CAVES ON PENNSYLVANIA’S GEOHERITAGE LIST

Pennsylvania has a Pennsylvania natural diversity index (PNDI) list which provides some level of protection for the site – if an activity may disturb a site the developer must look for viable alternative. Geologic features are included on this list thanks to the Pennsylvania Geological Survey’s Outstanding Scenic Geological Features of Pennsylvania publications by Geyer and Bolles, 1979 and 1987.

The PNDI list was designed to protect biota. To fit geoheritage sites into the PNDI list, geologists at the Pennsylvania Geological Survey needed to come up with a classification scheme that could fit into a list designed for biota. We divided our geoheritage sites into six broad categories: Hydrodynamic, Geomorphic, Compositional, Tectonic, Earth History, and Cultural and Historical. Primarily, caves on the geoheritage list are classified as Erosional Geomorphic features and are subdivided into Solutional carbonate-rock weathering features and Non-solutional weathering features. But, several caves on the PNI list also have secondary classifications. For example, Harlansburg Cave and the cave on the Barbara Schomer Preserve both include interesting iron minerals due to the iron ore that formed directly over the limestone in which those caves formed. The cave on the Barbara Schomer Preserve was mined for iron ore in the mid 1800’s and thus has historic importance. Passage development in Laurel Caverns was partially controlled by folding and faulting in the Chestnut Ridge Anticline. With including caves on the PNDI list, there are some concerns that we are still working out. For example, caves are not a single point and all the data on the list is shown as point data. Revealing the location of caves can be a safety issue not only for the preservation of the cave and its biology but also for the safety of inexperienced people who may visit the cave. These issues may be addressed by establishing a buffer zone around points designated as caves on the PNDI list.