The Sierra Nevada ( , Spanish: Ã, ['sjera ne' ? aÃ? Â ° a] , snow saw range ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. Most ranges are located in the state of California, though the Carson Range spur lies mainly in Nevada. Sierra Nevada is part of the American Cordillera, a series of mountains consisting of an almost continuous sequence of ranges that form the "backbone" of western North America, Central America, South America and Antarctica.
Sierra runs 400 miles (640 km) north-to-south, and approximately 70 miles (110 km) east-to-west. Famous Sierra features include Lake Tahoe, North America's largest alpine lake; Mount Whitney at 14,505 ft (4,421 m), the highest point in the United States adjacent; and the Yosemite Valley, carved by glaciers of hundred million years old granite. Sierra is home to three national parks, twenty wilderness areas, and two national monuments. These areas include Yosemite National Park, Sequoia and Kings Canyon; and Devils Postpile National Monument.
The character of the range is shaped by its geology and ecology. More than a hundred million years ago during the Nevadan orogeny, granite was formed deep underground. The range began to rise four million years ago, and erosion by glaciers exposes granite and forms brightly colored mountains and cliffs that make up the range. This increase led to various elevations and climates in Sierra Nevada, reflected in the presence of five life zones (areas with similar plant and animal communities). The stroke continues due to errors caused by tectonic forces, creating a spectacular faultline along the eastern edge of the southern Sierra.
Sierra Nevada has a significant history. The Gold Rush of California occurred in the western foothills from 1848 to 1855. Due to inaccessibility, the range was not fully explored until 1912.
Video Sierra Nevada (U.S.)
Geography
The Sierra Nevada is located in Central and Eastern California, with a very small but historically important spur extends into Nevada. From west to east, the Sierra Nevada elevation gradually increases from 1,000 feet (300 m) in Central Valley to a height of about 14,000 feet (4,300 m) at its peak of 50-75 miles (80-121 km) to the east. The eastern slope forms a steep Sierra Escarpment. Unlike its surroundings, this range receives large amounts of snow and rainfall due to orographic removal.
Settings
The irregular northern border of the Sierra Nevada stretches from the Susan River and Fredonyer Pass to the North Fork Feather River. This is where the granite bedrock of the Sierra Nevada dives below the southern level of the Cenozoic frozen surface rocks of the Cascade Range. It is bordered on the west by California Central Valley and on the east by the Basin and Range Province. Southern boundary is in Tehachapi Pass.
Physiographically, Sierra is part of the Cascade-Sierra Mountain Province, which in turn is part of the larger Pacific Mountain System physique division. The California Geological Survey states that "the northern Sierra boundary is marked where the bedrocks disappear under the cover of the Cenozoic volcano from the Cascade Mountains."
DAS
This range is drained on the west slope of the Central Valley Watershed, dumped into the Pacific Ocean in San Francisco. The third part of northern Sierra west is part of the Sacramento River basin (including the Feather, Yuba, and American River tributaries), and the middle third is drained by the San Joaquin River (including Mokelumne, Stanislaus, Tuolumne, and River Merced tributaries). The southern part of the region is drained by the rivers of Kings, Kaweah, Tule, and Kern, which flows into the endoric basin of Tulare Lake, which rarely overflows into San Joaquin during wet years.
The eastern slopes of the Sierra are much narrower; its rivers flow into the Great Basin endorheic eastern California and western Nevada. From north to south, the Susan River flows into the alternating Honey Lakes, the Truckee River flows from Lake Tahoe to the Pyramid Lake, Carson River flows into Carson Sink, Walker River to Walker Lake; Rush, Lee Vining and Mill Creeks flow into Mono Lake; and the Owens River to the dry Owens Lake. Although no eastern river reaches the sea, many rivers from Mono Lake to the south are diverted to the Los Angeles Aqueduct that provides water to Southern California.
Altitude
The altitude of the mountains in Sierra Nevada gradually increases from north to south. Between Fredonyer Pass and Lake Tahoe, the peak starts from 5,000 feet (1,500 m) to over 9,000 feet (2,700 m). The peak near Lake Tahoe is about 9,000 feet (2,700 m) high, with some peaks approaching Freel Peak's heights (10,881 ft or 3,317 m). Further south, the highest peak in Yosemite National Park is Mount Lyell (13,120 feet or 3,999 m). Sierra rose to nearly 14,000 feet (4,300 m) with Mount Humphreys near Bishop, California. Finally, near Lone Pine, Mount Whitney is at 14,505 feet (4,421 m), the highest point in the United States adjacent.
