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136-566: The original performance was conducted by Grofe with the Hollywood Bowl Symphony on December 3, 1949 in the Desolation Canyon area of Death Valley National Monument (now Death Valley National Park ). The music was used in the background as a procession of covered wagons entered the area. Actor James Stewart narrated the pageant celebration. The 1949 pageant was attended by 65,000 people. The movements are titled: The total length

272-583: A national monument in and around Death Valley on February 11, 1933, setting aside almost two million acres (8,100 km ) of southeastern California and small parts of Nevada. The Civilian Conservation Corps (CCC) developed infrastructure in Death Valley National Monument during the Great Depression and on into the early 1940s. The CCC built barracks, graded 500 miles (800 km) of roads, installed water and telephone lines, and

408-500: A reflexive verb . The lower plate itself is the subject. It subducts, in the sense of retreat, or removes itself, and while doing so, is the "subducting plate". Moreover, the word slab is specifically attached to the "subducting plate", even though in English the upper plate is just as much of a slab. The upper plate is left hanging, so to speak. To express it geology must switch to a different verb, typically to override . The upper plate,

544-406: A consequence of the rigidity of the plate. The point where the slab begins to plunge downwards is marked by an oceanic trench . Oceanic trenches are the deepest parts of the ocean floor. Beyond the trench is the forearc portion of the overriding plate. Depending on sedimentation rates, the forearc may include an accretionary wedge of sediments scraped off the subducting slab and accreted to

680-460: A larger portion of Earth's crust to deform in a more brittle fashion than it would in a normal geothermal gradient setting. Because earthquakes can occur only when a rock is deforming in a brittle fashion, subduction zones can cause large earthquakes. If such a quake causes rapid deformation of the sea floor, there is potential for tsunamis . The largest tsunami ever recorded happened due to a mega-thrust earthquake on December 26, 2004 . The earthquake

816-457: A minimum estimate of how far the continent has subducted. The results show at least a minimum of 229 kilometers of subduction of the northern Australian continental plate. Another example may be the continued northward motion of India, which is subducting beneath Asia. The collision between the two continents initiated around 50 my ago, but is still active. Oceanic-Oceanic plate subduction zones comprise roughly 40% of all subduction zone margins on

952-460: A point of no return. Sections of crustal or intraoceanic arc crust greater than 15 km (9.3 mi) in thickness or oceanic plateau greater than 30 km (19 mi) in thickness can disrupt subduction. However, island arcs subducted end-on may cause only local disruption, while an arc arriving parallel to the zone can shut it down. This has happened with the Ontong Java Plateau and

1088-471: A series of minerals in these slabs such as serpentine can be stable at different pressures within the slab geotherms, and may transport significant amount of water into the Earth's interior. As plates sink and heat up, released fluids can trigger seismicity and induce melting within the subducted plate and in the overlying mantle wedge. This type of melting selectively concentrates volatiles and transports them into

1224-513: A short series of prospecting mines failed to yield evidence of significant ore (these mines now dot the entire area and are a significant hazard to anyone who enters them). The boom towns which sprang up around these mines flourished during the first decade of the 1900s, but soon declined after the Panic of 1907 . The first documented tourist facilities in Death Valley were a set of tent houses built in

1360-411: A steeper angle is characterized by the formation of back-arc basins . According to the theory of plate tectonics , the Earth's lithosphere , its rigid outer shell, is broken into sixteen larger tectonic plates and several smaller plates. These plates are in slow motion, due mostly to the pull force of subducting lithosphere. Sinking lithosphere at subduction zones are a part of convection cells in

1496-537: A total of 76 buildings. Trails in the Panamint Range were built to points of scenic interest, and an adobe village, laundry and trading post were constructed for the Timbisha Shoshone Tribe . Five campgrounds, restrooms, an airplane landing field and picnic facilities were also built. The creation of the monument resulted in a temporary closing of the lands to prospecting and mining. However, Death Valley

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1632-510: A zone of shortening and crustal thickening in which there may be extensive folding and thrust faulting . If the angle of subduction steepens or rolls back, the upper plate lithosphere will be put in tension instead, often producing a back-arc basin . The arc-trench complex is the surface expression of a much deeper structure. Though not directly accessible, the deeper portions can be studied using geophysics and geochemistry . Subduction zones are defined by an inclined zone of earthquakes ,

1768-418: Is "consumed", which happens the geological moment the lower plate slips under, even though it may persist for some time until its remelting and dissipation. In this conceptual model, plate is continually being used up. The identity of the subject, the consumer, or agent of consumption, is left unstated. Some sources accept this subject-object construct. Geology makes to subduct into an intransitive verb and

1904-523: Is 9b with an average annual extreme minimum temperature of 28.0 °F (−2.2 °C). Death Valley is the hottest and driest place in North America due to its lack of surface water and low relief. It is so frequently the hottest spot in the United States that many tabulations of the highest daily temperatures in the country omit Death Valley as a matter of course. On the afternoon of July 10, 1913,

2040-456: Is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second plate, the heavier plate dives beneath the other and sinks into the mantle. A region where this process occurs is known as a subduction zone , and its surface expression

2176-499: Is accreted to (scraped off) the continent, resulting in exotic terranes . The collision of this oceanic material causes crustal thickening and mountain-building. The accreted material is often referred to as an accretionary wedge or prism. These accretionary wedges can be associated with ophiolites (uplifted ocean crust consisting of sediments, pillow basalts, sheeted dykes, gabbro, and peridotite). Subduction may also cause orogeny without bringing in oceanic material that accretes to

2312-506: Is approximately 17 minutes. Ferde Grofé was commissioned by the California State Centennial Commission and the Death Valley '49ers to write the suite for the 1949 California Centennial Pageant. Background on history, pageant pictures, and pageant advertising can be seen at the following links: Death Valley National Park Death Valley National Park is a national park of the United States that straddles

2448-457: Is available, an abundance of vegetation is usually present. These zones and the adjacent desert support a variety of wildlife species , including 51 species of native mammals , 307 species of birds , 36 species of reptiles , 3 species of amphibians , and 2 species of native fish . Small mammals are more numerous than large mammals, such as bighorn sheep , coyotes , bobcats , kit foxes , cougars , and mule deer . Mule deer are present in

