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Hummeln Structure
The Hummeln structure was confirmed, in 2015, as an impact crater in Småland province, Sweden. It is a wide depression within Lake Hummeln and is estimated to have formed between 470 and 443 Ma ago, during the Ordovician. Description The depression was first described in 1826 but was considered to be the result of volcanism or tectonics.L. Ferrière, C. Alwmark, S. Holm-Alwmark, J. Ormö, H. Leroux, and E. Sturkell (2015)The Hummeln Structure (Sweden) – Impact Origin Confirmed And Its Link To The L-Chondrite Parent Body Break-Up Event 46th Lunar and Planetary Science Conference In the 1960s, mapping of the lake topography gave the first hints of an impact event. More conclusive evidence was found recently when scientists from Lund University, while trying to get to nearby Siljan crater, found shocked quartz around the lake.Daniel Kelly (2015)Space Rock Created Sweden’s Hummeln Lake Lake Scientist, Mar 2015. Further investigation led to more details such as breccia that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), 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 Celtic Britons, 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 (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, 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 Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lund University
, motto = Ad utrumque , mottoeng = Prepared for both , established = , type = Public research university , budget = SEK 9 billion Facts and figures Lund University web site. , head_label = , head = Erik Renström , academic_staff = 4,780 (2022) (academic staff, researchers and employed research students) , administrative_staff = 2,890 (2022) , students = 46 000 (29 000 full-time e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Cambrian Perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Cambrian Perio ... [...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 See also * Ordovician meteor event The Ordovician meteor event was a dramatic increase in the rate at which L chondrite meteorites fell to Earth during the Middle Ordovician period, about 467.5±0.28 million years ago. This is indicated by abundant fossil L chondrite meteorites in ...H. 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 Sweden [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltoscandia
Baltoscandian Confederation or Baltoscandia is a geopolitical concept of a Baltic–Scandinavian ( Nordic) union comprising Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway, and Sweden. The idea was proposed by a Swedish Professor Sten de Geer (1886–1933) in the journal ''Geografiska Annaler'' in 1928 and further developed by Professor Kazys Pakštas (1893–1960), a Lithuanian scientist in the field of geography and geopolitics. Development of the concept Pakštas states in his book ''The Baltoscandian Confederation'' that the term Baltoscandia was first used by Sten de Geer in an article in "Geografiska Annaler" in 1928. In this book Baltoscandia is described in several different dimensions: as a geographical and cultural, as an economic and as a political and military unit. Kazys Pakštas proposed that one of the ways for the small nations to withstand the influence coming from the large ones is to unite and to cooperate more closely among each other. As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granby Crater
Granby is an impact crater in Östergötland, Sweden, located to the southeast of Vadstena. It is estimated to have formed about 470 million years ago (Middle Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...). The crater is in diameter and is not exposed at the surface. References Impact craters of Sweden Ordovician impact craters Ordovician Sweden Landforms of Östergötland County {{Östergötland-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. A megabreccia is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides, impact events, or caldera collapse. Types Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. These indicate that the gravel was deposited very close to its source area, since otherwise th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shocked Quartz
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These planes, which show up as lines under a microscope, are called planar deformation features (PDFs), or shock lamellae. Discovery Shocked quartz was discovered following underground nuclear weapons testing, which generated the intense pressures required to alter the quartz lattice. Eugene Shoemaker showed that shocked quartz is also found inside craters created by meteor impact, such as the Barringer Crater and Chicxulub crater. The presence of shocked quartz supports that such craters were formed by impact, because a volcanic eruption would not generate the required pressure. Lightning is now known to contribute to the surface record of shocked quartz grains, complicating identification of hypervelocity impact features. Formation Shocked q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siljan Ring
The Siljan Ring ( sv, Siljansringen) is a prehistoric impact crater in Dalarna, central Sweden. It is one of the 15 largest known impact craters on Earth and the largest in Europe, with a diameter of about . The impact that created the Siljan Ring occurred when a meteorite collided with the Earth's surface during the Devonian period, about 376.8 ± 1.7 Ma. This coincides around the first Devonian extinction, the Kellwasser Event or Late Frasnian extinction at 376.1 Ma ± 1.6 Ma. The effects of the impact can clearly be seen in the bedrock in the area. The Cambrian, Ordovician and Silurian sedimentary rocks deformed by the impact are rich in fossils. The area around the Siljan Ring has been the site of recent prospecting for oil and natural gas, though none of the projects has so far been commercially viable. There are large deposits of lead and zinc near Boda at the eastern edge of the Ring. There are several lakes in the vicinity, the largest of which is Siljan on the south-so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topography
Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary science and is concerned with local detail in general, including not only relief, but also natural, artificial, and cultural features such as roads, land boundaries, and buildings. In the United States, topography often means specifically ''relief'', even though the USGS topographic maps record not just elevation contours, but also roads, populated places, structures, land boundaries, and so on. Topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms; this is also known as geomorphometry. In modern usage, this involves generation of elevation data in digital form (DEM). It is often considered to include the graphic representation of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrite
A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet's gravity well become the most common type of meteorite by (whether quickly, or after many orbits) arriving on a trajectory toward the planet's surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%. Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the origin of life and the presence of water on Earth. One of their characteristics is the presence of chondrules (from the Ancient Greek χόνδρος ''chondros'', grain), which are round grains formed as molten, or partially molten droplets, in the space by distinct minerals, that normally consti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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