MASS WASTING ALONG THE ACCESS ROAD TO THE KOLOB CANYONS SECTION OF ZION NATIONAL PARK, WASHINGTON COUNTY, UTAH

The 8.9 kilometer long access road, which leads from the Kolob Canyons Visitor Center to the Kolob Canyons Viewpoint, crosses several major geologic features. Initially, the road ascends northward, crossing over the main Hurricane Fault Zone. At the junction with Taylor Creek Canyon, the road turns eastward and rests on the north-facing slope of the Taylor Creek Canyon wall, where it follows the drainage in a southeasterly direction. Eastward dipping Triassic and Lower Jurassic sediments that were deformed during the late Cretaceous Sevier Orogenic event underlie both sides of the canyon. This dipping, thrust faulted sequence is buttressed to the east against the nearly horizontal Navajo Formation (670 meters thick). Northward facing canyon walls, where the road lies, have been eroded into an eastward dipping Sandstone-Shale-Gypsum sequences that combine to create an unstable site for the access road. Rates of soil movement along the canyon walls are markedly different—varying with the slope of the hillside combined with the underlying lithology