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164-676: Mount Mazama ( Tum-sum-ne in the Native American language Klamath ) is a complex volcano in the western U.S. state of Oregon , in a segment of the Cascade Volcanic Arc and Cascade Range . The volcano is in Klamath County , in the southern Cascades, 60 miles (97 km) north of the Oregon– California border. Its collapse, due to the eruption of magma emptying the underlying magma chamber , formed

328-548: A caldera that holds Crater Lake ( Giiwas in the Native American language Klamath ). Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m). Crater Lake is 1,943 feet (592 m) deep, the deepest freshwater body in the U.S. and the second deepest in North America after Great Slave Lake in Canada. Mount Mazama formed as

492-424: A cirque landform (alternatively known as a corrie or as a cwm ) – a typically armchair-shaped geological feature (such as a depression between mountains enclosed by arêtes ) – which collects and compresses through gravity the snow that falls into it. This snow accumulates and the weight of the snow falling above compacts it, forming névé (granular snow). Further crushing of the individual snowflakes and squeezing

656-571: A stress field in the upper crust nearby. Mazama is underlain by the Quaternary High Cascade basalt and mafic (rich in magnesium and iron) andesite to the west and southwest, with high-volume rhyodacite lava flows from 600,000 to 700,000 years old underlying Mazama deposits to the south, southeast, east, and northeast. It is a major Cascade volcano, and is at the intersection of the Cascade Range and Klamath graben,

820-567: A camp site, but not a permanent place of habitation. Sagebrush sandals have been discovered to the east of the mountain. These populations faced an increasingly dry climate and the hazards associated with volcanic activity. In civilizations south of Mazama, stories about the volcano's eruption have been transmitted for many generations. Native populations did not tell settlers about the area because it held sacred importance among tribes throughout Oregon and northern California. Shamans did not allow local Native Americans to look towards Crater Lake, and

984-518: A cluster of overlapping edifices. Made up of shield volcanoes and small stratocones, it had an irregular shape. Mount Scott , at a height of 8,934 feet (2,723 m), marks the oldest visible remnant of this original cluster. Scott was the first of the composite volcanoes that created the Mazama complex, formed by a quick and active cone-building phase and becoming inactive long before the most recent eruption at Mazama. With time, eruptive activity moved to

1148-434: A few composite cones in the vicinity of the caldera. At about 420,000 years old, Mount Scott has a conical shape, but has been extensively altered by Pleistocene glacial erosion, which carved a large cirque on its western flank and smaller ones on its eastern and northeastern sides. Scott lacks a summit crater. Hillman Peak was the youngest composite cone in the Mazama eruptive center, forming about 70,000 years ago. It lies on

1312-522: A glacier is usually assessed by determining the glacier mass balance or observing terminus behavior. Healthy glaciers have large accumulation zones, more than 60% of their area is snow-covered at the end of the melt season, and they have a terminus with a vigorous flow. Following the Little Ice Age 's end around 1850, glaciers around the Earth have retreated substantially . A slight cooling led to

1476-601: A glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions , but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand . Between latitudes 35°N and 35°S, glaciers occur only in

1640-411: A glacier via moulins . Streams within or beneath a glacier flow in englacial or sub-glacial tunnels. These tunnels sometimes reemerge at the glacier's surface. Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. The bed's temperature, roughness and softness define basal shear stress, which in turn defines whether movement of

1804-424: A gold mine called "Lost Cabin." Financed by a successful gold miner named John Wesley Hillman , Skeeters led a team with ten other Oregonians to find the mine. On June 12, they reached Crater Lake, which Skeeters noted had the bluest water he had ever seen, suggesting they name it "Deep Blue Lake." The trip failed to procure gold before running low on provisions. With the absence of gold in that region, their discovery

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1968-478: A group of overlapping volcanic edifices such as shield volcanoes and small composite cones , becoming active intermittently until its climactic eruption 7,700 years ago. This eruption, the largest known within the Cascade Volcanic Arc in a million years, destroyed Mazama's summit, reducing its approximate 12,000-foot (3,700 m) height by about 1 mile (1,600 m). Much of the edifice fell into

2132-502: A group of overlapping volcanic edifices, which included shield volcanoes and small composite cones. Cone-building eruptions took place within short periods of time. Shield volcanoes fed Mazama's expansion with basaltic andesite lava flows that covered large expanses on the slopes of the mountain. Forming lava fountains similar to those observed in Hawaiian eruptions , the shield volcanoes erupted incandescent lava bombs and were deposited on

2296-1018: A high vent density with many shields and monogenetic volcanic centers. After Newberry Volcano , Mazama is the second largest Quaternary volcanic edifice in Oregon, and the most voluminous, with an overall volume of 29 cubic miles (120 km). Mazama is the newest of the Quaternary calderas in the Cascade Volcanic Arc, which also include the Newberry calderas and the caldera at the Medicine Lake Volcano . Quaternary monogenetic volcanism throughout Oregon's High Cascades includes cinder cones, lava fields , and small shield volcanoes, which have produced lava ranging from low-potassium, high-alumina olivine tholeiite to medium-potassium calc-alkaline basalt, basaltic andesite to shoshonitic basaltic andesite. The Mazama volcanic complex originally formed as

2460-408: A kilometer per year. Eventually, the ice will be surging fast enough that it begins to thin, as accumulation cannot keep up with the transport. This thinning will increase the conductive heat loss, slowing the glacier and causing freezing. This freezing will slow the glacier further, often until it is stationary, whence the cycle can begin again. The flow of water under the glacial surface can have

2624-404: A large effect on the motion of the glacier itself. Subglacial lakes contain significant amounts of water, which can move fast: cubic kilometers can be transported between lakes over the course of a couple of years. This motion is thought to occur in two main modes: pipe flow involves liquid water moving through pipe-like conduits, like a sub-glacial river; sheet flow involves motion of water in

2788-404: A large shield volcano from 170,000 to 120,000 years ago. Other andesitic lava deposits can be observed in the caldera wall's northern side. The Mazama complex was inactive between 100,000 and 75,000 years ago. About 75,000 years ago, the volcano erupted effusive lava flows of andesite that formed 980-foot (300 m) thick deposits below Hillman Peak that extended at least 4.3 miles (7 km) from

2952-460: A lower heat conductance, meaning that the basal temperature is also likely to be higher. Bed temperature tends to vary in a cyclic fashion. A cool bed has a high strength, reducing the speed of the glacier. This increases the rate of accumulation, since newly fallen snow is not transported away. Consequently, the glacier thickens, with three consequences: firstly, the bed is better insulated, allowing greater retention of geothermal heat. Secondly,

3116-486: A nearly vertical-walled crater, producing pumice and creating a dome over the Redcloud vent. Grouse Hill's lava flow deposit and lava dome formed at about the same time, about 27,000 years ago. At the end of this eruptive sequence, rhyodacite lava domes formed on the northeastern slopes of the volcano. Between 100 and 200 years before the climactic eruption, Llao Rock, a 1,200-foot (370 m) thick block of dark lava with

3280-666: A rhyodacite lava dome, about 2,400 years after the first period of postcaldera activity. Given that Mazama has had periods of sporadic eruptions for 420,000 years, the United States Geological Survey thinks that it is "virtually certain" that Mazama will erupt again in the future. Mazama is considered dormant, but it remains monitored by the United States Geological Survey Cascades Volcano Observatory . Future eruptions would likely take place near

3444-502: A significant event at Pumice Castle on the eastern wall of Mazama. This formed welded deposits near the vent, also forming non-welded deposits to the south and on the northern part of Mazama. Between 40,000 years ago and Mazama's major eruption, no andesitic or dacitic volcanism took place. However, rhyodacitic magma was erupted at Grouse Hill, Steel Bay, and Redcloud Cliff in the form of pumice and lava flows made of hornblende - phyric , or chemically evolved, rhyodacite. During this period of

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3608-432: A site at Birch Creek where non-diagnostic artifacts were discovered beneath Glacier Peak Ash. Since the climactic eruption 7,700 years ago, all eruptive activity at Mazama has occurred within the caldera. After the caldera formed, the original crater was widened by avalanches from the walls. These gave a scalloped profile to the caldera, such as the coves at Llao Bay, Steel Bay, and Grotto Cove. The Chaski slide, for example,

