Crater Lake National Park

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Crater Lake National Park
IUCN Category II (National Park)
Location of Crater Lake in southwest Oregon
Location:	Oregon, USA
Nearest city:	Medford, Oregon
Coordinates:	42°56′0″N, 122°07′0″W
Area:	183,224 acres (741.48 km²)
Established:	May 22, 1902
Total Visitation:	496,840 (in 2005)
Governing body:	National Park Service

Crater Lake National Park is a United States National Park located in Southern Oregon whose primary feature is Crater Lake. It was established on May 22, 1902 as the fifth National Park in the U.S.^[1] The park encompasses Crater Lake's caldera, which rests in the remains of a destroyed volcano posthumously called Mount Mazama. The lake is 1,958 feet (597 m) deep at its deepest point, which makes it the deepest lake in the United States and the seventh deepest anywhere in the world. The caldera rim ranges in elevation from 7000 to 8000 feet (2100 to 2400 m). The average elevation of the lake itself is 6178 ft (1883 m). The park covers 286 mi² (741 km²). Crater Lake has no streams flowing into or out of it. The water is extraordinarily clear with a striking blue hue.

Contents 1 Geology 2 Park features 3 History 4 Activities 5 Noted references 6 See also 7 External links

[edit] Geology

Volcanic activity in the area is fed by subduction off the coast of Oregon as the Juan de Fuca Plate slips below the North American Plate (see plate tectonics). Heat and compression generated by this movement has created a mountain chain topped by a series of volcanoes, which together are called the Cascade Range. The large volcanoes in the range are called the High Cascades. However, there are many other volcanoes in the range as well, most of which are much smaller.

About 400,000 years ago, Mount Mazama began life in much the same way as the other mountains of the High Cascades, as overlapping shield volcanoes. Over time, alternating layers of lava flows and pyroclastic flows built Mazama's overlapping cones until it reached about 11000 feet (3400 m) in height.

As the young stratovolcano grew, many smaller volcanoes and volcanic vents were built in the area of the park and just outside what are now the park's borders. Chief among these were cinder cones. Although the early examples are gone—cinder cones erode easily—there are at least 13 much younger cinder cones in the park, and at least another 11 or so outside its borders, that still retain their distinctive cinder cone appearance. There continues to be debate as to whether these minor volcanoes and vents were parasitic to Mazama's magma chamber and system or if they were related to background Oregon Cascade volcanism.

After a period of dormancy, Mazama became active again. Then, around 4860 BC, Mazama collapsed into itself during a tremendous volcanic eruption, losing 2500 to 3500 feet (760 to 1100 m) in height. The eruption formed a large caldera that was later filled with a deep blue lake known today as Crater Lake.

The eruptive period that decapitated Mazama also laid waste to much of the greater Crater Lake area and deposited ash as far east as the northwest corner of what is now Yellowstone National Park, as far south as central Nevada, and as far north as southern British Columbia. It produced more than 150 times as much ash as the May 18, 1980 eruption of Mount St. Helens.

[edit] Park features

Some notable park features created by this huge eruption are:

• The Pumice Desert: A very thick layer of pumice and ash leading away from Mazama in a northerly direction. Even after thousands of years, this area is largely devoid of plants due to excessive porosity (meaning water drains through quickly) and poor soil composed primarily of regolith.
• The Pinnacles: When the very hot ash and pumice came to rest near the volcano, it formed 200 to 300-foot (60 to 90 m) thick gas-charged deposits. For perhaps years afterward, hot gas moved to the surface and slowly cemented ash and pumice together in channels and escaped through fumaroles. Erosion later removed most of the surrounding loose ash and pumice, leaving tall pinnacles and spires.

Other park features:

• Mount Scott is a steep andesitic cone whose lava came from magma from Mazama's magma chamber; geologists call such volcano a "parasitic" or "satellite" cone. Volcanic eruptions apparently ceased on Scott sometime before the end of the Pleistocene; one remaining large cirque on Scott's northwest side was left unmodified by post-ice age volcanism.
• In the southwest corner of the park stands Union Peak, an extinct volcano whose primary remains consist of a large volcanic plug, which is lava that solidified in the volcano's neck.
• Crater Peak is a shield volcano primarily made of andesite and basalt lava flows topped by andesitic and dacite tephra.
• Timber Crater is a shield volcano located in the northeast corner of the park. Like Crater Peak, it is made of basaltic and andesitic lava flows, but, unlike Crater, it is topped by two cinder cones.
• Rim Drive is the most popular road in the park; it follows a scenic route around the caldera rim.

