Natural Rock Arches

North Window overlooking Turret Arch at sunrise. Photo by Grant Ordelheide

Standing on the desert floor, looking up at the sheer magnitude of these natural stone bridges, one can’t help but think, I see sky where there should be rock. It seems impossible, absurd even, that something so large, so heavy, and so brittle should be practically floating hundreds of feet in the air. Horizontal pillars in the sky, they evoke an almost primal instinct that the world is very large, and we are very small.

These geological phenomena are formed through a deceivingly simple process of erosion. Water percolates through the cracks in the rock, and in the winter it freezes and expands, cracking and carving bits and pieces of the rock into natural arches. Over millions of years it becomes possible for even such dramatic structures as Kolob Arch, one of the largest arches in the world, to form.

Around 300 million of years ago the entire Colorado plateau was covered by an ancient sea. When it eventually dried up, it left behind unstable salt deposits within the Navajo sandstone that dominates this region. Eventually the salt deposits collapsed under the weight of the sandstone and pushed huge sections of rock upward, while entire sections sunk into the ground. That’s half the story of this rugged terrain; the other being the deftness of nature’s hand on this type of rock. Within a few miles, we find that Navajo sandstone is subtle enough to carve the winding grace of the narrows while strong enough to hold aloft the humbling Court of the Patriarchs.

Utah honored the arch on its centennial license plate in 1996 with the image of Delicate Arch from Arches National Park. Three of its earliest national parks were set aside to protect the state’s arches: Natural Bridges National Monument (1908), Rainbow Bridge National Monument (1910), and Arches National (Monument in 1929) Park (1971).