3772-645: A solid, dense interior rich with angular lava blocks . Research by Howel Williams superimposed the Crater Lake caldera on other Cascade stratovolcanoes including Mount Shasta in California and Mount Rainier in Washington state, and concluded that Mazama stood at 12,000 feet (3,700 m) pre-collapse, which has been accepted as the standard estimate by geologists. By the Holocene, the Mazama volcano

3936-488: A thin layer. A switch between the two flow conditions may be associated with surging behavior. Indeed, the loss of sub-glacial water supply has been linked with the shut-down of ice movement in the Kamb ice stream. The subglacial motion of water is expressed in the surface topography of ice sheets, which slump down into vacated subglacial lakes. The speed of glacial displacement is partly determined by friction . Friction makes

4100-410: A tremendous impact as the iceberg strikes the water. Tidewater glaciers undergo centuries-long cycles of advance and retreat that are much less affected by climate change than other glaciers. Thermally, a temperate glacier is at a melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing threshold from the surface to its base, although

4264-469: A volume of 0.25 cubic miles (1.0 km), was produced from a rhyodacite flow erupted from Mazama. It has a round center and extensions on the sides, resembling a bird of prey . The formation of Llao Rock was preceded by explosive eruptions of rhyodacite, creating pumice and ash that were ejected high into the atmosphere and carried for several hundred miles into northern and eastern Washington state, eastern Oregon, and western Nevada. A large crater formed but

4428-468: Is a persistent body of dense ice that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries . It acquires distinguishing features, such as crevasses and seracs , as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques , moraines , or fjords . Although

4592-456: Is above or at freezing at the interface and is able to slide at this contact. This contrast is thought to a large extent to govern the ability of a glacier to effectively erode its bed , as sliding ice promotes plucking at rock from the surface below. Glaciers which are partly cold-based and partly warm-based are known as polythermal . Glaciers form where the accumulation of snow and ice exceeds ablation . A glacier usually originates from

4756-407: Is affected by factors such as slope, ice thickness, snowfall, longitudinal confinement, basal temperature, meltwater production, and bed hardness. A few glaciers have periods of very rapid advancement called surges . These glaciers exhibit normal movement until suddenly they accelerate, then return to their previous movement state. These surges may be caused by the failure of the underlying bedrock,

4920-414: Is an exception, and there is evidence suggesting this is a consequence of a recent sound change . Albert Samuel Gatschet recorded geminated /sː/ in the late 19th century, but this sound was consistently recorded as degeminated /s/ by M. A. R. Barker in the 1960s. Sometime after Gatschet recorded the language and before Barker did the same, */sː/ may have degeminated into /s/ . Klamath word order

5084-411: Is because these peaks are located near or in the hyperarid Atacama Desert . Glaciers erode terrain through two principal processes: plucking and abrasion . As glaciers flow over bedrock, they soften and lift blocks of rock into the ice. This process, called plucking, is caused by subglacial water that penetrates fractures in the bedrock and subsequently freezes and expands. This expansion causes

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5248-406: Is by basal sliding, where meltwater forms between the ice and the bed itself. Whether a bed is hard or soft depends on the porosity and pore pressure; higher porosity decreases the sediment strength (thus increases the shear stress τ B ). Porosity may vary through a range of methods. Bed softness may vary in space or time, and changes dramatically from glacier to glacier. An important factor

5412-434: Is called glaciology . Glaciers are important components of the global cryosphere . Glaciers are categorized by their morphology, thermal characteristics, and behavior. Alpine glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier , or alternatively, an alpine glacier or mountain glacier . A large body of glacial ice astride a mountain, mountain range, or volcano

5576-416: Is called rock flour and is made up of rock grains between 0.002 and 0.00625 mm in size. Abrasion leads to steeper valley walls and mountain slopes in alpine settings, which can cause avalanches and rock slides, which add even more material to the glacier. Glacial abrasion is commonly characterized by glacial striations . Glaciers produce these when they contain large boulders that carve long scratches in

5740-439: Is conditioned by pragmatics. There is no clearly defined verb phrase or noun phrase. Alignment is nominative–accusative, with nominal case marking also distinguishing adjectives from nouns. Many verbs obligatorily classify an absolutive case. There are directive and applicative constructions. Glacier A glacier ( US : / ˈ ɡ l eɪ ʃ ər / ; UK : / ˈ ɡ l æ s i ər , ˈ ɡ l eɪ s i ər / )

5904-597: Is found at a higher layer than the Glacier Peak ash, estimated to have deposited over 13,000 years ago. Mazama Ash is the most widely distributed tephra layer from the late Quaternary in the United States and southwestern Canada, extending to eight states to the west and three Canadian provinces. It forms orange colored deposits. Like the Glacier Peak Ash deposits, Mazama Ash is well preserved in

6068-647: Is higher, and the mountains above 5,000 m (16,400 ft) usually have permanent snow. Even at high latitudes, glacier formation is not inevitable. Areas of the Arctic , such as Banks Island , and the McMurdo Dry Valleys in Antarctica are considered polar deserts where glaciers cannot form because they receive little snowfall despite the bitter cold. Cold air, unlike warm air, is unable to transport much water vapor. Even during glacial periods of

6232-466: Is only about 50 people, more than 270,000 live within 62 miles (100 km) of the volcano. Even so, highly consequential eruptions at Mazama seem unlikely in the near future. Large, pyroclastic eruptions like the climactic eruption are unlikely for thousands of years. Similarly, the release of lethal gases like carbon dioxide from Crater Lake, similar to the eruption from Lake Nyos in Cameroon in 1986,

6396-897: Is termed an ice cap or ice field . Ice caps have an area less than 50,000 km (19,000 sq mi) by definition. Glacial bodies larger than 50,000 km (19,000 sq mi) are called ice sheets or continental glaciers . Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces. The only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of freshwater, enough that if both melted, global sea levels would rise by over 70 m (230 ft). Portions of an ice sheet or cap that extend into water are called ice shelves ; they tend to be thin with limited slopes and reduced velocities. Narrow, fast-moving sections of an ice sheet are called ice streams . In Antarctica, many ice streams drain into large ice shelves . Some drain directly into

6560-413: Is the region where there is a net loss in glacier mass. The upper part of a glacier, where accumulation exceeds ablation, is called the accumulation zone . The equilibrium line separates the ablation zone and the accumulation zone; it is the contour where the amount of new snow gained by accumulation is equal to the amount of ice lost through ablation. In general, the accumulation zone accounts for 60–70% of

6724-402: Is the underlying geology; glacial speeds tend to differ more when they change bedrock than when the gradient changes. Further, bed roughness can also act to slow glacial motion. The roughness of the bed is a measure of how many boulders and obstacles protrude into the overlying ice. Ice flows around these obstacles by melting under the high pressure on their stoss side ; the resultant meltwater

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6888-552: Is then forced into the cavity arising in their lee side , where it re-freezes. As well as affecting the sediment stress, fluid pressure (p w ) can affect the friction between the glacier and the bed. High fluid pressure provides a buoyancy force upwards on the glacier, reducing the friction at its base. The fluid pressure is compared to the ice overburden pressure, p i , given by ρgh. Under fast-flowing ice streams, these two pressures will be approximately equal, with an effective pressure (p i – p w ) of 30 kPa; i.e. all of

7052-507: Is unlikely as a result of the natural mixing of deep and surface water within the lake. There is no known mechanism by which Crater Lake's water could be catastrophically drained or by which the caldera walls would fail suddenly. Minor hydrothermal explosions could still potentially be dangerous, as the ejection of ballistic blocks or tall waves could threaten people standing near the lake, traveling at speeds from 330 to 820 feet per second (100 to 250 m/s). Landslides could threaten visitors to

7216-416: Is unlikely to produce mudflows far from the caldera, though a nearby vent outside the caldera could erupt and mix with snow. Eruptions are unlikely to produce waves that extend beyond Crater Lake, but powerful explosions could produce tall waves in the caldera. An eruption as explosive as the one 7,700 years ago is unlikely given that it would require larger volumes of magma than are known to be available within

