GEOMORPHIC RESPONSE TO CONTRASTING LITHOLOGIC SOLUBILITIES OF BEDROCK CHANNELS ON THE BUFFALO NATIONAL RIVER

Recent interest in bedrock channel evolution has led to research addressing controls of sediment cover, rock uplift rates, and contrasting lithologic strengths on erosion processes. Much of the research has been conducted in areas of active tectonically-driven uplift and considers elastic strength as the dominant lithologic control, typically entirely ignoring solubility of bedrock. When channels form in highly soluble rocks, such as limestone, dissolution processes may play an important role. The intent of this study is to develop an understanding of stream geomorphic response to channel bed lithologic characteristics, with a particular focus on rock solubility. Stream channel profiles and widths will be determined using LiDAR data from the Buffalo National River(BNR). LiDAR data is converted into GEOTIFF files in ArcGIS, and stream profiles and channel widths are then extracted using the GeoNet C++ framework developed by Passalacqua et al. 2010. Widths and depths of the reaches will be compared to lithologic characteristics to identify the effect of channel geology on stream geometry. The BNR provides a study area with numerous streams incising through the same lithologies which have contrasting solubilities; this allows for the comparison of multiple streams. Stream properties will be normalized using basin area and statistical comparisons of channel geometry on different lithologies will be conducted. Field work will test the validity of the widths processed from the LiDAR data and collect additional relevant lithologic data such as rock strength and fracture spacing.