2584-625: Is being withdrawn. The highest range within the park is the Panamint Range, with Telescope Peak being its highest point at 11,049 feet (3,368 m). The Death Valley region is a transitional zone in the northernmost part of the Mojave Desert and consists of five mountain ranges removed from the Pacific Ocean. Three of these are significant barriers: the Sierra Nevada , the Argus Range , and

2720-488: Is characterized by low geothermal gradients and the associated formation of high-pressure low-temperature rocks such as eclogite and blueschist . Likewise, rock assemblages called ophiolites , associated with modern-style subduction, also indicate such conditions. Eclogite xenoliths found in the North China Craton provide evidence that modern-style subduction occurred at least as early as 1.8  Ga ago in

2856-493: Is driven mostly by the negative buoyancy of the dense subducting lithosphere. The down-going slab sinks into the mantle largely under its own weight. Earthquakes are common along subduction zones, and fluids released by the subducting plate trigger volcanism in the overriding plate. If the subducting plate sinks at a shallow angle, the overriding plate develops a belt of deformation characterized by crustal thickening, mountain building , and metamorphism . Subduction at

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2992-444: Is fairly well understood, the process by which subduction is initiated remains a matter of discussion and continuing study. Subduction can begin spontaneously if the denser oceanic lithosphere can founder and sink beneath the adjacent oceanic or continental lithosphere through vertical forcing only; alternatively, existing plate motions can induce new subduction zones by horizontally forcing the oceanic lithosphere to rupture and sink into

3128-593: Is found behind the Aleutian Trench subduction zone in Alaska. Volcanoes that occur above subduction zones, such as Mount St. Helens , Mount Etna , and Mount Fuji , lie approximately one hundred kilometers from the trench in arcuate chains called volcanic arcs . Plutons, like Half Dome in Yosemite National Park, generally form 10–50 km below the volcanoes within the volcanic arcs and are only visible on

3264-536: Is known about the history of the oldest exposed rocks in the area due to extensive metamorphism (alteration of rock by heat and pressure). Radiometric dating gives an age of 1,700 million years for the metamorphism during the Proterozoic . About 1,400 million years ago a mass of granite now in the Panamint Range intruded this complex. Uplift later exposed these rocks to nearly 500 million years of erosion. The Proterozoic sedimentary formations of

3400-447: Is known as an arc-trench complex . The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with rates of convergence as high as 11 cm/year. Subduction is possible because the cold and rigid oceanic lithosphere is slightly denser than the underlying asthenosphere , the hot, ductile layer in the upper mantle . Once initiated, stable subduction

3536-477: Is more buoyant and as a result will rise into the lithosphere, where it forms large magma chambers called diapirs. Some of the magma will make it to the surface of the crust where it will form volcanoes and, if eruptive on earth's surface, will produce andesitic lava. Magma that remains in the lithosphere long enough will cool and form plutonic rocks such as diorite, granodiorite, and sometimes granite. The arc magmatism occurs one hundred to two hundred kilometers from

3672-411: Is old, goes down the subduction zone. As this happens, metamorphic reactions increase the density of the continental crustal rocks, which leads to less buoyancy. One study of the active Banda arc-continent collision claims that by unstacking the layers of rock that once covered the continental basement, but are now thrust over one another in the orogenic wedge, and measuring how long they are, can provide

3808-689: Is ongoing beneath part of the Andes , causing segmentation of the Andean Volcanic Belt into four zones. The flat-slab subduction in northern Peru and the Norte Chico region of Chile is believed to be the result of the subduction of two buoyant aseismic ridges, the Nazca Ridge and the Juan Fernández Ridge , respectively. Around Taitao Peninsula flat-slab subduction is attributed to the subduction of

3944-562: Is the largest national park in the contiguous United States , as well as the hottest, driest and lowest of all the national parks in the United States. It contains Badwater Basin , the second-lowest point in the Western Hemisphere and lowest in North America at 282 feet (86 m) below sea level. More than 93% of the park is a designated wilderness area . The park is home to many species of plants and animals which have adapted to

4080-545: Is the second-lowest depression in the Western Hemisphere (behind Laguna del Carbón in Argentina ), while Mount Whitney , only 85 miles (137 km) to the west, rises to 14,505 feet (4,421 m) and is the tallest mountain in the contiguous United States . This topographic relief is the greatest elevation gradient in the contiguous United States and is the terminus point of the Great Basin 's southwestern drainage. Although

4216-588: 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 Valley and most of Saline Valley . The park occupies an interface zone between the arid Great Basin and Mojave deserts, protecting the northwest corner of the Mojave Desert and its diverse environment of salt-flats , sand dunes , badlands , valleys, canyons and mountains. Death Valley

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4352-519: The Cascade Volcanic Arc , that form along the coast of continents. Island arcs (intraoceanic or primitive arcs) are produced by the subduction of oceanic lithosphere beneath another oceanic lithosphere (ocean-ocean subduction) while continental arcs (Andean arcs) form during the subduction of oceanic lithosphere beneath a continental lithosphere (ocean-continent subduction). An example of a volcanic arc having both island and continental arc sections

4488-698: The Chile Rise , a spreading ridge . The Laramide Orogeny in the Rocky Mountains of the United States is attributed to flat-slab subduction. During this orogeny, a broad volcanic gap appeared at the southwestern margin of North America, and deformation occurred much farther inland; it was during this time that the basement -cored mountain ranges of Colorado, Utah, Wyoming, South Dakota, and New Mexico came into being. The most massive subduction zone earthquakes, so-called "megaquakes", have been found to occur in flat-slab subduction zones. Although stable subduction

4624-538: The Ediacara fauna and trilobites , the evolution of the latter being part of the Cambrian Explosion of life. The sandy mudflats gave way about 550 million years ago to a carbonate platform (similar to the one around the present-day Bahamas ), which lasted for the next 300 million years of Paleozoic time (refer to the middle of the timescale image ). Death Valley's position was then within ten or twenty degrees of

4760-621: The Nevares Spring People , were hunters and gatherers who arrived in the area perhaps 9,000 years ago (7000 BC) when there were still small lakes in Death Valley and neighboring Panamint Valley. A much milder climate persisted at that time, and large game animals were still plentiful. By 5,000 years ago (3000 BC) the Mesquite Flat People displaced the Nevares Spring People. Around 2,000 years ago

