1.
Supercontinent
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In geology, a supercontinent is the assembly of most or all of Earths continental blocks or cratons to form a single large landmass. However, the definition of a supercontinent can be ambiguous, Many earth scientists, such as P. F. Hoffman, use the term supercontinent to mean a clustering of all continents. This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times, the landmass of Pangaea is the collective name describing all of these continental masses when they were most recently in proximity to one another. This would classify Pangaea as a supercontinent, according to the definition by Rogers and Santosh, a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past, the positions of continents have been accurately determined back to the early Jurassic. However, beyond 200 Ma, continental positions are less certain. The following table displays historical supercontinents, using a general definition, there are two contrasting models for supercontinent evolution through geological time. The first model theorizes that at least two separate supercontinents existed comprising Vaalbara and Kenorland, the Neoarchean supercontinent consisted of Superia and Sclavia. These parts of Neoarchean age broke off at ~2300 and 2090 Ma, Nuna continued to develop during the Mesoproterozoic, primarily by lateral accretion of juvenile arcs, and in ~1000 Ma Nuna collided with other land masses, forming Rodinia. Between ~800 and 700 Ma Rodinia broke apart, however, before completely breaking up, some fragments of Rodinia had already come together to form Gondwana by ~530 Ma. Pangaea formed by ~300 Ma through the collision of Gondwana, Laurentia, Baltica, during the intervening periods, the poles conform to a unified apparent polar wander path. The explanation for the duration of the Protopangea-Paleopangea supercontinent appears to be that Lid Tectonics prevailed during Precambrian times. Plate Tectonics as seen on the contemporary Earth became dominant only during the part of geological times. The Phanerozoic supercontinent Pangaea began to break up 180 Ma and is doing so today. Because Pangaea is the most recent of Earths supercontinents, it is the most well known, contributing to Pangaeas popularity in the classroom is the fact that its reconstruction is almost as simple as fitting the present continents bordering the Atlantic-type oceans like puzzle pieces. A supercontinent cycle is the break-up of one supercontinent and the development of another, supercontinent cycles are not the same as the Wilson cycle, which is the opening and closing of an individual oceanic basin. The Wilson cycle rarely synchronizes with the timing of a supercontinent cycle, however, supercontinent cycles and Wilson cycles were both involved in the creation of Pangaea and Rodinia
2.
Paleozoic
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The Paleozoic Era is the earliest of three geologic eras of the Phanerozoic Eon, from 541 to 252.17 million years ago. It is the longest of the Phanerozoic eras, and is subdivided into six periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous. The Paleozoic comes after the Neoproterozoic era of the Proterozoic and is followed by the Mesozoic, the Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earths history, known as the Cambrian explosion, fish, arthropods, amphibians, anapsids, synapsids, euryapsids and diapsids all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America. Towards the end of the era, large, sophisticated diapsids and synapsids were dominant, the Paleozoic Era ended with the largest extinction event in the history of Earth, the Permian–Triassic extinction event. The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic Era to recover, recovery of life in the sea may have been much faster. The Paleozoic era began and ended with supercontinents and in between were the rise of mountains along the margins, and flooding and draining of shallow seas between. At its start, the supercontinent Pannotia broke up, paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwana formed or was forming, by mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. There are six periods in the Paleozoic Era, Cambrian, Ordovician, Silurian, Devonian, Carboniferous, the Cambrian spans from 541 million years to 485 million years and is the first period of the Paleozoic era of the Phanerozoic. The Cambrian marked a boom in evolution in an event known as the Cambrian explosion in which the largest number of creatures evolved in any period of the history of the Earth. Creatures like algae evolved, but the most ubiquitous of that period were the armored arthropods, almost all marine phyla evolved in this period. During this time, the supercontinent Pannotia begins to break up, the Ordovician spanned from 485 million years to 443 million years ago. The Ordovician is a time in Earths history in many of the biological classes still prevalent today evolved, such as primitive fish, cephalopods. The most common forms of life, however, were trilobites, snails, more importantly, the first arthropods went ashore to colonize the empty continent of Gondwana. By the end of the Ordovican, Gondwana was at the pole, early North America had collided with Europe. Glaciation of Africa resulted in a drop in sea level
3.
Mesozoic
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The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. This Era is also called from a paleobotanist view the Age of Conifers, Mesozoic means middle life, deriving from the Greek prefix meso-/μεσο- for between and zōon/ζῷον meaning animal or living being. It is one of three eras of the Phanerozoic Eon, preceded by the Paleozoic and succeeded by the Cenozoic. The era is subdivided into three periods, the Triassic, Jurassic, and Cretaceous, which are further subdivided into a number of epochs. The Mesozoic was a time of significant tectonic, climate and evolutionary activity, the era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would eventually move into their current positions. The climate of the Mesozoic was varied, alternating between warming and cooling periods, overall, however, the Earth was hotter than it is today. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs, the first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg —until the Cenozoic. Following the Paleozoic, the Mesozoic extended roughly 186 million years and this time frame is separated into three geologic periods. It is also known as the Great Dying because it is considered the largest mass extinction in the Earths history, the upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event, which may have been caused by the impactor that created Chicxulub Crater on the Yucatán Peninsula. Towards the Late Cretaceous large volcanic eruptions are believed to have contributed to the Cretaceous–Paleogene extinction event. Approximately 50% of all genera became extinct, including all of the non-avian dinosaurs, the Triassic ranges roughly from 252 million to 201 million years ago. The Triassic is a time in Earths history bracketed between the Permian Extinction and the Triassic–Jurassic extinction event, two of the big five, and precedes the Jurassic Period and it has three major epochs, the Early Triassic, the Middle Triassic and the Late Triassic. The Early Triassic was between about 252 million to 247 million years ago and was dominated by deserts as Pangaea had not yet broken up, thus the interior was nothing, the Earth had just witnessed a massive die-off in which 95% of all life became extinct. The most common life on earth were Lystrosaurus, labyrinthodonts. Temnospondyls evolved during this time and would be the dominant predator for much of the Triassic, the Middle Triassic spans roughly from 247 million to 237 million years ago. The Middle Triassic featured the beginnings of the breakup of Pangaea, the ecosystem had recovered from the devastation that was the Great Dying. Algae, sponge, corals, and crustaceans all had recovered, new aquatic reptiles evolved, such as ichthyosaurs and nothosaurs. Meanwhile, on land, pine forests flourished, as did groups of insects like mosquitoes, the first ancient crocodilians evolved, which sparked competition with the large amphibians that had since ruled the freshwater world
4.
Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
5.
Southern Hemisphere
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The Southern Hemisphere is the half sphere of Earth which is south of the equator. It contains all or parts of five continents, four oceans and its surface is 80. 9% water, compared with 60. 7% water in the case of the Northern Hemisphere, and it contains 32. 7% of Earths land. Due to the tilt of Earths rotation relative to the Sun, September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox. The South Pole is in the middle of the southern hemispherical region, Southern Hemisphere climates tend to be slightly milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic which is colder than the Arctic. This is because the Southern Hemisphere has significantly more ocean and much land, water heats up. In the Southern Hemisphere the sun passes from east to west through the north, sun-cast shadows turn anticlockwise throughout the day and sundials have the hours increasing in the anticlockwise direction. Cyclones and tropical storms spin clockwise in the Southern Hemisphere due to the Coriolis effect, the southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. Forests in the Southern Hemisphere have special features which set apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique species or Nothofagus. The eucalyptus is native to Australia but is now planted in Southern Africa and Latin America for pulp production and, increasingly. Approximately 800,000,000 humans live in the Southern Hemisphere and this is due to the fact that there is significantly less land in the Southern Hemisphere than in the Northern Hemisphere. Africa Antarctica Asia Australia South America Zealandia Media related to Southern Hemisphere at Wikimedia Commons
6.
Panthalassa
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Panthalassa, also known as the Panthalassic or Panthalassan Ocean, was the superocean that surrounded the supercontinent Pangaea. During the Paleozoic—Mesozoic transition c.250 Ma it occupied almost 70% of Earths surface and its ocean-floor has completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific or Proto-Pacific because the Pacific Ocean developed from its centre in the Mesozoic to the present, the supercontinent Rodinia began to break-up 870–845 Ma probably as a consequence of a superplume caused by mantle slab avalanches along the margins of the supercontinent. In the Late Jurassic the Pacific Plate opened originating from a junction between the Panthalassic Farallon, Phoenix, and Izanagi plates. Panthalassa can be reconstructed based on magnetic lineations and fracture zones preserved in the western Pacific, in western Laurentia, a tectonic episode that preceded this rifting produced failed rifts that harboured large depositional basins in Western Laurentia. The global ocean of Mirovia, an ocean that surrounded Rodinia, started to shrink as the Pan-African ocean, between 650 million and 550 million years ago, another supercontinent started to form, Pannotia, which was shaped like a V. Inside the V was Panthalassa, outside of the V were the Pan-African Ocean, furthermore, seismic tomography is being used to identify subducted slabs in the mantle, from which the location of former Panthalassic subduction zones can be derived. A series of such zones, called Telkhinia, defines two separate oceans or systems of oceanic plates — the Pontus and Thalassa oceans. Named marginal oceans or oceanic plates include Mongol-Okhotsk, Oimyakon, Slide Mountain Ocean, the western margin of Laurentia originated during the Neoproterozoic break-up of Rodinia. The North American Cordillera is an accretionary orogen which grew by the addition of allochthonous terranes along this margin from the Late Palaeozoic. Devonian back-arc volcanism reveals how this eastern Panthalassic margin developed into the margin it still is in the mid-Palaeozoic. Most of the fragments, volcanic arcs, and ocean basins added to Laurentia this way contained faunas of Tethyan or Asian affinity. Similar terranes added to the northern Laurentia, in contrast, have affinities with Baltica, Siberia, and these latter terranes were probably accreted along the eastern Panthalassa margin by a Caribbean–Scotia-style subduction system. Today the region is dominated by the collision of the Australian Plate with a network of plate boundaries in south-east Asia. Spreading along the Pacific-Phoenix ridge ended 83 Ma at the Osbourn Trough at the Tonga-Kermadec Trench, during the Permian atolls developed near the Equator on the mid-Panthalassic seamounts. One such migrating atoll complex now form a 2-kilometre-long and 100-to-150-metre-wide body of limestone in central Kyushu, south-west Japan. The Permian–Triassic extinction event c.260 Ma, however, put an end to development with only dwarf taxa persisting throughout the Permian until the final fusuline extinction c.252 Ma. Permian fusulines also developed a remarkable provincialism by which fusulines can be grouped into six domains, because of the large size of Panthalassa a hundred million years could separate the accretion of different groups of fusulines
7.
