HYDROGEOLOGIC CONCEPTUAL MODEL OF PSEUDO-KARST IN THE GARBER-WELLINGTON FORMATION, OKLAHOMA

Pseudo-karst occurs when non-dissolution processes create structures analogous to traditional karst landscapes. To understand the development of pseudo-karst in Payne County, Oklahoma, the sandstones and siltstones of the Garber-Wellington Formation (GWF) were studied in an area containing a blind valley with an intermittent spring. Electrical Resistivity Imaging (ERI) was applied to evaluate the structure of flow paths leading to spring formation and the development of the blind valley. Electrical data were compared with hydrological data from pressure and EC transducers, providing information about the aquifer and potential microbial activity. Differential GPS was utilized to map the surface features and evaluate hydrologic gradients. The data suggest the variation of groundwater gradients influences discharge from the blind valley. During storm events, the head in the aquifer increases dramatically. This increase causes the intermittent spring to originate from the upward vertical movement of fluids through the fault, instead of from the soil above the bedrock boundary. Conceptualizing the processes that lead to the creation of blind valleys in sandstone will help us better understand the mechanisms of this and other pseudo-karst landscapes, which may include microbial degradation of sandstone cements.