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93-667: The Pend Oreille River begins at Lake Pend Oreille in Bonner County, Idaho in the Idaho Panhandle , draining the lake from its western end near Sandpoint (The Clark Fork River enters the lake from its eastern end). It flows west, receiving the Priest River from the north at the town of Priest River , then flows into southern Pend Oreille County in northeastern Washington at Newport . Once in Washington it turns north, flowing along

186-408: A distinctive composition or mode or origin. Special names still in wide use include amphibolite, greenschist , phyllite, marble, serpentinite , eclogite, migmatite , skarn , granulite , mylonite, and slate. The basic classification can be supplemented by terms describing mineral content or texture. For example, a metabasalt showing weak schistosity might be described as a gneissic metabasalt, and

279-451: A distinctive layering called foliation (derived from the Latin word folia , meaning "leaves"). Foliation develops when a rock is being shortened along one axis during recrystallization. This causes crystals of platy minerals, such as mica and chlorite , to become rotated such that their short axes are parallel to the direction of shortening. This results in a banded, or foliated, rock, with

372-464: A marble will not be identical with the amphibolite facies of a pelite. However, the facies are defined such that metamorphic rock with as broad a range of compositions as is practical can be assigned to a particular facies. The present definition of metamorphic facies is largely based on the work of the Finnish geologist, Pentti Eskola , with refinements based on subsequent experimental work. Eskola drew upon

465-522: A metamorphic rock to be classified in this manner, the protolith should be identifiable from the characteristics of the metamorphic rock itself, and not inferred from other information. Under the British Geological Survey's classification system, if all that can be determined about the protolith is its general type, such as sedimentary or volcanic, the classification is based on the mineral mode (the volume percentages of different minerals in

558-564: A peak in World War II when the metals were desperately needed for the productions of weapons, ships and planes. In the 19th century, logging was the other major industry of the Pend Oreille River area and attracted hundreds to thousands of men to the region, many of them Scandinavian . Logging was profitable because almost the entire Pend Oreille watershed was forested with various types of trees. However, shipping logs to ports lower on

651-413: A pelite containing abundant staurolite might be described as a staurolite pelite. [REDACTED] A metamorphic facies is a set of distinctive assemblages of minerals that are found in metamorphic rock that formed under a specific combination of pressure and temperature. The particular assemblage is somewhat dependent on the composition of that protolith, so that (for example) the amphibolite facies of

744-519: A relatively mild grade of metamorphism, at temperatures of 350–500 °C (662–932 °F) and pressures of 200–500 MPa (2,000–5,000 bar). They can be divided into a lower group of metabasalts, including rare meta komatiites ; a middle group of meta-intermediate-rock and meta-felsic-rock; and an upper group of metasedimentary rock. The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F)) metamorphism to

837-410: A variety of metamorphic facies. Where subduction is taking place, the basalt of the subducting slab is metamorphosed to high-pressure metamorphic facies. It initially undergoes low-grade metamorphism to metabasalt of the zeolite and prehnite-pumpellyite facies , but as the basalt subducts to greater depths, it is metamorphosed to the blueschist facies and then the eclogite facies . Metamorphism to

930-417: Is a great variety of metamorphic rock types. In general, if the protolith of a metamorphic rock can be determined, the rock is described by adding the prefix meta- to the protolith rock name. For example, if the protolith is known to be basalt , the rock will be described as a metabasalt. Likewise, a metamorphic rock whose protolith is known to be a conglomerate will be described as a metaconglomerate . For

1023-577: Is among the five deepest lakes in the United States. The area around the lake is the traditional home of the Kalispel Indian peoples. David Thompson established a North West Company trading post on the lake in 1809. A Canadian fur trader in Thompson's party is believed to have given the lake its name. The words "Pend Oreille" are French for an ear-hanging or pendant. Ear pendants were characteristic of

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1116-426: Is called a paired metamorphic belt . The main islands of Japan show three distinct paired metamorphic belts, corresponding to different episodes of subduction. Metamorphic rock is also exposed in metamorphic core complexes , which form in region of crustal extension. They are characterized by low-angle faulting that exposes domes of middle or lower crust metamorphic rock. These were first recognized and studied in

