Sandstone arches are formed when large pieces of sandstone flaked off, withered or cut down due to the affect of high current winds. The sandstones which are exposed to such high speed winds forms bridge or arch creating a cavity in the sandstone.
Wind may be involved in the formation of sandstone arches by facilitating erosion which wore away exposed sections of rocks and enlarges the cracks on the surface forming marrow sandstone fins.
Explanation
Sandstone arches can be formed when a large piece of sandstone flaked off as a result of high winds. In addition to that, alternative frost and thawing can result into crumbling of porous sandstone which will in the long run cut through some fins. These resulting holes enlarge to form arches with effects of weathering and rock fall caused by wind.