Ancient Greek
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Ancient Greek includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often divided into the Archaic period, Classical period. It is antedated in the second millennium BC by Mycenaean Greek, the language of the Hellenistic phase is known as Koine. Koine is regarded as a historical stage of its own, although in its earliest form it closely resembled Attic Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects, Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical phases of the language, Ancient Greek was a pluricentric language, divided into many dialects. The main dialect groups are Attic and Ionic, Aeolic, Arcadocypriot, some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are also several historical forms, homeric Greek is a literary form of Archaic Greek used in the epic poems, the Iliad and Odyssey, and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic, the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period and they have the same general outline, but differ in some of the detail. The invasion would not be Dorian unless the invaders had some relationship to the historical Dorians. The invasion is known to have displaced population to the later Attic-Ionic regions, the Greeks of this period believed there were three major divisions of all Greek people—Dorians, Aeolians, and Ionians, each with their own defining and distinctive dialects. Often non-west is called East Greek, Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, thessalian likewise had come under Northwest Greek influence, though to a lesser degree. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, and Northern Peloponnesus Doric. The Lesbian dialect was Aeolic Greek and this dialect slowly replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek, by about the 6th century AD, the Koine had slowly metamorphosized into Medieval Greek
8.
Gaia (mythology)
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In Greek mythology, Gaia, also spelled Gaea, is the personification of the Earth and one of the Greek primordial deities. Gaia is the mother of all life, the primal Mother Earth goddess. She is the parent of Uranus, from whose sexual union she bore the Titans and the Giants. Her equivalent in the Roman pantheon was Terra, the Greek word γαῖα is a collateral form of γῆ meaning Earth, a word of uncertain origin. R. S. P. Beekes has suggested a Pre-Greek origin, in Mycenean Greek Ma-ka also contains the root ga-. Gaia is the personification of the Earth and these are her offspring as related in various myths, some are related consistently, some are mentioned only in minor variants of myths, and others are related in variants that are considered to reflect a confusion of the subject or association. *Some said that those marked with a * were born from Uranus blood when Cronus castrated him, hesiods Theogony tells how, after Chaos, wide-bosomed Gaia arose to be the everlasting seat of the immortals who possess Olympus above, and the depths of Tartarus below. He then tells that Gaia brought forth her equal Uranus to cover her on every side, Gaia also bore the hills, and Pontus, without sweet union of love. After them was born Cronos the wily, youngest and most terrible of her children, as each of the Cyclopes and Hecatonchires were born, Uranus hid them in a secret place within Gaia, causing her great pain. She created a grey flint sickle, and Cronus used the sickle to castrate his father Uranus as he approached Gaia to have sex with her. From Uranus spilled blood, Gaia produced the Erinyes, the Giants, from the testicles of Uranus in the sea came forth Aphrodite. By her son Pontus, Gaia bore the sea-deities Nereus, Thaumas, Phorcys, Ceto, and Eurybia. Because Cronus had learned from Gaia and Uranus that he was destined to be overthrown by one of his children, but when Rhea was pregnant with her youngest child, Zeus, she sought help from Gaia and Uranus. When Zeus was born, Rhea gave Cronus a stone wrapped in swaddling-clothes in his place, which Cronus swallowed, with the help of Gaias advice, Zeus defeated the Titans. But afterwards, Gaia, in union with Tartarus, bore the youngest of her sons Typhon, according to Hyginus, Earth, along with Heaven and Sea were the children of Aether and Day. According to Apollodorus, Gaia and Tartarus were the parents of Echidna, Zeus hid Elara, one of his lovers, from Hera by stowing her under the earth. His son by Elara, the giant Tityos, is sometimes said to be a son of Gaia. Gaia is believed by some sources to be the deity behind the Oracle at Delphi
9.
Mother goddess
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A mother goddess is a goddess who represents, or is a personification of nature, motherhood, fertility, creation, destruction or who embodies the bounty of the Earth. When equated with the Earth or the world, such goddesses are sometimes referred to as Mother Earth or as the Earth Mother. Many different goddesses have represented motherhood in one way or another, others have represented the fertility of the earth. Several small, voluptuous figures have been found during excavations of the Upper Paleolithic. This sculpture is estimated to have been carved 35,000 years ago, some archaeologists believe they were intended to represent goddesses, while others believe that they could have served some other purpose. The Paleolithic period extends from 2.5 million years ago to the introduction of agriculture around 10,000 BCE, archaeological evidence indicates that humans migrated to the Western Hemisphere before the end of the Paleolithic, so cultures around the world share its characteristics. It is the prehistoric era distinguished by the development of stone tools, regional differences in the development of this stage of tool development are quite varied. During this time, native cultures appear in the Western Hemisphere, regular seasonal occupation or permanent settlements begin to be seen in excavations. Herding and keeping of cattle, goats, sheep, and pigs is evidenced along with the presence of dogs, almost without exception, images of what Marija Gimbutas interpreted as mother goddesses have been discovered in all of these cultures. Numerous female figurines from Neolithic Çatalhöyük in Anatolia have been interpreted as evidence of a mother-goddess cult, james Mellaart, who led excavation at the site in the 1960s, suggests that the figures represent a Great goddess, who headed the pantheon of an essentially matriarchal culture. A seated female figure, flanked by what Mellaart describes as lionesses, was found in a grain-bin, she may have intended to protect the harvest and grain. The seated or enthroned goddess-like figure flanked by lionesses, has suggested as a prototype Cybele. They also left behind many ceramic remains of pottery and clay figurines, some of these figurines appear to represent the mother goddess. Malta has some of the oldest buildings in the world, and has many fertility figures or pieces of fertility figures throughout the temples, the most famous is the Sleeping Lady, recovered from the Hypogeum of Ħal-Saflieni, and held in the National Museum of Archaeology, Malta. Similarly, mother goddess figurines are found in the contemporaneous Ozieri culture of Sardinia. James Frazer and others advance the idea that worship in ancient Europe. According to Gimbutas Kurgan Hypothesis, Old European cultures were disrupted by expansion of Indo-European speakers from modern-day Ukraine, in 1968 the archaeologist Peter Ucko proposed that the many images found in graves and archaeological sites of Neolithic cultures were toys. The graves he was describing dated from Predynastic Egypt and Neolithic Crete, Mother goddesses are present in the earliest images discovered among the archaeological finds in Ancient Egypt
10.
Alfred Wegener
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Alfred Lothar Wegener was a German polar researcher, geophysicist and meteorologist. Wegener was involved in expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Alfred Wegener was born in Berlin on 1 November 1880 as the youngest of five children in a clergymans family and his father, Richard Wegener, was a theologian and teacher of classical languages at the Berlinisches Gymnasium zum Grauen Kloster. In 1886 his family purchased a manor house near Rheinsberg. Today there is an Alfred Wegener Memorial site and tourist information office in a building that was once the local schoolhouse. He was cousin to movie pioneer Paul Wegener, Wegener attended school at the Köllnisches Gymnasium on Wallstrasse in Berlin, graduating as the best in his class. Afterward he studied Physics, meteorology and Astronomy in Berlin, Heidelberg, from 1902 to 1903 during his studies he was an assistant at the Urania astronomical observatory. He obtained a doctorate in astronomy in 1905 based on a dissertation written under the supervision of Julius Bauschinger at Friedrich Wilhelms University, Wegener had always maintained a strong interest in the developing fields of meteorology and climatology and his studies afterwards focused on these disciplines. In 1905 Wegener became an assistant at the Aeronautisches Observatorium Lindenberg near Beeskow and he worked there with his brother Kurt, two years his senior, who was likewise a scientist with an interest in meteorology and polar research. The two pioneered the use of balloons to track air masses.5 hours from April 5–7,1906. In that same year 1906, Wegener participated in the first of his four Greenland expeditions, the expedition was led by the Dane Ludvig Mylius-Erichsen and charged with studying the last unknown portion of the northeastern coast of Greenland. Here Wegener also made his first acquaintance with death in a wilderness of ice when the expedition leader, after his return in 1908 and until World War I, Wegener was a lecturer in meteorology, applied astronomy and cosmic physics at the University of Marburg. His students and colleagues in Marburg particularly valued his ability to clearly and understandably explain even complex topics, after a stopover in Iceland to purchase and test ponies as pack animals, the expedition arrived in Danmarkshavn. Even before the trip to the ice began the expedition was almost annihilated by a calving glacier. The Danish expedition leader, Johan Peter Koch, broke his leg when he fell into a glacier crevasse, Wegener and Koch were the first to winter on the inland ice in northeast Greenland. Inside their hut they drilled to a depth of 25 m with an auger, in summer 1913 the team crossed the inland ice, the four expedition participants covering a distance twice as long as Fridtjof Nansens southern Greenland crossing in 1888. Only a few kilometers from the western Greenland settlement of Kangersuatsiaq the small team ran out of food while struggling to find their way through difficult glacial breakup terrain. But at the last moment, after the last pony and dog had eaten, they were picked up at a fjord by the clergyman of Upernavik
11.
Scientific theory
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Established scientific theories have withstood rigorous scrutiny and are a comprehensive form of scientific knowledge. It is important to note that the definition of a theory as used in the disciplines of science is significantly different from the common vernacular usage of the word theory. These different usages are comparable to the differing, and often opposing, usages of the prediction in science versus prediction in vernacular speech. The strength of a theory is related to the diversity of phenomena it can explain. In certain cases, the less-accurate unmodified scientific theory can still be treated as an if it is useful as an approximation under specific conditions. Scientific theories are testable and make falsifiable predictions and they describe the causal elements responsible for a particular natural phenomenon, and are used to explain and predict aspects of the physical universe or specific areas of inquiry. Scientists use theories as a foundation to further scientific knowledge. As with other forms of knowledge, scientific theories are both deductive and inductive in nature and aim for predictive power and explanatory capability. Paleontologist, evolutionary biologist, and science historian Stephen Jay Gould said, “. facts and theories are different things, not rungs in a hierarchy of increasing certainty. Theories are structures of ideas that explain and interpret facts. ”The defining characteristic of all scientific knowledge, the relevance and specificity of those predictions determine how potentially useful the theory is. A would-be theory that makes no observable predictions is not a theory at all. Predictions not sufficiently specific to be tested are similarly not useful, in both cases, the term theory is not applicable. A body of descriptions of knowledge can be called a theory if it fulfills the following criteria and it is well-supported by many independent strands of evidence, rather than a single foundation. It is consistent with preexisting experimental results and at least as accurate in its predictions as are any preexisting theories and these qualities are certainly true of such established theories as special and general relativity, quantum mechanics, plate tectonics, the modern evolutionary synthesis, etc. It is among the most parsimonious explanations, economical in the use of proposed entities or explanatory steps as per Occams razor. The United States National Academy of Sciences defines scientific theories as follows and it refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. Such fact-supported theories are not guesses but reliable accounts of the real world, the theory of biological evolution is more than just a theory. It is as factual an explanation of the universe as the theory of matter or the germ theory of disease
12.