7380-993: The Andes , the Himalayas , the Rocky Mountains , the Caucasus , Scandinavian Mountains , and the Alps . Snezhnika glacier in Pirin Mountain, Bulgaria with a latitude of 41°46′09″ N is the southernmost glacial mass in Europe. Mainland Australia currently contains no glaciers, although a small glacier on Mount Kosciuszko was present in the last glacial period . In New Guinea, small, rapidly diminishing, glaciers are located on Puncak Jaya . Africa has glaciers on Mount Kilimanjaro in Tanzania, on Mount Kenya , and in

7544-644: The Faroe and Crozet Islands were completely glaciated. The permanent snow cover necessary for glacier formation is affected by factors such as the degree of slope on the land, amount of snowfall and the winds. Glaciers can be found in all latitudes except from 20° to 27° north and south of the equator where the presence of the descending limb of the Hadley circulation lowers precipitation so much that with high insolation snow lines reach above 6,500 m (21,330 ft). Between 19˚N and 19˚S, however, precipitation

7708-760: The Himalayas , Andes , and a few high mountains in East Africa, Mexico, New Guinea and on Zard-Kuh in Iran. With more than 7,000 known glaciers, Pakistan has more glacial ice than any other country outside the polar regions. Glaciers cover about 10% of Earth's land surface. Continental glaciers cover nearly 13 million km (5 million sq mi) or about 98% of Antarctica 's 13.2 million km (5.1 million sq mi), with an average thickness of ice 2,100 m (7,000 ft). Greenland and Patagonia also have huge expanses of continental glaciers. The volume of glaciers, not including

7872-508: The National Park Service because of their remoteness and ecological importance. Recreational activities including hiking , biking , snowshoeing , fishing , as well as cross-country skiing are available; during the summer, campgrounds and lodges at Crater Lake are open to visitors. Mount Mazama is in Klamath County , within the U.S. state of Oregon, 60 miles (97 km) north of the border with California . It lies in

8036-562: The Quaternary , Manchuria , lowland Siberia , and central and northern Alaska , though extraordinarily cold, had such light snowfall that glaciers could not form. In addition to the dry, unglaciated polar regions, some mountains and volcanoes in Bolivia, Chile and Argentina are high (4,500 to 6,900 m or 14,800 to 22,600 ft) and cold, but the relative lack of precipitation prevents snow from accumulating into glaciers. This

8200-476: The Rwenzori Mountains . Oceanic islands with glaciers include Iceland, several of the islands off the coast of Norway including Svalbard and Jan Mayen to the far north, New Zealand and the subantarctic islands of Marion , Heard , Grande Terre (Kerguelen) and Bouvet . During glacial periods of the Quaternary, Taiwan , Hawaii on Mauna Kea and Tenerife also had large alpine glaciers, while

8364-448: The 1990s and 2000s. In a study using data from January 1993 through October 2005, more events were detected every year since 2002, and twice as many events were recorded in 2005 as there were in any other year. Ogives or Forbes bands are alternating wave crests and valleys that appear as dark and light bands of ice on glacier surfaces. They are linked to seasonal motion of glaciers; the width of one dark and one light band generally equals

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8528-595: The 7,700 years ago Mazama eruption as the largest explosive eruption within the Cascades in the past million years, however recent studies say that the volume of the Rockland ash, which erupted from the Lassen Volcanic Center about 600,000 years ago could be up to 326.7 km, which would make it over twice the size of the Mazama ash. Mazama's climactic eruption was one of the largest eruptions during

8692-600: The Annie Spring fault within the West Klamath Lake fault zone, which might produce damaging earthquakes. Likewise, the Red Cone Spring fault cuts through basaltic andesite deposits at Red Cone from 35,000 years ago; together, the two faults move at an average rate of 0.012 inches (0.3 mm) each year. There do not appear to be faults present in the Crater Lake caldera wall, but the volcano induced

8856-553: The Cascades, the topography and elevation have influenced local climate patterns, also shaping global climate when volcanic gas and dust have been released into the atmosphere. The southern region of the park supports ponderosa pine forests, and for elevations from 5,000 to 7,000 feet (1,500 to 2,100 m), mixed coniferous , fir , and hemlock forests are common. Subalpine zones occur above 7,000 feet (2,100 m), often featuring whitebark pine . Ecological disturbances tend to cause decreasing damage with increasing distance from

9020-726: The Cleetwood lava was still hot enough to flow and move. Tephra from the last major eruption that was emplaced atop Cleetwood deposits has been altered by heat and gas from the Cleetwood lava. Both these eruptive periods took place on the northern flank of the Mazama complex, not far from the magma chamber that produced the climactic eruption shortly after. Mazama's climactic eruption has been dated to about 6,845 ± 50 years ago via radiocarbon dating, or about 7,700 years ago via dendrochronology . Other scientists have determined ages of 6,730 ± 40 years ago or roughly 7,470–7,620 calendar years ago, as well as 7,627 ± 150 calendar years ago. Fallout from

9184-637: The High Cascades. Extending from the eastern half of Mazama and to the southeast lies a volcanic field consisting of rhyodacitic lava domes and lava flows between 700,000 and 600,000 years old, which encompasses an area of more than 140 square miles (350 km). This large field is underlain by rhyodacite in its southeastern segment, and is cut by north–south trending normal faults. Moving from west to northwest, Mazama stratovolcanoes and shield volcanoes grow progressively younger. The oldest, at 400,000 years old, occur at Phantom Ship and Mount Scott, while

9348-417: The Holocene epoch. Considering Mazama's eruptive output within the past 420,000 years, it may have produced more than 43 cubic miles (180 km) of eruptive volume, making it either the third or fourth most productive Quaternary volcanic center in the Cascade Range. The eruption had a Volcanic Explosivity Index of 7, as determined from eruption cloud height, eruptive volume, and qualitative observations. In

9512-475: The Klamath people believed that just looking at Mazama would cause death. Some Native Americans still refuse to look at the water. During the 19th century, one Klamath leader named Lalek predicted scientific discoveries that described Mount Mazama's destruction, claiming that it had collapsed as a result of a particularly violent eruption. Geologists had not discovered this mechanism for caldera formation yet, but

9676-552: The Mazama vicinity. Landslides could flood adjacent shoreline regions, but they are not likely to induce failure of the caldera's walls, as they rise more than 500 feet (150 m) above the lake's surface. Earthquakes from the nearby West Klamath Lake fault zone could reach magnitudes up to 7.0 on the Richter scale , but these only occur every 3,000 to 10,000 years; they could generate tall waves by creating landslides. Though local earthquakes from volcanic activity would create motion in

9840-582: The Merriam Cone, and Wizard Island were produced, as well as lava flows. These eruptions produced 1 cubic mile (4.2 km) of andesitic lava, half of that in the Wizard Island cone. Wizard Island lava interacted with water to form breccia piles, and as the water levels rose, only the top of the Wizard Island edifice stayed above the water. The edifice has a lavaberg shape, as it sits above a larger, ovular pedestal rising 1,200 feet (370 m) above

10004-633: The National Park area also include various species of squirrel, mice, vole , and gophers, as well as yellow-bellied marmots and North American porcupines . Carnivorous mammals consist of coyotes , red foxes , gray foxes , American black bears , raccoons , martens , fishers , ermines , long-tailed weasels , minks , wolverines , American badgers , western spotted skunks , striped skunks , North American river otters , cougars , and lynxes such as bobcats . Elk , mule deer , and pronghorns can also be found, though more frequently during

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10168-601: The National Park area, particularly the Sun Creek and lower Annie Creek areas. Locals began stocking streams with non-native trout populations, forcing Brook trout to compete for resources and leading to their local extinction in Annie Creek, along with a significant decline in Sun Creek by the end of the 1980s. By 1992, Crater Lake National Park initiated a bull trout conservation project, removing invasive fish populations with electrofishing, snorkeling, and introduction of

10332-539: The Pacific Northwest. It is distinguishable from the lump pumice deposits ejected from the Glacier Peak volcano, which contain more phenocrysts . Mazama Ash also has more soda , yttrium , ytterbium , and zirconium , and less silica and lime than eruptive products from Glacier Peak, and it forms finer deposits than Glacier Peak Ash. With an age between 6,000 and 7,000 years, Mazama Ash corresponds to

