2026 CSDMS meeting-062
From CSDMS
(if you haven't already)
Log in (or create account for non-CSDMS members)
Forgot username? Search or email:CSDMSweb@colorado.edu
Browse abstracts
An (over-) simplified model of sinkhole plain development near multistory cave systems in dipping rocks
Dylan Ward,
University of Cincinnati Cincinnati Ohio, United States. dylan.ward@uc.edu
Rai Bosch, AECOM Cincinnati Ohio, United States. Rachel.Bosch@aecom.com
Levels in multi-level caves are often inferred to result from periods of stability of the base level river, such that larger and longer passages have more time to develop near the water table, or from changes in rock solubility as the base level river incises through layered stratigraphy. At Mammoth Cave, USA, cave passages that drain to the Green River are connected hydrologically along dipping bedding planes to the cuesta bench of the Dripping Springs Escarpment, which is retreating down dip toward the river. This escarpment is capped by chemically resistant and relatively impermeable sandstone. The cuesta bench (i.e., the sinkhole plain) hosts only dissected, deranged fluvial catchments that each drain to one of thousands of sinkholes connected through karst conduits under the cuesta escarpment to the Green River. Recent cosmogenic data suggest a reduced lowering rate for the sinkhole plain relative to incision of the Green River.
Here we use simple analytic and numerical models to explore the dynamics of base level history, phreatic conduit growth, and their interactions with cuesta-bench sinkhole plains. Across a series of incision and stability periods, the model tracks the position of the dip-projection of base level to the surface, the position of the cuesta escarpment, and the expected length of conduit development during periods of base level stability. As the base level river in the model lowers, the fluvially-connected cuesta bench lowers at the same rate, and the cuesta escarpment retreats toward the river. If base level becomes stable for long enough, growing karst conduits break through and create efficient drainage of the bench through the subsurface. At this time, the model erosion rate on the bench is decreased as the surface streams become disconnected from each other and from base level. The reduced erosion rate of the bench increases its relief above base level and slows cuesta retreat. If a period of subsequent incision is long enough, the fluvial network recaptures the elevated karst region, and erosion rates on the bench catch up with base level lowering. The outcomes of these dynamics are path-dependent, such that the timing of connection of one cave level to the bench influences the likelihood and timing of future episodes of connection, and dictates the specific periods over which a sinkhole plain forms.
 |
