California - Death Valley National Park
Mesquite Flat Dunes
Death Valley National Park is an American national park that straddles the California-Nevada border, east of the Sierra Nevada. 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 is the largest national park in the lower 48 states, and the hottest, driest and lowest of all the national parks in the United States. The second-lowest point in the Western Hemisphere is in Badwater Basin, which is 282 feet (86 m) below sea level. Approximately 91% of the park is a designated wilderness area. The park is home to many species of plants and animals that have adapted to this harsh desert environment. Some examples include creosote bush, bighorn sheep, coyote, and the 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 the Timbisha around 1000 AD who migrated between winter camps in the valleys and summer grounds in the mountains. A group of European-Americans, trapped in the valley in 1849 while looking for a shortcut to the gold fields of California, gave the valley its 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 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 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 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.
In 2013, Death Valley National Park 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 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 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 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). 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 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 the park extends 40 miles (64 km) from the Ashford Mill Site to the Salt Creek Hills, covering some 200 square miles (520 km2) of the valley floor. The best known playa in the park is the Racetrack, known for its moving rocks.
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, the United States Weather Bureau recorded a high temperature of 134 °F (56.7 °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 (136.4 °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 the winter. July is the hottest month, with an average high of 115 °F (46 °C) and an average low of 88 °F (31 °C). December is the coldest month, with an average high of 65 °F (18 °C) and an average low of 39 °F (4 °C). The record low is 15 °F (−9.4 °C).
(Wikipedia)
Many first time visitors to Death Valley are surprised it is not covered with a sea of sand. Less than one percent of the desert is covered with dunes, yet the shadowed ripples and stark, graceful curves define "desert" in our imaginations.
For dunes to exist there must be a source of sand, prevailing winds to move the sand, and a place for the sand to collect. The eroded canyons and washes provide plenty of sand, the wind seems to always blow (especially in the springtime), but there are only a few areas in the park where the sand is "trapped" by geographic features such as mountains.
The sand dunes of Death Valley National Park are excellent places for nature study and recreation. All of the dunes in Death Valley National Park are protected as wilderness, off-road vehicle travel is not permitted anywhere in the park. Sand boarding is only allowed on the Mesquite Flat Dunes and prohibited on all other dune systems in the park to protect sensitive plants and animals.
Mesquite Flat Dunes
These dunes are the best known and easiest to visit in the national park. Located in central Death Valley near Stovepipe Wells, access is from Hwy. 190 or from the unpaved Sand Dunes Road. Although the highest dune rises only about 100 feet, the dunes actually cover a vast area. This dune field includes three types of dunes: crescent, linear, and star shaped. Polygon-cracked clay of an ancient lakebed forms the floor. Mesquite trees have created large hummocks that provide stable habitats for wildlife.
(nps.gov)
Der Death-Valley-Nationalpark (Tal des Todes) liegt in der Mojave-Wüste und ist der trockenste Nationalpark in den USA. Er liegt südöstlich der Sierra Nevada, zum größten Teil auf dem Gebiet Kaliforniens und zu einem kleineren Teil in Nevada. Die Region ist ein Hitzepol.
Der tiefste Punkt des Tales liegt 85,95 Meter unter dem Meeresspiegel. Es gibt zwei Haupttäler innerhalb des Parks, das Death Valley und das Panamint Valley. Beide Täler sind wenige Millionen Jahre alt. Das Death Valley ist von mehreren Gebirgen umschlossen, die höchste Gebirgskette bildet die Panamint Range mit dem 3366 m hohen Telescope Peak. 1933 wurde das Death Valley zum National Monument ernannt. 1994 wurde es, stark erweitert, zum Nationalpark aufgewertet. Eine kleine Enklave, Devils Hole weiter östlich in Nevada in der Nähe des Ash Meadows National Wildlife Preserve gelegen, gehört ebenfalls zum Park.
Am 20. Februar 2011 wurde der Nationalpark als Lichtschutzgebiet von der International Dark Sky Association auch als International Dark Sky Park (IDSP, in Gold) anerkannt, und nennt sich seither auch Death Valley International Dark Sky Park. Es ist das weitaus größte solche Schutzgebiet der USA und das zweitgrößte weltweit (nach dem IDSR Wood Buffalo in Kanada).