Continental drift
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Continental drift is the movement of the Earths continents relative to each other, thus appearing to drift across the ocean bed. The speculation that continents might have drifted was first put forward by Abraham Ortelius in 1596, the concept was independently and more fully developed by Alfred Wegener in 1912, but his theory was rejected by some for lack of a mechanism and others because of prior theoretical commitments. The idea of continental drift has been subsumed by the theory of plate tectonics, W. J. Kious described Ortelius thoughts in this way, Abraham Ortelius in his work Thesaurus Geographicus. Suggested that the Americas were torn away from Europe and Africa, by earthquakes and floods and went on to say, The vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three. In his Manual of Geology,1863, Dana says The continents, Dana was enormously influential in America – his Manual of Mineralogy is still in print in revised form – and the theory became known as Permanence theory. This suggested that the oceans were a permanent feature of the earths surface and this led Mantovani to propose an Expanding Earth theory which has since been shown to be incorrect. Continental drift without expansion was proposed by Frank Bursley Taylor, who suggested in 1908 that the continents were moved into their present positions by a process of continental creep. Wegener said that of all theories, Taylors, although not fully developed, had the most similarities to his own. In the mid-20th century, the theory of drift was referred to as the Taylor-Wegener hypothesis. Alfred Wegener first presented his hypothesis to the German Geological Society on January 6,1912 and his hypothesis was that the continents had once formed a single landmass, called Pangea, before breaking apart and drifting to their present locations. Wegener was the first to use the continental drift and formally publish the hypothesis that the continents had somehow drifted apart. Although he presented evidence for continental drift, he was unable to provide a convincing explanation for the physical processes which might have caused this drift. The Polflucht hypothesis was studied by Paul Sophus Epstein in 1920. The theory of drift was not accepted for many years. One problem was that a driving force was missing. A second problem was that Wegeners estimate of the velocity of continental motion,250 cm/year, was implausibly high, and it did not help that Wegener was not a geologist. Other geologists also believed that the evidence that Wegener had provided was not sufficient, the British geologist Arthur Holmes championed the theory of continental drift at a time when it was deeply unfashionable. He proposed in 1931 that the Earths mantle contained convection cells that dissipated radioactive heat and his Principles of Physical Geology, ending with a chapter on continental drift, was published in 1944
13.
Supercontinent cycle
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The supercontinent cycle is the quasi-periodic aggregation and dispersal of Earths continental crust. There are varying opinions as to whether the amount of continental crust is increasing, decreasing, or staying about the same, one complete supercontinent cycle is said to take 300 to 500 million years. Continental collision makes fewer and larger continents while rifting makes more, the most recent supercontinent, Pangaea, formed about 300 million years ago. There are two different views on the history of earlier supercontinents, the first proposes a series of supercontinents, Vaalbara, Ur, Kenorland, Columbia, Rodinia, and Pannotia, whose dispersal produced the fragments that ultimately collided to form Pangaea. During the intervening periods, the appear to have conformed to a unified apparent polar wander path. Thus the paleomagnetic data are adequately explained by the existence of a single Protopangea–Paleopangea supercontinent with prolonged quasi-integrity, the prolonged duration of this supercontinent could be explained by the operation of lid tectonics during Precambrian times, as opposed to the plate tectonics seen on the contemporary Earth. The kinds of minerals found inside ancient diamonds suggest that the cycle of supercontinental formation, before 3.2 billion years ago only diamonds with peridotitic compositions formed, whereas after 3.0 billion years ago eclogitic diamonds became prevalent. This change is thought to have come about because the process of subduction, the hypothesized supercontinent cycle is complemented by the Wilson cycle named after plate tectonics pioneer J. Tuzo Wilson, which describes the periodic opening and closing of ocean basins. It is known that sea level is low when the continents are together. For example, sea level was low at the time of formation of Pangaea and Pannotia, and rose rapidly to maxima during Ordovician and Cretaceous times, when the continents were dispersed. This is because the age of the oceanic lithosphere provides a control on the depth of the ocean basins. Oceanic lithosphere forms at mid-ocean ridges and moves outwards, as this happens, it conductively cools and shrinks. As the mean level of the sea decreases, the volume of the ocean basins increases. The converse is true, younger oceanic lithosphere leads to shallower oceans. Area A, of the oceans, can change when continents rift or as a result of continental collision, increasing sea level will flood the continents, while decreasing sea level will expose continental shelves. Because the continental shelf has a low slope, a small increase in sea level will result in a large change in the percent of continents flooded. If the world ocean on average is young, the seafloor will be relatively shallow, if the world ocean is on average old, seafloor will be relatively deep, and sea level will be low, more of the continents will be exposed. There is thus a simple relationship between the supercontinent cycle and the mean age of the seafloor
14.
Rodinia
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Rodinia is a Neoproterozoic supercontinent that was assembled 1. 13–1.071 billion years ago and broke up 750–600 million years ago. Valentine & Moores 1970 were probably the first to recognise a Precambrian supercontinent and it was renamed Rodinia by McMenamin & McMenamin 1990 who also were the first to produce a reconstruction and propose a temporal framework for the supercontinent. Rodinia formed at c.1.071 Ga by accretion and collision of fragments produced by breakup of a supercontinent, Columbia. Rodinia broke up in the Neoproterozoic with its continental fragments reassembled to form Pannotia 620–555 million years ago, in contrast with Pannotia, little is known yet about the exact configuration and geodynamic history of Rodinia. The idea that a supercontinent existed in the early Neoproterozoic arose in the 1970s, examples are the Grenville orogeny in North America and the Dalslandian orogeny in Europe. Since then, many reconstructions have been proposed for the configuration of the cratons in this supercontinent. Most of these reconstructions are based on the correlation of the orogens on different cratons, though the configuration of the core cratons in Rodinia is now reasonably well known, recent reconstructions still differ in many details. Geologists try to decrease the uncertainties by collecting geological and paleomagnetical data, aUSWUS-Configuration, Australia is at the West of Laurentia. AUSMEX-Configuration, Australia is at the location of nowadays Mexico relative to Laurentia, the Missing-link model by Li et al.2008 which has South China between Australia and the west coast of Laurentia. A revised Missing-link model is proposed in which Tarim Block serves as an extended or alternative missing-link between Australia and Laurentia, Siberia attached to the western US, as in Sears & Price 2000. Little is known about the paleogeography before the formation of Rodinia, paleomagnetic and geologic data are only definite enough to form reconstructions from the breakup of Rodinia onwards. Rodinia is considered to have formed between 1.13 billion and 1.071 billion years ago and broke up again before 750 million years ago, Rodinia was surrounded by the superocean geologists are calling Mirovia. Piper, Rodinia is one of two models for the configuration and history of the continental crust in the part of Precambrian times. The other is Paleopangea, Pipers own concept, piper proposes an alternative hypothesis for this era and the previous ones. Rifting progressed in the same cratons 800—750 Ma and spread into Laurentia, india and the Congo-Säo Francisco Craton were either detached from Rodinia during this period or simply never were part of the supercontinent. 650–550 Ma several events coincided, the opening of the Iapetus Ocean, the closure of the Braziliano, Adamastor, and Mozambique oceans, the result was the formation of Gondwana. The Rodinia hypothesis assumes that rifting did not start everywhere simultaneously, extensive lava flows and volcanic eruptions of Neoproterozoic age are found on most continents, evidence for large scale rifting about 750 million years ago. This rift developed into the Adamastor Ocean during the Ediacaran, around 550 million years ago, on the boundary between the Ediacaran and Cambrian, the first group of cratons eventually fused again with Amazonia, West Africa and the Rio de la Plata cratons
15.
Accretion (geology)
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Accretion is a process by which material is added to a tectonic plate or a landmass. This material may be sediment, volcanic arcs, seamounts or other igneous features, accretion involves the addition of material to a tectonic plate. When two tectonic plates collide, one of the plates may slide under the other, a known as subduction. The plate which is being subducted, is floating on the asthenosphere and is pushed against the other, sediment on the ocean floor will often be scraped from the subducting plate. This causes the sediment to accumulate as a mass of material called an accretionary wedge, volcanic island arcs or seamounts may collide with the continent, and as they are of relatively light material they will often not be subducted, but are added to the side of the continent. Continental plates are formed of rocks that are noticeably different from the rocks that form the ocean floor. The ocean floor is composed of basaltic rocks which have a higher density than continental plates. In places where plate accretion has occurred, land masses may contain the dense and this process occurs wherever plates collide. Many examples occur around the Pacific Rim, including the western coast of North America, the Nankai accretionary complex of Japan, the Barbados Ridge in the Caribbean, the Mediterranean Ridge and the Franciscan Assemblage of California are examples. New York, Lee & Shepard,1995
16.
