Carolina Environmental Diversity Explorations
Lonely mountains · By Dirk Frankenberg
The quartzite layers that make up the pinnacle of Pilot Mountain also comprise the erosion-resistant cap rocks of Hanging Rock and the two ridges that separate these pinnacles. This uniformity suggests a common origin of this material, and geologists theorize that all of it was formed when deep crustal rocks were thrust over one another during formation of the Appalachians.
The compression that led to the overthrusting and the overthrusting itself combined to generate enough heat to alter old beach sands. The sand subsequently crystallized into today’s quartzite. The huge forces involved caused the quartzite to fold back on itself like a fold in a rug to create the high crest of horizontal beds that characterize the pinnacles of Pilot Mountain.
The bedding planes of the quartzite further east are not horizontal; rather they are tilted upward to the west. But the somewhat lower ridges of the Sauratowns have tilted bedding planes that are consistent with the idea that layers of rock were deformed into folds during their creation. Figure 7 shows these bedding planes near the crest of Sauratown Mountain.