Das Tal erhielt seinen Namen, nachdem 1849 zwei Gruppen von Reisenden mit insgesamt etwa 100 Wagen eine Abkürzung des Old Spanish Trail suchten und dabei in das Tal gerieten. Nachdem sie wochenlang keinen Ausweg aus dem Tal gefunden hatten und bereits gezwungen waren, mehrere ihrer Ochsen zu verspeisen (wobei sie das Holz ihrer Wagen als Brennholz verwendeten), ließen sie ihre restlichen Wagen zurück und verließen das Tal über den Wingate Pass. Dabei drehte sich eine der Frauen aus der Gruppe um und rief dem Tal ein „Goodbye, Death Valley“ hinterher.
Trotz einer weitverbreiteten Legende soll niemand aus der Gruppe bei der Taldurchquerung umgekommen sein, bis auf einen Greis namens Culverwell, der schon beim Betreten des Tales sterbensmatt gewesen war. Als Teilnehmer der Reisegruppe beschrieb William Lewis Manly in seinem autobiographischen Werk Death Valley in ’49 die Begebenheiten.
Obwohl das Tal des Todes nur wenige hundert Kilometer vom Pazifischen Ozean entfernt liegt, ist es eine der trockensten Gegenden der Erde. Dies liegt daran, dass sich die feuchten Winde auf ihrem Weg vom Pazifik an fünf Bergrücken abregnen, bevor sie über das Gebiet des Parks ziehen können. Das Death Valley ist außerdem eine der heißesten Gegenden Amerikas. Am 10. Juli 1913 wurde bei Greenland Ranch (heute bekannt als Furnace Creek Ranch) vom National Weather Service eine Temperatur von 56,7 °C (134 °F) gemessen. Am 12. Juli 2012 wurde im Death Valley mit 41,7 °C (107 °F) die wärmste nächtliche Tiefsttemperatur gemessen; der gleiche Wert wurde vorher nur einmal erreicht, nämlich am 27. Juni 2012 am Khasab-Flughafen in Oman.
Die 4 km² großen Mesquite Sand Dunes liegen im nördlichen Teil des Tales und wurden schon oft als Wüstenkulisse in Filmen, unter anderem in Star Wars, verwendet. Die größte Düne ist die Star Dune. Diese ist recht stabil, da der Wind den Sand vorzugsweise an genau dieser Stelle ablagert. Der Sand ist hier rund 50 Meter hoch.
(Wikipedia)
California - Death Valley National Park
Mesquite Flat Dunes
Death Valley National Park is an American national park that straddles the California-Nevada border, east of the Sierra Nevada. 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 is the largest national park in the lower 48 states, and the hottest, driest and lowest of all the national parks in the United States. The second-lowest point in the Western Hemisphere is in Badwater Basin, which is 282 feet (86 m) below sea level. Approximately 91% of the park is a designated wilderness area. The park is home to many species of plants and animals that have adapted to this harsh desert environment. Some examples include creosote bush, bighorn sheep, coyote, and the 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 the Timbisha around 1000 AD who migrated between winter camps in the valleys and summer grounds in the mountains. A group of European-Americans, trapped in the valley in 1849 while looking for a shortcut to the gold fields of California, gave the valley its 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 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 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 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.
In 2013, Death Valley National Park 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 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 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 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). 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 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 the park extends 40 miles (64 km) from the Ashford Mill Site to the Salt Creek Hills, covering some 200 square miles (520 km2) of the valley floor. The best known playa in the park is the Racetrack, known for its moving rocks.
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, the United States Weather Bureau recorded a high temperature of 134 °F (56.7 °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 (136.4 °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 the winter. July is the hottest month, with an average high of 115 °F (46 °C) and an average low of 88 °F (31 °C). December is the coldest month, with an average high of 65 °F (18 °C) and an average low of 39 °F (4 °C). The record low is 15 °F (−9.4 °C).
(Wikipedia)
Many first time visitors to Death Valley are surprised it is not covered with a sea of sand. Less than one percent of the desert is covered with dunes, yet the shadowed ripples and stark, graceful curves define "desert" in our imaginations.
For dunes to exist there must be a source of sand, prevailing winds to move the sand, and a place for the sand to collect. The eroded canyons and washes provide plenty of sand, the wind seems to always blow (especially in the springtime), but there are only a few areas in the park where the sand is "trapped" by geographic features such as mountains.
The sand dunes of Death Valley National Park are excellent places for nature study and recreation. All of the dunes in Death Valley National Park are protected as wilderness, off-road vehicle travel is not permitted anywhere in the park. Sand boarding is only allowed on the Mesquite Flat Dunes and prohibited on all other dune systems in the park to protect sensitive plants and animals.
