The Molasse basin is a foreland basin north of the Alps which formed during the Oligocene and Miocene epochs. The basin formed as a result of the flexure of the European plate under the weight of the wedge of the Alps that was forming to the south. In geology, the molasse basin is sometimes used in a general sense for a synorogenic foreland basin of the type north of the Alps. The Molasse basin stretches over a length of 1000 kilometers along the axis of the Alps, in France, Germany. The western end is at Lake Geneva, where the outcrop is just 20 km wide. Further to the northeast the basin becomes wider and it forms the subsurface of the Swiss Mittelland and reaches its largest width in the Bavarian foreland of the Alps. From Amstetten to Sankt Pölten the basin forms a narrow band, after that it widens again to the east. North of the Danube River it connects with the Vienna basin, the region where the molasse crops out is divided into two. The Subalpine Molasse zone along the Alps and the Foreland Molasse zone further into the foreland, in the Foreland Molasse zone the molasse sediments are relatively undisturbed, in the Subalpine Molasse zone the beds are often tilted and thrust over each other.
Before the development of the Molasse basin, in the Mesozoic era, the weight of the orogenic wedge made the European plate bend downward, resulting in the formation of a deep marine foredeep. In the Eocene epoch the basin became deeper until it formed a small oceanic trench north of the developing orogen, due to the huge amounts of sediments that were eroded from the forming mountain chain the basin was filled up and got shallower. During the Oligocene and Miocene epochs, undeep marine to continental molasse was deposited in the basin, around 10 to 5 million years ago, tectonic uplift had raised the basin to such a height that netto sedimentation stopped. From the south, the deposits were overthrust about 10 kilometers by the Helvetic nappes. The Jura mountains, a fold and thrust belt along the present Swiss-French border, in some places in the Jura mountains, molasse deposits were folded together with older Mesozoic limestones. Deformation instead localized further north, thus forming the relatively flat Swiss Mittelland between the Alps and the Jura Mountains, the Swiss part of the Molasse basin is now located in between the Alps and the Jura mountains, as a large piggy-back basin.
In the Eastern Alps an external mountain range such as the Jura Mountains never developed, the total thickness of molasse deposits in the basin can be up to 6 kilometers. Lithostratigraphically, this molasse is treated as a group that is divided into four formations and this division is made on whether the sedimentary facies is continental or marine. The lowermost formation is the Lower Marine Molasse and its age is Rupelian and it consists of shallow marine sand and marl
The continental crust is the layer of igneous and metamorphic rocks that forms the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial because its composition is more felsic compared to the oceanic crust. The continental crust consists of layers, with a bulk composition that is intermediate to felsic. The average density of continental crust is about 2.7 g/cm3, less dense than the material that makes up the mantle. Continental crust is less dense than oceanic crust, whose density is about 2.9 g/cm3. At 25 to 70 km, continental crust is thicker than oceanic crust. About 40% of Earths surface is occupied by continental crust. It makes up about 70% of the volume of Earths crust, because the surface of continental crust mainly lies above sea level, its existence allowed land life to evolve from marine life. There is little evidence of continental crust prior to 3.5 Ga, all continental crust ultimately derives from the fractional differentiation of oceanic crust over many eons.
This process has been and continues today primarily as a result of the associated with subduction. In contrast to the persistence of continental crust, the size, different tracts rift apart and recoalesce as part of a grand supercontinent cycle. There are currently about 7 billion cubic kilometers of continental crust, the relative permanence of continental crust contrasts with the short life of oceanic crust. Because continental crust is less dense oceanic crust, when active margins of the two meet in subduction zones, the oceanic crust is typically subducted back into the mantle. Continental crust is rarely subducted.01 Ga, whereas the oldest oceanic crust is from the Jurassic, Continental crust and the rock layers that lie on and within it are thus the best archive of Earths history. The height of mountain ranges is usually related to the thickness of crust and this results from the isostasy associated with orogeny. The crust is thickened by the compressive forces related to subduction or continental collision, the buoyancy of the crust forces it upwards, the forces of the collisional stress balanced by gravity and erosion.
This forms a keel or mountain root beneath the mountain range, the thinnest continental crust is found in rift zones, where the crust is thinned by detachment faulting and eventually severed, replaced by oceanic crust. The edges of continental fragments formed this way are termed passive margins, igneous rock may be underplated to the underside of the crust, i. e. adding to the crust by forming a layer immediately beneath it
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery.
Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer.
