Ubehebe Crater is a large

volcanic crater A volcanic crater is an approximately circular depression in the ground caused by Volcano, volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During Types of volcanic eruptions, volcanic eruptions, molten magm ...

of the

Ubehebe Craters The Ubehebe Craters are a volcanic field in the northern Death Valley of California, consisting of 14–16 volcanic crater, craters in a area. The largest of the craters is the wide and deep Ubehebe Crater. Many of the craters, though, are par ...

volcanic field in the northern half of

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...

, in

Death Valley National Park Death Valley National Park is an American national park that straddles the California–Nevada border, east of the Sierra Nevada. The park boundaries include Death Valley, the northern section of Panamint Valley, the southern section of Eureka ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, United States.

Geography

Ubehebe Crater (pronounced YOO-bee-HEE-bee) is located at the north tip of the Cottonwood Mountains. The crater is half a mile (one kilometer) wide and deep. The age of the crater is estimated from 2,000 to 7,000 years old. 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's still possible the crater is much older than that.In Death Valley, ancient volcano gives scientists a surprise
Christian Science Monitor, January 24, 2012

Geology

The crater was formed when

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

migrated close to the surface and the heat of the magma caused groundwater to flash into

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

, throwing large quantities of pulverized old rock and new magma across the stony

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...

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.

Eruptions

Geologists call the resulting large steam explosions hydrovolcanic or

phreatic eruption A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evapo ...

and the pits created are known as

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

s. 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 a

spatter cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

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 fragmented

volcanic rock Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic r ...

mixed with pulverized bedrock and are thickest immediately next to Ubehebe ().

Rill In hillslope geomorphology, a rill is a shallow channel (no more than a few inches/decimeters deep) cut into soil by the erosive action of flowing surface water. Similar but smaller incised channels are known as microrills; larger incised ch ...

s and

gullies A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble lar ...

that were deep dissected the area prior to the eruptions and were buried by the fallout.

Erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

has since re-excavated these features, exposing layers of cinder that still overlay adjacent ridges. A type of

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of bu ...

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. A

doughnut A doughnut or donut () is a type of food made from leavened fried dough. It is popular in many countries and is prepared in various forms as a sweet snack that can be homemade or purchased in bakeries, supermarkets, food stalls, and franc ...

-shaped cloud of hot ash and gas (the base surge) speed from the base of the column while staying close to the ground, plastering the Ubehebe-facing side of all objects in the area.

Sediments

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

-aged mostly reddish orange-colored conglomerate makes up the exposed bedrock in Ubehebe's walls. These

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

s were deposited by

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...

s and contain

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tect ...

and volcanic cobbles that are up to in diameter. There is also a difference in color between these seabed sediments: On the left these sediments are yellowish in hue while on the right they are orange. The reason is due to a fault that separates the two different sedimentary units; over time at least of vertical displacement along this fault has resulted in the abutment of these two different sedimentary units. Fallout debris dip over the

fault scarp A fault scarp is a small step or offset on the ground surface where one side of a fault has moved vertically with respect to the other. It is the topographic expression of faulting attributed to the displacement of the land surface by movement al ...

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 with talus slumps from

debris flow Debris flows are geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. They generally ...

s. White

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...

covers the crater bottom of Ubehebe and some surrounding craters.

Visiting

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 .

References