Pannotia
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Pannotia formed when Laurentia was located adjacent to the two major South American cratons, Amazonia and Río de la Plata. The opening of the Iapetus Ocean separated Laurentia from Baltica, Amazonia, piper 1976 was probably the first to propose a Proterozoic supercontinent preceding Pangaea, today known as Rodinia. The reconstruction of Bond et al. is virtually identical to that of Dalziel 1997, another term for the supercontinent that is thought to have existed at the end of Neoproterozoic time is Greater Gondwanaland, suggested by Stern 1994. This term recognizes that the supercontinent of Gondwana, which formed at the end of the Neoproterozoic, was part of the much larger end-Neoproterozoic supercontinent. Powell, however, objected to this renaming and instead proposed Stumps term for the latter supercontinent, the formation of Pannotia began during the Pan-African orogeny when the Congo continent got caught between the northern and southern halves of the previous supercontinent Rodinia some 750 Ma. The peak in this mountain building event was around 640–610 Ma, the formation of Pannotia was the result of Rodinia turning itself inside out. When Pannotia had formed Africa was located at the centre surrounded by the rest of Gondwana, South America, Arabia, Madagascar, India, Antarctica, Laurentia, who escaped out of Rodinia, Baltica, and Siberia kept the relative positions they had in Rodinia. The Cathaysian and Cimmerian terranes were located along the margins of east Gondwana. The Avalonian-Cadomian terranes were located along the northern margins of western Gondwana. This orogeny probably extended north into the Uralian margin of Baltica, Pannotia formed by subduction of exterior oceans over a geoid low, whereas Pangaea formed by subduction of interior oceans over a geoid high perhaps caused by superplumes and slab avalanche events. One of the major of these orogenies was the collision between East and West Gondwana or the East African Orogeny, 600-500 Ma two Brazilian interior orogenies got highly deformed and metamorphosed between a series of colliding cratons, Amazonia, West Africa-São Luís, and São Francisco-Congo-Kasai. The material that was accreted included 950-850 Ma mafic meta-igneous complexes, the break-up of Pannotia was accompanied by sea level rise, dramatic changes in climate and ocean water chemistry, and rapid metazoan diversification. Bond, Nickeson & Kominz 1984 found Neoproterozoic passive margin sequences worldwide — the first indication of a Late Neoproterozoic supercontinent, the Iapetus Ocean started to open while Pannotia was being assembled,200 m. y. after the break-up of Rodinia. Plate tectonics Supercontinent cycle Pan-African orogeny An image showing Pannotia according to Christopher Scotese, stampfli, G. M. von Raumer, J. F. Borel, G. D. Paleozoic evolution of pre-Variscan terranes, from Gondwana to the Variscan collision
17.
Laurasia
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Laurasia was the more northern of two supercontinents that formed part of the Pangaea supercontinent around 335 to 175 million years ago. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, the name combines the names of Laurentia, the name given to the North American craton, and Eurasia. To avoid confusion with the Mesozoic continent, this is referred to as Proto-Laurasia and it is believed that Laurasia did not break up again before it recombined with the southern continents to form the late Precambrian supercontinent of Pannotia, which remained until the early Cambrian. Laurasia was assembled, then broken up, due to the actions of plate tectonics, continental drift, and seafloor spreading. By the Devonian, North China was located near the Arctic Circle, no evidence, though, exists for any large-scale Carboniferous glaciation of the northern continents. Siberia moved southwards and joined with Kazakhstania, a continental region believed today to have been created during the Silurian by extensive volcanism. North China became, as it drifted southwards from near-Arctic latitudes, around 200 million years ago, Pangaea started to break up. Between eastern North America and northwest Africa, a new ocean formed - the Atlantic Ocean, though Greenland, the separation of Europe and Greenland occurred around 55 million years ago. Laurasia finally divided into the continents after which it is named, alexander du Toit Alfred Wegener Avalonia
18.
Gondwana
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In paleogeography, Gondwana, also Gondwanaland, is the name given to an ancient supercontinent. It is believed to have sutured about 600 to 530 million years ago, Gondwana formed prior to Pangaea, and later became part of it. Around 335 to 250 million years ago Gondwana and Laurasia joined together to form the supercontinent Pangaea, Gondwana then separated from Laurasia in the breakup of Pangaea, drifting farther south after the split. Gondwana itself then also broke apart, the continent of Gondwana was named by Austrian scientist Eduard Suess, after the Gondwana region of central northern India which is derived from Sanskrit for forest of the Gonds. The name had previously used in a geological context, first by H. B. From which the Gondwana sedimentary sequences are also described, for example, the plant family Proteaceae, known only from southern South America, South Africa, Australia, and New Zealand, is considered to have a Gondwanan distribution. This pattern is considered to indicate an archaic, or relict. The assembly of Gondwana was a protracted process, several orogenies led to its final amalgamation 550 to 500 million years ago at the end of the Ediacaran, and into the Cambrian. These include the Brasiliano Orogeny, the East African Orogeny, the Malagasy Orogeny, the final stages of Gondwanan assembly overlapped with the opening of the Iapetus Ocean between Laurentia and western Gondwana. During this interval, the Cambrian explosion occurred and this is the Famatinian block and it formerly continued the line of the Appalachians southwards. One of the sites of Gondwanan amalgamation was the East African Orogeny. The East African Orogeny at about 650–630 Mya affected a part of Arabia, north-eastern Africa, East Africa. Collins and Windley propose that in this orogeny, Azania collided with the Congo–Tanzania–Bangweulu Block, the later Malagasy orogeny at about 550–515 Mya affected Madagascar, eastern East Africa and southern India. In it, Neoproterozoic India collided with the already combined Azania and Congo–Tanzania–Bangweulu Block, at the same time, in the Kunga Orogeny Neoproterozoic India collided with the Australia/Mawson continent. Other large continental masses, including the core cratons of North America, Europe, when Pangaea broke up, two large masses, Gondwana and Laurasia, were formed. During the late Paleozoic, Gondwana extended from a point at or near the South Pole to near the Equator, across much of Gondwana, the climate was mild. During the Mesozoic, the world was on average warmer than it is today. Gondwana was then host to a variety of flora and fauna for many millions of years
19.
Congo Craton
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The Congo Craton, covered by the Palaeozoic-to-recent Congo Basin, is an ancient Precambrian craton that with four others makes up the modern continent of Africa. These cratons were formed between about 3.6 and 2.0 billion years ago and have been stable since that time. All of these cratons are bounded by younger fold belts formed between 2.0 billion and 300 million years ago, the Congo Craton occupies a large part of central southern Africa, extending from the Kasai region of the DRC into Sudan and Angola. It forms parts of the countries of Gabon, Cameroon, a small portion extends into Zambia as well, where it is called the Bangweulu Block. Around 2.11 Ga, Congo was part of the minor supercontinent Atlantica, around 1.82 Ga, Congo was part of the major supercontinent Nuna. Around 1.31 Ga, Congo was an independent continent, around 1.071 Ga, Congo was part of the major supercontinent Rodinia. Around 990 Ma, Congo was an indepandent continent, around 600 Ma, Congo was part of the major supercontinent Pannotia. Around Cambrian, Congo was part of the minor supercontinent Gondwana, around Carboniferous, all major continents collide against each other for forming the major supercontinent Pangaea. Around Jurassic, Pangaea rifted into two supercontinents, Laurasia and Gondwana. Congo was part of the minor supercontinent Gondwana, around Cretaceous, Congo was an independent continent called Africa. Around Neogene, Congo, in the form of Africa, crashed into Eurasia, around 250 Ma from now, all continents may crash together, forming the major supercontinent Pangaea Ultima. Congo would be part of Pangaea Ultima, around 450-600 Ma from now, Pangaea Ultima will eventually rift apart. Congo will be an independent continent
20.
Siberia (continent)
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Siberia, also known as Angaraland and Angarida, is an ancient craton located in the heart of Siberia. Today forming the Central Siberian Plateau, it formed an independent continent before the Permian, about 2.5 billion years ago, Siberia was part of a continent of Arctica, along with the Canadian Shield. Siberia was an independent continent through the lower Paleozoic until, during the Carboniferous Period, a subsequent collision with Baltica during the Permian completed the formation of the supercontinent Pangaea. Pangaea split up during the Jurassic though Siberia stayed with Laurasia, Laurasia gradually split up during the Cretaceous with Siberia remaining part of present-day northeastern Eurasia. Today, Siberia forms part of the supercontinent of Afro-Eurasia. In around 250 million years from now Siberia may be in the subtropical region, global Earth History, Sedimentation, Tectonics, and Paleogeography of Asia
21.
Baltica
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Baltica was a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago, before this time, the three segments/continents that now compose the East European craton were in different places on the globe. Baltica existed on a plate called the Baltic Plate. ~1.82 billion years ago, Baltica was part of the major supercontinent Columbia, ~1.5 billion years ago, Baltica along with Arctica and East Antarctica were part of the minor supercontinent Nena. ~1.07 billion years ago, Baltica was part of the major supercontinent Rodinia, ~750 million years ago, Baltica was part of the minor supercontinent Protolaurasia. ~600 million years ago, Baltica was part of the major supercontinent Pannotia, ~Cambrian, Baltica was an independent continent. ~Late Ordovician, Baltica collided with Avalonia ~Devonian, Baltica collided against Laurentia, ~Permian, all major continents collided against each other to form the major supercontinent Pangaea. ~Jurassic, Pangaea rifted into two supercontinents, Laurasia and Gondwana. Baltica was part of the minor supercontinent Laurasia, ~Cretaceous, Baltica was part of the minor supercontinent Eurasia. ~Present, Baltica is part of the minor supercontinent Afro-Eurasia. Around 250 million years from now, all continents may crash together, Baltica would be part of Pangaea Proxima. Around 450-600 Ma from now, Pangea Proxima will eventually rift apart
22.
