A Topographic and Lithologic Analysis of the Kittatinny Ridge and Their Implications for Appalachian Erosional History

The eastern-most ridge of the Appalachian Mountains, Kittatinny Ridge, extends from New York State south to West Virginia. The ridge is composed of erosion-resistant quartzite conglomerate throughout (Shawangunk Formation, Tuscarora Formation) underlain by sandstone, siltstone, slate and shale (Martinsburg Formation, Juniata Formation). The relatively consistent lithology of the Kittatinny Ridge makes it ideal for analyzing how variations in climate, glacial history and other topographic influences have impacted long-term erosion along the ridge. This project analyzed the lithologic consistency and topography of the Kittatinny Ridge at different locations and what geomorphological implications the results might have. Rock samples of the Shawangunk and Tuscarora Formations were collected at various locations along the ridge in New York, New Jersey, Pennsylvania and West Virginia. These samples were tested using a Scanning Electron Microscope (SEM) for bulk composition and porosity to determine erodability. Schmidt hammer measurements were also taken at the various collecting sites to determine rock hardness. River longitudinal profiles and their valley hypsometries were measured to determine long-term erosion amounts along the ridge. This was done using geographic information system (GIS) ArcMap v. 10.1 to delineate the ridge and determine valley and river geometries. One-third arc second digital elevation models (DEMs) were downloaded from the National Map, and standard hydrologic GIS procedures (sinks filled, flow direction determined, flow accumulation calculated, stream networks identified, and watersheds generated) were followed to determine watershed areas and river networks. Analysis of the Shawangunk and Tuscarora samples indicate that they are lithologically similar when compared to other rock types. Northern samples yielded a porosity of 1.15% and southern samples yielded a porosity of 1.67%. Schmidt hammer data revealed that the rock samples of Shawangunk are slightly harder than samples of the Tuscarora. GIS results suggest that there were higher erosion rates along the southern extent of the ridge. River long profiles and hypsometries show differences, with southern watersheds being more concave. This could be from an influence of the ridge’s glacial history, structural differences, or recent topographic rejuvenation from mantle upwelling. There was a data gap between New Jersey and West Virginia where samples were not collected due to distance and time. Future work includes sampling from these missing latitudes along the Kittatinny Ridge