Abstract

The geomorphic evolution of Mud Creek basin in eastern Iowa, U.S.A. serves to illustrate how geomorphic influences such as sediment supply, valley gradient, climate, and vegetation are recorded in the alluvial stratigraphic record. Sediment supply to the fluvial system increased significantly during the late Wisconsinan through a combination of periglacial erosion and loess accumulation. Subsequent evolution of the Holocene alluvial stratigraphic record reflects long-term routing of the late Wisconsinan sediment through the drainage basin in a series of cut-and-fill cycles whose timing was influenced by hydrologic response to change in climate and vegetation. When viewed in a regional context, the alluvial stratigraphic record appears to reflect a long-term complex response of the fluvial system to increased sediment supply during the late Wisconsinan. Hydrologic and sediment-supply changes accompanying the spread of Euroamerican agriculture to the basin in the 1800s dramatically upset trends in sedimentation and channel behavior established during the Holocene.

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