4896-619: The Old Spanish Trail . Called the Bennett-Arcane Party , they were unable to find a pass out of the valley for weeks; they were able to find fresh water at various springs in the area, but were forced to eat several of their oxen to survive. They used the wood of their wagons to cook the meat and make jerky. The place where they did this is today referred to as "Burnt Wagons Camp" and is located near Stovepipe Wells. After abandoning their wagons, they eventually were able to hike out of

5032-472: The Owens River . The large lake that covered much of Death Valley's floor, which geologists call Lake Manly , started to dry up 10,500 years ago. Salt pans and playas were created as ice age glaciers retreated, thus drastically reducing the lakes' water source. Only faint shorelines are left. Habitat varies from salt pan at 282 feet (86 m) below sea level to the sub-alpine conditions found on

5168-513: The Pacific plate along the San Andreas Fault (west of the region), is responsible for the lateral movement. Igneous activity associated with this stretching occurred from 12 million to 4 million years ago. Sedimentation is concentrated in valleys (basins) from material eroded from adjacent ranges. The amount of sediment deposited has roughly kept up with this subsidence, resulting in

5304-541: The Pahrump Group were deposited on these basement rocks. This occurred following uplift and erosion of any earlier sediments from the Proterozoic basement rocks. The Pahrump is composed of arkose conglomerate (quartz clasts in a concrete-like matrix) and mudstone in its lower part, followed by dolomite from carbonate banks topped by algal mats as stromatolites , and finished with basin-filling sediment derived from

5440-621: The Paleoproterozoic Era . The eclogite itself was produced by oceanic subduction during the assembly of supercontinents at about 1.9–2.0 Ga. Blueschist is a rock typical for present-day subduction settings. The absence of blueschist older than Neoproterozoic reflects more magnesium-rich compositions of Earth's oceanic crust during that period. These more magnesium-rich rocks metamorphose into greenschist at conditions when modern oceanic crust rocks metamorphose into blueschist. The ancient magnesium-rich rocks mean that Earth's mantle

5576-534: The Saratoga Spring People moved into the area, which by then was probably already a hot, dry desert. This culture was more advanced at hunting and gathering and was skillful at handcrafts. They also left mysterious stone patterns in the valley. One thousand years ago, the nomadic Timbisha (formerly called Shoshone and also known as Panamint or Koso) moved into the area and hunted game and gathered mesquite beans along with pinyon pine nuts. Because of

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5712-538: The Timbisha around 1000 AD who migrated between winter camps in the valleys and summer grounds in the mountains. A group of European-Americans, lost in the valley in 1849 while looking for a shortcut to the gold fields of California , gave this valley its grim name, even though only one of their group died there. Several short-lived boom towns sprang up during the late 19th and early 20th centuries to mine gold and silver. The only long-term profitable ore to be mined

5848-624: The United States Weather Bureau recorded a high temperature of 134 °F (57 °C) at Greenland Ranch (now Furnace Creek ) in Death Valley. This temperature stands as the highest ambient air temperature ever recorded at the surface of the Earth. (A report of a temperature of 58 °C (136 °F) recorded in Libya in 1922 was later determined to be inaccurate.) Daily summer temperatures of 120 °F (49 °C) or greater are common, as well as below freezing nightly temperatures in

5984-484: The Vitiaz Trench . Subduction zones host a unique variety of rock types created by the high-pressure, low-temperature conditions a subducting slab encounters during its descent. The metamorphic conditions the slab passes through in this process create and destroy water bearing (hydrous) mineral phases, releasing water into the mantle. This water lowers the melting point of mantle rock, initiating melting. Understanding

6120-533: The Wadati–Benioff zone , that dips away from the trench and extends down below the volcanic arc to the 660-kilometer discontinuity . Subduction zone earthquakes occur at greater depths (up to 600 km (370 mi)) than elsewhere on Earth (typically less than 20 km (12 mi) depth); such deep earthquakes may be driven by deep phase transformations , thermal runaway , or dehydration embrittlement . Seismic tomography shows that some slabs can penetrate

6256-406: The core–mantle boundary . Here the slabs are heated up by the ambient heat and are not detected anymore ~300 Myr after subduction. Orogeny is the process of mountain building. Subducting plates can lead to orogeny by bringing oceanic islands, oceanic plateaus, sediments and passive continental margins to convergent margins. The material often does not subduct with the rest of the plate but instead

6392-411: The lower mantle and sink clear to the core–mantle boundary . Here the residue of the slabs may eventually heat enough to rise back to the surface as mantle plumes . Subduction typically occurs at a moderately steep angle by the time it is beneath the volcanic arc. However, anomalous shallower angles of subduction are known to exist as well as some that are extremely steep. Flat-slab subduction

6528-416: The zeolite , prehnite-pumpellyite, blueschist , and eclogite facies stability zones of subducted oceanic crust. Zeolite and prehnite-pumpellyite facies assemblages may or may not be present, thus the onset of metamorphism may only be marked by blueschist facies conditions. Subducting slabs are composed of basaltic crust topped with pelagic sediments ; however, the pelagic sediments may be accreted onto

6664-520: The 1920s where Stovepipe Wells is now located. People flocked to resorts built around natural springs thought to have curative and restorative properties. In 1927, Pacific Coast Borax turned the crew quarters of its Furnace Creek Ranch into a resort, creating the Furnace Creek Inn and resort. The spring at Furnace Creek was harnessed to develop the resort, and as the water was diverted, the surrounding marshes and wetlands started to shrink. Soon

6800-501: The Alaskan crust. The concept of subduction would play a role in the development of the plate tectonics theory. First geologic attestations of the "subduct" words date to 1970, In ordinary English to subduct , or to subduce (from Latin subducere , "to lead away") are transitive verbs requiring a subject to perform an action on an object not itself, here the lower plate, which has then been subducted ("removed"). The geological term

6936-584: The Alps. The chemistry of the inclusions supports the existence of a carbon-rich fluid in that environment, and additional chemical measurements of lower pressure and temperature facies in the same tectonic complex support a model for carbon dissolution (rather than decarbonation) as a means of carbon transport. Elastic strain caused by plate convergence in subduction zones produces at least three types of earthquakes. These are deep earthquakes, megathrust earthquakes, and outer rise earthquakes. Deep earthquakes happen within