He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, usage sometimes includes Greenland and Mexico, as well as offshore islands
Switzerland, officially the Swiss Confederation, is a federal republic in Europe. It consists of 26 cantons, and the city of Bern is the seat of the federal authorities. The country is situated in western-Central Europe, and is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland is a country geographically divided between the Alps, the Swiss Plateau and the Jura, spanning an area of 41,285 km2. The establishment of the Old Swiss Confederacy dates to the medieval period, resulting from a series of military successes against Austria. Swiss independence from the Holy Roman Empire was formally recognized in the Peace of Westphalia in 1648. The country has a history of armed neutrality going back to the Reformation, it has not been in a state of war internationally since 1815, nevertheless, it pursues an active foreign policy and is frequently involved in peace-building processes around the world. In addition to being the birthplace of the Red Cross, Switzerland is home to international organisations.
On the European level, it is a member of the European Free Trade Association. However, it participates in the Schengen Area and the European Single Market through bilateral treaties, spanning the intersection of Germanic and Romance Europe, Switzerland comprises four main linguistic and cultural regions, French and Romansh. Due to its diversity, Switzerland is known by a variety of native names, Suisse, Svizzera. On coins and stamps, Latin is used instead of the four living languages, Switzerland is one of the most developed countries in the world, with the highest nominal wealth per adult and the eighth-highest per capita gross domestic product according to the IMF. Zürich and Geneva have each been ranked among the top cities in the world in terms of quality of life, with the former ranked second globally, according to Mercer. The English name Switzerland is a compound containing Switzer, a term for the Swiss. The English adjective Swiss is a loan from French Suisse, in use since the 16th century.
The name Switzer is from the Alemannic Schwiizer, in origin an inhabitant of Schwyz and its associated territory, the Swiss began to adopt the name for themselves after the Swabian War of 1499, used alongside the term for Confederates, used since the 14th century. The data code for Switzerland, CH, is derived from Latin Confoederatio Helvetica. The toponym Schwyz itself was first attested in 972, as Old High German Suittes, ultimately related to swedan ‘to burn’
Radiolarite is a siliceous, comparatively hard, fine-grained, chert-like, and homogeneous sedimentary rock that is composed predominantly of the microscopic remains of radiolarians. This term is used for indurated radiolarian oozes and sometimes as a synonym of radiolarian earth. However, radiolarian earth is regarded by Earth scientists to be the unconsolidated equivalent of a radiolarite. A radiolarian chert is well-bedded, microcrystalline radiolarite that has a well-developed siliceous cement or groundmass, radiolarites are biogenic, finely layered sedimentary rocks. The layers reveal an interchange of clastic mica grains, radiolarian tests, clay minerals are usually not abundant. Radiolarites deposited in shallow depths can interleave with carbonate layers. Yet most often radiolarites are pelagic, deep water sediments, radiolarites are very brittle rocks and hard to split. They break conchoidally with sharp edges, during weathering they decompose into small, rectangular pieces. The colors range from light to dark via red, radiolarites are composed mainly of radiolarian tests and their fragments.
The skeletal material consists of amorphous silica, radiolarians are marine, planktonic protists with an inner skeleton. Their sizes range from 0.1 to 0.5 millimeters, amongst their major orders albaillellaria, the spherical spumellaria and the hood-shaped nassellaria can be distinguished. According to Takahashi radiolarians stay for 2 to 6 weeks in the zone before they start sinking. Their descent through 5000 meters of water can take from two weeks to as long as 14 months. As soon as the protist dies and starts decaying silica dissolution affects the skeleton, the dissolution of silica in the oceans parallels the temperature/depth curve and is most effective in the uppermost 750 meters of the water column, farther below it rapidly diminishes. Upon reaching the interface the dissolution drastically increases again. Several centimeters below this interface the dissolution continues within the sediment and it is in fact astonishing that any radiolarian tests survive at all. It is estimated that only as little as one percent of the skeletal material is preserved in radiolarian oozes.
The organic wrappings act as a protection for the tests and spare them from dissolution, after deposition diagenetic processes start affecting the freshly laid down sediment
Basalt is a common extrusive igneous rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of basalt flows. By definition, basalt is an igneous rock with generally 45-55% silica and less than 10% feldspathoid by volume. Basalt commonly features a very fine-grained or glassy matrix interspersed with visible mineral grains, the average density is 3.0 gm/cm3. Basalt is defined by its content and texture, and physical descriptions without mineralogical context may be unreliable in some circumstances. Basalt is usually grey to black in colour, but rapidly weathers to brown or rust-red due to oxidation of its mafic minerals into hematite, although usually characterized as dark, basaltic rocks exhibit a wide range of shading due to regional geochemical processes. Due to weathering or high concentrations of plagioclase, some basalts can be quite light-coloured and these phenocrysts usually are of olivine or a calcium-rich plagioclase, which have the highest melting temperatures of the typical minerals that can crystallize from the melt.
