Lockne Crater

	Lockne Crater Lockne is a meteorite crater, located approximately south of the city of Östersund in northern Sweden. It has been suggested that it is a doublet with the nearby smaller Målingen Crater, apart.Raul Rincon (2014BBC News: "Ancient Earth hammered by double space impact", 18 March 2014 accessed 19 March 2014. Computer simulations suggest that the asteroid that created the Lockne crater was some in diameter, and the one that carved out Målingen crater was about across. It is in diameter and the age is estimated, based on accompanying chitinozoan microfossils, to be 458 million years (Late Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...). The crater is exposed at the surface. Its fossils, typical of shallow marine environments, show it to be a marine target impac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples " bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. Meteorites that are recovered after being observed as they transit the atmosphere and impact the Earth are called meteorite falls. All others are known as meteorite finds. Meteorites have traditionally been divided into three broad categories: stony meteorites t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Impact Crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Lunar impact craters range from microscopic craters on lunar rocks returned by the Apollo Program and small, simple, bowl-shaped depressions in the lunar regolith to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Europa, Io and Titan, visible impact craters are less common because they become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Östersund Östersund (; sma, Staare) is an urban area (city) in Jämtland in the middle of Sweden. It is the seat of Östersund Municipality and the capital of Jämtland County. Östersund is located at the shores of Sweden's fifth-largest lake, Storsjön, opposite the island Frösön. It is the only city in Jämtland. The northern part of the urban area is located inside of the municipality of Krokom. Östersund is the region's cultural and economical centre and by tradition a city of trade and commerce. The city had one of the most extensive garrisons in Sweden prior to its closure in the early-21st century. Östersund has the Mid Sweden University's largest campus site with approximately 7,000 students. With a total population of 50,960 (2017) Östersund is the 22nd most populous city in Sweden, the 46th most populous city in Scandinavia, and by far the largest inland city in Northern Sweden. The city was the only Swedish city founded and chartered in the 18th century. Östersund ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Målingen Crater Målingen was confirmed as an impact crater in 2014. It is located near the city of Östersund in northern Sweden. It is "probable" that it formed simultaneously with the nearby Lockne crater.Raul Rincon (2014)BBC News: "Ancient Earth hammered by double space impact", 18 March 2014 accessed 19 March 2014. Computer simulations suggest the asteroid pieces that created the Lockne and Målingen craters were some 600 meters and 250 meters in diameter, respectively. Målingen is 1 km in diameter and its age is estimated, using chitinozoan microfossils, which were also found in Lockne, to be 458 million years (Late Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...). References Impact craters of Sweden Ordovician impact craters Ordovician Sweden Sandbian La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Chitinozoan Chitinozoa (singular: chitinozoan, plural: chitinozoans) are a group of flask-shaped, organic walled marine microfossils produced by an as yet unknown organism. Common from the Ordovician to Devonian periods (i.e. the mid-Paleozoic), the millimetre-scale organisms are abundant in almost all types of marine sediment across the globe. This wide distribution, and their rapid pace of evolution, makes them valuable biostratigraphic markers. Their bizarre form has made classification and ecological reconstruction difficult. Since their discovery in 1931, suggestions of protist, plant, and fungal affinities have all been entertained. The organisms have been better understood as improvements in microscopy facilitated the study of their fine structure, and it has been suggested that they represent either the eggs or juvenile stage of a marine animal. However, recent research has suggested that they represent the hard shell of a group of protists with uncertain affinities. Chitinozoan ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Microfossil A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, such as a hand lens, is referred to as a macrofossil. Microfossils are a common feature of the geological record, from the Precambrian to the Holocene. They are most common in deposits of marine environments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits. While every kingdom of life is represented in the microfossil record, the most abundant forms are protist skeletons or microbial cysts from the Chrysophyta, Pyrrhophyta, Sarcodina, acritarchs and chitinozoans, together with pollen and spores from the vascular plants. Overview A microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Impact Event An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale. Impact events appear to have played a significant role in the evolution of the Solar System since its formation. Major impact events have significantly shaped Earth's history, and have been implicated in the formation of the Earth–Moon system. Impact events also appear to have played a significant role in the evolutionary hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Impact Craters Of Sweden In early 2018 there were eight known impact craters in Sweden. They range in age from 90 mya to 470 mya, and in diameter from 1 km to 52 km. Six of them are exposed, that is they are visible at the surface, in the natural landscape, although their nature and origin might need to be pointed out to the untrained layman. List * Dellen * Granby crater * Hummeln structure * Lockne crater * Målingen Crater * Mien (lake) * Siljan Ring * Tvären Tvären is a circular bay close to Studsvik, Sweden. Within the bay is an ancient buried impact crater about 2 km in diameter. It was first identified using reflection seismology. The crater is estimated to be about 455 million years old (La ... See also * Ordovician meteor eventH. Haack et al. ''Meteorite, asteroidal, and theoretical constraints on the 500-Ma disruption of the L chondrite parent body'', Icarus, Vol. 119, p. 182 (1996). References {{Commons category, Impact craters of Sweden Geology of Sweden Landforms of Sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Ordovician Impact Craters The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Ordovician Sweden The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]