Driving into Arches National Park from nearby Moab, my first impression was; "I've never seen so much red rock in one place before, but where are the arches?" You don't see any upon entering the park but there are over 2,000 documented natural stone arches in addition to soaring fins, pinnacles and massive balanced rocks.
Arches National Park has the greatest concentration of natural stone arches on earth. To form stone arches requires a perfect combination of sandstone, rain, time and stable earth. Not all sandstone is the same. Arches National Park, made up of Entrada Sandstone, was once a massive desert made up of shifting dunes of fine grained sand. The grains are spherical and, when packed together with calcite, form a very porous rock. The park receives 8-10 inches of precipitation a year. That's the perfect amount to keep eroding the rock over time. The water easily seeps into the Estrada Sandstone and slowly dissolves the calcite bond, rotting the rock from the inside out. Rock that started out as huge domes of sand eventually erodes into arches. The earth in the region is very stable. Otherwise the fragile rock formations would crumble. The fact there are over 2,000 arches tells us that there have been relatively few earthquakes in Arches National Park for at least 50,000 years.
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.
Delicate Arch is a 65-foot (20 m) tall Entrada Sandstone arch. It is the most iconic landmark in Arches National Park and is depicted on the Utah state license plates and on a postage stamp commemorating Utah's centennial anniversary of statehood in 1996. To find out more about the iconic Delicate Arch, go to my Hiking to Delicate Arch blog.
Arches usually form slowly, but sometimes large changes happen suddenly. In 1940, a boulder fell out of Skyline Arch, roughly doubling the size of the opening. The arch now has a span of 71 feet and a height of almost 34 feet.
Landscape Arch is a 306 foot span of sandstone that has slowly been eroding away for centuries. On September 1, 1991 a 60 foot long slab of the rock peeled away, leaving 180 tons of rock debris below the arch. Landscape Arch is in the Devil's Garden area of the park.
The forces of erosion shape more than just the many fins and arches. Balanced Rock is an example of the various layers of rock that seem to defy gravity. The top boulder is hard Entrada Sandstone perched on a pedestal of mudstone. The overall height of Balanced Rock is 128 feet and the boulder alone weighs 3500 tons. Eventually erosion and gravity will cause this delicate formation to collapse.
Fiery Furnace is a maze with long rows of fins and canyons. This is an environment of sheer walls, exposed cliffs and narrow passages. Within this maze there are many rare plants and fragile soils. For these reasons, hiking within the area is either ranger-led or by special permit.
President Herbert Hoover established Arches National Monument on April 12, 1929. Since then, the park boundary has been extended several times. In 1971, the United States Congress passed a bill that changed the national monument into Arches National Park.
Arches National Park has the greatest concentration of natural stone arches on earth. To form stone arches requires a perfect combination of sandstone, rain, time and stable earth. Not all sandstone is the same. Arches National Park, made up of Entrada Sandstone, was once a massive desert made up of shifting dunes of fine grained sand. The grains are spherical and, when packed together with calcite, form a very porous rock. The park receives 8-10 inches of precipitation a year. That's the perfect amount to keep eroding the rock over time. The water easily seeps into the Estrada Sandstone and slowly dissolves the calcite bond, rotting the rock from the inside out. Rock that started out as huge domes of sand eventually erodes into arches. The earth in the region is very stable. Otherwise the fragile rock formations would crumble. The fact there are over 2,000 arches tells us that there have been relatively few earthquakes in Arches National Park for at least 50,000 years.
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.
Delicate Arch is a 65-foot (20 m) tall Entrada Sandstone arch. It is the most iconic landmark in Arches National Park and is depicted on the Utah state license plates and on a postage stamp commemorating Utah's centennial anniversary of statehood in 1996. To find out more about the iconic Delicate Arch, go to my Hiking to Delicate Arch blog.
Arches usually form slowly, but sometimes large changes happen suddenly. In 1940, a boulder fell out of Skyline Arch, roughly doubling the size of the opening. The arch now has a span of 71 feet and a height of almost 34 feet.
Landscape Arch is a 306 foot span of sandstone that has slowly been eroding away for centuries. On September 1, 1991 a 60 foot long slab of the rock peeled away, leaving 180 tons of rock debris below the arch. Landscape Arch is in the Devil's Garden area of the park.
The forces of erosion shape more than just the many fins and arches. Balanced Rock is an example of the various layers of rock that seem to defy gravity. The top boulder is hard Entrada Sandstone perched on a pedestal of mudstone. The overall height of Balanced Rock is 128 feet and the boulder alone weighs 3500 tons. Eventually erosion and gravity will cause this delicate formation to collapse.
Fiery Furnace is a maze with long rows of fins and canyons. This is an environment of sheer walls, exposed cliffs and narrow passages. Within this maze there are many rare plants and fragile soils. For these reasons, hiking within the area is either ranger-led or by special permit.
President Herbert Hoover established Arches National Monument on April 12, 1929. Since then, the park boundary has been extended several times. In 1971, the United States Congress passed a bill that changed the national monument into Arches National Park.
This gallery contains some of my favorite Arches National Park images that are available as downloads and fine art prints. To view the gallery, click here or on the photo collage above. When you are in the gallery, click on a thumbnail to enlarge an image. To navigate the images click on the arrows. To see the captions click on the (i) symbol.
