Citizendia

The Rocky Mountain Trench, also called "the valley of a thousand peaks," is a physiographic feature extending ~1600 km (995 mi) from Flathead Lake, Montana, to the British Columbia-Yukon border. Flathead Lake is the largest Lake in the western part of the coterminous United States, surpassing Nevada/California's Lake Tahoe by. Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C Yukon (ˈjuːkɒn is the westernmost and smallest of Canada's three territories.

Although some of its topography has been carved into glacial valleys, it is primarily a by-product of faulting. Topography ( topo-, "place" and graphia, "writing" is the study of Earth 's Surface features or those of Planets In Geology, a valley (also called a vale, dale, glen or strath and near or in Appalachia, a draw) is In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement It separates the Rocky Mountains on its east from the Columbia Mountains and the Cassiar Mountains on its west. Mountain peaks of the Rocky Mountains The Rocky Mountains, often called the Rockies, are a Mountain range in western North America. Columbia Mountains is a group of Mountain ranges located in British Columbia, and partially in Montana, Idaho, Washington. The Cassiar Mountains are the most northerly group of the Northern Interior Mountains in the Canadian province of British Columbia. It also skirts part of the McGregor Plateau area of the Nechako Plateau subarea of the Interior Plateau of British Columbia. The Nechako Plateau is the northernmost subdivision of the Interior Plateau, one of the main geographic regions of the Canadian province of British Columbia Interior Plateau comprises a large region of central British Columbia, and lies between the Cariboo and Monashee Mountains on the east and the Hazelton British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C It is up to 25 km wide, peak-to-peak, and varies in depth, but is clearly visible from the air and discernible from high up on any of the mountain ridges lining it.

It is used by four major river basins: the Columbia, Fraser, Peace and Liard's. The Columbia River (known as For other uses of this name see Fraser River (disambiguation. This article is about the river For the town in Alberta see Peace River Alberta. The Liard River flows through the Yukon Territory British Columbia and the Northwest Territories, Canada. Three reservoirs of the Columbia River Treaty fill much of its length today - Lake Koocanusa, Lake Kinbasket and Lake Williston. The Columbia River Treaty is an international agreement between Canada and the United States of America (U Lake Koocanusa is a Reservoir in British Columbia ( Canada) and Montana ( United States) formed by the Damming of the Kinbasket Lake (or Kinbasket Reservoir) is a Reservoir on the Columbia River in southeast British Columbia, north of the town of Revelstoke and Williston Lake is a Reservoir located in central British Columbia, Canada. Rivers that use the trench are the Kootenay River, the Columbia River, Canoe River, Fraser River, Parsnip River, Finlay River, Fox River, and the Kechika River. The Kootenay River (spelled Kootenai River for its American portions is the uppermost major tributary of the Columbia River, flowing through British Columbia Canoe River is a Tributary of the Columbia River in British Columbia, Canada. The Parsnip River is a 240 km long river in central British Columbia, Canada. Finlay River is a 402 km long river in north-central British Columbia flowing north and thence south from Thutade Lake in the Omineca Mountains to The Kechika River is located in northern British Columbia, Canada. The Kechika and Fox are part of the Liard system, the Parsnip and Finlay and part of the Peace River system. The Canoe River is a short tributary of the Columbia system, draining into Lake Kinbasket. Kinbasket Lake (or Kinbasket Reservoir) is a Reservoir on the Columbia River in southeast British Columbia, north of the town of Revelstoke and The Kootenay River is a tributary of the Columbia, joining it near Trail B.C. after a quick trip through the United States as the Kootenai River. The Columbia River (known as Trail is a city in the West Kootenay region of the Interior of British Columbia, Canada. The Kootenai River, however, does not follow the trench but exits it southwest (as the Lake Koocanusa reservoir to the Libby Dam). Libby Dam is a Dam on the Kootenai River in the US state of Montana.