Iapetus Ocean
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The Iapetus Ocean was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale. The Iapetus Ocean was situated in the hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia. The ocean disappeared with the Acadian, Caledonian and Taconic orogenies, the southern Iapetus Ocean has been proposed to have closed with the Famatinian and Taconic orogenies, meaning a collision between Western Gondwana and Laurentia. The Iapetus Ocean was therefore named for the titan Iapetus, who in Greek mythology was the father of Atlas, after whom the Atlantic Ocean was named. Geologists of the early 20th century presumed that a large trough, with the development of plate tectonics in the 1960s, geologists such as Arthur Holmes and John Tuzo Wilson concluded that the Atlantic Ocean must have had a precursor before the time of Pangaea. Wilson also noticed that the Atlantic had opened at roughly the place where its precursor ocean had closed. This led him to his Wilson cycle hypothesis, in many spots in Scandinavia basaltic dikes are found with ages between 670 and 650 million years. These are interpreted as evidence that by that time, rifting had started that would form the Iapetus Ocean, in Newfoundland and Labrador, the Long Range dikes are also thought to have formed during the formation of the Iapetus Ocean. The southern Iapetus Ocean opened between Laurentia and southwestern Gondwana about 550 Ma in the Ediacaran–Cambrian transition, at the time it did so the Adamastor Ocean further east closed. However, the formation of both oceans seems unrelated, southwest of the Iapetus, a volcanic island arc evolved from the early Cambrian onward. This volcanic arc was formed above a subduction zone where the lithosphere of the Iapetus Ocean subducted southward under other oceanic lithosphere. From Cambrian times the western Iapetus Ocean began to grow progressively narrower due to this subduction, the same happened further north and east, where Avalonia and Baltica began to move towards Laurentia from the Ordovician onward. In the west, the Iapetus Ocean closed with the Taconic orogeny, some authors consider the oceanic basin south of the island arc also a part of the Iapetus, this branch closed during the later Acadian orogeny, when Avalonia collided with Laurentia. It has been suggested that the southern Iapetus Ocean closed during a collision between Laurentia and Western Gondwana. If factual the Taconic orogen would be the continuation of the Famatinian orogen exposed in Argentina. Avalonia Baltica Geologic timescale Khanty Ocean London-Brabant Massif Plate tectonics Southern uplands of Scotland Cocks, L. R. N. Fortey, Biogeography of Ordovician and Silurian faunas. In McKerrow, W. S. Scotese, C. F. Palaeozoic Palaeogeography and Biogeography, dalziel, I. W. Neoproterozoic-Paleozoic geography and tectonics, Review, hypothesis, environmental speculation. 1972, The Arctic Caledonides and earlier oceans, Geological Magazine 109,2003, The making and unmaking of a supercontinent, Rodinia revisited, Tectonophysics 375, pp. 261–288
23.
Cambrian
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The Cambrian Period was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago to the beginning of the Ordovician Period 485.4 mya and its subdivisions, and its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latinised form of Cymru, the Welsh name for Wales, as a result, our understanding of the Cambrian biology surpasses that of some later periods. The rapid diversification of lifeforms in the Cambrian, known as the Cambrian explosion, most of the continents were probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia, the seas were relatively warm, and polar ice was absent for much of the period. The United States Federal Geographic Data Committee uses a barred capital C ⟨Є⟩ character similar to the capital letter Ukrainian Ye ⟨Є⟩ to represent the Cambrian Period, the proper Unicode character is U+A792 Ꞓ LATIN CAPITAL LETTER C WITH BAR. Despite the long recognition of its distinction from younger Ordovician Period rocks and older Supereon Precambrian rocks, the base of the Cambrian lies atop a complex assemblage of trace fossils known as the Treptichnus pedum assemblage. Pedum in Namibia, Spain and Newfoundland, and possibly, in the western USA, the stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain. The Cambrian Period followed the Ediacaran Period and was followed by the Ordovician Period, the Cambrian is divided into four epochs and ten ages. Currently only two series and five stages are named and have a GSSP, because the international stratigraphic subdivision is not yet complete, many local subdivisions are still widely used. In some of these subdivisions the Cambrian is divided into three epochs with locally differing names – the Early Cambrian, Middle Cambrian and Furongian, rocks of these epochs are referred to as belonging to the Lower, Middle, or Upper Cambrian. Trilobite zones allow biostratigraphic correlation in the Cambrian, each of the local epochs is divided into several stages. The International Commission on Stratigraphy list the Cambrian period as beginning at 541 million years ago, the lower boundary of the Cambrian was originally held to represent the first appearance of complex life, represented by trilobites. The recognition of small shelly fossils before the first trilobites, and Ediacara biota substantially earlier and this formal designation allowed radiometric dates to be obtained from samples across the globe that corresponded to the base of the Cambrian. Early dates of 570 million years ago quickly gained favour, though the used to obtain this number are now considered to be unsuitable. A more precise date using modern radiometric dating yield a date of 541 ±0.3 million years ago, most continental land was clustered in the Southern Hemisphere at this time, but was drifting north. Large, high-velocity rotational movement of Gondwana appears to have occurred in the Early Cambrian, the sea levels fluctuated somewhat, suggesting there were ice ages, associated with pulses of expansion and contraction of a south polar ice cap. In Baltoscandia a Lower Cambrian transgression transformed large swathes of the Sub-Cambrian peneplain into a epicontinental sea, the Earth was generally cold during the early Cambrian, probably due to the ancient continent of Gondwana covering the South Pole and cutting off polar ocean currents
24.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also 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, Africa, 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, Asia 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, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
25.
Equator
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The Equator usually refers to an imaginary line on the Earths surface equidistant from the North Pole and South Pole, dividing the Earth into the Northern Hemisphere and Southern Hemisphere. The Equator is about 40,075 kilometres long, some 78. 7% lies across water and 21. 3% over land, other planets and astronomical bodies have equators similarly defined. Generally, an equator is the intersection of the surface of a sphere with the plane that is perpendicular to the spheres axis of rotation. The latitude of the Earths equator is by definition 0° of arc, the equator is the only line of latitude which is also a great circle — that is, one whose plane passes through the center of the globe. The plane of Earths equator when projected outwards to the celestial sphere defines the celestial equator, in the cycle of Earths seasons, the plane of the equator passes through the Sun twice per year, at the March and September equinoxes. To an observer on the Earth, the Sun appears to travel North or South over the equator at these times, light rays from the center of the Sun are perpendicular to the surface of the Earth at the point of solar noon on the Equator. Locations on the Equator experience the quickest sunrises and sunsets because the sun moves nearly perpendicular to the horizon for most of the year. The Earth bulges slightly at the Equator, the diameter of the Earth is 12,750 kilometres. Because the Earth spins to the east, spacecraft must also launch to the east to take advantage of this Earth-boost of speed, seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earths axis relative to the plane of revolution. During the year the northern and southern hemispheres are inclined toward or away from the sun according to Earths position in its orbit, the hemisphere inclined toward the sun receives more sunlight and is in summer, while the other hemisphere receives less sun and is in winter. At the equinoxes, the Earths axis is not tilted toward the sun, instead it is perpendicular to the sun meaning that the day is about 12 hours long, as is the night, across the whole of the Earth. Near the Equator there is distinction between summer, winter, autumn, or spring. The temperatures are usually high year-round—with the exception of high mountains in South America, the temperature at the Equator can plummet during rainstorms. In many tropical regions people identify two seasons, the wet season and the dry season, but many places close to the Equator are on the oceans or rainy throughout the year, the seasons can vary depending on elevation and proximity to an ocean. The Equator lies mostly on the three largest oceans, the Pacific Ocean, the Atlantic Ocean, and the Indian Ocean. The highest point on the Equator is at the elevation of 4,690 metres, at 0°0′0″N 77°59′31″W and this is slightly above the snow line, and is the only place on the Equator where snow lies on the ground. At the Equator the snow line is around 1,000 metres lower than on Mount Everest, the Equator traverses the land of 11 countries, it also passes through two island nations, though without making a landfall in either. Starting at the Prime Meridian and heading eastwards, the Equator passes through, Despite its name, however, its island of Annobón is 155 km south of the Equator, and the rest of the country lies to the north
26.
Ordovician
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The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya. Lapworth recognized that the fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods. It received international sanction in 1960, when it was adopted as a period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event considerably increased the diversity of life, fish, the worlds first true vertebrates, continued to evolve, and those with jaws may have first appeared late in the period. Life had yet to diversify on land, about 100 times as many meteorites struck the Earth during the Ordovician compared with today. The Ordovician Period began with a major extinction called the Cambrian–Ordovician extinction event and it lasted for about 42 million years and ended with the Ordovician–Silurian extinction event, about 443.8 Mya which wiped out 60% of marine genera. The dates given are recent radiometric dates and vary slightly from those found in other sources and this second period of the Paleozoic era created abundant fossils that became major petroleum and gas reservoirs. The boundary chosen for the beginning of both the Ordovician Period and the Tremadocian stage is highly significant and it correlates well with the occurrence of widespread graptolite, conodont, and trilobite species. The base of the Tremadocian allows scientists to relate these species not only to each other and this makes it easier to place many more species in time relative to the beginning of the Ordovician Period. A number of terms have been used to subdivide the Ordovician Period. In 2008, the ICS erected an international system of subdivisions. There exist Baltoscandic, British, Siberian, North American, Australian, the Ordovician Period in Britain was traditionally broken into Early, Middle and Late epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, the Floian corresponds to the lower Arenig, the Arenig continues until the early Darriwilian, subsuming the Dapingian. The Llanvirn occupies the rest of the Darriwilian, and terminates with it at the base of the Late Ordovician. The Sandbian represents the first half of the Caradoc, the Caradoc ends in the mid-Katian, during the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole, the small continent Avalonia separated from Gondwana and began to move north towards Baltica and Laurentia, opening the Rheic Ocean between Gondwana and Avalonia
27.
Avalonia
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Avalonia was a microcontinent in the Paleozoic era. Crustal fragments of this former microcontinent underlie south-west Great Britain, and it is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States. Avalonia is named for the Avalon Peninsula in Newfoundland, Avalonia developed as a volcanic arc on the northern margin of Gondwana. It eventually rifted off, becoming a drifting microcontinent, the Rheic Ocean formed behind it, and the Iapetus Ocean shrank in front. It collided with the continents Baltica, then Laurentia, and finally with Gondwana, when Pangea broke up, Avalonias remains were divided by the rift which became the Atlantic Ocean. The early development of Avalonia is believed to have been in volcanic arcs near a subduction zone on the margin of Gondwana, some material may have accreted from volcanic island arcs which formed further out in the ocean and later collided with Gondwana as a result of plate tectonic movements. The igneous activity had started by 730 million years ago and continued until around 570 million years ago, in the early Cambrian, the supercontinent Pannotia broke up and Avalonia drifted off northwards from Gondwana. This independent movement of Avalonia started from a latitude of about 60° South, the eastern end of Avalonia collided with Baltica, a continental plate occupying the latitudes from about 30°S to 55°S, as Baltica slowly rotated counterclockwise towards it. This happened at the end of the Ordovician and during the early Silurian, the result of this was the formation of Euramerica. At the completion of stage, the site of Britain was at 30°S. This collision is represented by the Caledonian folding or in North America as a phase in the Acadian orogeny. This was followed up by the arrival of Gondwana, the effects of these collisions are seen in Europe as the Variscan folding. In North America it shows as later phases of the Acadian orogeny and this was happening at around the Equator during the later Carboniferous, forming Pangaea with Avalonia near its centre but partially flooded by shallow sea. In the Jurassic, Pangaea split into Laurasia and Gondwana, with Avalonia as part of Laurasia, in the Cretaceous, Laurasia broke up into North America and Eurasia with Avalonia split between them. Iberia was later rotated away again as the African part of Gondwana strike-slipped past it and this last movement caused the Alpine orogeny including the raising of the Pyrenees during the Miocene and Pliocene. As a result of this, part of Avalonia is now to be found on side of the Straits of Gibraltar. The Avalonian part of Great Britain almost exactly coincides with England, part of the British-Belgian section formed an island in the Carboniferous, affecting the disposition of coalfields, this is known by names such as the London-Brabant Island. Its bulk had an effect on the structure between the Ardennes and the English Midlands by influencing the subsequent crustal folding resulting from the Variscan collision
28.
