PERIGLACIAL LEGACY OF VERNAL POOLS IN THE RIDGE AND VALLEY PROVINCE OF CENTRAL PENNSYLVANIA
In this project more than 150 shale saddles (potential depression hosts) have been identified through a swath of central Pennsylvania, 94 of which have been visited to confirm the presence or absence of wetlands. Here we present the results of the (ongoing) field surveys, evaluation of remotely sensed imagery and topographic maps, and intensive studies at two centrally located sites that include: standard field soil descriptions, geochemical analyses of the soil columns and cores, and ground penetrating radar surveys. A common characteristic of the depressions is the total absence of boulders or cobbles at the land surface which otherwise mantle the surrounding landscape. These efforts and results have led to the development of a conceptual model for the formation of the wetland depressions as pingo scars that developed during and after the Last Glacial Maximum. The conceptual model may provide a tool for predicting the location of these important features in otherwise obscure landscape positions.