10496-536: The Proto- Yokuts retroflexes */ʈ ʈʼ/ correspond to Klamath /tʃ tʃʼ/ , and the Proto-Yokuts dentals */t̪ t̪ʰ t̪ʼ/ correspond to the Klamath alveolars /t tʰ tʼ/ . Plosives in Klamath, aside from /ʔ/, come in triplets of unaspirated , aspirated, and ejective sounds. Sonorant triplets are voiced , voiceless, and glottalized sounds. Most consonants can be geminated . The fricative /s/

10660-754: The United States National Park Service closely monitors human and natural changes to the lake environment. The Klamath Native Americans of the area believed that Mount Mazama was inhabited by Llao , their "Chief of the Below World ." After the mountain destroyed itself the Klamaths recounted the events as a great battle between Llao and his rival Skell, their sky god, or "Chief of the Above World." The narrative has several slightly different iterations. A common variant of

10824-412: The advance of many alpine glaciers between 1950 and 1985, but since 1985 glacier retreat and mass loss has become larger and increasingly ubiquitous. Glaciers move downhill by the force of gravity and the internal deformation of ice. At the molecular level, ice consists of stacked layers of molecules with relatively weak bonds between layers. When the amount of strain (deformation) is proportional to

10988-520: The air from the snow turns it into "glacial ice". This glacial ice will fill the cirque until it "overflows" through a geological weakness or vacancy, such as a gap between two mountains. When the mass of snow and ice reaches sufficient thickness, it begins to move by a combination of surface slope, gravity, and pressure. On steeper slopes, this can occur with as little as 15 m (49 ft) of snow-ice. In temperate glaciers, snow repeatedly freezes and thaws, changing into granular ice called firn . Under

11152-430: The amount of melting at surface of the glacier, the faster the ice will flow. Basal sliding is dominant in temperate or warm-based glaciers. The presence of basal meltwater depends on both bed temperature and other factors. For instance, the melting point of water decreases under pressure, meaning that water melts at a lower temperature under thicker glaciers. This acts as a "double whammy", because thicker glaciers have

11316-713: The annual movement of the glacier. Ogives are formed when ice from an icefall is severely broken up, increasing ablation surface area during summer. This creates a swale and space for snow accumulation in the winter, which in turn creates a ridge. Sometimes ogives consist only of undulations or color bands and are described as wave ogives or band ogives. Glaciers are present on every continent and in approximately fifty countries, excluding those (Australia, South Africa) that have glaciers only on distant subantarctic island territories. Extensive glaciers are found in Antarctica, Argentina, Chile, Canada, Pakistan, Alaska, Greenland and Iceland. Mountain glaciers are widespread, especially in

11480-412: The area in the summer season; and mountain and western bluebirds in the fall and summer. Olive-sided flycatchers and chipping sparrows are common during the spring and summer seasons, while yellow-rumped warblers , pine siskins , and Cassin's finches can frequently be seen during spring, summer, and fall. In the early 20th century, Bull trout were present in many streams and rivers throughout

11644-432: The bedrock has frequent fractures on the surface, glacial erosion rates tend to increase as plucking is the main erosive force on the surface; when the bedrock has wide gaps between sporadic fractures, however, abrasion tends to be the dominant erosive form and glacial erosion rates become slow. Glaciers in lower latitudes tend to be much more erosive than glaciers in higher latitudes, because they have more meltwater reaching

11808-445: The bedrock. By mapping the direction of the striations, researchers can determine the direction of the glacier's movement. Similar to striations are chatter marks , lines of crescent-shape depressions in the rock underlying a glacier. They are formed by abrasion when boulders in the glacier are repeatedly caught and released as they are dragged along the bedrock. The rate of glacier erosion varies. Six factors control erosion rate: When

11972-427: The caldera rim. Many of the major cone-creating eruptions at Mazama were effusive rather than violently explosive, but explosive eruptions about 70,000 years ago yielded silicic lava that created thick pyroclastic deposits. These deposits include Pumice Castle, an orange edifice at the eastern wall of the caldera, which formed by the fusion of glassy pumice fragments. Similar activity on the northern side of Cloudcap and

12136-461: The caldera, all of which have been submerged except for Wizard Island. Mapping the caldera floor with high-resolution multibeam echo sounders, vehicle-motion sounders and navigators, and a dual-differential global positioning system (DGPS), scientists from the US government and universities detected volcanoes and landslide deposits under the water. Between 7,700 and 7,200 years ago, the central lava platform,

12300-543: The caldera, most hills show evidence of glacial alteration except those from the Holocene epoch and low elevation landforms including Pleistocene lava domes and cinder cones. Mount Scott has also been heavily eroded by ice, and the Union Peak volcano now consists only of a pyramidal horn. Though it now has dimensions of 5.0 by 6.2 miles (8 by 10 km) and a width of 5.0 to 6.2 miles (8 to 10 km), scientists think

12464-492: The climactic eruption, Mazama's peak was completely destroyed, replaced by a depression with a depth of 4,000 feet (1,200 m) surrounded by cliffs. The volume of magma erupted from Mazama during this eruption was 14 cubic miles (61 km). The lava produced was zoned vertically according to arrangement within the source magma chamber, and was calc-alkaline in composition. It consisted of roughly 90 percent uniform rhyodacitic pumice, which contained about 10 percent phenocrysts ,

12628-639: The climate was warm and dry, and the most recent period of glacial advance ceased about 27,000 years ago, so by the time Mazama collapsed, ice was likely only present at higher elevations. Using argon geochronology and paleoclimatic records, scientists have identified that the Sand Creek, Sun Creek, and Annie Creek canyons were carved by the advance of ice over lava flows, pushing debris towards Klamath Marsh and Klamath Graben or nearby rivers. A glacial cirque can be seen on Mount Scott's northwestern flank, and glacial till occurs on Mazama's slopes, especially on

12792-431: The complex, all cones have been covered with deposits from the climactic eruption at Mazama 7,700 years ago. Scientists now use the exposed contents of the caldera rim wall to investigate eruptions and mapping the eruptive history of the region. Throughout its known eruptions, Mazama has produced 43 percent rhyodacite, 42 percent andesite, 15 percent dacite, and less than 1 percent basaltic andesite. All of

12956-471: The crater was forming. Water interacted with lava flows to form pillow lava . Because of climate change patterns over time, Crater Lake's surface level has changed, dropping as much as 40 feet (12 m) for example at the beginning of the 20th century. The water from precipitation nearly equals water lost to evaporation and drainage, most leakage taking place at the Wineglass deposit at the northern side of

13120-402: The crater, without which the lake would likely have overflowed at the northern side. Average snowfall in the Crater Lake area has been decreasing since the 1930s. Crater Lake's mean surface water temperatures have increased about 5 °F (3 °C) since the 1960s. Though this may eventually cause algae to grow and obscure the water, Crater Lake remains one of the cleanest bodies of water in

13284-571: The created ice's density. The word glacier is a loanword from French and goes back, via Franco-Provençal , to the Vulgar Latin glaciārium , derived from the Late Latin glacia , and ultimately Latin glaciēs , meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial. The process of glacier establishment, growth and flow is called glaciation . The corresponding area of study

13448-467: The deep profile of fjords , which can reach a kilometer in depth as ice is topographically steered into them. The extension of fjords inland increases the rate of ice sheet thinning since they are the principal conduits for draining ice sheets. It also makes the ice sheets more sensitive to changes in climate and the ocean. Although evidence in favor of glacial flow was known by the early 19th century, other theories of glacial motion were advanced, such as

13612-483: The deformation to become a plastic flow rather than elastic. Then, the glacier will begin to deform under its own weight and flow across the landscape. According to the Glen–Nye flow law , the relationship between stress and strain, and thus the rate of internal flow, can be modeled as follows: where: The lowest velocities are near the base of the glacier and along valley sides where friction acts against flow, causing

13776-537: The east of the national park barrier at the Scott Creek Drainage, and the MZII-1 with a depth of 2,844 feet (867 m) to the south of the same boundary and to the east of Annie Creek. The maximum temperature they have observed at the southern well is 104 °F (40 °C), while the maximum temperature was 266 °F (130 °C) at the eastern well. The convective heat discharge in Crater Lake marks

