INTERPRETING CONTROLS ON PROCESSES OF CAVE FORMATION IN ENTERABLE AND NON-ENTERABLE PASSAGES IN POMPEY'S CAVE, ULSTER CO., NEW YORK

Pompey’s Cave is the longest solution cave in Ulster Co., NY. Formed along Kripplebush Creek, a tributary of the Rondout Creek that displays flashy discharge especially during spring snow-melt events, the cave has readily accessible multiple upstream insurgencies, enterable large passages that display multiple processes of cave formation, an intermittently dry streambed that overlies the main cave passage with multiple mid-cave entrances, and multiple downstream resurgencies at differing elevations. During very high-discharge events on Kripplebush Creek the entire cave floods and the creek also flows overland.

The cave is formed through an anticline in the Upper Silurian Rondout Formation, with the main passage oriented along the axis. Near the middle of the cave is a restriction that has resulted in differing processes of cave formation between the upstream and downstream sections. Downstream the cave is formed primarily of major trunk passage with a few small side passages. Upstream the cave has a primary trunk passage; however there are many small, interconnecting side passages. This difference is interpreted to be the result of pressurized solution in the upstream portions of the cave during high stream-flow events due to the mid-cave restriction.

The downstream end of the passage ends in a sump which has yet to be explored and is ~100 m from the primary resurgencies. Ground Penetrating Radar (GPR) exploration near the resurgencies indicates the existence of some large passages within a meter of the ground surface. Although it is not possible to determine precise cross-sections, it is possible to see that the passages are several meters wide with solution features extending upwards into the ceiling. These ceiling features are interpreted to be the result of pressurized backflooding as seen in the upstream portions of the cave. The GPR trace also suggests that the passages do not take a straight-line path from the sump to the resurgencies, but probably continue along N-S fracture some distance before cutting across. In this case, GPR has allowed us the opportunity to interpret processes of cave formation in as yet unentered cave passage.