Thursday, September 15, 2011, 4:30AM - 5:30AM
Full title of talk: "North American topographic and drainage evolution since the Last Glacial Maximum driven by ice sheet - solid earth interactions." The solid Earth, fluvial system, and climate have been in an interconnected state of change through the last glacial cycle. In North America at the last glacial maximum, ice masses covered much of the continent; as a result of these continental-scale ice sheets, relative sea levels and surface topographies changed dramatically. Drainage basin boundaries moved in response to this changing paleogeography, altering the timing, amount, and location of water discharge to the oceans. I will discuss the components of a self-consistent theory of topographic and sea level change: eustasy, isostatic adjustment, geoid deflection, and true polar wander. These concepts will then be connected to paleogeographic and drainage reconstructions of North America from the last glacial maximum to present, with examples drawn from the Mississippi River and the Bering Strait. Much of our work in understanding the last glacial cycle involves modeling to interpret limited data, so I will also provide a brief introduction to the Community Surface Dynamics Modeling System, an NSF center based at INSTAAR to build a computer modeling framework for Earth surface processes.