13940-455: The eastern segment of Llao Rock that ejected dacitic tephra and pyroclastic rock also formed fused edifices. About 50,000 years ago, a vent at Mazama erupted the Watchman flow, which filled a canyon at the southwestern wall of the complex. From 50,000 to 40,000 years ago, Mazama vents continued to erupt andesite lava flows onto the northern and southwestern slopes and create dacite lava domes on

14104-453: The effects of the 1815 eruption of Mount Tambora . Mazama's climactic eruption produced stratospheric mass loadings of 97,000,000 to 247,000,000 short tons (88 to 224 Mt) of sulfuric acid , with an estimated minimum sulfate degassing of 102,400,000 short tons (92.9 Mt) during its eruption. Aerosol from the eruption traveled as far as Greenland , falling for as long as six years. The United States Geological Survey has referred to

14268-481: The emplacements from these flows yielded fumarolic activity, still detectable in the Annie Creek and Sand Creek canyons. Erosion from rain and stream flow has left pipes from the andesitic lava flows as columns and spires. Before collapse due to eruption of magma emptying the underlying magma chamber, the Mazama edifice had an estimated volume of 27 cubic miles (112 km), though it may have exceeded 31 cubic miles (130 km) taking glacial erosion into account. After

14432-489: The eruption continued for roughly three years, though the major eruption only occurred for a few days. The eruption is thought to have occurred during autumn, as inferred from pollen data. The eruptive activity that led to Mazama's collapse proceeded in two phases. During the first phase, shortly after the eruption of the Cleetwood flow , a vent at a higher elevation on the northern side of the Mazama complex (but still below

14596-418: The essentially correct explanation in the 1840s, although it was several decades before it was fully accepted. The top 50 m (160 ft) of a glacier are rigid because they are under low pressure . This upper section is known as the fracture zone and moves mostly as a single unit over the plastic-flowing lower section. When a glacier moves through irregular terrain, cracks called crevasses develop in

14760-571: The estimated time for Mazama's climactic eruption 6,600 years ago, identified by radiocarbon dating of wood charred by ashflows. Some of the Glacier Peak ash has been found in strata beneath Mazama Ash in Washington state and in eastern Idaho , 419 miles (675 km) to the southeast of Glacier Peak . Studies of Glacier Peak Ash deposits suggest that they are older than Mazama Ash, at about 12,000 years old. Glacier Peak Ash has not been found in deposits less than 10,000 years old, and nearly all human artifacts have been found above its deposits, except for

14924-503: The floor of Crater Lake; just two percent of Wizard Island sits above the water surface. At the summit of the above-water cone, a small lava flow from a lava fountain appears, on the southwestern flank. There is also a volcanic plug poking out of the crater floor as a body of dark lava. Lava blocks with diameters of 6 to 7 feet (1.8 to 2.1 m) can be seen along the rim of the crater, possibly produced from later stages of cone-building eruptions that created Wizard Island. The central platform

15088-475: The fracture zone. Crevasses form because of differences in glacier velocity. If two rigid sections of a glacier move at different speeds or directions, shear forces cause them to break apart, opening a crevasse. Crevasses are seldom more than 46 m (150 ft) deep but, in some cases, can be at least 300 m (1,000 ft) deep. Beneath this point, the plasticity of the ice prevents the formation of cracks. Intersecting crevasses can create isolated peaks in

15252-453: The glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant. However, within high-altitude and Antarctic environments, the seasonal temperature difference is often not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g., precipitation , mean temperature , and cloud cover , glacial mass changes are considered among

15416-428: The glacier will be accommodated by motion in the sediments, or if it'll be able to slide. A soft bed, with high porosity and low pore fluid pressure, allows the glacier to move by sediment sliding: the base of the glacier may even remain frozen to the bed, where the underlying sediment slips underneath it like a tube of toothpaste. A hard bed cannot deform in this way; therefore the only way for hard-based glaciers to move

15580-510: The glacier's surface area, more if the glacier calves icebergs. Ice in the accumulation zone is deep enough to exert a downward force that erodes underlying rock. After a glacier melts, it often leaves behind a bowl- or amphitheater-shaped depression that ranges in size from large basins like the Great Lakes to smaller mountain depressions known as cirques . The accumulation zone can be subdivided based on its melt conditions. The health of

15744-585: The hypothesis was recorded by the soldier William M. Colvig in 1865, and then reprinted in Ella Clark's Indian Legends of the Pacific Northwest . The last major volcanic landform in the Cascade Range identified by white settlers, Mazama was first visited by non-indigenous people in the spring of 1853. Eleven miners from Yreka, California , stopped at a mercantile store in Jacksonville, Oregon , owned by Isaac Skeeters, boasting that they knew where to find

15908-619: The ice at the bottom of the glacier move more slowly than ice at the top. In alpine glaciers, friction is also generated at the valley's sidewalls, which slows the edges relative to the center. Mean glacial speed varies greatly but is typically around 1 m (3 ft) per day. There may be no motion in stagnant areas; for example, in parts of Alaska, trees can establish themselves on surface sediment deposits. In other cases, glaciers can move as fast as 20–30 m (70–100 ft) per day, such as in Greenland's Jakobshavn Isbræ . Glacial speed

16072-420: The ice sheets of Antarctica and Greenland, has been estimated at 170,000 km . Glacial ice is the largest reservoir of fresh water on Earth, holding with ice sheets about 69 percent of the world's freshwater. Many glaciers from temperate , alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause

16236-556: The ice to act as a lever that loosens the rock by lifting it. Thus, sediments of all sizes become part of the glacier's load. If a retreating glacier gains enough debris, it may become a rock glacier , like the Timpanogos Glacier in Utah. Abrasion occurs when the ice and its load of rock fragments slide over bedrock and function as sandpaper, smoothing and polishing the bedrock below. The pulverized rock this process produces

16400-488: The ice, called seracs . Crevasses can form in several different ways. Transverse crevasses are transverse to flow and form where steeper slopes cause a glacier to accelerate. Longitudinal crevasses form semi-parallel to flow where a glacier expands laterally. Marginal crevasses form near the edge of the glacier, caused by the reduction in speed caused by friction of the valley walls. Marginal crevasses are largely transverse to flow. Moving glacier ice can sometimes separate from

16564-411: The idea that meltwater, refreezing inside glaciers, caused the glacier to dilate and extend its length. As it became clear that glaciers behaved to some degree as if the ice were a viscous fluid, it was argued that "regelation", or the melting and refreezing of ice at a temperature lowered by the pressure on the ice inside the glacier, was what allowed the ice to deform and flow. James Forbes came up with

16728-418: The increased pressure can facilitate melting. Most importantly, τ D is increased. These factors will combine to accelerate the glacier. As friction increases with the square of velocity, faster motion will greatly increase frictional heating, with ensuing melting – which causes a positive feedback, increasing ice speed to a faster flow rate still: west Antarctic glaciers are known to reach velocities of up to

16892-423: The infrared OH stretching mode of the water molecule. (Liquid water appears blue for the same reason. The blue of glacier ice is sometimes misattributed to Rayleigh scattering of bubbles in the ice.) A glacier originates at a location called its glacier head and terminates at its glacier foot, snout, or terminus . Glaciers are broken into zones based on surface snowpack and melt conditions. The ablation zone

17056-601: The lake, they would likely only reach maximum magnitudes of 5.0 on the Richter scale. Crater Lake is poorly monitored, and not highly active seismically among the Cascade volcanoes. The largest earthquake threat originates from the Cascadia subduction zone , which could produce earthquakes with a magnitude of 8 or 9 that could lead to huge waves in Crater Lake. Though the population within 6.2 miles (10 km) of Mount Mazama

17220-614: The lake; this would have made it Oregon's highest peak. The Global Volcanism Program currently lists its elevation at 8,157 feet (2,486 m). Crater Lake National Park covers an area of 250 square miles (650 km), including forest areas, alpine terrain, the Crater Lake, and the vast majority of Mount Mazama. A wilderness area , it was dedicated in 1902 and is overseen by the National Park Service . It receives about 500,000 visitors each year, and these tourists can go hiking, take bike, ranger-guided, and trolley tours, swim, fish, camp, and participate in other recreational activities. While

