The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 Mya. It is the last period of the Mesozoic Era, the Cretaceous Period is usually abbreviated K, for its German translation Kreide. The Cretaceous was a period with a warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles and rudists, during this time, new groups of mammals and birds, as well as flowering plants, appeared. The Cretaceous ended with a mass extinction, the Cretaceous–Paleogene extinction event, in which many groups, including non-avian dinosaurs, pterosaurs. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary, the name Cretaceous was derived from Latin creta, meaning chalk. The Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series, in older literature the Cretaceous is sometimes divided into three series, Neocomian and Senonian.
A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide, in many parts of the world, alternative local subdivisions are still in use. As with other geologic periods, the rock beds of the Cretaceous are well identified. No great extinction or burst of diversity separates the Cretaceous from the Jurassic and this layer has been dated at 66.043 Ma. A140 Ma age for the Jurassic-Cretaceous boundary instead of the usually accepted 145 Ma was proposed in 2014 based on a study of Vaca Muerta Formation in Neuquén Basin. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a first step toward formally changing the age in the International Union of Geological Sciences, due to the high sea level there was extensive space for such sedimentation. Because of the young age and great thickness of the system. Chalk is a type characteristic for the Cretaceous. It consists of coccoliths, microscopically small calcite skeletons of coccolithophores, the group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea.
Chalk is not easily consolidated and the Chalk Group still consists of sediments in many places. The group has other limestones and arenites, among the fossils it contains are sea urchins, belemnites and sea reptiles such as Mosasaurus. In southern Europe, the Cretaceous is usually a marine system consisting of competent limestone beds or incompetent marls
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, Silurian, 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 and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earths history, known as the Cambrian explosion, arthropods, anapsids, synapsids 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, 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, Ordovician, Devonian, 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, were trilobites, 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
The Rhodopes are a mountain range in Southeastern Europe, with over 83% of its area in southern Bulgaria and the remainder in Greece. Its highest peak, Golyam Perelik, is the seventh highest Bulgarian mountain, the mountain range gives its name to the terrestrial ecoregion Rodope montane mixed forests that belongs in the Temperate broadleaf and mixed forests Biome and the Palearctic ecozone. The region is notable for its karst areas with their deep river gorges, large caves and specific sculptured forms. A significant part of Bulgarias hydropower resources is located in the areas of the range. There are a number of hydro-cascades and dams used for electricity production, irrigation, in Greece there are the HPPs of Thisavros and Platanovrysi. The name of the Rhodope mountains has a Thracian provenance, rhod-ope is interpreted as the first name of a river, meaning rusty/reddish river, where Rhod- has the same Indo-European root as the Bulgarian руда, ръжда, риж, Latin rufus and German rot. In Greek mythology, Queen Rhodope of Thrace offended the gods, the wife of King Haemus of Thrace, the mountains are associated with the mythic figure of Orpheus.
In geomorphological terms, the Rhodopes are part of the Rilo-Rhodope massif, the Rhodopes are spread over 14,735 square kilometers, of which 12,233 square kilometers are on Bulgarian territory. They have the greatest extent of any mountain range in Bulgaria. The mountains are about 240 kilometers long and about 100 to 120 kilometres wide, to the north the mountain slopes descend steeply towards the Upper Thracian Plain. To the west, the Rhodopes reach the Avram saddle, Yundola, to the south and east they extend over the border with Greece. The Rhodopes are a system of ridges and deep river valleys. Fifteen reserves have established in the region, some of which are under UNESCO protection. The location of the Rhodopes in the part of the Balkan Peninsula determines the climate in the region to a great extent. It is influenced both by the air coming from the north and by the warmer breeze from the Mediterranean. The average annual temperature in the Eastern Rhodopes is 13 °C, the precipitation is in December.
In the Western Rhodopes, the temperature varies from 5 to 9 °C, the mild climate, combined with some other factors, works in favour of the development of recreation and tourist activities. The Pamporovo resort, where the microclimate permits a heavy snow cover to be preserved for a time, is an excellent example
The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain. For the most part, the main crest forms a divide between France and Spain, with the microstate of Andorra sandwiched in between. The Crown of Aragon and the Kingdom of Navarre have historically extended on both sides of the range, with smaller northern portions now in France and larger southern parts now in Spain. The demonym for the noun Pyrenees in English is Pyrenean, in Greek mythology, Pyrene is a princess who gave her name to the Pyrenees. The Greek historian Herodotus says Pyrene is the name of a town in Celtic Europe, characteristically drunk and lustful, violates the sacred code of hospitality and rapes his hosts daughter. Pyrene gives birth to a serpent and runs away to the woods, she pours out her story to the trees, attracting the attention of wild beasts who tear her to pieces. After his victory over Geryon, Hercules passes through the kingdom of Bebryx again, and all the rock-cliffs and wild-beast haunts echo back Pyrene.