To the south of Mount Whitney, the rapidly decreasing range elevation. The peak elevation is nearly 10,000 feet (3,000 m) near Lake Isabella, but south of the lake, its peak reaches only 8,000 feet (2,400 m).
Important features
There are several important geographic features in the Sierra Nevada:
- Lake Tahoe is a large and clear freshwater lake north of the Sierra Nevada, with a height of 6,225 feet (1,897 m) and an area of ​​191 m² (490 km 2 ). Lake Tahoe is located between the main Sierra and Range Carson, spurring Sierra.
- The Hetch Hetchy Valley, Yosemite Valley, Kings Canyon, and Kern Canyon are examples of the many glacial dug valleys on the western side of the Sierra.
- Yosemite National Park is filled with important features such as waterfalls, granite domes, high mountains, lakes and grasslands.
- Groves of Giant Sequoias Sequoiadendron giganteum occurs along the narrow altitude on the western side of the Sierra Nevada. Giant Sequoia is the largest tree in the world.
- The two largest rivers in California, which form the Valley of the Middle and flow into the San Francisco Bay, acquire most of its stream from the western slope of the Sierra Nevada. The northern part of both is the Sacramento River (which also depletes the Cascade Range and Klamath Range); the south is the San Joaquin River.
Community
Communities in the Sierra Nevada include Carson City, Heaven, South Lake Tahoe, Truckee, Grass Valley, Mammoth Lake, Sonora, Nevada City, Placerville, Portola, Auburn, Colfax, and Kennedy Meadows.
Protected area
Most of the Sierra Nevada is made up of federal lands and is protected from development or strictly managed. Three National Parks (Yosemite, Kings Canyon, Sequoia), two National Monuments (Devils Postpile, Giant Sequoia), and 26 wilderness areas are located within the Sierra. These areas protect 15.4% of Sierra 63.118 km 2 (24,370Ã, sqÃ, mi) from logging and grazing.
The US Forest Service and the Land Management Bureau currently own 52% of land in Sierra Nevada. Logging and shepherding are usually allowed on land controlled by these institutions, under federal regulations that balance recreation and development on land.
The California Bighorn Sheep Zoological Area near Mount Williamson in the southern Sierra was established to protect the endangered Sierra Nevada bighorn sheep. Beginning in 1981, pedestrians can not enter the Area from 15 May to 15 December, to protect sheep. In 2010, restrictions have been revoked and access to open areas for the entire year.
Maps Sierra Nevada (U.S.)
Geological history
The earliest rocks in the Sierra Nevada are meteorphic Paleozoikum roof pendants, the oldest metasedimentary rocks from Cambrian in the Mount Morrison region. These dark hornfels, slate, marbles, and schists are found in the western foothills (especially around Coarsegold, west of the Tehachapi Pass) and east of Sierra Crest. The earliest granite of the Sierra began to form in the Triassic period. The granite is found mostly in the eastern and northern peaks of 37.2 Â ° N. In Triassic and to Jurassic, an arc island collides with the west coast of North America and lifts the chain of volcanoes, in an event called orogeny Nevadan. Almost all suberbial Sierra Arc volcanoes have disappeared; their bodies were copied back during the Great Valley Order and the subsequent Kenozoikum filling of the Great Valley, which is the source of many sedimentary rocks in California.
In Cretaceous, subduction zones form at the tip of the continent. This means the oceanic plate starts diving under the North American plate. Magma is formed through the subduction of the ancient Farallon Plate rising in plumes (plutons) deep underground, their combined mass forming what is called the Sierra Nevada batholith. This pluton is formed at various times, from 115 Ma to 87 Ma. Plutons formerly formed in the western part of the Sierra, while the pluton later formed in the eastern part of the Sierra. In the year 66 Ma, proto-Sierra Nevada has been damaged to various low mountains, several thousand feet tall.
Twenty million years ago, the extension of the crust associated with the Basin and Range Province caused extensive volcanism in the Sierra. Around 10 Ma, the Sierra Nevada began to form: a crustal block between Coastal Range and Basin and Range Province and began to tilt to the west because of the heat from the Basin and extension range attenuates the eastern part of the block, making it stronger than the western eportion of the block. The river starts cutting deep canyons on both sides of the range. The lava filled some of these gorges, which were then eroded from the table mountain that followed the old river channel.
Around 2.5Ã, Â ° Ma, the Earth's climate is cooled, and the ice age begins. Glaciers carve U-shaped valleys across the Sierra. The combination of rivers and erosion of glaciers exposed the top of the plutons planted millions of years earlier, leaving only the remains of metamorphic rocks atop a few peaks of the Sierra.