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7072-504: The Furnace Creek Formation is the primary source of borate minerals gathered from Death Valley's playas. Other visitors stayed to prospect for and mine deposits of copper , gold , lead , and silver . These sporadic mining ventures were hampered by their remote location and the harsh desert environment. In December 1903, two men from Ballarat were prospecting for silver. One was an out-of-work Irish miner named Jack Keane and

7208-546: The Paleozoic equator . Thick beds of carbonate-rich sediments were periodically interrupted by periods of emergence. Although details of geography varied during this immense interval of time, a north-northeastern coastline trend generally ran from Arizona up through Utah . The resulting eight formations and one group are 20,000 feet (6 km) thick and underlay much of the Cottonwood, Funeral, Grapevine, and Panamint ranges. In

7344-526: The Panamint Range were on top of rocks that would become the Black Mountains and the Cottonwood Mountains. Lateral and vertical transport of these blocks was accomplished by movement on normal faults . Right-lateral movement along strike-slip faults that run parallel to and at the base of the ranges also helped to develop the area. Torsional forces, probably associated with northwesterly movement of

7480-509: The Panamint Range. Air masses tend to lose moisture as they are forced up over mountain ranges, in what climatologists call a rainshadow effect . The exaggerated rain shadow effect for the Death Valley area makes it North America 's driest spot, receiving about 1.5 inches (38 mm) of rainfall annually at Badwater, and some years fail to register any measurable rainfall. Annual average precipitation varies from 1.92 inches (49 mm) overall below sea level to over 15 inches (380 mm) in

7616-570: The above, including possible glacial till from the hypothesized Snowball Earth glaciation. The very youngest rocks in the Pahrump Group are basaltic lava flows. A rift opened and subsequently flooded the region as part of the breakup of the supercontinent Rodinia in the Neoproterozoic (by about 755 million years ago) and the creation of the Pacific Ocean . A shoreline similar to

7752-622: The area from the Colorado River via a long-since dried-up system of rivers and lakes (see Lake Manly ). They now live in two separate populations: one in Salt Creek and another in Cottonball Marsh. Death Valley is one of the hottest and driest places in North America, yet it is home to over 1,000 species of plants ; 23 of which, including the very rare rock lady ( Holmgrenanthe ), are not found anywhere else. Subduction Subduction

7888-407: The area has been shaped largely by its geology. The valley is actually a graben with the oldest rocks being extensively metamorphosed and at least 1.7 billion years old. Ancient, warm, shallow seas deposited marine sediments until rifting opened the Pacific Ocean . Additional sedimentation occurred until a subduction zone formed off the coast. The subduction uplifted the region out of

8024-402: The area that comprises the park has experienced at least four major periods of extensive volcanism , three or four periods of major sedimentation , and several intervals of major tectonic deformation where the crust has been reshaped. Two periods of glaciation (a series of ice ages) have also had effects on the area, although no glaciers ever existed in the ranges now in the park. Little

8160-697: The area were also the easiest to collect and the most profitable: evaporite deposits such as salts, borate , and talc . Borax was found by Rosie and Aaron Winters near The Ranch at Death Valley (then called Greenland) in 1881. Later that same year, the Eagle Borax Works became Death Valley's first commercial borax operation. William Tell Coleman built the Harmony Borax Works plant and began to process ore in late 1883 or early 1884, continuing until 1888. This mining and smelting company produced borax to make soap and for industrial uses. The end product

8296-472: The area, except for some possibly Jurassic-age volcanic rocks (see the top of the timescale image ). Basin and Range -associated stretching of large parts of crust below southwestern United States and northwestern Mexico started around 16 million years ago and the region is still spreading. This stretching began to affect the Death and Panamint valleys area by 3 million years ago. Before this, rocks now in

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8432-472: The asthenosphere. Both models can eventually yield self-sustaining subduction zones, as the oceanic crust is metamorphosed at great depth and becomes denser than the surrounding mantle rocks. The compilation of subduction zone initiation events back to 100 Ma suggests horizontally-forced subduction zone initiation for most modern subduction zones, which is supported by results from numerical models and geologic studies. Some analogue modeling shows, however,

8568-437: The central extent of Death Valley. The result of this shearing action is additional extension in the central part of Death Valley which causes a slight widening and more subsidence there. Uplift of surrounding mountain ranges and subsidence of the valley floor are both occurring. The uplift on the Black Mountains is so fast that the alluvial fans (fan-shaped deposits at the mouth of canyons) there are small and steep compared to

8704-523: The colder oceanic lithosphere is, on average, more dense. Sediments and some trapped water are carried downwards by the slab and recycled into the deep mantle. Earth is so far the only planet where subduction is known to occur, and subduction zones are its most important tectonic feature. Subduction is the driving force behind plate tectonics , and without it, plate tectonics could not occur. Oceanic subduction zones are located along 55,000 km (34,000 mi) convergent plate margins, almost equal to

8840-435: The continent, away from the trench, and has been described in western North America (i.e. Laramide orogeny, and currently in Alaska, South America, and East Asia. The processes described above allow subduction to continue while mountain building happens concurrently, which is in contrast to continent-continent collision orogeny, which often leads to the termination of subduction. Continents are pulled into subduction zones by

8976-564: The crust would be melted and recycled into the Earth's mantle . In 1964, George Plafker researched the Good Friday earthquake in Alaska . He concluded that the cause of the earthquake was a megathrust reaction in the Aleutian Trench , a result of the Alaskan continental crust overlapping the Pacific oceanic crust. This meant that the Pacific crust was being forced downward, or subducted , beneath

9112-597: The crust, megathrust earthquakes on the subduction interface near the trench, and outer rise earthquakes on the subducting lower plate as it bends near the trench. Anomalously deep events are a characteristic of subduction zones, which produce the deepest quakes on the planet. Earthquakes are generally restricted to the shallow, brittle parts of the crust, generally at depths of less than twenty kilometers. However, in subduction zones quakes occur at depths as great as 700 km (430 mi). These quakes define inclined zones of seismicity known as Wadati–Benioff zones which trace

9248-609: The crust, through hotspot magmatism or extensional rifting, would the crust be able to break from its continent and begin subduction. Subduction can continue as long as the oceanic lithosphere moves into the subduction zone. However, the arrival of buoyant continental lithosphere at a subduction zone can result in increased coupling at the trench and cause plate boundary reorganization. The arrival of continental crust results in continental collision or terrane accretion that may disrupt subduction. Continental crust can subduct to depths of 250 km (160 mi) where it can reach

