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Särna Alkaline Complex
The Särna alkaline complex is a group of intrusive igneous rocks in Dalarna, Sweden. Emplacement and cooling of magma into rock occurred during the Carboniferous Period. The complex is aligned with the Oslo Rift, which formed around the same time; it is thought that they are related. See also *Alnö Complex *Fen Complex *Kola Alkaline Province *Norra Kärr Norra Kärr or Norra Kärr Alkaline Complex is an intrusive complex cropping out at the boundary between Östergötland and Småland, Sweden. The complex is chiefly made up of peralkaline nepheline syenite and is rich in exotic minerals. Rocks o ... References {{Geology of Fennoscandia Geology of Sweden Paleozoic Sweden Carboniferous Europe Carboniferous geology Geography of Dalarna County ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrusion (geology)
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March 27, 2017.Igneous intrusive rocks, accessdate: March 27, 2017.Britannica.comintrusive rock , geology , Britannica.com accessdate: March 27, 2017. Intrusion is one of the two ways igneous rock can form. The other is extrusion, such as a volcanic eruption or similar event. An intrusion is any body of intrusive igneous rock, formed from magma that cools and solidifies within the crust of the planet. In contrast, an ''extrusion'' consists of extrusive rock, formed above the surface of the crust. Some geologists use the term plutonic rock synonymously with intrusive rock, but other geologists subdivide intrusive rock, by crystal size, into coarse-grained plutonic rock (typically formed deeper in the Earth's crust in batholiths or stocks) an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alnö Complex
The Alnö Complex or Alnö Alkaline Complex is a group of carbonatite and alkaline igneous rocks in Alnö in the eastern coast of central Sweden that intruded the basement in Late Ediacaran times. The Alnö Complex is made up by a series of concentric dykes within a radius of 25 km of a main "central complex" of intrusions. In addition the Alnö Complex proper is surrounded by a 500 to 600 m broad zone of metasomatic rock that was formed by metasomatic alteration of the existing Precambrian migmatite gneiss basement. The specific type of metasomatic rock is referred by some authors as "fenite". The dykes of the complex consist of carbonatite and alkaline rocks such melilite and sövite. It has been proposed that both the Fen Complex in Southern Norway and the Alnö Complex formed as consequence to mild extensional tectonics in the ancient continent of Baltica following the opening of the Iapetus Ocean. Harry von Eckermann published a landmark study on the Aln ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous Europe
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian lineages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic Sweden
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the ocean but eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Sweden
The geology of Sweden is the regional study of rocks, minerals, tectonics, natural resources and groundwater in the country. The oldest rocks in Sweden date to more than 2.5 billion years ago in the Precambrian. Complex orogeny mountain building events and other tectonic occurrences built up extensive metamorphic crystalline basement rock that often contains valuable metal deposits throughout much of the country. Metamorphism continued into the Paleozoic after the Snowball Earth glaciation as the continent Baltica collided with an island arc and then the continent Laurentia. Sedimentary rocks are most common in southern Sweden with thick sequences from the last 250 million years underlying Malmö and older marine sedimentary rocks forming the surface of Gotland. Stratigraphy, Tectonics & Geologic History The oldest rocks in Sweden date to the Archean, more than 2.5 billion years ago. Archean crystalline basement rocks are restricted to a few areas in the far north and are mainl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norra Kärr
Norra Kärr or Norra Kärr Alkaline Complex is an intrusive complex cropping out at the boundary between Östergötland and Småland, Sweden. The complex is chiefly made up of peralkaline nepheline syenite and is rich in exotic minerals. Rocks of the complex intruded into the Paleoproterozoic-aged Växjo granites of the Transscandinavian Igneous Belt. Alfred Elis Törnebohm was the first to describe the rocks of Norra Kärr in 1906. Norra Kärr was discovered a few years earlier during regional geological maping by the Swedish Geological Survey. The complex derives its name from a local farm, which translates into English as "Northern Fen". In 1968 Harry von Eckermann published his investigations on the complex defining its boundaries and confirming the view of it as an intrusion. A study has shown that the elevated rare-earth element concentrations in the bedrock in the Norra Kärr area are particularly well reflected in high contents of these elements in the fern ''Dryopte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kola Alkaline Province
The Kola Alkaline Province or Kola Alkaline Carbonatite Province is a discontiguous group of unusual igneous rocks centered in the Kola Peninsula of Russia and with ouliers in nearby areas of Finland and in Arkhangelsk Oblast across the White Sea. The province is made up of alkaline-ultramafic rock complexes often associated to carbonatites and stand-alone dykes and pipes made up of carbonatites, kimberlites and similar rocks. To this it adds the large nepheline syenite bodies of the Lovozero Massif and the Khibiny Mountains. An estimate puts the total volume of the rocks of the Kola Alkaline Province at 15,000 ±2,700 km3. The more mafic silicate rocks of the province originated from small degrees of partial melting in a source region in Earth's mantle made up of garnet-bearing peridotite. The lithosphere had thicknesses similar to present-day (200 km) conditions when magmas originated in the Devonian. Prior to Devonian magmatism the Kola and Karelia region had exper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fen Complex
The Fen Complex ( no, Fensfeltet) in Nome, Telemark, Norway is a region noted for an unusual suite of igneous rocks. Several varieties of carbonatite are present in the area as well as lamprophyre, ijolite and other highly alkalic rocks. It is the type locality for fenite, a metasomatic rock commonly found around carbonatite and alkali intrusives.http://www.mindat.org/loc-14357.html Mindat location description The Fen Complex is a roughly circular area about three kilometres in diameter. It is located just west of the Oslo graben. Radiometric age dating on the carbonatites gave an age of 539 +/- 14 Myr. The host rocks for the intrusions are middle Proterozoic granites and gneiss and the complex was associated with the Cambrian rifting of the cratonic rocks.Faure, Gunter (2000) ''Origin of Igneous Rocks'', Springer, pp. 319-321 The complex is a protected location because of the rare minerals and rock types found there. The rocks were first described by Waldemar Christofer Brø ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithos (journal)
''Lithos'' is a peer-reviewed academic journal, publishing original research papers on the petrology, geochemistry and petrogenesis of igneous and metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ... rocks. Lithos is a hybrid open-access journal and publishes both subscription and open access articles. References English-language journals Geology journals Elsevier academic journals {{geology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from Partial melting, partial melts of existing rocks in either a Terrestrial planet, planet's mantle (geology), mantle or crust (geology), crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive (geology), extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form Volcanic glass, natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oslo Rift
The Oslo Graben or Oslo Rift is a graben formed during a geologic rifting event in Permian time, the last phase of the Variscan orogeny. The main graben forming period began in the late Carboniferous, which culminated with rift formation and volcanism, with associated rhomb porphyry lava flows. This activity was followed by uplifting, and ended with intrusions about 65 million years after the onset of the formation. It is located in the area around the Norwegian capital Oslo. The lava production was high when the rhomb porphyry lavas were deposited. The lavas reflect a period of abundant earthquake-related movements, when tectonic forces tore the crust apart. In the Vestfold district, one lava flow was deposited on average every 250,000 years, resulting in a 3000-metre thick sequence of mainly volcanic material. In the Oslo area, lavas were deposited on average every 800,000 years. Only a few plant remains have been found between these lavas. The bedrock in this area, roughly from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Period (geology)
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
