North-Central Section (36th) and Southeastern Section (51st), GSA Joint Annual Meeting (April 3–5, 2002)

Paper No. 0
Presentation Time: 8:00 AM-12:00 PM

KARST AND FLUVIAL CHARACTERISTICS OF KENTUCKY RIVER MEANDER BENDS


MARTIN, Linda and NORDBERG, Viva, Department of Geography, Univ of Kentucky, 1457 Patterson Office Tower, Lexington, KY 40506-0027, lmart2@uky.edu

Observations of meander bends of the Kentucky River indicate that the escarpment edge is a highly active zone of rapid karst and fluvial transformation. The entrenched bends typically have large concentrations of sinks as well as associated swallet and shaft forms emerging with variation in slope as shown by Chi-square analysis of mapped features. Stream ingress into the upland is encouraged by solution at points where the shallow subsurface flow accumulates and causes subsidence near the escarpment lip. The processes seen on the upper meander bends occur as erosion of the inherited karst features occurs. The downcutting of the Kentucky River has encouraged horizontal upland flow to enter shallow vertical pathways through the bluffs. Higher water table levels in the past encouraged solutional development, as indicated by abandoned horizontal conduits opening at fracture-bedding plane junctions in the outcrops, long stretches of bluffs with no surface runoff, and the sink-rich condition of the upper terraces of the river floodplain.