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Shut-in (river)
A shut-in is a type of rock formation found in streams in the Ozarks, comprising stream pool, pools, rivulets, rapids and plunge pools. The term has an origin in Appalachia. Description A shut-in is a rock formation that carves through a mountain range, causing a complex of pools, rivulets, rapids and plunge pools. They are found in streams in the Ozarks. Shut-ins are inherently confined to a narrow valley or canyon, with the river valley widening out both above and below the formation. Because the rock resists downcutting, streams typically descend at relatively steep gradient through shut-ins, with the downstream terminus of the formation often marked by a very large plunge pool. The river becomes unnavigable at shut-ins even by canoe due to the rapids and narrow channels. Etymology The term has an origin in Appalachia, where it was used to refer to a narrow river gorge confined by resistant rock layers. Examples Johnson's Shut-Ins State Park in Missouri, with its hard rhyol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnsons Shutins Autumn Panorama-panini 20130126
Johnsons may refer to: * ''The Johnsons'', a 1992 Dutch horror film * The Johnsons, original bandname of UK punk band Pussycat and the Dirty Johnsons * Johnsons, California, a settlement in California, US * The Shane Twins, a professional wrestling tag team formerly known as The Johnsons See also * Anohni and the Johnsons, an American music group * Johnson (surname), Johnson, the surname * Johnsons Coach & Bus Travel * {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorge
A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tendency to cut through underlying surfaces, eventually wearing away rock layers as sediments are removed downstream. A river bed will gradually reach a baseline elevation, which is the same elevation as the body of water into which the river drains. The processes of weathering and erosion will form canyons when the river's River source, headwaters and estuary are at significantly different elevations, particularly through regions where softer rock layers are intermingled with harder layers more resistant to weathering. A canyon may also refer to a rift between two mountain peaks, such as those in ranges including the Rocky Mountains, the Alps, the Himalayas or the Andes. Usually, a river or stream carves out such splits between mountains. Exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand, sandstone may be imparted any color by impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topography, topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the Southwestern United States, American Southwest. Rock formations composed of sandstone usually allow the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burden Falls Wilderness
The Burden Falls Wilderness is a 3,775-acre (15.3 km2) unit of the Shawnee National Forest. It is located in northwestern Pope County and southwestern Saline County, Illinois. The wilderness is characterized by road-less second-growth hardwood forest, punctuated by a small, seasonal waterfall on Burden Creek. ''Burden Falls'' falls 20 feet (6 m) over a sandstone ledge, and the falling creek then descends another 80 feet (25 m) in a series of cascades and cataracts. Although this is a small waterfall by the nationwide standards of the United States, Burden Falls is one of the highest waterfalls in Illinois. Unlike most of the state, Pope County and extreme southern Illinois escaped glaciation during the Ice ages, and steep slopes display the effects of lengthy erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint (geology)
In geology, and more specifically in structural geology, a joint is a break (fracture (geology), fracture) of natural origin in a layer or body of Rock (geology), rock that lacks visible or measurable movement parallel to the surface (plane) of the fracture ("Mode 1" Fracture). Although joints can occur singly, they most frequently appear as joint sets and systems. A ''joint set'' is a family of parallel, evenly spaced joints that can be identified through mapping and analysis of their orientations, spacing, and physical properties. A ''joint system'' consists of two or more intersecting joint sets. The distinction between joints and Fault (geology), faults hinges on the terms ''visible'' or ''measurable,'' a difference that depends on the scale of observation. Faults differ from joints in that they exhibit visible or measurable lateral movement between the opposite surfaces of the fracture ("Mode 2" and "Mode 3" Fractures). Thus a joint may be created by either strict movement o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black River (Arkansas)
