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Saxothuringian Zone
The Saxothuringian Zone, Saxo-Thuringian zone or Saxothuringicum is in geology a structural or tectonic zone in the Hercynian or Variscan orogen (380-270 million years old) of central and western Europe. Because rocks of Hercynian age are in most places covered by younger strata, the zone is not everywhere visible at the surface. Places where it crops out are the northern Bohemian Massif, the Spessart, the Odenwald, the northern parts of the Black Forest and Vosges and the southern part of the Taunus. West of the Vosges terranes on both sides of the English Channel are also seen as part of the zone, for example the Lizard complex in Cornwall or the Léon Zone of the Armorican Massif (Brittany). Location In central Europe the Saxothuringian Zone is situated between the Rhenohercynian Zone to the northwest and the Moldanubian Zone to the southeast. The Hercynian metamorphism of the former zone is generally lower grade; that of the latter zone higher grade than that of the Saxoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hercynian Structures Europe-en
The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes from the Medieval Latin name for the district '' Variscia'', the home of a Germanic tribe, the Varisci; Eduard Suess, professor of geology at the University of Vienna, coined the term in 1880. (Variscite, a rare green mineral first discovered in the Vogtland district of Saxony in Germany, which is in the Variscan belt, has the same etymology.) ''Hercynian'', on the other hand, derives from the Hercynian Forest. Both words were descriptive terms of strike directions observed by geologists in the field, ''variscan'' for southwest to northeast, ''hercynian'' for northwest to southeast. The ''variscan'' direction reflected the direction of ancient fold belts cropping out throughout Germany and adjacent countries and the meaning shifted from d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Léon Zone
Leon, Léon (French) or León (Spanish) may refer to: Places Europe * León, Spain, capital city of the Province of León * Province of León, Spain * Kingdom of León, an independent state in the Iberian Peninsula from 910 to 1230 and again from 1296 to 1301 * León (historical region), composed of the Spanish provinces León, Salamanca, and Zamora * Viscounty of Léon, a feudal state in France during the 11th to 13th centuries * Saint-Pol-de-Léon, a commune in Brittany, France * Léon, Landes, a commune in Aquitaine, France * Isla de León, a Spanish island * Leon (Souda Bay), an islet in Souda Bay, Chania, on the island of Crete North America * León, Guanajuato, Mexico, a large city * Leon, California, United States, a ghost town * Leon, Iowa, United States * Leon, Kansas, United States * Leon, New York, United States * Leon, Oklahoma, United States * Leon, Virginia, United States * Leon, West Virginia, United States * Leon, Wisconsin (other), United States, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eger Graben
The Eger Graben (much less commonly called the Ohre or Ohře Graben; cs, Oherský rift, german: Egergraben) is a geological structure in the Czech Republic. It runs southwards, parallel to the Ore Mountains and its formation is linked with that of the mountain range. Topography The Ohře (equally commonly known in English by its German name ''Eger'', hence the name of the trough) flows through the Eger Graben and separates the Ore Mountains from the Slavkov Forest and the Doupov Mountains. The trench continues to the northeast along the valley of the Bílina and later, as the North Bohemian Basin, separates the Ore Mountains from the Bohemian Central Mountains, where the River Ohře leaves the graben and flows into the Elbe south of the Bohemian Mountains. Geology The Eger Graben is part of the European Cenozoic Rift System and was created geologically on the same principle as the Rhine Rift Valley. It was formed by the almost complete erosion of the Variscan Mountains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotliegend
The Rotliegend, Rotliegend Group or Rotliegendes (german: the underlying red) is a lithostratigraphy, lithostratigraphic unit (a sequence of rock strata) of latest Carboniferous to Guadalupian (middle Permian) age that is found in the subsurface of large areas in western and central Europe. The Rotliegend mainly consists of sandstone layers. It is usually covered by the Zechstein and lies on top of regionally different formation (stratigraphy), formations of late Carboniferous age. The name Rotliegend has in the past not only been used to address the rock strata themselves, but also the time span in which they were formed (in which case the Rotliegend was considered a series (stratigraphy), series or subsystem of the Permian). This time span corresponds roughly with the length of the Cisuralian Epoch (reference date), epoch. Facies and formation In large parts of Pangaea, the last tectonic phase, phases of the Hercynian orogeny were still ongoing during the start of the Permian. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic context by Eduard Suess in 1883. The plural form is either ''graben'' or ''grabens''. Formation A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with horsts. Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst. Single or multiple graben can produce a rift valley. Half-g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bray Fault
Bray may refer to: Places France *Bray, Eure, in the Eure ''département'' * Bray, Saône-et-Loire, in the Saône-et-Loire ''département'' *Bray-Dunes, in the Nord ''département'' * Bray-en-Val, in the Loiret ''département'' *Bray-et-Lû, in the Val-d'Oise ''département'' *Bray-lès-Mareuil, in the Somme ''département'' * Bray-Saint-Christophe, in the Aisne ''département'' *Bray-sur-Seine, in the Seine-et-Marne ''département'' *Bray-sur-Somme, in the Somme ''département'' *Pays de Bray, a watershed in Normandy Ireland *Bray, County Wicklow **Bray Daly railway station ** Bray Male School, former name of Saint Cronan's Boys' National School *Bray Head, a hill just south of Bray, Wicklow *Bray Head, Kerry, a hill on Valentia Island, County Kerry *Bray Lower, a townland of County Kildare *Bray Upper, a townland of County Kildare United Kingdom *Bray, Berkshire, a village near Maidenhead *Bray Shop, a village in Cornwall *River Bray United States *Bray Place, a 1796 hom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strike-slip Fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrologists re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moldanubian Zone
The Moldanubian Zone is in the regional geology of Europe a tectonic zone formed during the Variscan or Hercynian Orogeny (400 to 300 million years ago, during the Devonian and Carboniferous periods). The Moldanubian Zone crops out in the Bohemian Massif and the southern part of the Black Forest and Vosges and contains the highest grade metamorphic rocks of Variscan age in Europe. The Moldanubian Zone was introduced by German geologist Franz Kossmat in 1927. It has a generally higher grade of metamorphism than the Saxothuringian Zone to the northwest. The contact between the two is a thrust over which the Moldanubian Zone moved over the Saxothuringian Zone during the Variscan Orogeny. In the east the Moldanubian Zone is thrust over the Moravo-Silesian Zone, which is also generally lower grade. Geology The Moldanubian Zone of the Bohemian Massif can be divided into two tectonic units: the Teplá-Barrandian Zone (or "Bohemicum") and the Moldanubian Zone sensu stricto ("Molda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
