AN INVESTIGATION OF EPIKARST IN THE MUSCATATUCK GROUP (MIDDLE DEVONIAN)

The most recent extension of Interstate 265/Indiana 265, from the Ohio River to Interstate 65, in Clark County, Indiana, has resulted in new exposures of Middle Devonian carbonate rocks (North Vernon Limestone and Jeffersonville Limestone) of the Muscatatuck Group. Within the recently exposed bedrock are vertically oriented joint sets that are partially filled with alluvium or other unconsolidated deposits. The joints truncate vertically at either a glacio-karst pavement surface, a case-hardened surface, or a change in lithology. Current and past literature describes the biostratigraphy of the Muscatatuck Group in detail but does not explicitly discuss or identify epikarst features found in any exposure of the Muscatatuck Group.

The aim of this study is multifaceted: 1) elucidate if a relationship exists between the epikarst and Pleistocene glaciation through sedimentological and geochronological analysis of a suspected allogenic paleosol deposited within the epikarst; 2) if the epikarst does not date to the Quaternary, the study will seek to determine what the age of the features are if they represent paleokarst; 3) determine if epikarst and other karst features are present in unexposed areas of the Muscatatuck Group; 4) determine if paleoenvironmental data are preserved within the paleosol and/or karst infill; 5) identify control(s) of preferential joint enlargement within the carbonate rocks of the Muscatatuck Group.