9384-408: The cumulative plate formation rate 60,000 km (37,000 mi) of mid-ocean ridges. Sea water seeps into oceanic lithosphere through fractures and pores, and reacts with minerals in the crust and mantle to form hydrous minerals (such as serpentine) that store water in their crystal structures. Water is transported into the deep mantle via hydrous minerals in subducting slabs. During subduction,

9520-448: The degree of lower plate curvature of the subducting plate in great historical earthquakes such as the 2004 Sumatra-Andaman and the 2011 Tōhoku earthquake, it was determined that the magnitude of earthquakes in subduction zones is inversely proportional to the angle of subduction near the trench, meaning that "the flatter the contact between the two plates, the more likely it is that mega-earthquakes will occur". Outer rise earthquakes on

9656-440: The descending slab. Nine of the ten largest earthquakes of the last 100 years were subduction zone megathrust earthquakes. These included the 1960 Great Chilean earthquake which at M 9.5 was the largest earthquake ever recorded, the 2004 Indian Ocean earthquake and tsunami , and the 2011 Tōhoku earthquake and tsunami . The subduction of cold oceanic lithosphere into the mantle depresses the local geothermal gradient and causes

9792-455: The different regimes present in this setting. The models are as follows: In their 2019 study, Macdonald et al. proposed that arc-continent collision zones and the subsequent obduction of oceanic lithosphere was at least partially responsible for controlling global climate. Their model relies on arc-continent collision in tropical zones, where exposed ophiolites composed mainly of mafic material increase "global weatherability" and result in

9928-495: The early-to-mid- Mesozoic the western edge of the North American continent was pushed against the oceanic plate under the Pacific Ocean, creating a subduction zone. A subduction zone is a type of contact between different crustal plates where heavier crust slides below lighter crust. Erupting volcanoes and uplifting mountains were created as a result, and the coastline was pushed to the west. The Sierran Arc started to form to

10064-529: The extreme lack of water in the Great Basin makes this distinction of little current practical use, it does mean that in wetter times the lake that once filled Death Valley ( Lake Manly ) was the last stop for water flowing in the region, meaning the water there was saturated in dissolved materials. Thus, the salt pans in Death Valley are among the largest in the world and are rich in minerals, such as borax and various salts and hydrates . The largest salt pan in

10200-420: The forearc-hanging wall and not subducted. Most metamorphic phase transitions that occur within the subducting slab are prompted by the dehydration of hydrous mineral phases. The breakdown of hydrous mineral phases typically occurs at depths greater than 10 km. Each of these metamorphic facies is marked by the presence of a specific stable mineral assemblage, recording the metamorphic conditions undergone but

10336-401: The harsh desert environment including creosote bush , Joshua tree , bighorn sheep , coyote , and the endangered Death Valley pupfish , a survivor from much wetter times. UNESCO included Death Valley as the principal feature of its Mojave and Colorado Deserts Biosphere Reserve in 1984. A series of Native American groups inhabited the area from as early as 7000 BC, most recently

10472-481: The higher mountains that surround the valley. When rain does arrive it often does so in intense storms that cause flash floods which remodel the landscape and sometimes create very shallow ephemeral lakes. The hot, dry climate makes it difficult for soil to form. Mass wasting , the down-slope movement of loose rock, is therefore the dominant erosive force in mountainous areas, resulting in "skeletonized" ranges (mountains with very little soil on them). Sand dunes in

10608-524: The huge alluvial fans coming off the Panamint Range . Fast uplift of a mountain range in an arid environment often does not allow its canyons enough time to cut a classic V-shape all the way down to the stream bed. Instead, a V-shape ends at a slot canyon halfway down, forming a 'wine glass canyon.' Sediment is deposited on a small and steep alluvial fan. At 282 feet (86 m) below sea level at its lowest point, Badwater Basin on Death Valley's floor

10744-430: The idea of subduction initiation at passive margins is popular, there is no modern day example for this type of subduction nucleation. This is likely due to the strength of the oceanic or transitional crust at the continental passive margins, suggesting that if the crust did not break in its first 20 million years of life, it is unlikely to break in the future under normal sedimentation loads. Only with additional weaking of

10880-454: The larger Death Valley springs derive their water from a regional aquifer , which extends as far east as southern Nevada and Utah . Much of the water in this aquifer has been there for many thousands of years, since the Pleistocene ice ages , when the climate was cooler and wetter. Today's drier climate does not provide enough precipitation to recharge the aquifer at the rate at which water

11016-481: The latter four dune fields are accessible only via unpaved roads. Prevailing winds in the winter come from the north, and prevailing winds in the summer come from the south. Thus, the overall position of the dune fields remains more or less fixed. There are rare exceptions to the dry nature of the area. In 2005, an unusually wet winter created a 'lake' in the Badwater Basin and led to the greatest wildflower season in

11152-500: The local Chamber of Commerce estimates that 6,000 people are moving to the city every month. Between 1985 and 1995, the population of the Las Vegas Valley increased from 550,700 to 1,138,800. In 1977, parts of Death Valley were used by director George Lucas as a filming location for Star Wars , providing the setting for the fictional planet Tatooine . The park has a diverse and complex geologic history. Since its formation,

11288-574: The lower plate occur when normal faults oceanward of the subduction zone are activated by flexure of the plate as it bends into the subduction zone. The 2009 Samoa earthquake is an example of this type of event. Displacement of the sea floor caused by this event generated a six-meter tsunami in nearby Samoa. Seismic tomography has helped detect subducted lithospheric slabs deep in the mantle where no earthquakes occur. About one hundred slabs have been described in terms of depth and their timing and location of subduction. The great seismic discontinuities in

11424-415: The mantle and is recycled. They are found at convergent plate boundaries, where the heavier oceanic lithosphere of one plate is overridden by the leading edge of another, less-dense plate. The overridden plate (the slab ) sinks at an angle most commonly between 25 and 75 degrees to Earth's surface. This sinking is driven by the temperature difference between the slab and the surrounding asthenosphere, as

11560-484: The mantle, at 410 km (250 mi) depth and 670 km (420 mi), are disrupted by the descent of cold slabs in deep subduction zones. Some subducted slabs seem to have difficulty penetrating the major discontinuity that marks the boundary between the upper mantle and lower mantle at a depth of about 670 kilometers. Other subducted oceanic plates have sunk to the core–mantle boundary at 2890 km depth. Generally, slabs decelerate during their descent into