17384-978: The late Pleistocene or early Holocene, lava domes such as those at Sharp Peak, Grouse Hill, and Merriam Point formed, sharing chemical compositions, with silica contents at about 70%. Pyroclastic cones at Mazama include Wizard Island, Bald Crater, Maklaks Crater (also known as Diller Cone) and Forgotten Cone. In addition to its crater, referred to as Williams Crater or the Forgotten Crater, Mazama's various volcanic vents occur at Cleetwood, Llao Rock, and Redcloud, which are at elevations of 7,005 feet (2,135 m), 8,045 feet (2,452 m), and 7,949 feet (2,423 m), respectively. Nearby cinder cones include Bear Butte, Crater Peak, Desert Cone, Lookout Butte, Pothole Butte, Red Cone, Scout Hill, and Union Peak. There are at least 13 cinder cones within Crater Lake National Park, and at least eleven more in

17548-471: The legend recounts that Llao saw a beautiful Klamath woman, the daughter of a chief, and became angry when she refused his offer of immortality if she would be his consort. Furious, Llao emerged from Mazama and threw fire upon the people beneath the mountain, and Skell stood on Mount Shasta , trying to defend the people against Llao's fury. As the earth shook and volcanic rock fell from the sky, two holy men sacrificed themselves to Mount Mazama's crater, and Skell

17712-537: The mafic andesite deposits display textures that indicate they underwent greater mixing than andesite and dacite deposits. Formed of a complex of stratovolcanoes and shield volcanoes, there are about 35 known satellite vents in the Mazama complex. Mazama is surrounded by monogenetic cinder cones, lava fields, and shield volcanoes made up of calc-alkaline basalt and andesite, tholeiite , and shoshonitic andesite. Varying in age from 600,000 to 40,000 years old, these edifices closely resemble other monogenetic volcanoes in

17876-568: The magma chamber that produced the climactic Mazama eruption 7,700 years ago. The lake shows convective mixing that cycles every three years as thermal fluid moves into the lake through its floor, creating thermal springs that formed silica spires with heights up to 33 feet (10 m). As a result, the California Energy Company drilled two geothermal exploration wells: the MZI-11A with a depth of 4,669 feet (1,423 m) to

18040-612: The major volcanoes in the High Cascades branch of the greater Cascade Range. It was the largest volcanic edifice between Mount Shasta in California and the Three Sisters complex in Oregon. Before the eruption, it had been significantly altered by glacial erosion, which carved U-shaped valleys on its southern and southeastern slopes. The northern and western sides of the caldera do not show prominent evidence of glacial erosion, since they feature lava flows that only underwent alteration by late Pleistocene epoch glacial motion. Outside of

18204-538: The mantle. These magmas vary from 47.6 percent to 73.2 percent silicon dioxide . Mazama and Crater Lake form part of the Mazama reach (section) of the Oregon Cascades, which stretches for 25 miles (40 km) from Timber Crater to the Big Bunchgrass shield volcano. This includes 175 Quaternary volcanic vents within a belt that ranges from 16 to 19 miles (25 to 30 km) in width, which has

18368-679: The most deformation. Velocity increases inward toward the center line and upward, as the amount of deformation decreases. The highest flow velocities are found at the surface, representing the sum of the velocities of all the layers below. Because ice can flow faster where it is thicker, the rate of glacier-induced erosion is directly proportional to the thickness of overlying ice. Consequently, pre-glacial low hollows will be deepened and pre-existing topography will be amplified by glacial action, while nunataks , which protrude above ice sheets, barely erode at all – erosion has been estimated as 5 m per 1.2 million years. This explains, for example,

18532-433: The most prominent landslide detectable on the caldera wall, occurred long after the formation of the crater. Located on the southern side, it contains lava blocks between 850 and 1,400 feet (260 and 430 m) in length, many of which now reside underwater on the floor of Crater Lake. As the crater filled with landslides, lava, and water, the caldera's appearance changed over time. New cones and lava fields have formed inside

18696-445: The most sensitive indicators of climate change and are a major source of variations in sea level . A large piece of compressed ice, or a glacier, appears blue , as large quantities of water appear blue , because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing

18860-485: The national park or researchers by creating tsunami-sized waves, also potentially damaging infrastructure surrounding the lake. Studies of heat flow and the water chemistry in Crater Lake and the alteration of rocks older than 120,000 years ago suggest that hydrothermal areas exist in the Mazama vicinity. Most springs show similar chemistry, from the weathering of volcanic glass and clinopyroxene . These features probably formed due to processes related to residual heat from

19024-426: The nearby area. They were fed by a different magma chamber than Mazama, though they likely received magma from basaltic andesite reservoirs in the vicinity. The exception is Williams crater, which erupted basalt and dacite and got silicic lava from the western part of Mazama's magma chamber. Stratovolcanoes in Mazama's vicinity consist of Sentinel Rock, Mount Scott, Phantom Cone, Dutton Cliff, and Danger Bay. Mazama has

19188-486: The northeast. The ejecta featured blocks of medium-grain granodiorite , as well as inclusions of diabase , quartz diorite , granite , aplite , and granophyre . Ashfall layers have been eroded by pyroclastic flows and with time, but they are still visible at Hillman Peak and along the Cleetwood Trail. The Plinian column from the eruption devastated the area hundreds of miles north and northeast of Mazama, but to

19352-595: The northwestern side of the Mazama complex shows a representative structure for the shields that helped form Mazama. The Mazama vicinity formed gradually, its earliest deposits consisting of dacite from up to 1.28 million years ago. Between 725,000 and 500,000 years ago, rhyodacite was erupted, eventually forming a lava dome field with a volume of 4.8 cubic miles (20 km) and dimensions of 9.9 by 14.9 miles (16 by 24 km). This featured up to 40 rhyodacitic domes and lava flows, produced between 470,000 and 410,000 years ago before stratocone formation began. Mazama formed as

19516-552: The north–northwest trending basin also surrounded by fault zones. The Basin and Range Province lies to the east. Mazama lies within the broad segment of the Cascades arc, where smaller volcanoes are common because of melting patterns of the Earth's mantle within the region. Erupting magma that ranged from high-alumina olivine tholeiite to magnesian basaltic andesite, these volcanoes show increased contents of subduction -produced or melted fluids that mixed with another magma chamber in

19680-465: The original collapse diameter was 3.1 miles (5 km). It now includes several small lava domes and cinder cones, including Wizard Island and the underwater volcano Merriam Cone. The highest elevation in the Mazama Complex is now Mount Scott, at an elevation of 8,929 feet (2,722 m), with a relief of 2,000 feet (610 m) above Crater Lake's surface waters. Except for the tallest slopes of

19844-647: The park area include the little brown bat , hoary bat , and big brown bat , while the California myotis , silver-haired bat , Yuma myotis , long-eared myotis , long-legged myotis , and pallid bat are more rare. There are populations of American pikas , snowshoe hares , and white-tailed jackrabbits in the region, as well as many rodent species. Chipmunks like yellow-pine chipmunks , least chipmunks , Siskiyou chipmunks , and Townsend's chipmunks can be seen, along with various beaver species including mountain beavers and North American beavers . The mammals of

20008-449: The park area remains open throughout the year, certain roads and facilities close in the winter season. There was frequent glacier formation on the mountain as Mazama developed. They carved trenches in the flanks of the volcano in addition to U-shaped valleys under the base of the volcanic cone. These can be seen at three large glacial canyons on its southern slopes: Kerr Notch, Munson Valley, and Sun Notch. Whenever eruptions took place in

20172-453: The past few decades. Likewise, as a result of climate change, mountain pine beetle infestations have become more frequent among Whitebark pines on the rim of Crater Lake and present on nearby peaks. The National Park Service estimates that roughly half of the whitebark pines in Crater Lake National Park have died or are dying. Because the ecosystem in Crater Lake is isolated from the regional area, it holds particular interest from ecologists, so

20336-725: The pooling of meltwater at the base of the glacier  — perhaps delivered from a supraglacial lake  — or the simple accumulation of mass beyond a critical "tipping point". Temporary rates up to 90 m (300 ft) per day have occurred when increased temperature or overlying pressure caused bottom ice to melt and water to accumulate beneath a glacier. In glaciated areas where the glacier moves faster than one km per year, glacial earthquakes occur. These are large scale earthquakes that have seismic magnitudes as high as 6.1. The number of glacial earthquakes in Greenland peaks every year in July, August, and September and increased rapidly in