The push of the Sierra Nevada continues today, especially along the east side. This appointment caused great earthquakes, such as the Lone Pine earthquake of 1872.
Climate and meteorology
The Sierra Nevada climate is influenced by the Mediterranean climate of California. During autumn, winter and spring, the Sierra rainfall ranges from 20 to 80 in (510 to 2,030 mm) where most occur when snow is over 6,000 feet (1,800 m). The highest rainfall in the central and northern slopes between 5,000 and 8,000 feet (1,500 and 2,400 m), due to orographic lift. Above 8,000 feet (2,400 m), rainfall is reduced in the western slopes to the summit, as most of the rainfall has been squeezed at lower altitudes. Most of the eastern region of the peak is in the shadow of rain, and receives less than 25 inches of rainfall per year. While most of the summer days are dry, afternoon thunderstorms sometimes occur, especially during the North American rainy season in mid- and late-summer. Some of these summer thunderstorms drop an inch of rain in no time, and lightning can start a fire. Summer high temperatures average 42-90 Â ° F (6-32 Â ° C). Winter is relatively light, and its temperature is usually only low enough to support a heavy snowpack. For example, Tuolumne Meadows, at an altitude of 8,600 feet (2,600 m), has a winter daily height of about 40 ° F (4 ° C) with a daily low of about 10 ° F (-12 ° C). The planting season lasts 20 to 230 days, depending on the height. The highest altitude Sierra has an alpine climate.
The Sierra Nevada snowpack is a major source of water and a significant source of power generation in California. Many reservoirs were built in the Sierra Valley throughout the 20th century, Some of the major waterways serving both the farm and the urban areas are distributing Sierra water throughout the state. However, Sierra cast a shadow of rain, which greatly affected the climate and ecology of the Central Great Basin. This shadow of rain is largely responsible for Nevada being the driest country in the United States.
Precipitation varies from year to year. It is not uncommon for several years to receive total rainfall well above or below normal.
Altitude range and steepness of Sierra Escarpment, especially at the southern end of the range, produces a wind phenomenon known as "Sierra Rotor". This is the horizontal rotation of the atmosphere to the east of the Sierra peak, which moves as a result of strong west winds.
Due to the large number of aircraft that crashed in the Sierra Nevada, mainly due to complex weather and atmospheric conditions such as downdrafts and microbursts caused by geography there, part of the area, a triangle whose vertices are Reno, Nevada; Fresno, California; and Las Vegas, Nevada, has been dubbed the "Nevada Triangle", referring to the Bermuda Triangle. A number of people consider the number of accidents in the triangle at 2,000, including millionaire and record-breaking leaflet, Steve Fossett. Theories that collisions are related in some way to Area 51 of the United States Air Force, or alien space activity, have no evidence to support it.
Ecology
Sierra Nevada is divided into several biotic zones, each of which is defined by its climate and supports a number of interdependent species. Life in higher altitude zones adapted to colder weather, and much of it rained like snow. Sierra's rain shadow causes the eastern slopes to be warmer and drier: each zone of life is higher in the east. A list of biotic zones, and appropriate elevations, is presented below:
- Western hill zones, 1,000-2,500 feet (300-760 m), with grasslands, savanna grasslands and oak-kaparral woodlands. North of Sequoia National Park, Gray pine (also known as pine digger) mixes with oak forest.
- Pinyon Fir-Juniper forest, just east side of 5,000-7,000 feet (1,500-2,100 m).
- Lower Sierra Nevada mountain forest (indicator species: Ponderosa pine, Jeffrey pine), western side of 2,700-7,000 ft (760-2.130 m), east side of 7,000-9,000 ft (2,100-2,700 m). This biotic zone is famous for containing Giant Sequoia.
- Upper mountainous forest (indicator species: Lodgepole pine, Red fir) 7,000-9,000Ã, ft (2,100-2,700Ã, m) west side, east side 9,000-10,500Ã, ft (2,700-3,200Ã, m).
- The Sierra Nevada subalpine zone 9,000-10,500Ã, ft (2,700-3,200 m) west side, 10,500-11,500Ã,
- The alpine area is over 10,500 feet (3,200 m), and is larger than the 11,500 ft (3,500 m) east side.