1209-511: Is dominated by metamorphic rock that has reached the amphibolite facies. Within the upper crust, which is the only part of the Earth's crust geologists can directly sample, metamorphic rock forms only from processes that can occur at shallow depth. These are contact (thermal) metamorphism , dynamic (cataclastic) metamorphism , hydrothermal metamorphism , and impact metamorphism . These processes are relatively local in occurrence and usually reach only

1302-476: Is formed as tectonic plates move apart. Hydrothermal metamorphism is extensive here. This is characterized by metasomatism by hot fluids circulating through the rock. This produces metamorphic rock of the greenschist facies. The metamorphic rock, serpentinite , is particularly characteristic of these settings, and represents chemical transformation of olivine and pyroxene in ultramafic rock to serpentine group minerals. Contact metamorphism takes place when magma

1395-836: Is in Kootenai County and is home to Farragut State Park , formerly the Farragut Naval Training Station during World War II , of which a small part is still active and conducts U.S. Navy acoustic underwater submarine research. The surrounding forests consist of ponderosa pine , Douglas fir , red cedar , poplar , quaking aspen , hemlock , paper birch and western larch . Local animal species include white-tailed deer , elk , gray wolves , moose , mice , squirrels , chipmunks , black bears , grizzly bear , coyotes , mountain goat , cougar and bobcats , along with bald eagles , wild turkeys , osprey , owls , hummingbirds , hawks , woodpeckers , ducks , and

1488-403: Is injected into the surrounding solid rock ( country rock ). The changes that occur are greatest wherever the magma comes into contact with the rock because the temperatures are highest at this boundary and decrease with distance from it. Around the igneous rock that forms from the cooling magma is a metamorphosed zone called a contact aureole . Aureoles may show all degrees of metamorphism from

1581-405: Is known as burial metamorphism . This tends to produce low-grade metamorphic rock. Much more common is metamorphic rock formed during the collision process itself. The collision of plates causes high temperatures, pressures and deformation in the rocks along these belts. Metamorphic rock formed in these settings tends to shown well-developed schistosity. Metamorphic rock of orogenic belts shows

1674-879: Is notable in that it cuts right between the Bitterroot Range and Selkirk Range , two major chains of the Rocky Mountains . The only other river to do so is the Kootenay, just to the north. The Rocky Mountain Trench runs across the northeast part of the watershed, through the Flathead Valley, and eventually terminating in mountains near the Clark Fork's confluence with the Flathead. The Pend Oreille River starts in northern Idaho, at Lake Pend Oreille, Idaho's largest lake. Cocolalla Creek

1767-506: Is sufficiently hard and dense that it is difficult to quarry. However, some quartzite is used as dimension stone , often as slabs for flooring, walls, or stairsteps. About 6% of crushed stone, used mostly for road aggregate, is quartzite. Marble is also prized for building construction and as a medium for sculpture. Schistose bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. A hazard may exist even in undisturbed terrain. On August 17, 1959,

1860-623: Is that these cataclysmic floods, known as the Missoula Floods , traveled down the Pend Oreille Valley into the Columbia. Rather, it is now thought that the water completely breached the western divide of the Pend Oreille River valley and rushed out towards the direction of Spokane . Native people who lived along the river included the Pend d'Oreilles and Kalispel (considered as a single tribe by

1953-634: Is the first major tributary. The next one is the Priest River, this is 68 miles (109 km) long, and has three rivers flowing into it. Sullivan Creek is the last big tributary. The Clark Fork is also considered a tributary, as is the Pack. Much of the Pend Oreille valley consists of relatively ancient metamorphic rock , uplifted over 500 million years ago from the former floor of the Precambrian sea that covered

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2046-683: Is the fourth largest by discharge (after the Snake, Kootenay and Willamette Rivers ) and drains the second largest area (second only to the Snake). The Pend Oreille River watershed divide is formed on the east side by the Continental Divide . On the south, the Spokane River and Snake River drainage basins border on the Clark Fork. To the west smaller rivers such as the Colville River and tributaries of

2139-545: Is transformed physically or chemically at elevated temperature, without actually melting to any great degree. The importance of heating in the formation of metamorphic rock was first noted by the pioneering Scottish naturalist, James Hutton , who is often described as the father of modern geology. Hutton wrote in 1795 that some rock beds of the Scottish Highlands had originally been sedimentary rock but had been transformed by great heat. Hutton also speculated that pressure