Basalt with a texture is called vesicular basalt, when the bulk of the rock is mostly solid. Gabbro is often marketed commercially as black granite and these ultramafic volcanic rocks, with silica contents below 45% are usually classified as komatiites. Agricola applied basalt to the black rock of the Schloßberg at Stolpen. Tholeiitic basalt is relatively rich in silica and poor in sodium, included in this category are most basalts of the ocean floor, most large oceanic islands, and continental flood basalts such as the Columbia River Plateau. Basalt rocks are in some cases classified after their content in High-Ti and Low-Ti varieties. High-Ti and Low-Ti basalts have been distinguished in the Paraná and Etendeka traps and it has greater than 17% alumina and is intermediate in composition between tholeiite and alkali basalt, the relatively alumina-rich composition is based on rocks without phenocrysts of plagioclase. Alkali basalt is relatively poor in silica and rich in sodium and it is silica-undersaturated and may contain feldspathoids, alkali feldspar and phlogopite.
Boninite is a form of basalt that is erupted generally in back-arc basins. Ocean island basalt Lunar basalt On Earth, most basalt magmas have formed by melting of the mantle. Basalt commonly erupts on Io, the third largest moon of Jupiter, and has formed on the Moon, Venus. The crustal portions of oceanic tectonic plates are composed predominantly of basalt, produced from upwelling mantle below, the mineralogy of basalt is characterized by a preponderance of calcic plagioclase feldspar and pyroxene
The term molasse refers to sandstones and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a basin, especially on top of flysch—like, for example. These deposits are typically the non-marine alluvial and fluvial sediments of lowlands, sedimentation stops when the orogeny stops, or when the mountains have eroded flat. The molasse can sometimes fill an foreland basin, creating a nearly flat depositional surface. Molasse can be very thick near the front, but usually thins out towards the interior of a craton, such massive
The Iberian Peninsula /aɪˈbɪəriən pəˈnɪnsjᵿlə/, known as Iberia /aɪˈbɪəriə/, is located in the southwest corner of Europe. The peninsula is divided between Portugal and Spain, comprising most of their territory. With an area of approximately 582,000 km2, it is the second largest European peninsula, at that time, the name did not describe a single political entity or a distinct population of people. Strabos Iberia was delineated from Keltikē by the Pyrenees and included the land mass southwest of there. The ancient Greeks reached the Iberian Peninsula, of which they had heard from the Phoenicians, hecataeus of Miletus was the first known to use the term Iberia, which he wrote about circa 500 BC. Herodotus of Halicarnassus says of the Phocaeans that it was they who made the Greeks acquainted with. According to Strabo, prior historians used Iberia to mean the country side of the Ἶβηρος as far north as the river Rhône in France. Polybius respects that limit, but identifies Iberia as the Mediterranean side as far south as Gibraltar, elsewhere he says that Saguntum is on the seaward foot of the range of hills connecting Iberia and Celtiberia.
Strabo refers to the Carretanians as people of the Iberian stock living in the Pyrenees, according to Charles Ebel, the ancient sources in both Latin and Greek use Hispania and Hiberia as synonyms. The confusion of the words was because of an overlapping in political, the Latin word Hiberia, similar to the Greek Iberia, literally translates to land of the Hiberians. This word was derived from the river Ebro, which the Romans called Hiberus, hiber was thus used as a term for peoples living near the river Ebro. The first mention in Roman literature was by the annalist poet Ennius in 200 BC. Virgil refers to the Ipacatos Hiberos in his Georgics, the Roman geographers and other prose writers from the time of the late Roman Republic called the entire peninsula Hispania. As they became interested in the former Carthaginian territories, the Romans began to use the names Hispania Citerior. At the time Hispania was made up of three Roman provinces, Hispania Baetica, Hispania Tarraconensis, and Lusitania, Strabo says that the Romans use Hispania and Iberia synonymously, distinguishing between the near northern and the far southern provinces.