Newfoundland (island)
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Newfoundland is a large Canadian island off the east coast of the North American mainland, and the most populous part of the Canadian province of Newfoundland and Labrador. It has 29 percent of the land area. The island is separated from the Labrador Peninsula by the Strait of Belle Isle and it blocks the mouth of the Saint Lawrence River, creating the Gulf of Saint Lawrence, the worlds largest estuary. Newfoundlands nearest neighbour is the French overseas community of Saint-Pierre and Miquelon, with an area of 108,860 square kilometres, Newfoundland is the worlds 16th-largest island, Canadas fourth-largest island, and the largest Canadian island outside the North. The provincial capital, St. Johns, is located on the southeastern coast of the island, Cape Spear, just south of the capital, is the easternmost point of North America, excluding Greenland. It is common to consider all directly neighbouring islands such as New World, Twillingate, Fogo, by that classification, Newfoundland and its associated small islands have a total area of 111,390 square kilometres. Additionally 6. 1% claimed at least one parent of French ancestry, the islands total population as of the 2006 census was 479,105. Long settled by peoples of the Dorset culture, the island was visited by the Icelandic Viking Leif Eriksson in the 11th century. The next European visitors to Newfoundland were Portuguese, Basque, Spanish, French, the island was visited by the Genoese navigator John Cabot, working under contract to King Henry VII of England on his expedition from Bristol in 1497. In 1501, Portuguese explorers Gaspar Corte-Real and his brother Miguel Corte-Real charted part of the coast of Newfoundland in a attempt to find the Northwest Passage. Newfoundland is considered Britains oldest colony, at the time of English settlement, the Beothuk inhabited the island. While there is evidence of ancient indigenous peoples on the island. LAnse aux Meadows was a Norse settlement near the northernmost tip of Newfoundland, the site is considered the only undisputed evidence of Pre-Columbian contact between the Old and New Worlds, if the Norse-Inuit contact on Greenland is not counted. There is a second suspected Norse site in Point Rosee, the island is a likely location of Vinland, mentioned in the Viking Chronicles, although this has been disputed. The indigenous people on the island at the time of European settlement were the Beothuk, later immigrants developed a variety of dialects associated with settlement on the island, Newfoundland English, Newfoundland French. In the 19th century, it also had a dialect of Irish known as Newfoundland Irish, Scottish Gaelic was spoken on the island during the 19th and early 20th centuries, particularly in the Codroy Valley area, chiefly by settlers from Cape Breton Island, Nova Scotia. The Gaelic names reflected the association with fishing, in Scottish Gaelic, it was called Eilean a Trosg, or literally, similarly, the Irish Gaelic name Talamh an Éisc means Land of the Fish. The first inhabitants of Newfoundland were the Paleo-Eskimo, who have no link to other groups in Newfoundland history
29.
British Isles
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The British Isles are a group of islands off the north-western coast of continental Europe that consist of the islands of Great Britain, Ireland and over six thousand smaller isles. Situated in the North Atlantic, the islands have an area of approximately 315,159 km2. Two sovereign states are located on the islands, Ireland and the United Kingdom of Great Britain, the oldest rocks in the group are in the north west of Scotland, Ireland and North Wales and are 2,700 million years old. During the Silurian period the north-western regions collided with the south-east, the topography of the islands is modest in scale by global standards. Ben Nevis rises to an elevation of only 1,344 metres, and Lough Neagh, the climate is temperate marine, with mild winters and warm summers. The North Atlantic Drift brings significant moisture and raises temperatures 11 °C above the average for the latitude. This led to a landscape which was dominated by temperate rainforest. The region was re-inhabited after the last glacial period of Quaternary glaciation, Ireland, which became an island by 12,000 BC, was not inhabited until after 8000 BC. Great Britain became an island by 5600 BC, Hiberni, Pictish and Britons tribes, all speaking Insular Celtic, inhabited the islands at the beginning of the 1st millennium AD. Much of Brittonic-controlled Britain was conquered by the Roman Empire from AD43, the first Anglo-Saxons arrived as Roman power waned in the 5th century and eventually dominated the bulk of what is now England. Viking invasions began in the 9th century, followed by permanent settlements. Most of Ireland seceded from the United Kingdom after the Irish War of Independence, the term British Isles is controversial in Ireland, where there are objections to its usage due to the association of the word British with Ireland. The Government of Ireland does not recognise or use the term, as a result, Britain and Ireland is used as an alternative description, and Atlantic Archipelago has had limited use among a minority in academia, while British Isles is still commonly employed. Within them, they are sometimes referred to as these islands. The earliest known references to the islands as a group appeared in the writings of sea-farers from the ancient Greek colony of Massalia. The original records have been lost, however, later writings, e. g. Avienuss Ora maritima, in the 1st century BC, Diodorus Siculus has Prettanikē nēsos, the British Island, and Prettanoi, the Britons. Strabo used Βρεττανική, and Marcian of Heraclea, in his Periplus maris exteri, historians today, though not in absolute agreement, largely agree that these Greek and Latin names were probably drawn from native Celtic-language names for the archipelago. Along these lines, the inhabitants of the islands were called the Πρεττανοί, the shift from the P of Pretannia to the B of Britannia by the Romans occurred during the time of Julius Caesar
30.
Belgium
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Belgium, officially the Kingdom of Belgium, is a sovereign state in Western Europe bordered by France, the Netherlands, Germany, Luxembourg, and the North Sea. It is a small, densely populated country which covers an area of 30,528 square kilometres and has a population of about 11 million people. Additionally, there is a group of German-speakers who live in the East Cantons located around the High Fens area. Historically, Belgium, the Netherlands and Luxembourg were known as the Low Countries, the region was called Belgica in Latin, after the Roman province of Gallia Belgica. From the end of the Middle Ages until the 17th century, today, Belgium is a federal constitutional monarchy with a parliamentary system of governance. It is divided into three regions and three communities, that exist next to each other and its two largest regions are the Dutch-speaking region of Flanders in the north and the French-speaking southern region of Wallonia. The Brussels-Capital Region is a bilingual enclave within the Flemish Region. A German-speaking Community exists in eastern Wallonia, Belgiums linguistic diversity and related political conflicts are reflected in its political history and complex system of governance, made up of six different governments. Upon its independence, declared in 1830, Belgium participated in the Industrial Revolution and, during the course of the 20th century, possessed a number of colonies in Africa. This continuing antagonism has led to several far-reaching reforms, resulting in a transition from a unitary to a federal arrangement during the period from 1970 to 1993. Belgium is also a member of the Eurozone, NATO, OECD and WTO. Its capital, Brussels, hosts several of the EUs official seats as well as the headquarters of major international organizations such as NATO. Belgium is also a part of the Schengen Area, Belgium is a developed country, with an advanced high-income economy and is categorized as very high in the Human Development Index. A gradual immigration by Germanic Frankish tribes during the 5th century brought the area under the rule of the Merovingian kings, a gradual shift of power during the 8th century led the kingdom of the Franks to evolve into the Carolingian Empire. Many of these fiefdoms were united in the Burgundian Netherlands of the 14th and 15th centuries, the Eighty Years War divided the Low Countries into the northern United Provinces and the Southern Netherlands. The latter were ruled successively by the Spanish and the Austrian Habsburgs and this was the theatre of most Franco-Spanish and Franco-Austrian wars during the 17th and 18th centuries. The reunification of the Low Countries as the United Kingdom of the Netherlands occurred at the dissolution of the First French Empire in 1815, although the franchise was initially restricted, universal suffrage for men was introduced after the general strike of 1893 and for women in 1949. The main political parties of the 19th century were the Catholic Party, French was originally the single official language adopted by the nobility and the bourgeoisie
31.
France
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France, officially the French Republic, is a country with territory in western Europe and several overseas regions and territories. The European, or metropolitan, area of France extends from the Mediterranean Sea to the English Channel and the North Sea, Overseas France include French Guiana on the South American continent and several island territories in the Atlantic, Pacific and Indian oceans. France spans 643,801 square kilometres and had a population of almost 67 million people as of January 2017. It is a unitary republic with the capital in Paris. Other major urban centres include Marseille, Lyon, Lille, Nice, Toulouse, during the Iron Age, what is now metropolitan France was inhabited by the Gauls, a Celtic people. The area was annexed in 51 BC by Rome, which held Gaul until 486, France emerged as a major European power in the Late Middle Ages, with its victory in the Hundred Years War strengthening state-building and political centralisation. During the Renaissance, French culture flourished and a colonial empire was established. The 16th century was dominated by civil wars between Catholics and Protestants. France became Europes dominant cultural, political, and military power under Louis XIV, in the 19th century Napoleon took power and established the First French Empire, whose subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a succession of governments culminating with the establishment of the French Third Republic in 1870. Following liberation in 1944, a Fourth Republic was established and later dissolved in the course of the Algerian War, the Fifth Republic, led by Charles de Gaulle, was formed in 1958 and remains to this day. Algeria and nearly all the colonies became independent in the 1960s with minimal controversy and typically retained close economic. France has long been a centre of art, science. It hosts Europes fourth-largest number of cultural UNESCO World Heritage Sites and receives around 83 million foreign tourists annually, France is a developed country with the worlds sixth-largest economy by nominal GDP and ninth-largest by purchasing power parity. In terms of household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, France remains a great power in the world, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a member state of the European Union and the Eurozone. It is also a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, originally applied to the whole Frankish Empire, the name France comes from the Latin Francia, or country of the Franks
32.
