FOR ROCK CLIMBING, NOT ALL SANDSTONES ARE CREATED EQUAL; AN ANALYSIS OF THE NUTTALL SANDSTONE, NEW RIVER GORGE, WV

The New River Gorge National River (NERI) is known for world class rafting and rock climbing because of the Pennsylvanian Nuttall Sandstone of the Pottsville Group. Large colluviated blocks of Nuttall Sandstone lie in the riverbed, creating rapids and an active whitewater industry. The Nuttall Sandstone also forms 15-30 m high cliffs along the gorge wall in NERI that contain > 1500 documented climbing routes. This project investigates why the Nuttall Sandstone in NERI creates one of the premiere climbing areas in the Eastern U.S. and why the Nuttall Sandstone is climbed instead of other cliff-forming sandstones in the gorge. Outcrop investigations on climbed routes, including rebound hammer determinations, show the Nuttall Sandstone’s competence, surface features, jointing, and bedding are controlling variables on climbing. Presence and absence of features were statistically compared to climbing popularity in order to determine geologic features preferred by “trad” or sport climbers. Thin sections were sampled throughout the Nuttall Sandstone and other sandstones to document petrology as it relates to competence. A 15-20 m interval in the Nuttall Sandstone composed of homogenous quartz arenite that lacks partings along bedding planes is the most desirable stratigraphic interval for expert climbers. Throughout NERI, the Nuttall Sandstone has a basal conglomerate and underlying shale that are less strong and less resistant to weathering than the massively bedded quartz arenite layers. Differential erosion of the basal conglomerate and shale, combined with vertical tectonic joints, leads to large blocks of the Nuttall Sandstone failing in a predictable pattern that creates planar cliff faces and opens joints that provide climbing appeal. Nuttall Sandstone cliffs and blocks may exhibit case hardening and veins of limonite cement along tectonic joints, which add to the rock’s resistant nature. Differential weathering of the veins, and weathering along bedding and other sedimentary structures, have created surface features that affect climbing desirability. Other cliff-forming New River Group units have not been widely developed for expert climbing because they exhibit more heterogeneity and are more thinly bedded, making them less challenging for expert climbers and decreasing competence.