GEOLOGIC AND PALEONTOLOGIC SIGNIFICANCE OF HISTORIC PHOTOGRAPHS IN BADLANDS NATIONAL PARK, SOUTH DAKOTA

From 1920 through 1923 Harold Rollin Wanless (the father of the second author) took a many photographs of the White River Badlands in South Dakota while working on his doctoral project. These photographs provide an opportunity to study the erosional and depositional changes in Badlands National Park. Prints of Wanless’ images are taken into the field, the sites where the original photographs were taken are found, and the scene is digitally reimaged and recorded. Some landforms show remarkably little change over time while others have had major changes during the past 97 years. Qualitatively this data indicates that erosion of the badlands is primarily along ridge crests. Badland slopes show some retreat, but the individual slope features typically show little change. The flats and drainages at the base of the badlands were eroding in the 1920s, but now these low areas have become areas of sediment accumulation. North-facing slopes in deep canyons show greater erosion than do south-facing slopes. Vegetation at the base of the badland landforms has increased in the park, primarily because of the lack of grazing by livestock. However, the vegetation on landslides during the intervening 97 years show shifts in areas with active surface flow associated with the lack of trees, and areas of more stable landslide surfaces vegetated by junipers.

The original photographs also show places where significant fossils were collected by Wanless and his mentor, William Sinclair. Many of these fossils became type specimens that can now be located precisely both geographically and stratigraphically. These relocated fossil sites provide important historical records for resource managers in Badlands National Park and provenance data for collection managers in museums where these fossils are curated.