TERRACE CHRONOLOGIES OF THE MAUMEE RIVER VALLEY, NW OHIO

Stream terrace morphology, lithology and association with adjacent landforms reflect a regional history of dynamic changes induced by internal forces such as fluctuations in stream discharge and/or sediment load variations plus external forces that might include climatic shifts, isostatic rebound, and/or base level changes. The incipient Maumee River in the western Lake Erie basin emerged as the LIS and its pro-glacial lakes retreated from northwest Ohio. Over the millennia that followed the Maumee carved its way through glacial-lacustrine sediments, till, and eventually into bedrock.

This poster reviews investigations at the lowest terraces of the Maumee River. A complimentary suite of data including sedimentology, geomorphology, and radiocarbon dates is presented that elucidates a refined understanding of stream responses to Late Pleistocene and Early Holocene base level fluctuations in the Lake Erie basin, and other extrinsic forces. At least one abandoned terrace is identified in the lower reaches of the Maumee, paired with an adjacent paleochannel that was subjected to vibracore sampling. Cores reveal modern disturbance and historic period infilling of the paleochannel above coarser sands and channel gravels (i.e., refusal) achieved some 5 meters below the modern surface and 2 meters below the base of the extant paleochannel. The encountered channel gravels are roughly coincident with bedrock elevations present in the current river channel suggesting earlier Holocene paleochannels along this reach of the stream were also bedrock defended. Radiocarbon dates reveal an accelerated rate of infilling of the paleochannel and abandoned landforms was likely induced with the onset of agrarian activities in the mid-19^th century.