Black River is a common name for streams and communities around the world: in Spanish and Portuguese, ''Rio Negro''; in French, ''Rivière Noire''; in Turkish, ''Kara Su''; in Serbo-Croatian, ''Crna Reka'', Црна Река or ''Crna Rijeka'', Црна Ријека; in Macedonian, Црна Река, ''Crna Reka''. Streams Africa * Bafing River, also known as ''Black River'' * Black River (Cape Town) * Niger River, named by European mapmakers during the Middle Ages, perhaps from Latin ''niger'' "black" Australia * Black River (Queensland) * Black River (Tasmania) * Black River (Victoria) Brazil and Colombia * Black River (Amazon), known as Rio Negro in Portuguese and Río Negro or Río Guainía in Spanish Canada * Black River (New Brunswick) * Black River (Ontario), listing eight rivers of the name * Black River (Portneuf), Quebec * Black River, a river on Vancouver Island, British Columbia * Noire River (Ottawa River tributary), Quebec, English translation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (geology)
In geology, a dike or dyke is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.Essentials of Geology, 3rd Ed, Stephen Marshak Magmatic dikes A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies. The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. It is from these natural walls that dikes get their name. Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reaches the surface. They are studied by geologists for the clues they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diabase
Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained to aphanitic chilled margins which may contain tachylite (dark mafic glass). ''Diabase'' is the preferred name in North America, while ''dolerite'' is the preferred name in the rest of the English-speaking world, where sometimes the name ''diabase'' refers to altered dolerites and basalts. Some geologists prefer to avoid confusion by using the name ''microgabbro''. The name ''diabase'' comes from the French , and ultimately from the Greek 'act of crossing over, transition', whereas the name ''dolerite'' comes from the French , from the Greek 'deceitful, deceptive', because it was easily confused with diorite. Petrography Diabase normally has a fine but visible texture of euhedral lath-shaped plagioclase crystals (62%) set i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnson's Shut-Ins State Park
Johnson's Shut-Ins State Park is a public recreation area covering on the Black River (Arkansas), East Fork Black River in Reynolds County, Missouri. The state park is jointly administered with adjoining Taum Sauk Mountain State Park, and together the two parks cover more than sixteen thousand acres in the St. Francois Mountains region of the Missouri Ozarks. The term "shut-in (river), shut-in" refers to a place where the river's breadth is limited by hard rock that is resistant to erosion. In these shut-ins, the river cascades over and around smooth-worn igneous rock, creating a natural water park that is used by park visitors when water levels are not dangerously high. Geologic features The bedrock of the area is an erosion resistant rhyolite Porphyry (geology), porphyry and dark colored diabase dike (geology), dikes of Proterozoic age. Waters of the Black River (Missouri), East Fork Black River became confined, or "Shut-in (river), shut-in", to a narrow channel following Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downcutting
Downcutting, also called erosional downcutting, downward erosion or vertical erosion, is a geological process by hydraulic action that deepens the channel of a stream or valley by removing material from the stream bed or the valley floor. The speed of downcutting depends on the stream's ''base level'', the lowest point to which the stream can erode. Sea level is the ultimate base level, but many streams have a higher "temporary" base level because they empty into another body of water that is above sea level or encounter bedrock that resists erosion. A concurrent process called '' lateral erosion'' is the widening of a stream channel or valley. When a stream is high above its base level, downcutting will take place faster than lateral erosion; but as the level of the stream approaches its base level, the rate of lateral erosion increases. This is why streams in mountainous areas tend to be narrow and swift, forming V-shaped valleys, while streams in lowland areas tend to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Formation
A rock formation is an isolated, scenic, or spectacular surface rock (geology), rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock Geological formation, formation'' can also refer to specific sedimentary stratum, strata or other rock unit in stratigraphy, stratigraphic and petrology, petrologic studies. A rock structure can be created in any rock type or combination: * Igneous rocks are created when molten rock cools and solidifies, with or without crystallisation. They may be either plutonic bodies or volcanic extrusive. Again, erosive forces sculpt their current forms. * Metamorphic rocks are created by rocks that have been transformed into another kind of rock, usually by some combination of heat, pressure, and chemical alteration. * Sedimentary rocks are created by a variety of processes but usually involving deposition, grain by grain, layer by layer, in water or, in the case of terrestrial se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
