ABSTRACT

Paleokarsts developed on most of the several unconformities found in the carbonate sections. The best exposed is at the top of the Redwall Limestone. It developed in late Mississippian times during a regional emergence that subjected the upper part of the unit to a tropical environment. Dolines were abundant, and were laterally interconnected in the subsurface by integrated cave networks. The karst was drained by low-gradient westward-flowing streams that incised valleys into the otherwise flat surface. The depth of karstification increased westward in proportion to the depth of the valleys. A modern analogue is the Floridan karst. With subsidence, Mississippian and Pennsylvanian sediments covered the karst. Burial by several hundred metres of younger Paleozoic and Mesozoic sediments caused significant collapse and cementation. Now the paleokarst is expressed as infilled and buried karst topography at the top of the unit, as extensive karst breccia layers, and as filled or collapsed paleocaves. Most caves in the upper Redwall Limestone are remnants that have been re-excavated a short distance back from the cliff faces, but these are invariably filled in beyond this. Isolated, open cavities within the Redwall paleokarst were nucleation points for numerous breccia pipes that have subsequently developed throughout the region (Wenrich, 1985).