History
Native Americans
Archaeological excavations placed the Martyrs of the Paleo-Indians north of the Sierra Nevada during the period 3,000 BC to 500 CE. The earliest indigenous populations identified in the Sierra Nevada are the northern Paiute tribe on the east side, with the Mono tribe and the Sierra Miwok tribe on the west side, and the Kawaiisu and Tubatulabal tribes in the southern Sierra. Today, several routes of historical intertribal routes through mountain roads are known as artifact locations, such as the Duck Pass with its obsidian arrows. The tribes of California and the Sierra Native Americans live mostly peacefully, with occasional territorial disputes between the Paiute and Sierra Miwok tribes in the mountains. Washo and Maidu also reside in this area before the era of European exploration and displacement.
Etymology
Used in 1542 by Juan RodrÃÆ'guez Cabrillo to describe the Pacific Coast Range (Santa Cruz Mountains), the term "sierra nevada" is a common identification of less familiar range to the interior. In 1776, the Pedro Font map applied its name to the range currently known as Sierra Nevada.
The literal translation is "snowy mountain", from sierra "various hills", 1610, from the Spanish "sierra " jagged mountains ", lit. "see", from Latin serra "saw"; and from fem. Spanish nevado "snow".
Early European-American exploration
American exploration in the mountains began in 1827. Although before 1820 there were Spanish missions, pueblos (cities), presidios (forts), and ranchos along the California coast, no Spanish explorer is visiting the Sierra Nevada. The first Americans to visit the mountains were among groups led by feather trap Jedediah Smith, crossing the north of the Yosemite area in May 1827, at Ebbetts Pass.
In 1833, a subgroup of the Bonneville Expedition led by Joseph Reddeford Walker was sent westward to find a land route to California. Eventually, the party found a route along the current Humboldt River in Nevada, hiking the Sierra Nevada, starting near Bridgeport this time and descending between Tuolumne and the river Merced River. This group is probably the first non-native to see the Yosemite Valley. The Walker might visit Tuolumne or Merced Groves from Giant Sequoia, becoming the first non-native to see a giant tree, but the journals associated with the Walker party were destroyed in 1839, in a fire in Philadelphia.
In the winter of 1844, Lieutenant John C. França, accompanied by Kit Carson, was the first American to see Lake Tahoe. The monte mont camping party is at 8,050 ft (2,450 m).
Gold rush
California Gold Rush begins at Sutter's Mill, near Coloma, in the foothills of the western Sierra. On January 24, 1848, James W. Marshall, a foreman working for Sacramento pioneer John Sutter, found a sparkling metal in the tailgate of a Marshall-built wooden mill for Sutter on the American River. Rumors soon began to spread and were confirmed in March 1848 by a San Francisco newspaper publisher and merchant Samuel Brannan. Brannan walked through the streets of San Francisco, holding a gold bottle, shouting "Gold, Gold! Gold from the American River!"
On August 19, 1848, the New York Herald was the first major newspaper on the East Coast to report the discovery of gold. On December 5, 1848, President James Polk confirmed the discovery of gold in a speech at the Congress. Soon, a wave of immigrants from around the world, later called "forty-niners", invaded the Gold Country of California or "Mother Lode". Miners live in tents, wooden shelves, or deck cabins removed from abandoned vessels. Wherever gold is found, hundreds of miners will collaborate to build camps and stake their claims.
Because gold in gravel places in California is so richly concentrated, the forty-year-old predecessors are only looking for gold in the rivers and rivers of California. However, panning can not be done on a large scale, and miners and miner groups pass to more complex placer mines. Mining groups will divert water from all the rivers to the water gate along the river, and then dig the gold at the bottom of the newly opened river.
In 1853, most of the easily obtained gold was collected, and attention turned to extracting gold from more difficult locations. Hydraulic mining is used on ancient gold-bearing gravel beds on hillsides and cliffs in gold fields. In hydraulic mining, a high-pressure hose is directed toward a strong stream or water jet on a bed of gold gravel pads. It is estimated that by the mid-1880s, 11 million ounces (340Ã, t) of gold (worth about US $ 15 billion at December 2010 prices) have been discovered by "hydraulics". The byproduct of this method of extraction is that large quantities of gravel, silt, heavy metal, and other pollutants flow into rivers and streams. In 1999, many areas still bear the traces of hydraulic mining, because the sediments produced from soil and downstream pebbles do not support plant life.
Estimated in 1855, at least 300,000 gold seekers, merchants, and other immigrants have arrived in California from around the world. The large number of newcomers brought by Gold Rush keeps Native Americans out of hunting, fishing, and collecting their traditional food. To protect their homes and livelihoods, some Native Americans responded by attacking miners, provoking counterattacks in indigenous villages. Native Americans, who were shot dead, were often slaughtered.
