| Ubehebe Crater | |
|---|---|
 Ubehebe Crater, 2007 | |
| Impact crater/structure | |
| Diameter | 0.5 miles (0.80 km) |
| Depth | 500 to 777 feet (152 to 237 m) |
| Age | 2,000-7,000 years |
| Exposed | Yes |
| Pronunciation | [YOO-bee-HEE-bee] |
| Location | |
| Coordinates | 37°0′35″N117°27′1″W / 37.00972°N 117.45028°W /37.00972; -117.45028 |
| Country |  United States |
| State |  California |
| District | Inyo County |
  Ubehebe Crater | |
Ubehebe Crater (/jubiˈhiːbi/yoo-bee-HEE-bee) is a largevolcanic crater of theUbehebe Craters volcanic field in the northern half ofDeath Valley, inDeath Valley National Park,California, United States.
Ubehebe Crater is located at the north tip of theCottonwood Mountains. The crater is half a mile (one kilometer) wide and 500 to 777 feet (152 to 237 m) deep. The age of the crater is estimated from 2,000 to 7,000 years old.[1]
In 2012, new evidence suggested that the crater may be as young as 800 years old, although this estimation was a lower bound, and it is still possible the crater is much older than that.[2][3][4]
The crater was formed whenmagma migrated close to the surface and the heat of the magma caused groundwater to flash intosteam, throwing large quantities of pulverized old rock and new magma across the stonyalluvial fan draped across the valley floor. The magma rose through a fault that lies along the western base of Tin Mountain. Movement on this fault was responsible for uplift of the entire Cottonwood Mountains range.
Geologists call the resulting large steam explosions hydrovolcanic orphreatic eruption and the pits created are known asmaars. Ubehebe was the last and largest in a series of similar eruptions in the immediate area (its eruption exceeded the tensile strength of the bedrock by 10 times). Earlier eruptions created a group of much shallower maars to the south and another to the west. Little Hebe is aspatter cone that grew in the middle of one of the largest maars in the south group. The only significant deposit of lava in the volcanic field is contained in Little Hebe.
All of the maar-forming eruptions sent out fallout debris that mantled a broad area around the volcanic field (dozens of steam explosions issued from Ubehebe alone). The resulting light to dark gray cinder deposits consist of finely fragmentedvolcanic rock mixed with pulverized bedrock and are thickest immediately next to Ubehebe (80 feet; 24 m).Rills andgullies that were 15-to-20-foot (4.6 to 6.1 m) deep dissected the area prior to the eruptions and were buried by the fallout.Erosion has since re-excavated these features, exposing layers of cinder that still overlay adjacent ridges.
A type ofpyroclastic flow called a base surge was sent out of Ubehebe by one of the explosions. It started after a large column of debris was thrown skyward then began to collapse. Adoughnut-shaped cloud of hot ash and gas (the base surge) speed 100 to 200 mph (160 to 320 km/h) from the base of the column while staying close to the ground, plastering the Ubehebe-facing side of all objects in the area.
Reddish-orangeMioceneconglomerate makes up the exposed bedrock in Ubehebe's walls. Thesesediments were deposited bystreams and containlimestone,mudstone,quartzite and volcanic cobbles that are up to 8 inches (20 cm) in diameter. These seabed sediments are of different colors, yellowish on the left and orange on the right. The reason for the difference is that a fault separates the two sedimentary units. Over time at least 400 feet (120 m) of vertical displacement along this fault has resulted in the abutment of these two different sedimentary units. Fallout debris dip 30 feet (9.1 m) over thefault scarp on the pre-eruption surface but have not been offset by it.
Within Ubehebe small alluvial fans have been built on the crater wall along withtalus slumps fromdebris flows. Whitesilt covers the crater bottom of Ubehebe and some surrounding craters.
There are three major trails at the crater. One trail goes from the parking area to the bottom of Ubehebe, a second circumnavigates the crater rim, while a third trail leads off to Little Hebe.
Winds at the rim of Ubehebe are very strong and often gust above 50 mph (80 km/h). There is no restroom at the site.
