Geological and Historical Development of the Mount Baldy Dune, Indiana Dunes National Park

The Mount Baldy dune has been a subject of study for more than 50 years. Exposures along the lakeward margin of the dune, associated with erosion down-drift of the Michigan City Harbor in the 1980s, provided sedimentologic and stratigraphic information that was used to understand the mid-Holocene to recent development of the Tolleston Beach. Later investigations using newer chronological techniques and subsurface imaging have more firmly established the dune’s geological history and internal architecture. Several investigations focused on a 2013 incident that highlighted potential hazards associated with the development of collapse features resulting from the dune’s migration over an oak forest. This manuscript consolidates all these investigations into a single document, updates the chronological data, and highlights areas of ongoing hazard concern.