Whatever language may generally have been spoken on the peninsula soon gave way to Latin, except for that of the Vascones, the Iberian Peninsula has always been associated with the Ebro, Ibēros in ancient Greek and Ibērus or Hibērus in Latin. The association was so known it was hardly necessary to state, for example. Pliny goes so far as to assert that the Greeks had called the whole of Spain Hiberia because of the Hiberus River, the river appears in the Ebro Treaty of 226 BC between Rome and Carthage, setting the limit of Carthaginian interest at the Ebro. The fullest description of the treaty, stated in Appian, uses Ibērus, with reference to this border, Polybius states that the native name is Ibēr, apparently the original word, stripped of its Greek or Latin -os or -us termination
The Adriatic or Apulian Plate is a small tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic Plate is usually used when referring to the part of the plate. This part of the plate was deformed during the Alpine orogeny, the Adriatic/Apulian Plate is thought to still move independently of the Eurasian Plate in NNE direction with a small component of counter-clockwise rotation. The fault zone that separates the two is the Periadriatic Seam that runs through the Alps, studies indicate that in addition to deforming, the Eurasian continental crust has actually subducted to some extent below the Adriatic/Apulian Plate, an unusual circumstance in plate tectonics. This subduction is responsible for the volcanics of southern Italy. The eastern Italian Peninsula, the part of Slovenia and the Adriatic Sea are on the Adriatic/Apulian Plate. Mesozoic sedimentary rocks deposited on the plate include the limestones that form the Southern Calcareous Alps
The Helvetic zone, Helvetic system or the Helveticum is a geologic subdivision of the Alps. The Helvetic zone crops out mainly in Switzerland, hence the name, rocks in the Helvetic zone are sedimentary and were originally deposited at the southern margin of the European plate. The Helvetic zone correlates with the French Dauphinois zone, French geologists often prefer the French name, in Switzerland the Helvetic zone is found in outcrops on the northern side of the Alpine mountain ranges. The French Alps consist mainly of Helvetic material, in Germany and Austria the Helvetic nappes crop out as a narrow band. The Helvetic zone consists of a number of very different units. The Helvetic nappes are a stack that was thrusted over the molasse of the Molasse basin in the Alpine foreland. They are composed of Mesozoic marine limestone and shales, the Helvetic nappes are completely detached from their former basement. The Helvetic nappes are thrusted over the Infrahelvetic complex in eastern Switzerland, the Infrahelvetic complex is composed of autochthonous Mesozoic sediments on top of Hercynian basement rock.
The Mesozoic of this unit is contemporary with that of the Helvetic nappes, the Infrahelvetic is internally deformed by thrusting and folding that continues into the Hercynian basement. Because basement and cover were not detached, geologists do not call the Infrahelvetic units nappes, at places throughout the Alps the European basement was, after being detached of its cover rocks, tectonically uplifted in a late stage of the orogeny. Thus the external massivs were formed, places where the Hercynian basement rock crops out in large anticlinoria at the side of the Helvetic zone. Seen from the north the hard competent crystalline rocks of these external massivs form the first of the ranges of the Alps. These chains are, the Mercantour, the Massif des Écrins, the Belledonne, the Aiguilles Rouges and the Mont Blanc Massif, the Aarmassif, geology of the western and central Alps, website of S. M
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, in contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the southern hemisphere and surrounded by a superocean, Panthalassa. Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists, the name Pangaea/Pangea is derived from Ancient Greek pan and Gaia. The name Pangea occurs in the 1920 edition of Die Entstehung der Kontinente und Ozeane, but only once, the forming of supercontinents and their breaking up appears to have been cyclical through Earths history. There may have many others before Pangaea. When Rodinia broke up, it split into three pieces, the supercontinent of Proto-Laurasia, the supercontinent of Proto-Gondwana, and the smaller Congo craton, Proto-Laurasia and Proto-Gondwana were separated by the Proto-Tethys Ocean.
Next Proto-Laurasia itself split apart to form the continents of Laurentia, Baltica moved to the east of Laurentia, and Siberia moved northeast of Laurentia. The splitting created two new oceans, the Iapetus Ocean and Paleoasian Ocean, most of the above masses coalesced again to form the relatively short-lived supercontinent of Pannotia. This supercontinent included large amounts of land near the poles and, near the equator, Pannotia lasted until 540 Ma, near the beginning of the Cambrian period and broke up, giving rise to the continents of Laurentia and the southern supercontinent of Gondwana. Baltica and Avalonia all came together by the end of the Ordovician to form a supercontinent called Euramerica or Laurussia. The collision resulted in the formation of the northern Appalachians, Siberia sat near Euramerica, with the Khanty Ocean between the two continents. While all this was happening, Gondwana drifted slowly towards the South Pole and this was the first step of the formation of Pangaea.
The second step in the formation of Pangaea was the collision of Gondwana with Euramerica, by Silurian time,440 Ma, Baltica had already collided with Laurentia, forming Euramerica. Avalonia had not yet collided with Laurentia, but as Avalonia inched towards Laurentia, southern Europe broke off from Gondwana and began to move towards Euramerica across the newly formed Rheic Ocean. It collided with southern Baltica in the Devonian, though this microcontinent was an underwater plate, the Iapetus Oceans sister ocean, the Khanty Ocean, shrank as an island arc from Siberia collided with eastern Baltica. Behind this island arc was a new ocean, the Ural Ocean, by late Silurian time and South China split from Gondwana and started to head northward, shrinking the Proto-Tethys Ocean in their path and opening the new Paleo-Tethys Ocean to their south. In the Devonian Period, Gondwana itself headed towards Euramerica, causing the Rheic Ocean to shrink, South America moved northward to southern Euramerica, while the eastern portion of Gondwana headed toward the South Pole from the equator.
North and South China were on independent continents, the Kazakhstania microcontinent had collided with Siberia