Nova Scotia
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Nova Scotia is one of Canadas three Maritime provinces, and one of the four provinces which form Atlantic Canada. Nova Scotia is Canadas second-smallest province, with an area of 55,284 square kilometres, including Cape Breton, as of 2016, the population was 923,598. Nova Scotia is the second most-densely populated province in Canada with 17.4 inhabitants per square kilometre, Nova Scotia means New Scotland in Latin and is the recognized English language name for the province. In Scottish Gaelic, the province is called Alba Nuadh, which simply means New Scotland. Nova Scotia is Canadas second-smallest province in area after Prince Edward Island, the provinces mainland is the Nova Scotia peninsula surrounded by the Atlantic Ocean, including numerous bays and estuaries. Nowhere in Nova Scotia is more than 67 km from the ocean, Nova Scotia has many ancient fossil-bearing rock formations. These formations are rich on the Bay of Fundys shores. Blue Beach near Hantsport, Joggins Fossil Cliffs, on the Bay of Fundys shores, has yielded an abundance of Carboniferous age fossils, wassons Bluff, near the town of Parrsboro, has yielded both Triassic and Jurassic age fossils. Nova Scotia lies in the mid-temperate zone, since the province is almost surrounded by the sea, the climate is closer to maritime than to continental climate. The winter and summer temperature extremes of the climate are moderated by the ocean. However, winters are cold enough to be classified as continental – still being nearer the freezing point than inland areas to the west. The Nova Scotia climate is in ways similar to the central Baltic Sea coast in Northern Europe. This is in spite of Nova Scotia being some fifteen parallels south, areas not on the Atlantic coast experience warmer summers more typical of inland areas, and winter lows a little colder. The province includes regions of the Mikmaq nation of Mikmaki, the Mikmaq people inhabited Nova Scotia at the time the first European colonists arrived. In 1605, French colonists established the first permanent European settlement in the future Canada at Port Royal, the British conquest of Acadia took place in 1710. The Treaty of Utrecht in 1713 formally recognized this and returned Cape Breton Island to the French, present-day New Brunswick then still formed a part of the French colony of Acadia. The British changed the name of the capital from Port Royal to Annapolis Royal, in 1749, the capital of Nova Scotia moved from Annapolis Royal to the newly established Halifax. In 1755 the vast majority of the French population were removed in the Expulsion of the Acadians
33.
New England
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New England is a geographical region comprising six states of the northeast United States, Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and south, the Atlantic Ocean is to the east and southeast, and Long Island Sound is to the south. Its largest metropolitan area is Greater Boston, which also includes Worcester, Manchester, ten years later, more Puritans settled north of Plymouth Colony in Boston, thus forming Massachusetts Bay Colony. Over the next 126 years, people in the region fought in four French and Indian Wars, until the British and their Iroquois allies defeated the French and their Algonquin allies in North America. In 1692, the town of Salem, Massachusetts and surrounding areas experienced one of the most infamous cases of hysteria in the history of the Western Hemisphere. The Boston Tea Party was a protest to which Britain responded with a series of punitive laws stripping Massachusetts of self-government, the confrontation led to the first battles of the American Revolutionary War in 1775, and the expulsion of the British authorities from the region in spring 1776. Each state is subdivided into small incorporated municipalities known as towns. The only unincorporated areas in the region exist in the populated northern regions of Vermont, New Hampshire. The region is one of the U. S. Census Bureaus nine regional divisions, the earliest known inhabitants of New England were American Indians who spoke a variety of the Eastern Algonquian languages. Prominent tribes included the Abenaki, Mikmaq, Penobscot, Pequot, Mohegans, Narragansett Indians, Pocumtuck, prior to the arrival of Europeans, the Western Abenakis inhabited New Hampshire, New York, and Vermont, as well as parts of Quebec and western Maine. Their principal town was Norridgewock in present-day Maine, the Penobscot lived along the Penobscot River in Maine. The Narragansett and smaller tribes under Narragansett sovereignty lived in most of modern-day Rhode Island, west of Narragansett Bay, the Wampanoag occupied southeastern Massachusetts, Rhode Island, and the islands of Marthas Vineyard and Nantucket. The Pocumtucks lived in Western Massachusetts, and the Mohegan and Pequot tribes in the Connecticut region, the Connecticut River Valley includes parts of Vermont, New Hampshire, Massachusetts, and Connecticut, and linked different indigenous communities culturally, linguistically, and politically. As early as 1600, French, Dutch, and English traders began exploring the New World, trading metal, glass, on April 10,1606, King James I of England issued a charter for each of the Virginia Companies, London and Plymouth. These were privately funded ventures, intended to land for England, conduct trade. In 1620, Plymouth in present-day Massachusetts was settled by Pilgrims from the Mayflower, in 1616, English explorer John Smith named the region New England. As the first colonists arrived in Plymouth, they wrote and signed the Mayflower Compact, the Massachusetts Bay Colony came to dominate the area and was established by royal charter in 1629 with its major town and port of Boston established in 1630. Massachusetts Puritans began to settle in Connecticut as early as 1633, roger Williams was banished from Massachusetts for heresy, led a group south, and founded Providence Plantation in the area that became the Colony of Rhode Island and Providence Plantations in 1636
34.
Iberian Peninsula
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The Iberian Peninsula /aɪˈbɪəriən pəˈnɪnsjᵿlə/, also 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
35.
Euramerica
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Euramerica was a minor supercontinent created in the Devonian as the result of a collision between the Laurentian, Baltica, and Avalonia cratons,433 million years ago. In the Late Carboniferous, tropical rainforests lay over the equator of Euramerica, a major, abrupt change in vegetation occurred when the climate aridified. The forest fragmented and the lycopsids which dominated these wetlands thinned out, there was also a great loss of amphibian diversity and simultaneously the drier climate spurred the diversification of reptiles. Euramerica became a part of the major supercontinent Pangaea in the Permian, in the Jurassic, when Pangaea rifted into two continents, Gondwana and Laurasia, Euramerica was a part of Laurasia. In the Cretaceous, Laurasia split into the continents of North America, the Laurentian craton became a part of North America while Baltica became a part of Eurasia, and Avalonia was split between the two. Permian, Euramerica became a part of the supercontinent Pangaea, Jurassic, Pangaea rifted into Gondwana and Laurasia. Cretaceous, Laurasia split into the continents of North America and Eurasia, continental drift Eurasia Main Uralian Fault Palaeos Earth, Geography, Euramerica Paleogeographic globe of the Devonian Earth
36.
Appalachians
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The Appalachian Mountains, often called the Appalachians, are a system of mountains in eastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period and it once reached elevations similar to those of the Alps and the Rocky Mountains before naturally occurring erosion. The Appalachian chain is a barrier to east-west travel, as it forms a series of alternating ridgelines, definitions vary on the precise boundaries of the Appalachians. A common variant definition does not include the Adirondack Mountains, which belong to the Grenville Orogeny and have a different geological history from the rest of the Appalachians. The range covers parts of the islands of Saint Pierre and Miquelon, the system is divided into a series of ranges, with the individual mountains averaging around 3,000 ft. The highest of the group is Mount Mitchell in North Carolina at 6,684 feet, the term Appalachian refers to several different regions associated with the mountain range. Most broadly, it refers to the mountain range with its surrounding hills. The Ouachita Mountains in Arkansas and Oklahoma were originally part of the Appalachians as well, the name was soon altered by the Spanish to Apalachee and used as a name for the tribe and region spreading well inland to the north. Pánfilo de Narváezs expedition first entered Apalachee territory on June 15,1528, now spelled Appalachian, it is the fourth-oldest surviving European place-name in the US. After the de Soto expedition in 1540, Spanish cartographers began to apply the name of the tribe to the mountains themselves. The first cartographic appearance of Apalchen is on Diego Gutierrezs map of 1562, the name was not commonly used for the whole mountain range until the late 19th century. A competing and often more popular name was the Allegheny Mountains, Alleghenies, in the early 19th century, Washington Irving proposed renaming the United States either Appalachia or Alleghania. In U. S. dialects in the regions of the Appalachians. In northern parts of the range, it is pronounced /ˌæpəˈleɪtʃᵻnz/ or /ˌæpəˈleɪʃᵻnz/, the third syllable is like lay. There is often debate between the residents of the regions as to which pronunciation is the more correct one. Elsewhere, a commonly accepted pronunciation for the adjective Appalachian is /ˌæpəˈlætʃiən/, the whole system may be divided into three great sections, Northern, The northern section runs from the Canadian province of Newfoundland and Labrador to the Hudson River. The Monteregian Hills, which cross the Green Mountains in Quebec, are also unassociated with the Appalachians, Central, The central section goes from the Hudson Valley to the New River running through Virginia and West Virginia. Southern, The southern section runs from the New River onwards and it consists of the prolongation of the Blue Ridge, which is divided into the Western Blue Ridge Front and the Eastern Blue Ridge Front, the Ridge-and-Valley Appalachians, and the Cumberland Plateau
37.
Silurian
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The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago, to the beginning of the Devonian Period,419.2 Mya. As with other periods, the rock beds that define the periods start and end are well identified. The base of the Silurian is set at a major Ordovician-Silurian extinction event when 60% of marine species were wiped out, a significant evolutionary milestone during the Silurian was the diversification of jawed and bony fish. However, terrestrial life would not greatly diversify and affect the landscape until the Devonian, the Silurian system was first identified by British geologist Sir Roderick Impey Murchison, who was examining fossil-bearing sedimentary rock strata in south Wales in the early 1830s. He named the sequences for a Celtic tribe of Wales, the Silures, inspired by his friend Adam Sedgwick and this naming does not indicate any correlation between the occurrence of the Silurian rocks and the land inhabited by the Silures. As it was first identified, the Silurian series when traced farther afield quickly came to overlap Sedgwicks Cambrian sequence, however, charles Lapworth resolved the conflict by defining a new Ordovician system including the contested beds. An early alternative name for the Silurian was Gotlandian after the strata of the Baltic island of Gotland, the French geologist Joachim Barrande, building on Murchisons work, used the term Silurian in a more comprehensive sense than was justified by subsequent knowledge. He divided the Silurian rocks of Bohemia into eight stages and his interpretation was questioned in 1854 by Edward Forbes, and the later stages of Barrande, F, G and H, have since been shown to be Devonian. Despite these modifications in the groupings of the strata, it is recognized that Barrande established Bohemia as a classic ground for the study of the earliest fossils. The epoch is named for the town of Llandovery in Carmarthenshire, the Wenlock, which lasted from 433.4 ±1.5 to 427.4 ±2.8 mya, is subdivided into the Sheinwoodian and Homerian ages. It is named after Wenlock Edge in Shropshire, England, during the Wenlock, the oldest known tracheophytes of the genus Cooksonia, appear. The first terrestrial animals also appear in the Wenlock, represented by air-breathing millipedes from Scotland. The Ludlow, lasting from 427.4 ±1.5 to 423 ±2.8 mya, comprises the Gorstian stage, lasting until 425.6 million years ago, and it is named for the town of Ludlow in Shropshire, England. The Pridoli, lasting from 423 ±1.5 to 419.2 ±2.8 mya, is the final and it is named after one locality at the Homolka a Přídolí nature reserve near the Prague suburb Slivenec in the Czech Republic. Přídolí is the old name of a field area. The high sea levels of the Silurian and the flat land resulted in a number of island chains. The southern continents remained united during this period, the melting of icecaps and glaciers contributed to a rise in sea level, recognizable from the fact that Silurian sediments overlie eroded Ordovician sediments, forming an unconformity. The continents of Avalonia, Baltica, and Laurentia drifted together near the equator and this event is the Caledonian orogeny, a spate of mountain building that stretched from New York State through conjoined Europe and Greenland to Norway
38.
