LITHOLOGICAL CONTROLS OF SCALLOPS IN KARST CONDUITS

Erosional features, such as scallops, preserve valuable information on the paleohydrologic conditions forming karst conduits. While these features are commonly used to interpret past conditions, questions about their formation remain. Mathematical models of speleogenesis under a turbulent regime predict that the conditions for forming scallops do not occur in natural carbonate systems. However, scallops are found in caves throughout the world. This conundrum has several possible resolutions, but each lacks field-based observations. We present a field-based study of the environments and controls of scallops in gypsum, limestone, and dolostone caves. Our results are based on field observation, petrography, confocal microscopy, and environmental scanning microscopy. We show that scallops are primarily lithologically controlled, with rock texture and hydrologic conditions acting as second and third-order controls. We will also discuss the erosional processes active in karst conduits and the implications for models of speleogenesis.