LITHOLOGIC COMPOSITION OF THREE STUDY SITES IN THE UPPER MISSISSIPPI RIVER VALLEY: SEDIMENT PROVENANCE, CHARACTERISTICS, AND CORRELATION

Very little research has focused on the formation of channel islands in the Upper Mississippi River (UMR). However, understanding the deposition and composition of these islands is important for identifying the nature of sedimentation on a vital waterway, as well as for gaining insight into the geomorphology of fluvial processes. UMR sediment is a product of its tributaries and thus reflects each tributary's sedimentary composition. This project analyzes bed-load deposits from multiple tributaries of the UMR so that their mineralogical “fingerprints” can be determined in order to identify the provenance of sediments in downstream islands. Five sediment cores were extracted from three locations in the UMR valley, two of which were removed with a Geoprobe®. Additionally, bed-load deposits were sampled from the main channel of the UMR at Rock Island, Illinois and from the Rock, Wisconsin, and Chippewa Rivers along with the UMR headwaters and some lesser tributaries. Two separate islands in the UMR proper near the Quad Cities were chosen for core-drilling, and an additional core was taken on the shore of the Rock River in Moline, Illinois. Sediment size analysis and relative mineralogies of samples from within these cores will yield information on depositional processes and provenance of the island sediments. Grain fractions of 1 Φ and coarser were isolated to compare the lithologic characteristics of deposits between core sites and to match them with the mineralogical provenance from a UMR tributary or tributaries that have contributed the most to island deposition.