Southern Europe
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Southern Europe is the southern region of the European continent. Most definitions of Southern Europe, also known as Mediterranean Europe, include the countries of the Iberian peninsula, different methods can be used to define Southern Europe, including its political, economic, and cultural attributes. Southern Europe can also be defined by its natural features — its geography, climate, geographically, Southern Europe is the southern half of the landmass of Europe. This definition is relative, with no clear limits and those areas of Mediterranean climate present similar vegetations and landscapes throughout, including dry hills, small plains, pine forests and olive trees. Cooler climates can be found in parts of Southern European countries, for example within the mountain ranges of Spain. Additionally, the north coast of Spain experiences a wetter Atlantic climate, Southern Europes flora is that of the Mediterranean Region, one of the phytochoria recognized by Armen Takhtajan. The period known as classical antiquity began with the rise of the city-states of Ancient Greece, Greek influence reached its zenith under the expansive empire of Alexander the Great, spreading throughout Asia. The Roman Empire came to dominate the entire Mediterranean basin in a vast empire based on Roman law and it promoted trade, tolerance, and Greek culture. By 300 AD the Roman Empire was divided into the Western Roman Empire based in Rome, during the Middle Ages, the Eastern Roman Empire survived, though modern historians refer to this state as the Byzantine Empire. In Western Europe, Germanic peoples moved into positions of power in the remnants of the former Western Roman Empire and established kingdoms, the period known as the Crusades, a series of religiously motivated military expeditions originally intended to bring the Levant back into Christian rule, began. Several Crusader states were founded in the eastern Mediterranean, the Crusaders would have a profound impact on many parts of Europe. Their Sack of Constantinople in 1204 brought an end to the Byzantine Empire. Though it would later be re-established, it would never recover its former glory, the Crusaders would establish trade routes that would develop into the Silk Road and open the way for the merchant republics of Genoa and Venice to become major economic powers. The Reconquista, a movement, worked to reconquer Iberia for Christendom. The Late Middle Ages represented a period of upheaval in Europe, the epidemic known as the Black Death and an associated famine caused demographic catastrophe in Europe as the population plummeted. Dynastic struggles and wars of conquest kept many of the states of Europe at war for much of the period, in the Balkans, the Ottoman Empire, a Turkish state originating in Anatolia, encroached steadily on former Byzantine lands, culminating in the Fall of Constantinople in 1453. An unprecedented series of wars and political revolutions took place around Europe. Observers at the time, and many historians since, have argued that wars caused the revolutions, galileo Galilei, invented the telescope and the thermometer which allowed him to observe and describe the solar system
39.
Devonian
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The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian,419.2 million years ago, to the beginning of the Carboniferous,358.9 Mya. It is named after Devon, England, where rocks from this period were first studied, the first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents, by the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established, Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fish. The first ray-finned and lobe-finned bony fish appeared, while the placodermi began dominating almost every aquatic environment. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their strong pectoral, in the oceans, primitive sharks became more numerous than in the Silurian and Late Ordovician. The first ammonites, species of molluscs, appeared, trilobites, the mollusk-like brachiopods and the great coral reefs, were still common. The Late Devonian extinction which started about 375 million years ago severely affected marine life, killing off all placodermi, and all trilobites, save for a few species of the order Proetida. The palaeogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, while the rock beds that define the start and end of the Devonian period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, the Devonian extends from the end of the Silurian 419.2 Mya, another common term is Age of the Fishes, referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian, Breconian and Farlovian stages, in the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common. The Devonian Period is formally broken into Early, Middle and Late subdivisions, the rocks corresponding to those epochs are referred to as belonging to the Lower, Middle and Upper parts of the Devonian System. Early Devonian The Early Devonian lasted from 419.2 ±2.8 to 393.3 ±2.5 and began with the Lochkovian stage, which lasted until the Pragian. It spanned from 410.8 ±2.8 to 407.6 ±2.5, and was followed by the Emsian, which lasted until the Middle Devonian began,393. 3±2.7 million years ago. Middle Devonian The Middle Devonian comprised two subdivisions, first the Eifelian, which gave way to the Givetian 387. 7±2.7 million years ago. Late Devonian Finally, the Late Devonian started with the Frasnian,382.7 ±2.8 to 372.2 ±2.5, during which the first forests took shape on land. The first tetrapods appeared in the record in the ensuing Famennian subdivision. This lasted until the end of the Devonian,358. 9±2.5 million years ago, the Devonian was a relatively warm period, and probably lacked any glaciers
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Island arc
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An island arc is a type of archipelago, often composed of a chain of volcanoes, with arc-shaped alignment, situated parallel and close to a boundary between two converging tectonic plates. Most of these island arcs are formed as one oceanic plate subducts another one and. For example, large parts of the Andes/Central American/Canadian mountain chain may be known as a volcanic arc, on the other hand, the Aegean or Hellenic arc in the Mediterranean area, composed of numerous islands such as Crete, is an island arc, but is not volcanic. Parallel to it is the South Aegean Volcanic Arc, which is the island arc of the same tectonic system. There is some debate about the usefulness of the distinction between island arcs and volcanic arcs, the term volcanic island arc is merely a sub-classification of island arc. Island arcs are tectonically created arc-shaped mountain belts that are partly below sea level, essentially, they represent a specific geographic-topographic situation in which a mountain belt is partly submerged in ocean. Many of these are composed of volcanoes, and can thus be classified as volcanic island arcs. This process, called flux melting, generates low-density calc-alkaline magma that rises to intrude. The resulting volcano chain has the shape of an arc parallel to the convergent plate boundary, on the subducting side of the island arc is a deep and narrow oceanic trench, which is the trace at the Earth’s surface of the boundary between the downgoing and overriding plates. This trench is created by the pull of the relatively dense subducting plate pulling the leading edge of the plate downward. Multiple earthquakes occur along this boundary with the seismic hypocenters located at increasing depth under the island arc. Ocean basins that are being reduced by subduction are called remnant oceans as they will slowly be shrunken out of existence and this process has happened repeatedly in the geological history of the Earth. Insular Islands Intermontane Islands Back-arc basin High island Volcanic arc
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North China Craton
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The North China Craton is one of the smaller continental cratons of Earth. It covers a area of around 1. The North China Craton is composed of several blocks that have been heavily tilted and folded over time as a result of collisions with other continental land masses. The main blocks include the Eastern Block, the Western Block, the Central Orogenic Belt runs from western Liaoning through Beijing municipality to western Henan and contains chiefly igneous rocks of Paleoproterozoic age. The Western Block extends west from this region through Shanxi, Shaanxi, Inner Mongolia, in the Changbai Mountains and Shandong there has been extensive volcanism in the Tertiary. The crustal thinning of the Eastern Block is believed to be due to heat flow within the plates surrounding the North China Craton. Prior to the Triassic, the North China Craton was an independent continent surrounded by oceans, the Eastern Block of the North China Craton consists mainly of the densely settled and very fertile North China Plain, one of the most densely populated rural regions in the world. Annual rainfall in the part of the North China Plain averages around 1,150 millimetres. Temperatures vary widely, but summer is hot with the average July maximum usually around 31 °C with high humidity. January temperatures range from about 3 °C in the south to −10 °C north of Beijing. In complete contrast, the Western Block is a dry, elevated plateau averaging over 1,000 metres in elevation and having a dry, annual rainfall is typically only around 300–400 millimetres and winter temperatures are often as low as −20 °C, whereas summers can be blistering. Because of the accumulations of loess from Himalayan glaciation, the soils are very fertile when irrigated. Sheep are grazed in large numbers away from the rivers, the Central Orogenic Belt is mainly rocky mountains up to 2,360 metres in elevation. Because of the cold and erosion risk, most of this mountainous land is not cultivated. South China Intraplate Tectonics, North China and Other Regions Greater North China Initiative
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South China (continent)
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South China had been part of many past supercontinents, including Rodinia, Pannotia, Gondwana, Pangaea, Laurasia, and Eurasia. About a billion years ago, the supercontinent, Rodinia formed, South China was part of the supercontinent. South China was bordered by Mirovia Ocean to the north, Siberia to the east, Australia to the west,750 million years ago, Rodinia rifted and South China became an isolated continent. A hundred million years later, these pieces of continent assembled back together to create the supercontinent of Pannotia. South China collided with North China and Eastern Gondwana, when Pannotia disintegrated 550 million years ago, South China became part of and remained with Eastern Gondwana for millions of years. Late in the Silurian, South China, rifted away from Gondwana and moved across the ancient, a new ocean was forming in its southern end, Paleo-Tethys Ocean. By the Late Carboniferous, while North China collided with Siberia and Kazakhstania, completely closing the Proto-Tethys, for much of the Permian Period, South China remained in the tropical latitudes. And also, while most of the giant lycopods of the Carboniferous disappeared, giant lycopods remained in South China, Cimmeria, a microcontinent that consisted of todays Tibet, Iran, Turkey, and parts of Southeast Asia rifted away from Gondwana, and was heading towards Laurasia. Paleo-Tethys Ocean started to shrink, while the new Tethys Ocean expanded, in the Middle Triassic, the eastern portion of Cimmeria collided with South China, and together drew northwards, towards Laurasia. In the Late Triassic Epoch, South China collided with North China, North China and South China had been together since their collision in the Jurassic. Much of South China became a mountain range because of Indias collision with Cimmerias southern coastline
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