GEOLOGIC MAPPING AND STRATIGRAPHIC CHARACTERIZATION OF ALLUVIAL LANDFORMS WITHIN THE LOWER KANSAS RIVER VALLEY: AN UNDERGRADUATE USGS EDMAP EXPERIENCE

The Kansas River valley provides a unique setting for studying river-climate linkages because unlike other Great Plains fluvial systems (i.e., the Platte and Arkansas Rivers), the Kansas River drainage and its tributaries lie entirely within the Great Plains. GIS-based LiDAR, historical maps, and field reconnaissance were used to map river terraces within a 25 km reach of the lower Kansas River valley. Four terraces were mapped: the Menoken, Buck Creek, Newman, and Holliday. Sample sites were established on each terrace and stratigraphy was ascertained through hand augering, machine coring, and Rotosonic drilling (deep machine coring). OSL and AMS ¹⁴C samples were taken at selected sites and used to develop a chronostratigraphy. The Menoken is a highly variable, glaciofluvial terrace that thickens in proximity to the river. The Menoken is ascribed to the Kansan Glaciation, a period of two glacial advances between 600-700 ka. Overlaying the Menoken are eolian dunes winnowed from alluvium that date between 31-36 ka. The Buck Creek is a thick, fine-grain deposit only found in two small localities within the study area and has been previously dated at ~15 ka. The Newman is extensive on the north side of the river valley and consists of a variably thick basal soil that formed between 10-14 ka and overlying Holocene alluvial sediments. The Holliday is late Holocene in age (~4.1 ka), and consists of primarily abandoned meander scrolls and channels.

Terrace mapping results and collected stratigraphic data were integrated into GIS and used to produce various databases and maps including a 3D river valley bedrock map created through Kriging interpolation. New data resulting from this project can be used to provide a modern perspective of the recent geologic history of the region and enhance our understanding of river response to climate change in the Great Plains. This project highlights the importance of 3D mapping in geological research and has implications for future environmental remediation and groundwater modeling, soil remapping and reclassification, and cultural resource management within the lower Kansas River valley.