Ubehebe Crater

Ubehebe Crater. It is a large volcanic maar crater located in the northern part of Death Valley National Park in Inyo County, California. The dramatic, half-mile-wide depression is a prominent geological feature within the Cottonwood Mountains and stands as a testament to the region's relatively recent explosive volcanic activity. The name is derived from a Timbisha word often translated as "big basket in the rock."

Description

Ubehebe Crater presents a stark, bowl-shaped depression approximately 500 feet deep, with its rim rising about 250 feet above the surrounding Racetrack Playa basin. The interior walls expose layered deposits of volcanic ash and fragmented country rock, primarily composed of sedimentary rock from the Paleozoic era. Surrounding the main crater are several smaller maar vents, including **Little Hebe Crater**, which collectively form the **Ubehebe Craters** volcanic field. The site offers dramatic vistas of the surrounding Panamint Range and the vast expanse of Death Valley.

Formation

The crater formed during a **phreatomagmatic eruption**, a violent steam-driven explosion caused when rising **basaltic magma** intersected a shallow aquifer or water-saturated sediments. The instantaneous flash of water to steam created a tremendous explosion, fragmenting the magma and the surrounding bedrock into fine **tephra** and ejecting it from the vent. This process excavated the circular crater and deposited the characteristic low-profile **tuff ring** of mixed ash and rock fragments that encircles the rim. Similar formation mechanisms are observed at other maars like those in the Eifel region of Germany.

Age and eruption history

Recent geological studies, employing **argon–argon dating** techniques, have determined that the Ubehebe Craters are much younger than previously thought. The primary eruptive event that created the main crater occurred approximately 2,100 years ago, during the **Holocene** epoch, making it one of the most recent volcanic events in California. This revised timeline places the eruption potentially within the period of human habitation in the region by groups such as the Timbisha people. The eruption was likely a single, short-lived sequence of explosions.

Geology and composition

The eruptive material at Ubehebe consists of **basaltic** cinders, **volcanic bombs**, and **lithic fragments** of the underlying sedimentary rock, including dolomite and limestone. The deposits are classified as **maar-diatreme** volcanoes. The source magma is believed to have originated from the regional **Basin and Range Province** extensional tectonics. The crater provides a clear cross-sectional view of the pre-existing geology, with the Paleozoic strata sharply juxtaposed against the juvenile volcanic material, offering valuable insights for fields like **volcanology** and **geomorphology**.

Access and tourism

Ubehebe Crater is accessible via a paved spur road off the **Scotty's Castle Road** in Death Valley National Park, maintained by the National Park Service. A parking area at the rim provides direct access to an unguarded trail that circumnavigates the crater's edge, though hiking into the crater is strongly discouraged due to unstable slopes and extreme heat. The site is a popular stop for visitors traveling between landmarks like the **Mesquite Flat Sand Dunes** and **Scotty's Castle**, with informational plaques detailing its geological history. Visitors are cautioned about the extreme desert environment, particularly during summer months.

Category:Volcanic craters of California Category:Death Valley National Park Category:Maars of the United States Category:Inyo County, California Category:Holocene volcanoes