The Rocky Mountain Trench can be divided into the Northern Rocky Mountain Trench and Southern Rocky Mountain Trench by a break in the valley system at ~54°N near Prince George, British Columbia. Prince George, with a population of 70981 ( census agglomeration of 83225 is the largest city in northern British Columbia British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C The northern portion of the trench is dominated by strike-slip faulting while the southern part of the trench was created by normal faults. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement Despite differences in timing and faulting styles of the northern and southern portions, they were aligned with each other because faulting for both was controlled by a pre-existing, west-facing, deep basement ramp with over 10 km of vertical offset.

Northern Rocky Mountain Trench

The Northern Rocky Mountain Trench is closely aligned with the Tintina Trench near the British Columbia-Yukon border, and the two could arguably be classified as one and the same. The Tintina Trench extends through the Yukon into Alaska. Yukon (ˈjuːkɒn is the westernmost and smallest of Canada's three territories. Alaska ( Аляска Alyaska) is a state in the United States of America, in the northwest of the North American continent Right-lateral strike-slip fault movement on the Tintina-Northern Rocky Mountain Trench may have begun during the middle Jurassic. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement The Jurassic is a geologic period and system that extends from about Ma (million years ago to  Ma that is from the end of the Triassic to the beginning The fastest rates of slip probably occurred during two pulses in the middle Cretaceous and early Cenozoic, respectively, with the latter probably occurring during the Eocene. The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new" The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in Between 750 km to > 900 km of total right-lateral movement has occurred, of which 450 km of offset has occurred since the mid-Cretaceous. The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of The end result is that terrains to the west of the fault system have moved toward the north. In the context of plate tectonics, strike-slip movement on the Tintina-Northern Rocky Mountain Trench is also related to strike-slip movement along the San Andreas Fault, the extension of the Basin and Range Provence, and other extensional or strike-slip fault systems in western North America. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere The San Andreas Fault is a geologic Transform fault that runs a length of roughly 800 miles (1300 km through California in the United States. Basin and range is a geologic term for a type of Topography characterized by a series of separate and parallel mountain ranges with broad valleys interposed extending An Extensional Fault is a fault that extends the pre-existing geological layering

Southern Rocky Mountain Trench

The Southern Rocky Mountain Trench was created mainly by Cenozoic-aged extension (normal faulting). In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement What little strike-slip movement that is found in the southern trench is not considered significant. The extensional faulting was nonetheless substantial, having extended as deep as 13. 5 km (8. 39 mi). The southern trench also differs from the northern trench in that it is more sinuous and is asymmetrical in cross-section (perpendicular to its length). The western side of the Southern Rocky Mountain Trench is more subdued and irregular than the east side. During late Paleozoic to Mesozoic time, rapid sediment deposition and subsidence to the west transitioned in the area of the modern Rocky Mountain Trench into a stable continental shelf in the east. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. In Geology, Engineering, and Surveying, subsidence is the motion of a surface (usually the Earth's surface as it shifts downward relative to The continental shelf is the extended perimeter of each Continent and associated Coastal plain, which is covered during interglacial periods such The Nevadan Orogeny destroyed the western wedge of sedimentary rocks during Jurassic to middle Cretaceous time, thrusting them up into metamorphic fold belts. The Nevadan Orogeny was a major Mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic Currently, strata on either side of the Southern Rocky Mountain Trench consist mainly of Precambrian and Paleozoic metasedimentary and sedimentary rocks. The Precambrian ( Pre-Cambrian) is an informal name for the supereon comprising the eons of the Geologic timescale that came before the current In Geology, metasediment is Sediment or Sedimentary rock that shows evidence of having been subjected to Metamorphism. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) Within the trench are unconsolidated Cenozoic sandstones and conglomerates. Sandstone is a Sedimentary rock composed mainly of Sand -size Mineral or rock grains. A conglomerate (kɒnˈglɒmərət is a rock consisting of individual stones that have become cemented together

The aforementioned basement ramp along which orogeny-related thrust faulting and subsequent strike-slip and normal faulting occurred is probably associated with the ancient continental shelf of Paleozoic and Mesozoic time. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and A thrust fault is a type of fault, or break in the Earth's crust with resulting movement of each side against the other in which a lower stratigraphic position is pushed up The continental shelf is the extended perimeter of each Continent and associated Coastal plain, which is covered during interglacial periods such

References

For a more in-depth geological overview, the following sources are recommended:

© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic