THE PROCESS OF LANDFORM DENUDATION AS ILLUSTRATED BY THE EROSION PATTERN OBSERVED IN THE GUERNSEY COUNTY, OHIO

This study is based on a simple hypothesis on the process of landform denudation: the erosion of land follows the existed fracture pattern on the ground. Furthermore, the degree of erosion should be enhanced along tensional fractures than along shear fractures. The western Guernsey County of Ohio, located at the west side of the Appalachian Plateau, is identified as the study area. Besides a quick accessibility, the selected area shows a clear match between the lineation, which is identified on aerial images, and the pattern of valley/ridge distribution. GIS software ArcMap is used to identify and to quantify linear features over the study area. Linear features are traced and measured on SID files of Guernsey County according to: 1. The extension of linear expression, 2. The orientation of valleys and ridges, 3. The width of valleys. Measured data are presented by maps and rose diagrams. Field survey on joint pattern is made at outcrops. Type of joint is determined by the nature of fracture and the attitude of joint. In all outcrops, both tension joints and shear joints are identified. Strikes of joint are plotted on map together with the lineation data.

It is not surprised that our field survey and GIS observation confirmed the hypothesis that the denudation of landform over the studied area has been controlled by the joint type and joint pattern. A critical implication of this study is that the suggested mechanism of landform denudation should also be applied to other areas in the western Appalachian Plateau. If it is true, then the topographic relief over the plateau area should continue to increase with time, and the relief should be significantly higher than what it is observed today. The low-relief landform shown in the Guernsey County does not match the active erosion process, which is illustrated in this study. It is obvious that there are other unidentified factors, that overshadowed the fracture-controlled denudation process.