11696-463: The mantle, from typically several cm/yr (up to ~10 cm/yr in some cases) at the subduction zone and in the uppermost mantle, to ~1 cm/yr in the lower mantle. This leads to either folding or stacking of slabs at those depths, visible as thickened slabs in seismic tomography. Below ~1700 km, there might be a limited acceleration of slabs due to lower viscosity as a result of inferred mineral phase changes until they approach and finally stall at

11832-400: The mountain ridges where they harvested pine nuts before moving back to the valley bottom for winter. The California Gold Rush brought the first people of European descent known to visit the immediate area. In December 1849 two groups of California Gold Country -bound travelers with perhaps 100 wagons total stumbled into Death Valley after getting lost on what they thought was a shortcut off

11968-583: The national monument. The public outcry that ensued led to greater protection for all national park and monument areas in the United States. In 1976, Congress passed the Mining in the Parks Act, which closed Death Valley National Monument to the filing of new mining claims, banned open-pit mining and required the National Park Service to examine the validity of tens of thousands of pre-1976 mining claims. Mining

12104-444: The northwest from heat and pressure generated from subduction, and compressive forces caused thrust faults to develop. A long period of uplift and erosion was concurrent with and followed the above events, creating a major unconformity, which is a large gap in the geologic record. Sediments worn off the Death Valley region were carried both east and west by wind and water. No Jurassic- to Eocene -aged sedimentary formations exist in

12240-484: The ocean floor, studied the Mid-Atlantic Ridge and proposed that hot molten rock was added to the crust at the ridge and expanded the seafloor outward. This theory was to become known as seafloor spreading . Since the Earth's circumference has not changed over geologic time, Hess concluded that older seafloor has to be consumed somewhere else, and suggested that this process takes place at oceanic trenches , where

12376-429: The oldest oceanic lithosphere. Continental lithosphere is up to 200 km (120 mi) thick. The lithosphere is relatively cold and rigid compared with the underlying asthenosphere , and so tectonic plates move as solid bodies atop the asthenosphere. Individual plates often include both regions of the oceanic lithosphere and continental lithosphere. Subduction zones are where cold oceanic lithosphere sinks back into

12512-572: The other was a one-eyed Basque butcher named Domingo Etcharren. Quite by accident, Keane discovered an immense ledge of free-milling gold by the duo's work site and named the claim the Keane Wonder Mine . This started a minor and short-lived gold rush into the area. The Keane Wonder Mine, along with mines at Rhyolite , Skidoo and Harrisburg , were the only ones to extract enough metal ore to make them worthwhile. Outright shams such as Leadfield also occurred, but most ventures quickly ended after

12648-412: The overlying plate. If an eruption occurs, the cycle then returns the volatiles into the oceans and atmosphere. The surface expressions of subduction zones are arc-trench complexes. On the ocean side of the complex, where the subducting plate first approaches the subduction zone, there is often an outer trench high or outer trench swell . Here the plate shallows slightly before plunging downwards, as

12784-399: The overriding continent. When the lower plate subducts at a shallow angle underneath a continent (something called "flat-slab subduction"), the subducting plate may have enough traction on the bottom of the continental plate to cause the upper plate to contract by folding, faulting, crustal thickening, and mountain building. Flat-slab subduction causes mountain building and volcanism moving into

12920-510: The overriding plate. However, not all arc-trench complexes have an accretionary wedge. Accretionary arcs have a well-developed forearc basin behind the accretionary wedge, while the forearc basin is poorly developed in non-accretionary arcs. Beyond the forearc basin, volcanoes are found in long chains called volcanic arcs . The subducting basalt and sediment are normally rich in hydrous minerals and clays. Additionally, large quantities of water are introduced into cracks and fractures created as

13056-625: The park extends 40 miles (64 km) from the Ashford Mill Site to the Salt Creek Hills, covering some 200 square miles (520 km ) of the valley floor. The best known playa in the park is the Racetrack , known for its moving rocks. According to the Köppen climate classification system, Death Valley National Park has a hot desert climate ( BWh ). The plant hardiness zone at Badwater Basin

13192-545: The park's history. In October 2015, a "1000 year flood event" with over three inches of rain caused major damage in Death Valley National Park. A similar widespread storm in August 2022 damaged pavement and deposited debris on nearly every road, trapping 1,000 residents and visitors overnight. Four Native American cultures are known to have lived in the area during the last 10,000 years. The first known group,

13328-640: The park, and some of the highest in North America, are located in the Eureka Valley about 50 miles (80 km) to the north of Stovepipe Wells, while the Panamint Valley dunes and the Saline Valley dunes are located west and northwest of the town, respectively. The Ibex dune field is near the seldom-visited Ibex Hill in the southernmost part of the park, just south of the Saratoga Springs marshland. All

13464-431: The park, while famous, are not nearly as widespread as their fame or the dryness of the area may suggest. The Mesquite Flat dune field is the most easily accessible from the paved road just east of Stovepipe Wells in the north-central part of the valley and is primarily made of quartz sand. Another dune field is just 10 miles (16 km) to the north but is instead mostly composed of travertine sand. The highest dunes in

13600-401: The park. Many of the larger cities and towns within the boundary of the regional groundwater flow system that the park and its plants and animals rely upon are experiencing some of the fastest growth rates of any place in the United States. Notable examples within a 100-mile (160 km) radius of Death Valley National Park include Las Vegas and Pahrump, Nevada . In the case of Las Vegas,

13736-556: The pinyon/juniper associations of the Grapevine, Cottonwood, and Panamint ranges. Bighorn sheep are a rare species of mountain-dwelling sheep that exist in isolated bands in the Sierra and in Death Valley. These are highly adaptable animals and can eat almost any plant. They have no known predators, but humans and burros compete for habitat. The ancestors of the Death Valley pupfish swam to

13872-404: The planet. The ocean-ocean plate relationship can lead to subduction zones between oceanic and continental plates, therefore highlighting how important it is to understand this subduction setting. Although it is not fully understood what causes the initiation of subduction of an oceanic plate under another oceanic plate, there are three main models put forth by Baitsch-Ghirardello et al. that explain

