Goblin Valley State Park
Photographer: Michael Vanden Berg © 2017
Early morning sun casts shadows on “goblins” formed within the Entrada Sandstone, which consists of sediment deposited 160 million years ago in tidal flats and coastal dunes. Erosion forms the goblins, leaving resistant sandstone boulders perched atop softer siltstone and shale layers that erode more quickly.
A Colorado River ferry operator named Arthur Chaffin created quite a stir more than half-a-century ago in 1949 when, armed solely with his camera, he set off from his cabin in Hite to a remote place in the Utah outback he’d known about for years he called Mushroom Valley.
Named for its thousands of bizarre, goblin-like rock formations, Utah’s Goblin Valley State Park is a hidden gem in the San Rafael Desert. The goblins, known scientifically as “hoodoos,” were formed through the gradual erosion of Entrada sandstone, which was deposited about 170 millions years ago when the area was situated next to an ancient sea.
Goblin Valley State Park • This iconic park and its hundreds of aptly-named rock formations probably didn’t need the kind of worldwide publicity it received after Glenn Tuck Taylor toppled one of its goblins last October.
At Goblin Valley State Park on the southeast side of the San Rafael Swell, morning sun gives Wild Horse Butte an ethereal glow. The butte exposes all four geologic units present in the park: the Entrada Sandstone and Curtis, Summerville, and Morrison Formations. These strata record profound changes in Utah’s geography during Middle and Late Jurassic time, including the existence of coastal sand dunes, inundation by a shallow inland sea, and then uplift, erosion, and sediment deposition in stream channels and flood plains.
Certain rock types weather into curious shapes and patterns by combinations of internal factors such as fractures and sediment grain size and external factors such as frost action and salt crystallization. Sandstone, granite, volcanic rocks, and limestone are all excellent mediums for creating bizarre rockscapes that can include smooth, rounded, and undulating forms (hoodoos or “goblins”), pinnacles, tafoni (holes and small alcoves), and honeycomb structures.
Where horizontal bedding, alternating hard and soft rock layers, and vertical fractures combine, the Entrada Sandstone weathers into rounded, columnar “goblins”.
One of the most photographed geologic formations in Utah if not the world, the Entrada Sandstone is the featured rock unit of Arches National Park, Goblin Valley State Park, Kodachrome Basin State Park, and parts of Glen Canyon National Recreation Area. Variations in the Entrada’s appearance across the state are due to differences in internal structure and composition as well as external stresses.