Mesquite Flat Dunes
These dunes are the best known and easiest to visit in the national park. Located in central Death Valley near Stovepipe Wells, access is from Hwy. 190 or from the unpaved Sand Dunes Road. Although the highest dune rises only about 100 feet, the dunes actually cover a vast area. This dune field includes three types of dunes: crescent, linear, and star shaped. Polygon-cracked clay of an ancient lakebed forms the floor. Mesquite trees have created large hummocks that provide stable habitats for wildlife.
(nps.gov)
Der Death-Valley-Nationalpark (Tal des Todes) liegt in der Mojave-Wüste und ist der trockenste Nationalpark in den USA. Er liegt südöstlich der Sierra Nevada, zum größten Teil auf dem Gebiet Kaliforniens und zu einem kleineren Teil in Nevada. Die Region ist ein Hitzepol.
Der tiefste Punkt des Tales liegt 85,95 Meter unter dem Meeresspiegel. Es gibt zwei Haupttäler innerhalb des Parks, das Death Valley und das Panamint Valley. Beide Täler sind wenige Millionen Jahre alt. Das Death Valley ist von mehreren Gebirgen umschlossen, die höchste Gebirgskette bildet die Panamint Range mit dem 3366 m hohen Telescope Peak. 1933 wurde das Death Valley zum National Monument ernannt. 1994 wurde es, stark erweitert, zum Nationalpark aufgewertet. Eine kleine Enklave, Devils Hole weiter östlich in Nevada in der Nähe des Ash Meadows National Wildlife Preserve gelegen, gehört ebenfalls zum Park.
Am 20. Februar 2011 wurde der Nationalpark als Lichtschutzgebiet von der International Dark Sky Association auch als International Dark Sky Park (IDSP, in Gold) anerkannt, und nennt sich seither auch Death Valley International Dark Sky Park. Es ist das weitaus größte solche Schutzgebiet der USA und das zweitgrößte weltweit (nach dem IDSR Wood Buffalo in Kanada).
Das Tal erhielt seinen Namen, nachdem 1849 zwei Gruppen von Reisenden mit insgesamt etwa 100 Wagen eine Abkürzung des Old Spanish Trail suchten und dabei in das Tal gerieten. Nachdem sie wochenlang keinen Ausweg aus dem Tal gefunden hatten und bereits gezwungen waren, mehrere ihrer Ochsen zu verspeisen (wobei sie das Holz ihrer Wagen als Brennholz verwendeten), ließen sie ihre restlichen Wagen zurück und verließen das Tal über den Wingate Pass. Dabei drehte sich eine der Frauen aus der Gruppe um und rief dem Tal ein „Goodbye, Death Valley“ hinterher.
Trotz einer weitverbreiteten Legende soll niemand aus der Gruppe bei der Taldurchquerung umgekommen sein, bis auf einen Greis namens Culverwell, der schon beim Betreten des Tales sterbensmatt gewesen war. Als Teilnehmer der Reisegruppe beschrieb William Lewis Manly in seinem autobiographischen Werk Death Valley in ’49 die Begebenheiten.
Obwohl das Tal des Todes nur wenige hundert Kilometer vom Pazifischen Ozean entfernt liegt, ist es eine der trockensten Gegenden der Erde. Dies liegt daran, dass sich die feuchten Winde auf ihrem Weg vom Pazifik an fünf Bergrücken abregnen, bevor sie über das Gebiet des Parks ziehen können. Das Death Valley ist außerdem eine der heißesten Gegenden Amerikas. Am 10. Juli 1913 wurde bei Greenland Ranch (heute bekannt als Furnace Creek Ranch) vom National Weather Service eine Temperatur von 56,7 °C (134 °F) gemessen. Am 12. Juli 2012 wurde im Death Valley mit 41,7 °C (107 °F) die wärmste nächtliche Tiefsttemperatur gemessen; der gleiche Wert wurde vorher nur einmal erreicht, nämlich am 27. Juni 2012 am Khasab-Flughafen in Oman.
Die 4 km² großen Mesquite Sand Dunes liegen im nördlichen Teil des Tales und wurden schon oft als Wüstenkulisse in Filmen, unter anderem in Star Wars, verwendet. Die größte Düne ist die Star Dune. Diese ist recht stabil, da der Wind den Sand vorzugsweise an genau dieser Stelle ablagert. Der Sand ist hier rund 50 Meter hoch.
(Wikipedia)