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저희 설암에서 열심을 내고 있는 하이 시에라에 관한 공부입니다. 영어로 되어 있습니다만 역사적, 지리적, 또한 생태학적인 도움이 될만한 사항들이 있으니 천천이 읽어봐 주시기 바랍니다. The Sierra Nevada (Spanish for "Snowy Range") is a mountain range located in the U.S. state of California. In a few places, it overlaps into neighboring Nevada. The range is also known informally as the Sierra, the High Sierra, and the Sierras. The Sierra Nevada stretches 400 miles (650 km), from Fredonyer Pass in the north to Tehachapi Pass in the south. It is bounded on the west by California's Central Valley, and on the east by the Great Basin. Physiographically, it is a section of the Cascade-Sierra Mountains province, which in turn is part of the larger Pacific Mountain System physiographic division. In west-east cross section, the Sierra is shaped like a trapdoor: the elevation gradually increases on the west slope, while the east slope forms a steep escarpment. Thus, the crest runs principally along the eastern edge of the Sierra Nevada range. Rivers flowing west from the Sierra Crest eventually drain into the Pacific Ocean, while rivers draining east flow into the Great Basin and do not reach any ocean. However, water from several streams and the Owens River is redirected to the city of Los Angeles (see Los Angeles Aqueduct). Thus, by artificial means, some east-flowing river water does make it to the Pacific Ocean. There are several notable geographical features in the Sierra Nevada: Lake Tahoe is a large, clear freshwater lake in the northern Sierra Nevada, with an elevation of 6,225 feet (1,897 m) and an area of 191 square miles (489 km). Lake Tahoe lies between the main Sierra and the Carson Range, a spur of the Sierra. Hetch Hetchy Valley, Yosemite Valley, Kings Canyon, Tehipite Valley and Kern Canyon are the most well-known of many beautiful, glacially-scoured canyons on the west side of the Sierra. Yosemite National Park is filled with stunning features, such as waterfalls and granite domes. Mount Whitney, at 14,505 feet (4,421 m), is the highest point in the contiguous United States. Mt. Whitney is on the eastern border of Sequoia National Park. Groves of Giant Sequoias Sequoiadendron giganteum occur along a narrow band of altitude on the western side of the Sierra Nevada. Giant Sequoias are the most massive trees in the world. East Face of Mt. Whitney as seen from the way up on Whitney Portal. The height of the mountains in the Sierra Nevada gradually increases from north to south. Between Fredonyer Pass and Lake Tahoe, the peaks range from 5,000 feet (1,524 m) to 8,000 feet (2,438 m). The crest near Lake Tahoe is roughly 9,000 feet (2,700 m) high, with several peaks approaching the height of Freel Peak (10,881 feet, 3,316 m), including Mount Rose (10,776 feet, 3,285 m), which overlooks Reno from the north end of the Carson Range. The crest near Yosemite National Park is roughly 13,000 feet (4,000 m) high at Mount Dana and Mount Lyell, and the entire range attains its peak at Mount Whitney (14,505 feet, 4,421 m). South of Mount Whitney, the range diminishes in elevation, but there are still several high points like Florence Peak (12,405 feet, 3,781 m) and Olancha Peak (12,123 feet, 3,695 m). The range still climbs almost to 10,000 feet (3,048 m) near Lake Isabella, but south of the lake, the peaks reach only to a modest 8,000 feet (2,438 m). Geology The well-known granite that makes up most of the southern Sierra started to form in the Triassic period. At that time, an island arc collided with the West coast of North America and raised a set of mountains, in an event called the Nevadan orogeny. This event produced metamorphic rock. At roughly the same time, a subduction zone started to form at the edge of the continent. This means that an oceanic plate started to dive beneath the North American plate. Magma from the melting oceanic plate rose in plumes (plutons) deep underground, their combined mass forming what is called the Sierra Nevada batholith. These plutons formed at various times, from 115 million to 87 million years ago. By 65 million years ago, the proto-Sierra Nevada was worn down to a range of rolling low mountains, a few thousand feet high. 20 million years ago, crustal extension associated with the Basin and Range Province caused extensive volcanism in the Sierra. About 4 million years ago, the Sierra Nevada started to form and tilt to the west. Rivers started cutting deep canyons on both sides of the range. The Earth's climate cooled, and ice ages started about 2.5 million years ago. Glaciers carved out characteristic U-shaped canyons throughout the Sierra. The combination of river and glacier erosion exposed the uppermost portions of the plutons emplaced millions of years before, leaving only a remnant of metamorphic rock on top of some Sierra peaks. Uplift of the Sierra Nevada continues today, especially along its eastern side. This uplift causes large earthquakes, such as the Lone Pine earthquake of 1872. Ecology The Sierra Nevada is divided into a number of biotic zones. The Pinyon pine-Juniper woodland, 5,000-7,000 ft (1,500-2,100 m) east side only Notable species: Pinyon Jay, Desert Bighorn Sheep. The lower montane forest, 3,000-7,000 ft (1,000-2,100 m) west side, 7,000-8,500 ft (2,100-2,600 m) east side Notable species: Ponderosa pine and Jeffrey pine, California black oak, Incense-cedar, Giant Sequoia, Dark-eyed Junco, Mountain Chickadee, Western gray squirrel, Mule deer, American black bear The upper montane forest, 7,000-9,000 ft (2,100-2,700 m) west side, 8,500-10,500 ft (2,600-3,100 m) east side Notable species: Lodgepole pine, Red Fir, Mountain Hemlock, Sierra Juniper, Hermit Thrush, Sage Grouse, Great Grey Owl, Golden-mantled Ground Squirrel, Marten The subalpine forest, 9,000-10,500 ft (2,700-3,100 m) west side, 10,500-11,500 ft (3,100-3,500 m) east side Notable species: Whitebark pine and Foxtail pine, Clark's Nutcracker The alpine region >10,500 ft (>3,100 m) west side, >11,500 ft (>3,500 m) east side Notable species: Polemonium viscosum (Sky Pilot), Pika, Belding's ground squirrel, Yellow-Bellied Marmot, Sierra Nevada Bighorn Sheep History History of exploration The earliest identified inhabitants of the Sierra Nevada were the Paiute tribe on the east side and the Mono and Sierra Miwok tribe on the western side. Today, passes such as Duck Pass are littered with discarded obsidian arrowheads that date back to trade between tribes. There were also prehistorical territorial disputes between the Paiute and Sierra Miwok tribesEuropean-American exploration of the mountain range started in the 1840s. In the winter of 1844, Lieutenant John C. Fr?ont, accompanied by Kit Carson, was the first white man to see Lake Tahoe. By 1860, even though the California Gold Rush populated the flanks of the Sierra Nevada, most of the Sierra remained unexplored. Therefore, the state legislature authorized the California Geological Survey to officially explore the Sierra (and survey the rest of the state). Josiah Whitney was appointed to head the survey. Men of the survey, including William H. Brewer, Charles F. Hoffmann, and Clarence King, explored the backcountry of what would become Yosemite National Park in 1863. In 1864, they explored the area around Kings Canyon. King later recounted his adventures over the Kings-Kern divide in his book Mountaineering in the Sierra Nevada. In 1871, King mistakenly thought that Mount Langley was the highest peak in the Sierra and climbed it. However, before he could climb the true highest peak (Mount Whitney), fishermen from Lone Pine climbed it and left a note. Between 1892 and 1897, Theodore Solomons was the first explorer to attempt to map a route along the crest of the Sierra (what would eventually become the John Muir Trail, along a different route). On his 1894 expedition, he took along Leigh Bierce, son of writer Ambrose Bierce.