Description
Water shapes the landscape of the Colorado Plateau more than any other force. Rain erodes the sandstone and carries sediment down washes and canyons to the Colorado River. The sandstone forms rock fins that stick out of the surrounding landscape. A fin is a geologic formation that is a narrow, residual wall of hard sedimentary rock that remains standing after surrounding rock has been eroded away along parallel joints or fractures. Eventually the fins can become arches. Pine Tree Arch is in Arches National Park near Moab, Utah, USA.