HIGH-RESOLUTION MAPPING OF SURFICIAL GEOLOGY IN WESTERN KANSAS: AN APPLICATION ALONG THE ARKANSAS RIVER VALLEY CORRIDOR

Historically, the Kansas Geological Survey (KGS) commenced preliminary geologic mapping of western Kansas in the late 19th and early 20th centuries, with most county-level mapping being carried out in the years immediately following World War II. Beginning in the mid-1980s, the KGS initiated a digitally-based program, in cooperation with the U.S. Geological Survey (COGEOMAP and STATEMAP), to conduct high-resolution geologic mapping of county geology to replace these earlier reconnaissance-level maps. Due to groundwater mining for crop irrigation and expansion of agribusiness, one objective of this effort was to map geology of counties along and adjacent to the Arkansas River corridor of western Kansas. Fieldwork, conducted over a 10-year period by W.C. Johnson and graduate research assistants, resulted in geologic maps of eight counties. Regional geology consists of Late Cretaceous shales, chalks, limestones and sandstones; Tertiary alluvium (Ogallala Formation/Group), and an array of Late Quaternary deposits including loess, eolian sand sheets and dunes, playa basin fill, and alluvial fill. The combination of hillshaded DEMs and the geology provides an effective mode of visualization for the geology and associated topography of this corridor.