2232-400: Is uncertain. Special classifications exist for metamorphic rocks with a volcaniclastic protolith or formed along a fault or through hydrothermal circulation . A few special names are used for rocks of unknown protolith but known modal composition, such as marble, eclogite , or amphibolite . Special names may also be applied more generally to rocks dominated by a single mineral, or with

2325-426: Is used only when very little else is known about the rock that would allow a more definite classification. Textural classifications may be prefixed to indicate a sedimentary protolith ( para- , such as paraschist) or igneous protolith ( ortho- , such as orthogneiss). When nothing is known about the protolith, the textural name is used without a prefix. For example, a schist is a rock with schistose texture whose protolith

2418-475: Is usually devoid of schistosity and forms a tough, equigranular rock. If the rock was originally banded or foliated (as, for example, a laminated sandstone or a foliated calc- schist ) this character may not be obliterated, and a banded hornfels is the product. Contact metamorphism close to the surface produces distinctive low-pressure metamorphic minerals, such as spinel , andalusite, vesuvianite , or wollastonite . Similar changes may be induced in shales by

2511-470: Is very low in silica) to metafelsic-rock (with a high silica content). Where the mineral mode cannot be determined, as is often the case when rock is first examined in the field , then classification must be based on texture. The textural types are: A hornfels is a granofels that is known to result from contact metamorphism. A slate is a fine-grained metamorphic rock that easily splits into thin plates but shows no obvious compositional layering. The term

2604-566: The Basin and Range Province of southwestern North America, but are also found in southern Aegean Sea , in the D'Entrecasteaux Islands , and in other areas of extension. Continental shields are regions of exposed ancient rock that make up the stable cores of continents. The rock exposed in the oldest regions of shields, which is of Archean age (over 2500 million years old), mostly belong to granite-greenstone belts. The greenstone belts contain metavolcanic and metasedimentary rock that has undergone

2697-472: The Bureau of Indian Affairs ). Archaeological evidence suggests that people lived in the region as early as the end of the last ice age , about 11,000-12,000 years ago. The name Pend d'Oreille or Pend Oreille is variously stated to mean "earring", "hang from ears", or "shape of an ear". Kalispel is thought to mean " camas people", referring to the roots that provided their primary food. Both tribes lived around

2790-662: The Clark Fork River and the Pack River , and drains into the Pend Oreille River , as well as subsurfacely into the Spokane Valley–Rathdrum Prairie Aquifer . It is surrounded by national forests and a few small towns, with the largest population on the lake at Sandpoint . The majority of the shoreline is non-populated and all but the southern tip of the lake is in Bonner County . The southern tip

2883-479: The Idaho Batholith , a portion of which cooled and eroded to become the present main body of the Bitterroot Range , a major physiographic feature of the watershed which sweeps from northwest to southeast along the entire Clark Fork valley (and the border of Idaho and Montana), by about 70 million years ago. This time period is generally accepted as when the entire Rocky Mountains system was formed, although age of

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2976-450: The atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. Metamorphic rocks are characterized by their distinctive mineral composition and texture. Because every mineral is stable only within certain limits, the presence of certain minerals in metamorphic rocks indicates the approximate temperatures and pressures at which

3069-402: The crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. Metamorphic rocks are typically more coarsely crystalline than the protolith from which they formed. Atoms in the interior of a crystal are surrounded by a stable arrangement of neighboring atoms. This is partially missing at the surface of

3162-471: The mountain bluebird . The lake is a home for several species of migratory water fowl. Lake Pend Oreille was glacially formed during the ice age . It is also believed that the eastern side of the lake was in the path of the ancient Missoula Floods . The lake sits at the south end of the Purcell Trench, carved by glaciers moving south from Canada. The eastern side of the glacier is believed to have formed

3255-646: The Bitterroot Valley of south-western Montana. Sandpoint (population 7,000), near where the river flows out of Lake Pend Oreille, remains the largest city in close proximity to the river. There are five hydroelectric dams on the Pend Oreille River: Waneta (owned by Teck Cominco ) and Seven Mile (B.C. Hydro) dams in Canada, Boundary (Seattle City Light), Box Canyon , (Pend Oreille County PUD), and Albeni Falls (U.S. Army Corps of Engineers) dams in