14008-582: The possibility of spontaneous subduction from inherent density differences between two plates at specific locations like passive margins and along transform faults . There is evidence this has taken place in the Izu-Bonin-Mariana subduction system. Earlier in Earth's history, subduction is likely to have initiated without horizontal forcing due to the lack of relative plate motion, though a proposal by A. Yin suggests that meteorite impacts may have contributed to subduction initiation on early Earth. Though

14144-519: The present Atlantic Ocean margin of the United States lay to the east. An algal mat -covered carbonate bank was deposited, forming the Noonday Dolomite. Subsidence of the region occurred as the continental crust thinned and the newly formed Pacific widened, forming the Ibex Formation. An angular unconformity (an uneven gap in the geologic record) followed. A true ocean basin developed to

14280-520: The pressures and temperatures necessary for this type of metamorphism are much higher than what is observed in most subduction zones. Frezzoti et al. (2011) propose a different mechanism for carbon transport into the overriding plate via dissolution (release of carbon from carbon-bearing minerals into an aqueous solution) instead of decarbonation. Their evidence comes from the close examination of mineral and fluid inclusions in low-temperature (<600 °C) diamonds and garnets found in an eclogite facies in

14416-501: The retention of more or less the same valley floor elevation over time. Pleistocene ice ages started 2 million years ago, and melt from alpine glaciers on the nearby Sierra Nevada Mountains fed a series of lakes that filled Death and Panamint valleys and surrounding basins (see the top of the timescale image ). The lake that filled Death Valley was the last of a chain of lakes fed by the Amargosa and Mojave Rivers , and possibly also

14552-444: The rocks of the mantle. The mantle-derived magmas (which are initially basaltic in composition) can ultimately reach the Earth's surface, resulting in volcanic eruptions. The chemical composition of the erupting lava depends upon the degree to which the mantle-derived basalt interacts with (melts) Earth's crust or undergoes fractional crystallization . Arc volcanoes tend to produce dangerous eruptions because they are rich in water (from

14688-507: The sea and created a line of volcanoes . Later the crust started to pull apart, creating the current Basin and Range landform. Valleys filled with sediment and, during the wet times of glacial periods , with lakes, such as Lake Manly . Death Valley is the fifth-largest American national park and the largest in the contiguous United States . It is also larger than the states of Rhode Island and Delaware combined, and nearly as large as Puerto Rico . In 2013, Death Valley National Park

14824-436: The sedimentary and volcanic cover is mostly scraped off to form an orogenic wedge. An orogenic wedge is larger than most accretionary wedges due to the volume of material there is to accrete. The continental basement rocks beneath the weak cover suites are strong and mostly cold, and can be underlain by a >200 km thick layer of dense mantle. After shedding the low density cover units, the continental plate, especially if it

14960-450: The sinking oceanic plate they are attached to. Where continents are attached to oceanic plates with no subduction, there is a deep basin that accumulates thick suites of sedimentary and volcanic rocks known as a passive margin. Some passive margins have up to 10 km of sedimentary and volcanic rocks covering the continental crust. As a passive margin is pulled into a subduction zone by the attached and negatively buoyant oceanic lithosphere,

15096-453: The slab and sediments) and tend to be extremely explosive. Krakatoa , Nevado del Ruiz , and Mount Vesuvius are all examples of arc volcanoes. Arcs are also associated with most ore deposits. Beyond the volcanic arc is a back-arc region whose character depends strongly on the angle of subduction of the subducting slab. Where this angle is shallow, the subducting slab drags the overlying continental crust partially with it, which produces

15232-447: The storage of carbon through silicate weathering processes. This storage represents a carbon sink , removing carbon from the atmosphere and resulting in global cooling. Their study correlates several Phanerozoic ophiolite complexes, including active arc-continent subduction, with known global cooling and glaciation periods. This study does not discuss Milankovitch cycles as a driver of global climate cyclicity. Modern-style subduction

15368-481: The stratosphere during violent eruptions can cause rapid cooling of Earth's climate and affect air travel. Arc-magmatism plays a role in Earth's Carbon cycle by releasing subducted carbon through volcanic processes. Older theory states that the carbon from the subducting plate is made available in overlying magmatic systems via decarbonation, where CO 2 is released through silicate-carbonate metamorphism. However, evidence from thermodynamic modeling has shown that

15504-526: The subducting slab bends downward. During the transition from basalt to eclogite, these hydrous materials break down, producing copious quantities of water, which at such great pressure and temperature exists as a supercritical fluid . The supercritical water, which is hot and more buoyant than the surrounding rock, rises into the overlying mantle, where it lowers the melting temperature of the mantle rock, generating magma via flux melting . The magmas, in turn, rise as diapirs because they are less dense than

15640-500: The subducting slab. Transitions between facies cause hydrous minerals to dehydrate at certain pressure-temperature conditions and can therefore be tracked to melting events in the mantle beneath a volcanic arc. Two kinds of arcs are generally observed on Earth: island arcs that form on the oceanic lithosphere (for example, the Mariana and the Tonga island arcs), and continental arcs such as

15776-451: The subject, performs the action of overriding the object, the lower plate, which is overridden. Subduction zones are important for several reasons: Subduction zones have also been considered as possible disposal sites for nuclear waste in which the action of subduction itself would carry the material into the planetary mantle , safely away from any possible influence on humanity or the surface environment. However, that method of disposal

15912-434: The summit of Telescope Peak, which rises to 11,049 feet (3,368 m). Vegetation zones include creosote bush , desert holly , and mesquite at the lower elevations and sage up through shadscale , blackbrush , Joshua tree , pinyon - juniper , to limber pine and bristlecone pine woodlands. The salt pan is devoid of vegetation, and the rest of the valley floor and lower slopes have sparse cover, although where water

16048-454: The surface once the volcanoes have weathered away. The volcanism and plutonism occur as a consequence of the subducting oceanic slab dehydrating as it reaches higher pressures and temperatures. Once the oceanic slab reaches about 100 km in depth, hydrous minerals become unstable and release fluids into the asthenosphere. The fluids act as a flux for the rock within the asthenosphere and cause it to partially melt. The partially melted material

16184-439: The timing and conditions in which these dehydration reactions occur is key to interpreting mantle melting, volcanic arc magmatism, and the formation of continental crust. A metamorphic facies is characterized by a stable mineral assemblage specific to a pressure-temperature range and specific starting material. Subduction zone metamorphism is characterized by a low temperature, high-ultrahigh pressure metamorphic path through

