Laurasia

Laurasia, the continental mass that during the Palaeozoic Era formed the northern part of the supercontinent called Pangaea, and which included what was to become North America, Greenland, northern and central Europe, and most of Asia. Pangaea, derived from the Greek for “all land”, started to fragment in the late Palaeozoic, about 240 million years ago, into Laurasia in the north and Gondwana in the south. Gondwana was the precursor to most of present-day South America, Australia, Antarctica, and India. Laurasia was named after the Laurentian Plateau of Canada by Alfred Wegener, the German meteorologist, who in 1915 formulated the first coherent theory of continental drift. Wegener’s ideas were largely rejected during his lifetime (he died in 1930), mainly because he could provide no acceptable mechanism by which the continents could move. During the past 50 years, palaeomagnetic studies (see palaeomagnetism) of the deep ocean floor have shown that lithospheric plates, hosting both continents and oceans, have moved through geological time in association with ocean-floor spreading from mid-ocean ridges. Our knowledge of the patterns of plate movements is more conjectural beyond 200 million years ago, the age of the oldest oceanic lithosphere, but it is generally agreed that initially scattered continental masses gradually converged during the Permian Period at the end of the Palaeozoic, about 300 million years ago, to form a single supercontinent called Pangaea. The assembly of Laurasia began at least 500 million years ago through the gradual merging of three main tectonic plates—the North American plate, the North European plate (Baltica), and the Siberian plate—plus a number of minor plates (such as the Kazakhstan plate), and terranes. Terranes are island arcs or small lithospheric plates (microplates) thought to have broken away from larger plates and which subsequently became attached, or accreted, to another plate. They are distinguished today as regions that have a stratigraphy (stratification over time), structure, and geology fundamentally different from that of adjacent areas. Terranes are also associated with orogeny—the episodes of mountain-building that result from the compression that occurs when two areas of continental lithosphere collide. The complex geology of the margins of the continents that once made up Laurasia, most notably the Cordillera ranges of the western coast of North America, is due to the fact that they comprise a mosaic of microplates and island arcs that accreted during Laurasia’s formation and break-up. About 300 million years ago, during the Permian period, Gondwana finally collided with southern Laurussia. The junction was in the area of what is now Italy, Greece, and the Balkans (at that time part of North Africa). At the same time, in the north, the Siberian plate collided with Laurussia, and the Kazakhstan plate collided with the Siberian plate. Two distinct palaeocontinents, Laurasia and Gondwana, were thus formed. Their formation initiated some of the most extensive mountain building the world has known, including the formation of the proto-Rocky Mountains and the Urals (at the Laurussian-Siberian juncture). Other areas affected included south-west England, north-west mainland Europe, the Appalachians, and the Andes. About 270 million years ago, during the Early Permian, the Cimmeria microplate, comprising Turkey, Iran, and Afghanistan, broke away from Gondwana, opening up the Tethys Sea between Laurasia and Gondwana. During the subsequent Triassic Period, Mexico collided with North America. About 200 million years ago, during the Early Jurassic Period, Pangaea began to fracture, initially along the line of what became the South Atlantic and Gulf of Mexico. As the break-up progressed, the Italian-Balkan and Iberian terranes were torn away from Gondwana and began moving north and east towards Laurasia. By the end of the Jurassic (about 142 million years ago) Gondwana had fully separated from Laurasia, leaving the Yucatán Peninsula behind. Turkey, Iran, and Afghanistan had collided with Laurasia, in the area of the former Baltic plate, initiating the Cimmerian orogeny. By 90 million years ago, in the Late Cretaceous Period, Eurasia began to drift away from North America, along the line of the eastern coast of Greenland, a process completed by the start of the Cenozoic Era, about 65 million years ago. Greenland had also begun to separate from North America. These separations were a result of the North Atlantic opening up as seafloor spreading from the nascent mid-Atlantic ridge occurred. The Caribbean arc had also been created by this time, and Italy, the Balkans, including Greece, and Iberia were closing in on the southern margins of Europe. The accretion of these terranes was completed during the Eocene and Oligocene Epochs (about 55 million to 24 million years ago), initiating the orogenies that created the Pyrenees, Alps, and Carpathian mountains. Following the break-up of Pangaea, India had broken away from Antarctica and begun a journey across the expanding Pacific Ocean towards southern Asia. About 30 million years ago India finally collided, initiating the orogeny that has created the Himalaya ranges and the Tibetan plateau. By the beginning of the Miocene (about 23 million years ago), Greenland had completed its separation from North America, and Africa had collided with the Eurasian plate, opening up the Red Sea and creating the Mediterranean Sea. During the break-up, Laurasia was moving northward and also rotating towards the present alignment of the continents. This rotation was not uniform; it occurred at different speeds and in different directions, contributing to the break-up. Throughout most of the period leading up to the creation of Laurasia, its component plates were lying across or relatively near to the equator and generally experienced tropical to warm climatic conditions. In contrast, parts of Gondwana experienced successive glaciations. During the Carboniferous Period (354 to 290 million years ago), warm conditions resulted in the laying down of the large coal measures that characterize parts of North America, Europe, and Siberia. As the central Atlantic Ocean opened up, Laurasia rotated clockwise, sending North America northwards and Eurasia southwards. Coals deposited in eastern Asia during the Early Jurassic were succeeded by salt and other evaporite deposits as Asia moved from the wet temperate belt to the dry subtropics. It was only following the break-up of Laurasia, as the newly delineated continents began moving north, that cooler conditions began to be felt, culminating in the ice age of the Pleistocene Epoch. Laurasia was the huge supercontinent that was the parts of another protocontinent during Mesozoic epoch. The majority of the geographical territories that are the separate regions of the Northern hemisphere were the part of this supercontinent. That is why it provoked the particular interest of scientists. Despite the fact that there are no proofs that there was some kind of civilization on this continent, some occultists and philosophers consider there was one civilization on this continent besides known in the whole world Atlantis and Lemuria that preceded the known ones. Such civilization was created by the inhabitants of Laurasia that lived there before the asteroid hit the Earth surface and before the supercontinent was divided into several continents. This civilization didn't have any great achievements and its knowledge was not so wide and of course it didn't have any supernatural powers. These people were simple society with the agricultural orientation. Together with hunting, fishing, agriculture they were fond of music. And if scientists at least tried to investigate other civilizations and the possibility of their existence, they consider inhabitants of Laurasia to be the myth and nothing more. That is why there is almost no information on the existence and way of life of this civilization as well as on its origins. By the way maybe members of this society were those who taught people of other parts of the world to play music.