3348-488: The Clark Fork ( Cabinet Gorge , Noxon Rapids and Thompson Falls ) and Flathead ( SKQ / Flathead Lake and Hungry Horse ) also generate power and to a lesser extent regulate the inflows to Lake Pend Oreille and the Pend Oreille River. In the 1920s, there was a proposal to divert the Pend Oreille through a 60 miles (97 km) gravity canal to irrigate the Grand Coulee and surrounding lands in eastern Washington as part of

3441-694: The Clark Fork. If the lengths of the North Fork Flathead, main Flathead, Clark Fork and Pend Oreille are added together, the total is over 510 miles (820 km) stretching from the Rocky Mountains north of Glacier National Park to the Canada-U.S. border south of Montrose, British Columbia . This makes the Pend Oreille system the second longest tributary of the Columbia River (after the Snake River ). It

3534-621: The Columbia River (to the southwest of the Pend Oreille River) was a problem. Not only was the river riddled with frightening waterfalls and rapids, but it flows north, in the opposite direction that the logging companies wanted to move their logs. At about this time, steamboats were introduced to the Pend Oreille River. The first steamboat on the river was The Bertha , built in 1887 at Albeni Falls . Other well-known craft included Ione , Spokane , and Metaline ( Pend Oreille ). These boats carried passengers and ore and also towed log rafts up

3627-452: The Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss , slate , marble , schist , and quartzite . Slate and quartzite tiles are used in building construction. Marble is also prized for building construction and as a medium for sculpture. On

3720-435: The Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distortion. Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at

3813-672: The Federal Energy Regulatory Committee ‘FERC’) for the continued license/operation of the Boundary Dam on the Pend Oreille, Seattle City and Light had to provide mitigation funding. This mitigation funding came in the form of removing the 50 foot (15 m) high ‘Mill Pond Dam’ on Sullivan Creek just upstream of the town of Metaline Falls. Mill Pond Dam was removed in the summer of 2017 and the project finished in 2018 with stream and bank stabilization and native tree plantings. Sullivan Creek now runs free from its headwaters in

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3906-619: The Kalispel tribe. The lake is shaped much like a human ear when viewed from above or on a map. In 1846, Great Britain ceded the bulk of its claims to the Pacific Nortwest pursuant to the Oregon Treaty . During World War II , the south end was the second largest naval training ground in the world and the largest "city" in the state. Built as a result of the Japanese attack on Pearl Harbor ,

3999-498: The Pend Oreille River. By the 1840s, Europeans and Americans were pouring into the region in increasing numbers, although growth was slow. These newcomers did not strike good relations with the Native Americans of the area, and diseases such as smallpox wiped out many indigenous (this happened with many other tribes across North and Middle America as they were not used to such a sickness). After numerous wars and treaties, much of

4092-481: The Pend Oreille were French-Canadian fur trappers working for various fur trading companies to provide beaver pelts to trade overseas. Some of these people were the ones to coin the term "Pend d'Oreille". Canadian explorer David Thompson saw the river in 1807, after a long and arduous journey from Saskatchewan . His primary mission was to find the source of the Columbia River ( Columbia Lake ), which he did. Afterwards he proceeded to establish trading posts throughout

4185-831: The Salmon-Priest Wilderness to the Pend Oreille River. Native trout species will assuredly benefit by this habitat restoration. The river is popular for boating and fishing. The Pend Oreille River Trail covers 70 miles (110 km) from the Idaho/Washington border to Boundary Dam near the Canadian border. Maps can be found on the Pend Oreille County website . The river is popular for boating, [REDACTED] Media related to Pend Oreille River at Wikimedia Commons Lake Pend Oreille Lake Pend Oreille ( / ˌ p ɒ n d ə ˈ r eɪ / POND -ə- RAY ) in

4278-773: The Spokane drain the lands past the watershed divide. In the north is the Kootenay River, a similar-sized tributary of the Columbia. To the east, in Montana, is the Missouri River and tributaries such as the Marias River and Milk River . In the southwest the watershed borders on the Big Hole River and Jefferson River , headwater streams of the Missouri. The Pend Oreille/Clark Fork system

4371-427: The United States. The combined generating capacity of all the dams is approximately 2480 megawatts (MW). Boundary Dam has the largest generating capacity of the five, at 1070 MW. The smaller Albeni Falls Dam regulates the level of Lake Pend Oreille to provide some flood control during the summer and increased flows during dry winters. None of the dams provide for fish passage or navigation. Numerous dams upstream along