20500-404: The presence of ice, lava was chilled by glaciers, creating glassy talus deposits. Sometimes, the lava coursed into areas previously carved by glaciers like at Sentinel Rock, filling canyons with volcanic rock. Moraines occur up to 17 miles (27 km) from the rim of Mazama's caldera, and there are glacial striations visible at several sites in the area. When the climactic eruption occurred,

20664-410: The pressure of the layers of ice and snow above it, this granular ice fuses into denser firn. Over a period of years, layers of firn undergo further compaction and become glacial ice. Glacier ice is slightly more dense than ice formed from frozen water because glacier ice contains fewer trapped air bubbles. Glacial ice has a distinctive blue tint because it absorbs some red light due to an overtone of

20828-609: The pyroclastic flows erupted contained andesitic, gray scoria that was deposited above the pale orange and yellow rhyodacite pumice from earlier phases of the eruption. The final eruptions formed the Pumice Desert, a treeless plain on the northern and northeastern side of Mazama, as well as filling the Pumice Creek valley and parts of the Klamath Marsh. Reaching thicknesses between 250 and 300 feet (76 and 91 m),

20992-562: The pyroclastic flows. Pyroclastic flows also moved to the east, reaching more than 25 miles (40 km) from the base of Mazama. These deposits have diameters between 1 and 2 feet (0.30 and 0.61 m), though they are punctuated by pumice blocks with diameters of 6 feet (1.8 m) that extend as far as 20 miles (32 km) from Mazama's summit. Flows containing pumice coursed into the Annie Creek and Sun Creek canyons southward of Mazama, depositing 250 feet (76 m) of material, which have still not been fully eroded after almost 8,000 years. To

21156-485: The rest made up of crystalline andesite scoria and mafic crystals. The total eruptive volume adds up to 42 cubic miles (176 km) of pumice, ignimbrite, and tephra. The eruption released aerosols that lowered temperatures globally in the Northern Hemisphere, with estimates of 1.1 to 1.3 °F (0.6 to 0.7 °C) for one to three years after the eruption. The temperature changes were possibly greater than

21320-625: The rhyodacite has been produced within the past 30,000 years of activity, suggesting that regional and local distribution of compositions were not uniform over time. Andesite and dacite lava flows from the volcano usually have plagioclase as their major phenocryst, though augite and hypersthene are also present, the latter more abundant. Olivine form minor phenocrysts, which are found throughout lava flows from Mazama, and hornblende can be found in some andesite lava flows. Basalt and mafic andesite lava flows from Mazama and nearby eruptive vents have relatively higher amounts of olivine and lack hypersthene, and

21484-514: The sea, often with an ice tongue , like Mertz Glacier . Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica, Baffin , Devon , and Ellesmere Islands in Canada, Southeast Alaska , and the Northern and Southern Patagonian Ice Fields . As the ice reaches the sea, pieces break off or calve, forming icebergs . Most tidewater glaciers calve above sea level, which often results in

21648-640: The source, but volcanic eruptions can lead to more uniform patterns of disruption for their surrounding landscapes. The immediate surroundings of Mazama continue to recover from the eruption. There are more than 50 mammal species in Crater Lake National Park. Opossum species such as the Virginia opossum can be found infrequently, while shrew and mole species in the park area include marsh shrews , Pacific shrews , American water shrews , fog shrews , Trowbridge's shrews , vagrant shrews , American shrew moles , and broad-footed moles . Bats frequently sighted within

21812-540: The southeast, pyroclastic flows coursed into Sand Creek and extended more than 10 miles (16 km) in that direction, some reaching Klamath Marsh, the Williamson River, and the Klamath Lakes. Mazama's eruptive activity drew from deeper layers of the magma chamber that fed its climactic eruption, with denser layers of andesite and basaltic andesite lying beneath lighter layers of rhyodacite. The last of

21976-431: The southern flanks. These domes often collapsed and produced pyroclastic flows that coursed down the southern slope of the volcano, forming deposits up to Devil's Backbone, a craggy volcanic dike that was exhumed when the volcano collapsed. Throughout its eruptive history, Mazama has produced basaltic andesite, andesite, and dacite lava. About 40,000 years ago, it underwent a dramatic shift to solely rhyodacite lava, which

22140-440: The southern portion of the Cascade Range. Crater Lake sits partly inside the volcano's caldera, with a depth of 1,943 feet (592 m); it is the deepest body of freshwater in the United States and the second deepest in North America after Great Slave Lake in Canada. Before its caldera-forming eruption, Mazama stood at an elevation between 10,800 and 12,100 feet (3,300 and 3,700 m), placing it about 1 mile (1.6 km) above

22304-484: The southern, western, and eastern flanks of the complex. They have average thicknesses of 15 to 20 feet (4.6 to 6.1 m). Roughly 215,000 years ago, another flank vent erupted dacitic lava that coursed to the west for at least 6.2 miles (10 km), with volcanic dikes that trend toward the vent still present in the Mazama caldera wall. The complex remained inactive for about 40,000 years before it resumed activity, erupting andesitic lava from another flank vent, building

22468-400: The southwest and west, little pumice or ash were deposited. The eruption's character changed dramatically as the column of pumice and ash collapsed. The exact cause is not well understood; it may have been the result of the enormous weight of the tephra or the expansion of the eruptive vent. The sudden deposition of so much pumice generated pyroclastic flows that moved down the northern side of

22632-494: The southwestern side of the caldera, and it represents the highest point on the Mazama rim, rising 2,000 feet (610 m) above Crater Lake. The cone was cut down the middle during Mazama's collapse post-eruption, creating a cross-section of its interior composition. Shield volcanoes that contributed to Mazama's growth only erupted for several hundred to several thousand years. They erupted rapidly, spraying fluid lava that included lava bombs and incandescent fragments. Llao shield on

22796-409: The stagnant ice above, forming a bergschrund . Bergschrunds resemble crevasses but are singular features at a glacier's margins. Crevasses make travel over glaciers hazardous, especially when they are hidden by fragile snow bridges . Below the equilibrium line, glacial meltwater is concentrated in stream channels. Meltwater can pool in proglacial lakes on top of a glacier or descend into the depths of

22960-548: The state government to expand Bull trout distributions from Sun Creek into neighboring forests with fish barriers and removal of invasive fish species. Climate change threatens the American pika populations in the Crater Lake area, as they cannot tolerate warm weather because their fur does not release heat efficiently. Climate change might be diminishing their food supply via disturbances of vegetation growth patterns. At least three pika populations in Oregon have disappeared within

23124-423: The stress being applied, ice will act as an elastic solid. Ice needs to be at least 30 m (98 ft) thick to even start flowing, but once its thickness exceeds about 50 m (160 ft) (160 ft), stress on the layer above will exceeds the inter-layer binding strength, and then it'll move faster than the layer below. This means that small amounts of stress can result in a large amount of strain, causing

23288-616: The summer season. Bird species in the Crater Lake National Park area include various biological families . Common bird species include hairy woodpeckers , great horned owls , blue grouse , common ravens , dark-eyed juncos , mountain chickadees , red-breasted nuthatches , brown creepers , Clark's nutcrackers , and Canada jays , which are visible throughout the year; American kestrels , northern flickers , golden-crowned kinglets , Cordilleran flycatchers , Steller's jays , western tanagers , Swainson's thrushes , hermit thrushes , American robins , and rufous hummingbirds that frequent

23452-582: The summit) produced a 30-mile (48 km) high ash column into the stratosphere and ejecting over half the eruption’s total magma. The second stage erupted material from a ring of vents. Ash extended to eight states in the west and three Canadian provinces. As a result, Mazama Ash has become a commonly used benchmark for measuring the relative age of objects, compared to its orange colored deposits. Pumice deposits reached depths of 20 feet (6.1 m) adjacent to Mazama's base, still reaching thicknesses more than 1 foot (0.30 m) as far as 70 miles (110 km) to

23616-438: The surface snowpack may experience seasonal melting. A subpolar glacier includes both temperate and polar ice, depending on the depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is often described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface and is thus frozen to the underlying substrate. A warm-based glacier

23780-415: The surfaces surrounding Mazama, removing ashfall and then depositing their contents in nearby valleys. Some of the flows traveled more than 40 miles (64 km) from their source, destroying timber in their paths, while others deposited their rock into river valleys to the north and west of Mazama, leaving layers of pumice between 20 and 30 feet (6.1 and 9.1 m) in thickness. Ash clouds also rose up from

