Mount Baldy dune is one of the largest active eolian dunes along the southern shore of Lake Michigan and a famous tourist attraction within the Indiana Dunes National Park. It is an anthropogenically disturbed landform where restoration efforts include native beach-grass plantings and restricted foot traffic. In July 2013, a 6-year-old boy was buried more than 3 m below the dune stoss surface after falling into a hole, or “collapse feature.” While previous work indicated that holes formed through the decay of buried oak trees (Quercus spp.), neither the origin of this hole in relation to the dune’s stratigraphy nor its significance as a potential geological hazard were understood. Groundpenetrating radar, sediment cores, and radiocarbon and optically stimulated luminescence dates were collected to define sedimentary packages and facies, and interpret the dune’s depositional history. The data show that an alongshore migrating coastal dune field stabilized ∼3000 ya atop backbarrier lagoonal deposits. Modern Mount Baldy evolved as sands were mobilized and transported onshore over the relict dune field, triggered by ongoing downdrift coastal erosion related to the development of the Michigan City Harbor. The internal architecture of the dune reveals how the topography of the forested landscape, now buried beneath the modern dune form, contributes to variations in the thickness of the upper dune package, controlling the relation of buried and decayed trees to the surface of the stoss slope. The data on sand thicknesses, were used with maps and aerial photographs to create a geohazard map of the dune.

巴尔迪山沙丘是密歇根湖南岸最大的活跃风成沙丘之一，也是印第安纳沙丘国家公园内的著名旅游景点。这是一个人为干扰的地貌，修复工作包括原生海滩草种植和限制步行交通。2013 年 7 月，一名 6 岁男孩掉入一个洞或“坍塌特征”后，被埋在沙丘表面以下 3 m 以上。虽然之前的工作表明，这些洞是由埋藏的橡树（栎属）腐烂形成的，但无论是这个洞的起源与沙丘地层的关系，还是其作为潜在地质灾害的重要性被理解。收集了探地雷达、沉积物核心、放射性碳和光激发发光数据，以定义沉积包和相，并解释沙丘的沉积历史。数据显示，一个沿海岸迁移的海岸沙丘场在后障泻湖沉积物上稳定了约 3000 年。现代的鲍尔迪山演变为沙子被动员并运送到陆上遗存的沙丘地带，这是由持续的向下漂移引发的与密歇根城港开发相关的海岸侵蚀。沙丘的内部结构揭示了现在掩埋在现代沙丘形式下的森林景观的地形如何导致上沙丘包的厚度变化，控制掩埋和腐烂的树木与斜坡表面的关系. 沙子厚度数据与地图和航空照片一起使用，以创建沙丘的地质灾害图。