4464-477: The amphibolite or granulite facies. These form most of the exposed rock in Archean cratons. The granite-greenstone belts are intruded by a distinctive group of granitic rocks called the tonalite - trondhjemite - granodiorite or TTG suite. These are the most voluminous rocks in the craton and may represent an important early phase in the formation of continental crust. Mid-ocean ridges are where new oceanic crust

4557-500: The area of Lake Pend Oreille occasionally ranging lower onto the Pend Oreille River (or maybe they did have settlements along the river?) but the lower (north) basin was generally less populated than the upper (south) portion. The Flathead tribe inhabited the upper (Clark Fork) part of the basin, especially the Bitterroot Valley . The Ktunaxa lived just to the east of the Pend Oreille river. The first non-indigenous people to see

4650-404: The bands showing the colors of the minerals that formed them. Foliated rock often develops planes of cleavage . Slate is an example of a foliated metamorphic rock, originating from shale , and it typically shows well-developed cleavage that allows slate to be split into thin plates. The type of foliation that develops depends on the metamorphic grade. For instance, starting with a mudstone ,

4743-420: The bulk composition of a rock. Hot fluids circulating through pore space in the rock can dissolve existing minerals and precipitate new minerals. Dissolved substances are transported out of the rock by the fluids while new substances are brought in by fresh fluids. This can obviously change the mineral makeup of the rock. However, changes in the mineral composition can take place even when the bulk composition of

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4836-399: The burning of coal seams. This produces a rock type named clinker . There is also a tendency for metasomatism between the igneous magma and sedimentary country rock, whereby the chemicals in each are exchanged or introduced into the other. In that case, hybrid rocks called skarn arise. Dynamic (cataclastic) metamorphism takes place locally along faults . Here intense shearing of

4929-435: The circulation of fluids through buried rock, to the list of processes that help bring about metamorphism. However, metamorphism can take place without metasomatism ( isochemical metamorphism ) or at depths of just a few hundred meters where pressures are relatively low (for example, in contact metamorphism ). Metamorphic processes change the texture or mineral composition of the metamorphosed rock. Metasomatism can change

5022-427: The collision of tectonic plates at convergent boundaries . Here formerly deeply buried rock has been brought to the surface by uplift and erosion. The metamorphic rock exposed in orogenic belts may have been metamorphosed simply by being at great depths below the Earth's surface, subjected to high temperatures and the great pressure caused by the immense weight of the rock layers above. This kind of regional metamorphism

5115-491: The contact area to unmetamorphosed (unchanged) country rock some distance away. The formation of important ore minerals may occur by the process of metasomatism at or near the contact zone. Contact aureoles around large plutons may be as much as several kilometers wide. The term hornfels is often used by geologists to signify those fine grained, compact, non-foliated products of contact metamorphism. The contact aureole typically shows little deformation, and so hornfels

5208-612: The crystal, producing a surface energy that makes the surface thermodynamically unstable. Recrystallization to coarser crystals reduces the surface area and so minimizes the surface energy. Although grain coarsening is a common result of metamorphism, rock that is intensely deformed may eliminate strain energy by recrystallizing as a fine-grained rock called mylonite . Certain kinds of rock, such as those rich in quartz, carbonate minerals , or olivine, are particularly prone to form mylonites, while feldspar and garnet are resistant to mylonitization. Many kinds of metamorphic rocks show

5301-508: The dam for the Missoula floods, at the point where the Clark Fork river enters the lake between the Cabinet and Bitterroot mountains. The lake is made slightly larger by the dam at Albeni Falls , just east of Oldtown ; the dam is ninety feet (27 m) high and operated by the U.S. Army Corps of Engineers . Along with Crater Lake , Lake Tahoe , Lake Chelan , and Lake Superior , Lake Pend Oreille

5394-584: The eastern side of the Selkirk Mountains . It flows roughly parallel to the Idaho border for approximately 50 miles (80 km), through the Colville National Forest , past Tiger and Metaline Falls . It crosses the international border into southeastern British Columbia, looping west for about 15 miles (24 km) and joining the Columbia from the east, approximately 0.2 miles (0.32 km) north of

