Summary: When you think of mountains, you probably think of features that rise topographically high relative to nearby areas, but mountains are just the ‘tip of the iceberg’. Non-volcanic mountains form in regions of thick crust that form during plate tectonic convergence, such as continental collision. If we peer under the mountains, as we can in regions where the roots of ancient mountains have been exposed, we see vast regions of melting and metamorphism that weakened the crust. Weak crust can flow long distances, laterally and vertically, moving crust rapidly (in geologic time) from one region to another. This flow can cause large mountain ranges to collapse and the formerly-thick crust to become very thin. Crustal flow is an important process in the chemical and physical evolution of continents.

Biography: Donna Whitney is from Maine and graduated from Smith College, where she discovered metamorphic petrology. Her PhD is from the University of Washington. After four years as an assistant professor at UNC-Chapel Hill, she was hired by the University of Minnesota in 1997, where she has been ever since. She has been the Head of the School of Earth & Environmental Sciences since 2012. Active field sites (when there isn’t a pandemic) are in the western US, central Australia, New Caledonia, France, Norway, and Turkey. Her husband is also a geology professor at UMN. Their daughter, Naomi (24), is not a geologist, but is nevertheless a wonderful person.