23944-468: The third largest in the Cascades, after the Austin Hot Springs and at Lassen Volcanic National Park . Scientists from the United States Geological Survey think that sources for geothermal energy use exist at Mazama and Crater Lake. Crater Lake National Park and the area surrounding Mount Mazama range in elevation from 4,000 to 8,929 feet (1,219 to 2,722 m), providing diverse habitats. In

24108-483: The toxin and inhibitor of cellular respiration antimycin A . They also created small barriers to keep new trout from reaching Sun Creek. In 1999, Bull trout were considered a "threatened" species by the Endangered Species Act, though locally, there are now about 2,000 Bull trout in the stream, almost ten times as many as the low point for Bull trout abundance at just 200 fish. The project now works with

24272-407: The volcano plays an important role in local folklore. European-American settlers first reached the region in the mid-19th century. Since the late 19th century, the area has been extensively studied by scientists for its geological phenomena and more recently for its potential sources of geothermal energy . Crater Lake and Mazama's remnants sustain diverse ecosystems, which are closely monitored by

24436-466: The volcano's partially emptied neck and magma chamber, creating a caldera. The region's volcanic activity results from the subduction of the offshore oceanic plate , and is influenced by local extensional faulting. Mazama is dormant, but the U.S. Geological Survey says eruptions on a smaller scale are likely, which would pose a threat to its surroundings. Native Americans have inhabited the area around Mazama and Crater Lake for at least 10,000 years and

24600-443: The volcano's summit, similar to a piston . Eventually, the top of Mazama's magma chamber subsided , and concentric openings formed by the summit, producing smaller vents surrounding the main eruptive cone. Pumice ejected from these new fractures created rapid pyroclastic flows that coursed down all the sides of Mazama, traveling over tall ridges and summits of subfeatures and extending tens of miles from their vents. These flows altered

24764-494: The volcano, coursing west–east from Llao Rock to Redcloud Cliff. The first of these pyroclastic flows were deposited at superheated temperatures, welding fragments and creating the Wineglass welded tuff, which consists of big blocks of orange-brown and gray rock. These emplacements can only be observed on the northern slopes; they are absent from the southern slopes of the volcano. Mazama was covered with incandescent pumice. The extreme weight of eruptive material began to push down on

24928-417: The weight of the ice is supported by the underlying water, and the glacier is afloat. Glaciers may also move by basal sliding , where the base of the glacier is lubricated by the presence of liquid water, reducing basal shear stress and allowing the glacier to slide over the terrain on which it sits. Meltwater may be produced by pressure-induced melting, friction or geothermal heat . The more variable

25092-607: The west, creating the Applegate Peak and Garfield Peak cones on the southern flanks of the volcanic center. Hawaiian eruptions from neighboring shield volcanoes also built up Mazama, producing basaltic andesite lava flows that ranged from 15 to 20 feet (4.6 to 6.1 m) on average in thickness. These flows, present on the southern, western, and eastern walls of Mazama's caldera, also contained lava bombs . Viscous eruptions of andesitic lava that reached thicknesses of several hundred feet further built up Mazama's cones, creating

25256-568: The western United States and Canada, volcanic ash often forms distinct layers among recent geological deposits, which can be used for stratigraphy among geologists and archaeologists . Given the large distribution of the historic eruption of Mount Mazama, Mazama Ash serves as a common geological marker. Mazama Ash had a minimum fallout area of 350,000 square miles (900,000 km), while ash from northwestern Washington's Glacier Peak volcano, known as Glacier Peak Ash, encompassed an area of more than 100,000 square miles (260,000 km). Mazama Ash

25420-571: The western side of the complex and within the caldera rim; they could occur underwater. The ejection of lava rich in gas from shallow water could produce huge ash columns, but submarine eruptions at deeper depths may decrease the explosiveness of the event. Nonetheless, the rapid mixing of water and lava could produce dangerous pyroclastic surges , which are more gaseous and less solid than pyroclastic flows. Such flows could pass over topographic barriers, move rock fragments at 800 feet per second (240 m/s), and travel several miles from their vent. Mazama

25584-488: The western slopes and at lower elevations. Till and fluvial sediments occur in the caldera walls, forming particularly thick deposits under Roundtop and Wineglass. Many lava flows that were glaciated have since been covered by more recent lava flows. Crater Lake formed from a network of lakes and ponds, eventually reaching a depth of 1,949 feet (594 m). Lake levels rose while the Wizard Island landform inside

25748-631: The world. Produced by the subduction of the Juan de Fuca Plate at the Cascadia subduction zone , which moves slowly in a northeastward direction with the Gorda tectonic plate under the North American tectonic plate , Mazama is part of the Cascade Volcanic Arc that stretches from northern California to southern British Columbia. It sits within a region of crustal extension marked by fault zones , including north–south-trending normal faults such as

25912-922: The youngest can be found at the Hillman Peak stratovolcano, dated to 70,000 years old. There are also andesite flows at the northern rim of Mazama dated to between 50,000 and 40,000 years old. Shield volcanoes near Mazama feature lava flows made of agglutinated mafic andesite, which form sheets about 16-foot (5 m) thick, as well as more deposits from more viscous andesite and dacite magma that reach thicknesses up to 98 feet (30 m). Many of these deposits (both dacitic and andesitic) contain undercooled, crystal-poor segments of andesite, including at Mount Scott and Phantom Cone. Lava and ice interactions are suggested by exposures of glassy breccia in Mazama's caldera, as well as lava flows covering glaciated lava deposits. About 70,000 years ago, several silicic (rich in silicon dioxide), explosive eruptions occurred, including

26076-545: Was able to force Llao back into the volcano, which then collapsed on top of him; other accounts tell that Skell smashed the peak on top of Llao. Torrential rain followed, filling in the hole left by Mazama's collapse to form Crater Lake. Native American people have lived in the area near Mazama for at least 10,000 years. At least part of the surrounding vicinity was occupied by indigenous populations when Mazama resumed activity about 8,000 years ago, following about 20,000 years of dormancy. Most evidence suggests that Mazama served as

26240-577: Was created by a similar vent eastward of Wizard Island, made up of effusive lava that created lava fields northward and eastward of its vent. Merriam Cone does not have a summit crater, but rises to 1,300 feet (400 m) above the northern lake floor. Merriam Cone was produced underwater, and was probably formed at the same or similar time as Wizard Island and the central platform. Mazama was last active about 4,800 years ago, when an eruption took place near Wizard Island's eastern base. This eruption took place underwater, and it produced viscous lava that created

26404-425: Was filled by subsequent lava flows. Shortly before the major, caldera-forming eruption at Mazama, the Cleetwood flow was produced. Also composed of rhyodacite lava, it originated from a vent on the northern side of the complex eastward of Llao Rock. It likely only occurred weeks or months before the major eruption, as Mazama's collapse formed a backward flow of lava when it cut through the Cleetwood lava, suggesting that

26568-421: Was highly viscous and had a silica content at about 70 percent. Between 30,000 and 25,000 years ago, rhyodacitic eruptions occurred at the complex, yielding pumiceous tephra and lava flows from Grouse Hill, Steel Bay, and Redcloud Cliff. At Redcloud Cliff, a lava flow formed with glassy columns that touched glaciers, creating a large, inverted stone triangle on the eastern rim of Mazama. These same eruptions formed

26732-510: Was made up of several, clustered peaks with Mount Scott on the eastern end and Hillman Peak on the far west side. The volcanoes likely rose in elevation from east to west, and they also featured volcanic cones and lava domes on their southern flanks. Glacial horns like the Watchman lava flow were also present, and the mountain may or may not have sustained glaciers close to the summit. At the time of its collapse, Mount Mazama encompassed an area of 150 square miles (400 km) and represented one of

26896-545: Was quickly forgotten. Klamath language Klamath is a member of the Plateau Penutian language family , which is in turn a branch of the proposed Penutian language family. Like other proposed Penutian languages, Plateau Penutian languages are rich in ablaut , much like Indo-European and Afro-Asiatic languages. Further evidence for this classification includes some consonant correspondences between Klamath and other alleged Penutian languages. For example,

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