5487-423: The eclogite facies releases a great deal of water vapor from the rock, which drives volcanism in the overlying volcanic arc . Eclogite is also significantly denser than blueschist, which drives further subduction of the slab deep into the Earth's mantle . Metabasalt and blueschist may be preserved in blueschist metamorphic belts formed by collisions between continents. They may also be preserved by obduction onto

5580-437: The following sequence develops with increasing temperature: The mudstone is first converted to slate, which is a very fine-grained, foliated metamorphic rock, characteristic of very low grade metamorphism. Slate in turn is converted to phyllite , which is fine-grained and found in areas of low grade metamorphism. Schist is medium to coarse-grained and found in areas of medium grade metamorphism. High-grade metamorphism transforms

5673-593: The former Farragut Naval Training Station was used to accommodate the 12th World Scout Jamboree (1 to 8 August), the dates being significant as it marked 60 years to the date after Sir Robert Baden Powell held his first scout camp on Brownsea Island in Poole Harbour, Dorset in England. The following towns are adjacent to the lake: The lake is viewed from the Pend Oreille Scenic Byway , State Highway 200 along

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5766-449: The identical composition, Al 2 SiO 5 . Likewise, forsterite is stable over a broad range of pressure and temperature in marble , but is converted to pyroxene at elevated pressure and temperature in more silicate-rich rock containing plagioclase , with which the forsterite reacts chemically. Many complex high-temperature reactions may take place between minerals without them melting, and each mineral assemblage produced indicates

5859-467: The international border and approximately 5 miles (8 km) south of Montrose . Spreading across 25,792 square miles (66,800 km), the Pend Oreille River watershed stretches across most of western Montana, northern Idaho and northeastern Washington, as well as tiny portions in southern British Columbia drained by the North Fork Flathead River and the lower Pend Oreille River. Much of

5952-611: The land in the Pend Oreille basin especially the upper Clark Fork area had been ceded to the settlers. The last land in the Bitterroot area was given up in 1889, and many tribes of the Pend Oreille basin were moved to reservations in northwestern Montana. In the late 1850s, a major influx of non-indigenous peoples occurred when gold was discovered near Metaline Falls on the Pend Oreille River. The first major white settlements in that area, however, were not created until 1884. Mining for gold soon ceased but lead and zinc mining continued, reaching

6045-437: The low-pressure facies, such as the hornfels and sanidinite facies . Most metamorphic rock is formed by regional metamorphism in the middle and lower crust, where the rock reaches the higher-pressure metamorphic facies. This rock is found at the surface only where extensive uplift and erosion has exhumed rock that was formerly much deeper in the crust. Metamorphic rock is extensively exposed in orogenic belts produced by

6138-854: The north shore. US 95 crosses the lake via Long bridge. Much of the shore is mountainous. The mountains to the east are the Green Monarchs; to the north are the Cabinet Mountains ; to the southwest the Coeur d'Alene Mountains ; and to northwest are the Selkirk Mountains . The lake is known to harbor several invasive species . Some of these species include: The lake is home to many species of fish, including rainbow trout , lake trout , bull trout , cutthroat trout , brown trout , cutbow , perch , black crappie , bluegill , largemouth bass , smallmouth bass , whitefish , walleye , northern pike , northern pikeminnow , and kokanee salmon . Lake Pend Oreille

6231-463: The northern Idaho Panhandle is the largest lake in the U.S. state of Idaho and the 38th-largest lake by area in the United States , with a surface area of 148 square miles (380 km ). It is 69 kilometres (43 mi) long, and 1,152 feet (351 m) deep in some regions, making it the fifth-deepest in the nation and having a volume of 43,939,940 acre feet = 54 km . The lake is fed by

6324-453: The other hand, schist bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. Metamorphic rocks form one of the three great divisions of rock types. They are distinguished from igneous rocks , which form from molten magma , and sedimentary rocks , which form from sediments eroded from existing rock or precipitated chemically from bodies of water. Metamorphic rocks are formed when existing rock

6417-460: The overriding plate as part of ophiolites . Eclogites are occasionally found at sites of continental collision, where the subducted rock is rapidly brought back to the surface, before it can be converted to the granulite facies in the hot upper mantle. Many samples of eclogite are xenoliths brought to the surface by volcanic activity. Many orogenic belts contain higher-temperature, lower-pressure metamorphic belts. These may form through heating of

