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Ganderia Terrane
Ganderia or Gander Terrane (located near the town Gander, Newfoundland) is a terrane in the northern Appalachians which broke off the supercontinent Gondwana (Ma) together with Avalonia, Megumia, and Carolinia. Extent The microcontinent Avalonia broke off Gondwana in the Late Neoproterozoic together with a series of terranes that either formed its eastern coast or a separate block called Ganderia in front of it, if so separated from the Avalon Zone by the several hundred metres-wide Dover Fault. These terranes include the Early Palaeozoic siliciclastic rocks of the Gander Zone, the eastern passive margin of the Iapetus Ocean, now found in Newfoundland, New Brunswick, and New England, but they also include the contemporaneous or slightly older rocks of the Bras d'Or terrane in Cape Breton Island, the 550 Ma Upsalquitch gabbro, the Brookville and New River terranes in New Brunswick, and the Seven Hundred Acre Island in Maine. The Gander Zone also extends to the Briti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gander, Newfoundland And Labrador
Gander is a town located in the northeastern part of the island of Newfoundland in the Canadian province of Newfoundland and Labrador, approximately south of Gander Bay, south of Twillingate and east of Grand Falls-Windsor. Located on the northeastern shore of Gander Lake, it is the site of Gander International Airport, once an important refuelling stop for transatlantic aircraft. The airport is still a preferred emergency landing point for aircraft facing on-board medical or security issues. When the U.S. closed its airspace soon after the September 11 attacks, Gander International Airport took in 38 aircraft and accommodated nearly 6,700 evacuees from Olympic Airways, Air France, Lufthansa, British Airways, Alitalia and more. Most of the streets in Gander are named after famous aviators, including Alcock and Brown, Amelia Earhart, Charles Lindbergh, Eddie Rickenbacker, Marc Garneau and Chuck Yeager. History Gander was chosen for the construction of an airport in 1935 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southeast Ireland
The South-East is a strategic planning area within the Southern Region in Ireland. It is a NUTS Level III statistical region of Ireland (coded IE052). It includes comprises the counties of Carlow, Kilkenny and Wexford and the city and county of Waterford. The South-East region spans 7,198 km2, 10.2% of the total area of the state and according to the 2016 census had a population of 422,062. From 1994 to 2014, the region was governed by the South-East Regional Authority. That body was abolished in June 2014, and from January 2015 it was succeeded by the Southern Regional Assembly. History and geography Ireland South East has a diverse mix of history – key towns and cities such as Waterford and Wexford have Viking origins, while Kilkenny city grew around a Norman merchant town. In terms of landscape and geography, Ireland South East is home to Europe's longest beaches, a number of mountain ranges (such as the Comeraghs, the Blackstairs and the Galtees) and rivers (suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheic Ocean
The Rheic Ocean was an ocean which separated two major palaeocontinents, Gondwana and Laurussia (Laurentia- Baltica-Avalonia). One of the principal oceans of the Palaeozoic, its sutures today stretch from Mexico to Turkey and its closure resulted in the assembly of the supercontinent Pangaea and the formation of the Variscan– Alleghenian– Ouachita orogenies. Etymology The ocean located between Gondwana and Laurentia in the Early Cambrian was named for Iapetus, in Greek mythology the father of Atlas (from which source the Atlantic Ocean ultimately gets its name), just as the Iapetus Ocean was the predecessor of the Atlantic Ocean. The ocean between Gondwana and Laurussia (Laurentia– Baltica–Avalonia) that existed from the Early Ordovician to the Early Carboniferous was named the Rheic Ocean after Rhea, sister of Iapetus. Geodynamic evolution At the beginning of the Paleozoic Era, about 540 million years ago, most of the continental mass on Earth was clustered aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clastic
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks by physical weathering.Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-5 Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits. Sedimentary clastic rocks Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ''clasts'' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transported by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back-arc Basin
A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of them result from tensional forces, caused by a process known as oceanic trench rollback, where a subduction zone moves towards the subducting plate. Back-arc basins were initially an unexpected phenomenon in plate tectonics, as convergent boundaries were expected to universally be zones of compression. However, in 1970, Dan Karig published a model of back-arc basins consistent with plate tectonics. Structural characteristics Back-arc basins are typically very long and relatively narrow, often thousands of kilometers long while only being a few hundred kilometers wide at most. For back-arc extension to form, a subduction zone is required, but not all subduction zones have a back-arc extension feature. Back-arc basins are found in area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magmatism
Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of magma or lava. Volcanism is the surface expression of magmatism. Magmatism is one of the main processes responsible for mountain formation. The nature of magmatism depends on the tectonic setting. For example, andesitic magmatism is associated with the formation of island arcs at convergent plate boundaries while basaltic magmatism is found at mid-ocean ridges during sea-floor spreading at divergent plate boundaries. On Earth, magma forms by partial melting of silicate rocks either in the mantle, continental or oceanic crust. Evidence for magmatic activity is usually found in the form of igneous rocks formed from magma. Convergent boundaries Magmatism is associated with all stages of the development of convergent plate boundaries, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Island Arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction, subduction zone. They are the principal way by which continental growth is achieved. Island arcs can either be active or inactive based on their seismicity and presence of volcanoes. Active arcs are ridges of recent volcanoes with an associated deep seismic zone. They also possess a distinct curved form, a chain of active or recently extinct volcanoes, a Oceanic trench, deep-sea trench, and a large negative Bouguer anomaly on the convex side of the volcanic arc. The small positive gravity anomaly associated with volcanic arcs has been interpreted by many authors as due to the presence of dense volcanic rocks beneath the arc. Inactive arcs are a chain of islands which contains older volcanic and volcaniclastic rocks. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazonian Craton
The Amazonian Craton is a geologic province located in South America. It occupies a large portion of the central, north and eastern part of the continent and represents one of Earth's largest cratonic regions. The Guiana Shield and Central Brazil Shield (Guaporé Shield) constitute respectively the northern and southern exhumed parts of the craton. Between the two shields lies the Amazon Rift, a zone of weakness within the craton. Smaller cratons of Precambrian rocks south of the Amazonian Shield are the Río de la Plata Craton and the São Francisco Craton, which lies to the east. The Río Apa Craton at the Paraguay-Brazil border is considered be likely just the southern part of the Amazonian Craton. The rocks of Río Apa were deformed during the Sunsás orogeny. It has been suggested that the Late Mesoproterozoic– Early Neoproterozoic aged Sveconorwegian Orogen in Fennoscandia could have been caused by a continent–continent collision between the Amazonia and Balti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromatolite
Stromatolites () or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral "microbial mats". In turn, these mats build up layer by layer, growing gradually over time. A stromatolite may grow to a meter or more. Although they are rare today, fossilized stromatolites provide records of ancient life on Earth. Morphology Stromatolites are layered, biochemical, accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains in biofilms (specifically microbial mats), through the action of certain microbial lifeforms, especially cyanobacteria. They exhibit a variety of forms and structures, or morphologies, including conical, stratiform, domal, columnar, and branching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basement (geology)
In geology, basement and crystalline basement are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment. The basement rocks lie below a sedimentation, sedimentary platform (geology), platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic rock, metamorphic or Igneous rock, igneous in origin. In the same way, the sediments or sedimentary rocks on top of the basement can be called a "cover" or "sedimentary cover". Crustal rocks are modified several times before they become basement, and these transitions alter their composition. Continental crust Basement rock is the thick foundation of ancient, and oldest, metamorphic and igneous rock that forms the Crust (geology), crust of continents, often in the form of granite. Basement rock is contrasted to overlying sedimentary rocks which are laid down ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iapetus Suture
The Iapetus Suture is one of several major geological faults caused by the collision of several ancient land masses forming a suture. It represents in part the remains of what was once the Iapetus Ocean. Iapetus was the father of Atlas in Greek mythology, making his an appropriate name for what used to be called the 'Proto-Atlantic Ocean'. When the Atlantic Ocean opened, in the Cretaceous period, it took a slightly different line from that of the Iapetus suture, with some originally Laurentian rocks being left behind in north-west Europe and other, Avalonian, rocks remaining as part of Newfoundland. Background The Iapetus Ocean was an ancient ocean which existed in the Southern Hemisphere approximately 600 million years ago and was bordered by several paleocontinents: Laurentia, Ganderia, Carolinia, Avalonia, and Baltica. During a series of geological events, the Salinic orogeny and Caledonian orogeny all three land masses began to converge upon each other slowly dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Indian Lake
Beothuk Lake, formerly Red Indian Lake, is located in the interior of central Newfoundland in the province of Newfoundland and Labrador, Canada. The lake drains into the Exploits River which flows through the interior of Newfoundland and exits into the Atlantic Ocean through the Bay of Exploits. Lloyds River, the Victoria River and Star River feed into the lake. History The Beothuk, also known as 'Red Indians,' inhabited several campsites on the shore of the lake. An expedition into the interior by John Cartwright and brother George Cartwright in search of the Beothuk found only abandoned campsites. At the time of their discovery of the lake they named it ''Lieutenant's Lake'' and they had assumed that the lake was part of the same system as ''Lake Mickmack'', known today as Grand Lake. In January 1811, an expedition led by David Buchan travelled up the Exploits River in an attempt to establish friendly relations with the Beothuk; Buchan found them, but the encounter went badl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
