Diagenetic Arch, Coconino County, Arizona
Photo by Danny Horowitz
NABSQNO 12S-481450-4091330. Diagenetic Arch is an irregular natural arch eroded through an iron concretion embedded in Navajo sandstone. It formed as the result of the coincidental action of two geologic processes not usually associated with each other. This unusual formation mode forces its classification as an irregular natural arch, and also suggested its name. Diagenetic Arch is located above Face Canyon just beyond the extent of Lake Powell, in Coconino County, Arizona. Access is usually by boat, followed by a hike whose length depends critically on lake levels. Vreeland listed Diagenetic Arch as number 23-6 in his catalog and reported a span of 25 feet.