6510-411: The region during that period. Granite batholiths overlain by layers of sedimentary rock compose most of the higher terrain, such as the Cabinet Mountains . The age of the rocks along the Pend Oreille generally decreases as one travels downstream (north), and the terrain is also more rugged towards the north than in the south. About 200 million years ago, increased tectonic activity caused the uplift of

6603-520: The region, including Kullyspell House on the north shore of Lake Pend Oreille. In 1808, Thompson again traveled into the Pend Oreille region. The following spring, he tried to reach the Columbia River by way of the Pend Oreille, but rapids and waterfalls hampered his attempt. He ended up retreating to another trading post in British Columbia a few months later. After these early explorations, however, there still were no permanent white settlements along

6696-511: The river. (Since it flows north, they had to tow the logs south, against the current, to ship it a shorter distance to the lumber mills and factories lower in the Columbia Basin.) Navigation on the Pend Oreille presented few problems upstream of the Box Canyon rapids about three-fourths of the way down the Pend Oreille River (today close to the site of Box Canyon Dam ). Many boats were wrecked in

6789-475: The rock by ascending magmas of volcanic arcs, but on a regional scale. Deformation and crustal thickening in an orogenic belt may also produce these kinds of metamorphic rocks. These rocks reach the greenschist , amphibolite, or granulite facies and are the most common of metamorphic rocks produced by regional metamorphosis. The association of an outer high-pressure, low-temperature metamorphic zone with an inner zone of low-pressure, high-temperature metamorphic rocks

6882-421: The rock does not change. This is possible because all minerals are stable only within certain limits of temperature, pressure, and chemical environment. For example, at atmospheric pressure, the mineral kyanite transforms to andalusite at a temperature of about 190 °C (374 °F). Andalusite, in turn, transforms to sillimanite when the temperature reaches about 800 °C (1,470 °F). All three have

6975-458: The rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous , sedimentary , or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture . They may be formed simply by being deeply buried beneath

7068-423: The rock to gneiss , which is coarse to very coarse-grained. Rocks that were subjected to uniform pressure from all sides, or those that lack minerals with distinctive growth habits, will not be foliated. Marble lacks platy minerals and is generally not foliated, which allows its use as a material for sculpture and architecture. Metamorphic rocks are one of the three great divisions of all rock types, and so there

7161-495: The rock typically forms mylonites. Impact metamorphism is unlike other forms of metamorphism in that it takes place during impact events by extraterrestrial bodies. It produces rare ultrahigh pressure metamorphic minerals, such as coesite and stishovite . Coesite is rarely found in eclogite brought to the surface in kimberlite pipes , but the presence of stishovite is unique to impact structures. Slate tiles are used in construction, particularly as roof shingle. Quartzite

7254-407: The rock underwent metamorphism. These minerals are known as index minerals . Examples include sillimanite , kyanite , staurolite , andalusite , and some garnet . Other minerals, such as olivines , pyroxenes , hornblende , micas , feldspars , and quartz , may be found in metamorphic rocks but are not necessarily the result of the process of metamorphism. These minerals can also form during

7347-486: The rock). Metasedimentary rocks are divided into carbonate-rich rock (metacarbonates or calcsilicate-rocks) or carbonate-poor rocks, and the latter are further classified by the relative abundance of mica in their composition. This ranges from low-mica psammite through semipelite to high-mica pelite . Psammites composed mostly of quartz are classified as quartzite. Metaigneous rocks are classified similarly to igneous rocks, by silica content, from meta-ultramafic-rock (which

7440-774: The rocks varies with location. In the previous Ice Age , a massive glacier of the Cordilleran Ice Sheet advanced southwards through the Idaho Panhandle, burying the Lake Pend Oreille and upper Pend Oreille River valley with ice hundreds to thousands of feet thick. This formed a pair of ice dams, one gigantic, and one significantly smaller. The one that caused the water of the Clark Fork and other smaller streams to back up into Glacial Lake Missoula , which stretched over two hundred miles southwest across western Montana, containing some 500 cubic miles (2,100 km) of water,

7533-406: The sedimentary rock limestone and chalk change into larger crystals in the metamorphic rock marble . In metamorphosed sandstone, recrystallization of the original quartz sand grains results in very compact quartzite, also known as metaquartzite, in which the often larger quartz crystals are interlocked. Both high temperatures and pressures contribute to recrystallization. High temperatures allow