[edit] History

Local Native Americans witnessed the collapse of Mount Mazama and kept the event alive in their legends. One ancient legend of the Klamath people closely parallels the geologic story which emerges from today's scientific research. The legend tells of two Chiefs, Llao of the Below World and Skell of the Above World, pitted in a battle which ended up in the destruction of Llao's home, Mt. Mazama.^[2] The battle was witnessed in the eruption of Mt. Mazama and the creation of Crater Lake.

The first known Caucasians to visit the lake were a trio of gold prospectors: John Wesley Hillman, Henry Klippel, and Issac Skeeters who, on June 12, 1853, stumbled upon the long, sloping mountain while looking for a lost mine. Stunned by vibrant blue color of the lake, they named the indigo body of water "Deep Blue Lake" and the place on the southwest side of the rim where he first saw the lake later became known as Discovery Point.^[1] But gold was more on the minds of settlers at the time and the discovery was soon forgotten. The suggested name later fell out of favor by locals, who preferred the name Crater Lake, although crater is a misnomer because the lake's basin is in fact a caldera, a volcanic feature that forms from subsidence, not from excavation.

William Gladstone Steel devoted his life and fortune to the establishment and management of a national park (US) at Crater Lake. His preoccupation with the lake began in 1870. In his efforts to bring recognition to the park, he participated in lake surveys that provided scientific support. He named many of the lake's landmarks, including Wizard Island, Llao Rock, and Skell Head.

With the help of geologist Clarence Dutton, Steel organized a USGS expedition to study the lake in 1886. The party carried the Cleetwood, a half-ton survey boat, up the steep slopes of the mountain then lowered it to the lake. From the stern of the Cleetwood, a piece of pipe on the end of a spool of piano wire sounded the depth of the lake at 168 different points. Their deepest sounding, 1,996 feet, was very close to the modern official depth of 1,932 feet (made in 1953 by sonar).^[1] At the same time, a topographer surveyed the area and created the first professional map of the Crater Lake area.

Partly based on data from the expedition and lobbying from Steel and others, Crater Lake National Park was established May 22, 1902 by President Theodore Roosevelt. And because of Steel's involvement, Crater Lake Lodge was opened in 1915 and the Rim Drive was completed in 1918.^[1]

Highways were later built to the park to help facilitate visitation. The 1929 edition of O Ranger! described access and facilities available by then:

“

Crater Lake National Park is reached by train on the Southern Pacific Railroad lines into Medford and Klamath Falls, at which stops motor stages make the short trip to the park. A hotel on the rim of the lake offers accommodations. For the motorist, the visit to the park is a short side trip from the Pacific and Dalles-California highways. He will find, in addition to the hotel, campsites, stores, filling stations. The park is open to travel from late June or July 1 for as long as snow does not block the roads, generally until October.[3]

”

[edit] Activities

There are many hiking trails inside the park, and several campgrounds. Unlicensed fishing is allowed without limitation of size, species or number. The lake is believed to have no indigenous fish, but were introduced beginning in 1888 until fish stocking ended in 1941. Kokanee Salmon (Oncorhynchus nerka) and Rainbow Trout (Oncorhynchus mykiss) now thrive naturally.^[4] Swimming is allowed in the lake, and boat tours operate daily during the summer which stops at Wizard Island, a cinder cone inside the lake. All lake access is from Cleatwood Trail, a steep walking trail.

Observation points along the caldera rim are easily accessible by car via Rim Drive. The best vantage point, however, is from Mt. Scott, 8929 feet (2721 m). Getting there requires a fairly steep 2.5 mile (4 km) hike from the Rim Drive trailhead. On a clear day from Mt. Scott's summit, visibility exceeds 100 miles (160 km) and can, in one single view, take in the entire caldera. Also visible from this point are the white peaked High Cascade volcanoes to the north, the Columbia River Plateau to the east, and the Western Cascades and the more distant Klamath Mountains to the west.

Crater Lake's features are fully accessible during the summer months: heavy snow in the park during the fall, winter, and spring forces road and trail closures, including popular Rim Drive (which is generally open from July to October).

[edit] Noted references

[edit] See also

• Crater Lake - More information about the lake
• Mount Mazama - Formation of the volcano and its collapse to form the lake more than 6000 years ago
• List of nationally protected areas of the United States

[edit] External links

• Official site: Crater Lake National Park
• NASA Earth Observatory images of Crater Lake
• Google Maps image of Crater Lake

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