16320-444: The trench and approximately one hundred kilometers above the subducting slab. Arcs produce about 10% of the total volume of magma produced each year on Earth (approximately 0.75 cubic kilometers), much less than the volume produced at mid-ocean ridges, but they have formed most continental crust . Arc volcanism has the greatest impact on humans because many arc volcanoes lie above sea level and erupt violently. Aerosols injected into

16456-400: The underlying ductile mantle . This process of convection allows heat generated by radioactive decay to escape from the Earth's interior. The lithosphere consists of the outermost light crust plus the uppermost rigid portion of the mantle . Oceanic lithosphere ranges in thickness from just a few km for young lithosphere created at mid-ocean ridges to around 100 km (62 mi) for

16592-481: The valley was a popular winter destination. Other facilities started off as private getaways but were later opened to the public. Most notable among these was Death Valley Ranch, better known as Scotty's Castle . This large ranch home built in the Spanish Revival style became a hotel in the late 1930s and, largely because of the fame of Death Valley Scotty , a tourist attraction. Death Valley Scotty, whose real name

16728-421: The valley. Just after leaving the valley, one of the women in the group turned and said, "Goodbye Death Valley," giving the valley its name. Included in the party was William Lewis Manly whose autobiographical book Death Valley in '49 detailed this trek and popularized the area (geologists later named the prehistoric lake that once filled the valley after him). The ores that are most famously associated with

16864-573: The wagon's image to promote the Boraxo brand of granular hand soap and the Death Valley Days radio and television programs. In 1914, the Death Valley Railroad was built to serve mining operations on the east side of the valley. Mining continued after the collapse of Coleman's empire, and by the late 1920s the area was the world's number one source of borax. Some four to six million years old,

17000-411: The west, breaking all the earlier formations along a steep front. A wedge of clastic sediment then began to accumulate at the base of the two underwater precipices, starting the formation of opposing continental shelves . Three formations developed from sediment that accumulated on the wedge. The region's first known fossils of complex life are found in the resulting formations. Notable among these are

17136-463: The wide altitude differential between the valley bottom and the mountain ridges, especially on the west, the Timbisha practiced a vertical migration pattern. Their winter camps were located near water sources in the valley bottoms. As the spring and summer progressed and the weather warmed, grasses and other plant food sources ripened at progressively higher altitudes. November found them at the very top of

17272-587: The winter. July is the hottest month, with an average high of 117 °F (47 °C) and an average low of 91 °F (33 °C). December is the coldest month, with an average high of 66 °F (19 °C) and an average low of 41 °F (5 °C). The record low is 15 °F (−9.4 °C). There are an average of 197.3 days annually with highs of 90 °F (32.2 °C) or higher and 146.9 days annually with highs of 100 °F (37.8 °C) or higher. Freezing temperatures of 32 °F (0 °C) or lower occur on an average of 8.6 days annually. Several of

17408-429: Was borax , which was transported out of the valley with twenty-mule teams . The valley later became the subject of books, radio programs, television series, and movies. Tourism expanded in the 1920s when resorts were built around Stovepipe Wells and Furnace Creek . Death Valley National Monument was declared in 1933 and the park was substantially expanded and became a national park in 1994. The natural environment of

17544-420: Was Walter Scott, was a gold miner who pretended to be the owner of "his castle", which he claimed to have built with profits from his gold mine. Neither claim was true, but the real owner, Chicago millionaire Albert Mussey Johnson , encouraged the myth. When asked by reporters what his connection was to Walter Scott's castle, Johnson replied that he was Mr. Scott's banker. President Herbert Hoover proclaimed

17680-459: Was allowed to resume on a limited basis in 1980 with stricter environmental standards. The last mine in the park, Billie Mine, closed in 2005. In 1952 President Harry Truman added the Devils Hole to Death Valley National Monument; it is the only habitat of the Devils Hole pupfish . Death Valley National Monument was designated a biosphere reserve in 1984. On October 31, 1994, the monument

17816-607: Was caused by subduction of the Indo-Australian plate under the Euro-Asian Plate, but the tsunami spread over most of the planet and devastated the areas around the Indian Ocean. Small tremors which cause small, nondamaging tsunamis, also occur frequently. A study published in 2016 suggested a new parameter to determine a subduction zone's ability to generate mega-earthquakes. By examining subduction zone geometry and comparing

17952-545: Was designated as a dark sky park by the International Dark-Sky Association . There are two major valleys in the park, Death Valley and Panamint Valley . Both of these valleys were formed within the last few million years and both are bounded by north–south-trending mountain ranges . These and adjacent valleys follow the general trend of Basin and Range topography with one modification: there are parallel strike-slip faults that perpendicularly bound

18088-574: Was expanded by 1.3 million acres (5,300 km ) and re-designated as a national park , via congressional passage of the California Desert Protection Act (Public Law 103–433). Consequently, the elevated status for Death Valley made it the largest national park in the contiguous United States . On March 12, 2019, the John D. Dingell, Jr. Conservation, Management, and Recreation Act added 35,292 acres (55 sq mi; 143 km ) to

18224-563: Was once hotter, but not that subduction conditions were hotter. Previously, the lack of pre-Neoproterozoic blueschist was thought to indicate a different type of subduction. Both lines of evidence refute previous conceptions of modern-style subduction having been initiated in the Neoproterozoic Era 1.0 Ga ago. Harry Hammond Hess , who during World War II served in the United States Navy Reserve and became fascinated in

18360-532: Was quickly reopened to mining by Congressional action in June 1933. As improvements in mining technology allowed lower grades of ore to be processed, and new heavy equipment allowed greater amounts of rock to be moved, mining in Death Valley changed. Gone were the days of the "single-blanket, jackass prospector" long associated with the romantic west. Open pit and strip mines scarred the landscape as international mining corporations bought claims in highly visible areas of

18496-560: Was shipped out of the valley 165 miles (266 km) to the Mojave railhead in 10-ton-capacity wagons pulled by " twenty-mule teams " that were actually teams of 18 mules and two horses each. The teams averaged two miles (3.2 km) an hour and required about 30 days to complete a round trip. The trade name 20-Mule Team Borax was established by Francis Marion Smith 's Pacific Coast Borax Company after Smith acquired Coleman's borax holdings in 1890. A memorable advertising campaign used

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