Thorough exploration
Gold Rush inhabits the western foothills of the Sierra Nevada, but even in 1860, most of the Sierra has not been explored. The state legislature endorsed the California Geological Survey to formally explore the Sierra (and survey other states). Josiah Whitney was appointed to lead the survey. Men from the survey, including William H. Brewer, Charles F. Hoffmann and Clarence King, explored inland from what would become Yosemite National Park in 1863. In 1864, they explored the area around Kings Canyon. In 1869, John Muir began his wandering in the Sierra Nevada ranks, and in 1871, the King was the first to climb Mount Langley as well that year, the fishermen were the first to climb Mount Whitney. From 1892-7 Theodore Solomons made the first attempt to map routes along the Sierra peak.
Others finish exploring and charting Sierra. Bolton Coit Brown explored the Kings River watershed in 1895-1899. Joseph N. LeConte maps the area around Yosemite National Park and what will become Kings Canyon National Park. James S. Hutchinson, a famous mountaineer, climbed Palisades (1904) and Mount Humphreys (1905). In 1912, the USGS published a set of maps of the Sierra Nevada, and the era of exploration was over.
Preservation
The tourism potential of Sierra Nevada is recognized at the beginning of Europe's history of reach. The Yosemite Valley was first protected by the federal government in 1864. The Valley and Mariposa Grove were handed over to California in 1866 and converted into state parks. John Muir considers excessive shepherding by sheep and the felling of Giant Sequoia to be a problem in the Sierra. Muir successfully lobbied for the protection of the rest of Yosemite National Park: The Congress made the Act to protect the park in 1890. The Valley and the Mariposa Grove were added to the Park in 1906. That same year, Sequoia National Park was formed to protect Giant Sequoia: all Sequoia logging stop at that moment.
In 1903, the city of San Francisco proposed the construction of a hydroelectric dam to flood the Hetch Hetchy Valley. The City and Sierra Club argued about the dam for 10 years, until the US Congress passed the Raker Act in 1913 and allowed the construction of the dam to continue. O'Shaughnessy Dam was completed in 1923.
Between 1912 and 1918, Congress argued three times to protect Lake Tahoe in the national park. None of these efforts succeeded, and after World War II, cities like South Lake Tahoe grew up around the shores of the lake. In 1980, the permanent population in the Lake Tahoe area grew by 50,000, while the summer population grew to 90,000. The development around Lake Tahoe affects the clarity of lake water. To maintain the clarity of the lake, the development in the Tahoe valley is currently regulated by the Tahoe Regional Planning Board.
As the 20th century progressed, more Sierra was available for recreation; other forms of economic activity decline. The John Muir Trail, a trail that follows the Sierra peak from the Yosemite Valley to Mount Whitney, was funded in 1915 and completed in 1938. Kings Canyon National Park was formed in 1940 to protect the deep canyons of the Kings River.
In 1964, the Wilderness Act protected the Sierra section as a primitive area where humans were only temporary visitors. Gradually, 20 areas of wilderness were established to protect the beautiful Sierra hinterland. These wilderness areas include the Wilderness John Muir (protecting the eastern slopes of the Sierra and the area between Yosemite and Kings Canyon Parks), and the jungle in each of the National Parks. Because of the Wilderness Act and the rocky terrain in the area, plans to build two trans-Sierra highways throughout the Sierra Escarpment section, State Route 168 and State Route 190, are abandoned; two highways each remain separate as non-consecutive segments on either side of the Sierra.
Sierra Nevada still faces a number of issues that threaten its preservation. Logging takes place on private land and public land, including controversial cutting methods and dwindling logging on private and public lands. Pastoral care takes place on private land as well as on National Forest land, which includes the Wilderness area. Excessive grazing can alter hydrological processes and vegetation composition, remove vegetation that serves as food and habitat for native species, and contribute to sedimentation and pollution in waterways. The recent increase in major forest fires such as Api Rim in Yosemite National Park and the Stanislaus National Forest and the King's Flame in the Eldorado National Forest, has sparked concerns. A 2015 study indicates that increased fire risk in California may be caused by human-caused climate change. A study reviewing more than 8,000 years found that warmer climatic periods suffered severe droughts and more fires replaced positions and concluded that because the climate is very influential on forest fires, trying to re-create preschool forest structures is unlikely in the future which is warmer.
See also
- Bibliography of the Sierra Nevada
- List of Sierra Nevada Street Paths
- List of Sierra Nevada topics
References
External links
- Map that can be clicked from the top of Sierra Nevada
- Sierra Nevada Info at SummitPost
Source of the article : Wikipedia
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