mathematical theory and computer modeling, shows that solifluction patterns form in a similar way due to spatial differences in soil moisture at the front of bumps on the landscape. This demonstrates how patterns in everyday fluids can be compared and contrasted with complex patterns in sediment to better understand how Earth's surface evolves.
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Biography:

Dr. Rachel Glade is a geomorphologist who studies sediment transport and landscape evolution using a combination of fieldwork, experiments, computer modeling, remote sensing, and theory. She received her bachelors degree in Geology from The University of Pennsylvania, her PhD in Geology from The University of Colorado Boulder, and did a postdoc at Los Alamos National Lab. She is currently an Assistant Professor at the University of Rochester with a joint appointment in Earth and Environmental Science and Mechanical Engineering. In 2023 she received the Packard Fellowship for Science and Engineering to make connections between Geomorphology and Soft Matter Physics.