7626-464: The sites of the sawmills that cut the lumber extracted from the region. Some emigrants also settled along the Clark Fork, but there were similar problems because for most of its course, the Clark Fork, like the Pend Oreille, flows in a steep and narrow gorge. Larger numbers of people settled in the Flathead River valley, around Flathead Lake and Lake Pend Oreille, in the Priest River valley, and in

7719-474: The southern drainage divide of the watershed forms the border of Idaho and Montana, and a very short portion of the northeastern divide forms the border of British Columbia and Alberta . The river is sometimes considered as one with the Clark Fork, which is the primary river flowing into Lake Pend Oreille. For example, in Stewart Holbrook's book The Columbia , he repeatedly refers to the Pend Oreille River as

7812-471: The stretch between Box Canyon and the river's mouth (including Metaline , which was the only large steamer to operate on the lower river on a regular basis). After the Idaho & Washington Northern Railroad was built in the area, steamboat commerce faded and the logs were transported by rail. The Idaho & Washington Northern was eventually succeeded by the Milwaukee Road . The Pend Oreille River valley

7905-404: The temperatures and pressures at the time of metamorphism. These reactions are possible because of rapid diffusion of atoms at elevated temperature. Pore fluid between mineral grains can be an important medium through which atoms are exchanged. The change in the particle size of the rock during the process of metamorphism is called recrystallization . For instance, the small calcite crystals in

7998-553: The tentative Columbia Basin Project . These plans were later dropped with the construction of Grand Coulee Dam and a pumping plant on the Columbia River. Variant names, according to the USGS , include: Bitter Root River, Bitterroot River, Clark Fork, Clarke Fork, Clarkes Fork, Clarks Fork, Deer Lodge River, Hell Gate River, Missoula River, Pend d'Oreille River, Silver Bow River, Clark's Fork, and Pend-d'Oreille River. As mitigation (mandated by

8091-627: The training station is now Farragut State Park . The lake's Large Scale Vehicle Range is still used by the Navy 's Acoustic Research Detachment for sonar testing with large-scale submarine prototypes on the Pend Oreille Calibration Station. The significant depth gives acoustic properties similar to the open ocean. Background noise is less than at ocean testing locations, and the sound signatures being investigated cannot be monitored by foreign governments in international waters. In 1967,

8184-451: The use of granulite as a classification for rock metamorphosed to the granulite facies. Instead, such rock will often be classified as a granofels. However, this approach is not universally accepted. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. The lower continental crust is mostly metamafic-rock and pelite which have reached the granulite facies . The middle continental crust

8277-561: The zonal schemes, based on index minerals, that were pioneered by the British geologist, George Barrow . The metamorphic facies is not usually considered when classifying metamorphic rock based on protolith, mineral mode, or texture. However, a few metamorphic facies produce rock of such distinctive character that the facies name is used for the rock when more precise classification is not possible. The chief examples are amphibolite and eclogite . The British Geological Survey strongly discourages

8370-554: Was also the home of the 37-pound (17-kilogram) state record gerrard rainbow trout (aka kamloops rainbow) caught by Wes Hamlet in 1947. Metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism . The original rock ( protolith ) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000  bar ) or more, causing profound physical or chemical changes. During this process,

8463-419: Was important in metamorphism. This hypothesis was tested by his friend, James Hall , who sealed chalk into a makeshift pressure vessel constructed from a cannon barrel and heated it in an iron foundry furnace. Hall found that this produced a material strongly resembling marble , rather than the usual quicklime produced by heating of chalk in the open air. French geologists subsequently added metasomatism ,

8556-415: Was never easy for early or later emigrants to settle in. The little arable land that did exist was mostly within the river's floodplain , and in many places there was only a narrow strip of flat ground that would soon run against vertical cliffs or dense forests with rocky soil. Nevertheless, some permanent settlements persisted, at Newport, Albeni Falls, Ione, Dalkena, Metaline Falls, Cusick, Usk, and many at

8649-442: Was over 2,000 feet (610 m) high. The second one blocked the upper Pend Oreille River near Sandpoint, creating an enlarged Lake Pend Oreille that could have connected with a similarly enlarged Kootenay Lake in the north. Water pressure and glacial melt destroyed the larger of the two ice dams several times, causing massive amounts of water to rush out across eastern Washington through the upper Pend Oreille River. A mistaken belief

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