Arches National Park is located in Utah and is known for its unique geologic features. The park is home to over 2,000 natural sandstone arches, as well as many other interesting rock formations. The geology of the area is fascinating, and there is much to learn about the history of the park. Keep reading to learn more about Arches National Park.
The Geology of Arches National Park
The geology of Arches National Park is incredibly diverse, with a wide variety of rocks and landforms on display. The park is located in an area that was once at the bottom of a large sea, and as such, features many types of sedimentary rock. The most common type of rock in the park is sandstone, which has been eroded over time to form the iconic arches and other landforms. Other types of rock found in the park include limestone, shale, and siltstone. The rocks in Arches National Park are incredibly fragile. This makes them susceptible to erosion, which is why so many of the formations in the park are constantly changing. Wind and water have both played a role in shaping the landscape over time, creating unique formations that can be found nowhere else on Earth.
The Formation
Arches National Park is located in Eastern Utah and is known for its over 2,000 natural sandstone arches. The park was first established as a national monument in 1916 and re-designated as a national park in 1971. The geological structures of Arches National Park is dominated by the Entrada Sandstone which was deposited during the Triassic period about 225 million years ago. The Entrada Sandstone forms large domes and erosional features such as arches, fins, spires, and pedestals. Other important rock units in the park include the Dewey Bridge Member of the Morrison Formation (Jurassic), the Salt Valley Member of the Moab Tongue of the Lewis Formation (Cretaceous), and the Navajo Sandstone (Cenozoic).
Shaped by Erosion
The area around Arches National Park has been shaped by wind and water erosion over time. The park is located in a basin that was created by a meteor impact millions of years ago. This basin was then filled with sediment, which was later eroded away, leaving the park’s sandstone formations. The park is also located in an area where the winds are constantly blowing, which helps to erode the rocks. Water also plays a role in erosion, as it can wear away rocks over time.
World-Famous Delicate Arch
The park is dominated by the Entrada Sandstone, which is a local name for the Organ Rock Shale. This sandstone was deposited about 140 million years ago in an epeiric sea that covered parts of Utah and New Mexico. The thickest section of the Entrada Sandstone is in the north-central part of the park, where it reaches up to 600 feet (183 m) in thickness. The Entrada Sandstone is a light pink to buff color and contains numerous fossilized oysters and clams. In some places, such as Delicate Arch and Wolfe Ranch, the Entrada has been eroded into spectacular shapes. The Moab Fault cuts across the park and is responsible for much of the erosion seen today. This fault is a result of the stretching of Earth’s crust that created the Rocky Mountains 15–20 million years ago. The rocks on either side of the fault have moved relative to each other over time, causing them to break and erode away. The Delicate Arch hike is a moderately difficult hike that takes you to one of the most recognizable arches in the world. The arch is 65 feet tall and has a span of 53 feet. The hike is three miles round trip and takes about two hours to complete. The trailhead begins at Wolfe Ranch, which is located six miles from the park visitor center.
Arches National Park is a geological wonderland. The park’s importance cannot be overstated; it is a must-see for people of all ages.
