KARST OF EASTERN WISCONSIN

Evidence of karstification of the Silurian dolostones is abundant in eastern Wisconsin. A wide range of karst landforms have been identified and mapped during studies focusing on groundwater resources. Although extensive, the karst is not well integrated and is in a somewhat immature stage of development in most areas. Feature from small karren through dolines of various sizes to dry valleys have been recognized. Bedrock fractures appear to control the location and orientation of many forms. Continental glaciations have played an important role in the preservation, destruction, and present expression of the features in the landscape. In addition, topographic relief, bedrock lithology, and time are important factors that have influence the type and density of development. Most of the features seem to pre-date the last major glacial advances, however, modification continues and the subsurface drainage systems are becoming more efficient as interface features plugged with drift are opened. Dates have not been obtained from speleoliths or cave decorations and the radiocarbon dates of organic materials from a cave fill are too young to indicate much about the cave origin.