… The mountains hold on to the name through the ages. Pliny the Elder connects the story of Hercules and Pyrene to Lusitania, the Spanish Pyrenees are part of the following provinces, from east to west, Barcelona, Huesca and Gipuzkoa. The French Pyrenees are part of the following départements, from east to west, Pyrénées-Orientales, Ariège, Haute-Garonne, Hautes-Pyrénées, the independent principality of Andorra is sandwiched in the eastern portion of the mountain range between the Spanish Pyrenees and French Pyrenees. Physiographically, the Pyrenees may be divided into three sections, the Atlantic, the Central, and the Eastern Pyrenees, they form a distinct physiographic province of the larger Alpine System division. In the Western Pyrenees, from the Basque mountains near the Bay of Biscay of the Atlantic Ocean, at the eastern end on the southern side lies a distinct area known as the Sub-Pyrenees. On the French side the slopes of the range descend abruptly. The Pyrenees are older than the Alps, their sediments were first deposited in coastal basins during the Paleozoic and Mesozoic eras, the intense pressure and uplifting of the Earths crust first affected the eastern part and moved progressively to the entire chain, culminating in the Eocene Epoch.
The eastern part of the Pyrenees consists largely of granite and gneissose rocks, the massive and unworn character of the chain comes from its abundance of granite, which is particularly resistant to erosion, as well as weak glacial development. Low passes are lacking, and the roads and the railroads between France and Spain run only in the lowlands at the western and eastern ends of the Pyrenees. A notable visual feature of mountain range is La Brèche de Roland, a gap in the ridge line. Coal deposits capable of being profitably worked are situated chiefly on the Spanish slopes, the open pit of Trimoun close to the commune of Luzenac is one of the greatest sources of talc in Europe
The Zagros Mountains form the largest mountain range in Iran and southeastern Turkey. This mountain range has a length of 1,500 km. The highest point in the Zagros Mountains is Dena, the Zagros fold and thrust belt was formed by collision of two tectonic plates, the Eurasian Plate and the Arabian Plate. This collision primarily happened during the Miocene and folded the rocks that had been deposited from the Carboniferous to the Miocene in the geosyncline in front of the Iranian Plate. The process of collision continues to the present and as the Arabian Plate is being pushed against the Eurasian Plate, the Zagros Mountains, a relatively dense GPS network which covered the Iranian Zagros proves a high rate of deformation within the Zagros. The GPS results show that the current rate of shortening in the southeast Zagros is ~10 mm/yr, the north-south Kazerun strike-slip fault divides the Zagros into two distinct zones of deformation. The GPS results show different shortening directions along the belt, normal shortening in the southeast, the sedimentary cover in the SE Zagros is deforming above a layer of rock salt whereas in the NW Zagros the salt layer is missing or is very thin.
This different basal friction is partly responsible for the different topographies on either side of the Kazerun fault. Higher topography and narrower zone of deformation in the NW Zagros is observed whereas in the SE, deformation was spread more, stresses induced in the Earths crust by the collision caused extensive folding of the preexisting layered sedimentary rocks. Subsequent erosion removed softer rocks, such as mudstone and siltstone while leaving harder rocks, such as limestone and this differential erosion formed the linear ridges of the Zagros Mountains. The depositional environment and tectonic history of the rocks were conducive to the formation and trapping of petroleum, salt domes and salt glaciers are a common feature of the Zagros Mountains. Salt domes are an important target for exploration, as the impermeable salt frequently traps petroleum beneath other rock layers. The Zagros Mountains have a totally sedimentary origin and are primarily of limestone. In the Elevated Zagros or the Higher Zagros, the Paleozoic rocks could be found mainly in the upper and higher sections of the peaks of the Zagros Mountains along the Zagros main fault.
On the both sides of this fault, there are Mesozoic rocks, a combination of Triassic and Jurassic rocks that are surrounded by Cretaceous rocks on the both sides. The Folded Zagros is formed mainly of Tertiary rocks, with the Paleogene rocks south of the Cretaceous rocks, the mountains are divided into many parallel sub-ranges, and orogenically have the same age as the Alps. Irans main oilfields lie in the central foothills of the Zagros mountain range. The southern ranges of the Fars Province have somewhat lower summits and they contain some limestone rocks showing abundant marine fossils
The Cantabrian Mountains or Cantabrian Range are one of the main systems of mountain ranges in Spain. They stretch for over 300 km across northern Spain, from the limit of the Pyrenees to the Galician Massif in Galicia. Their easternmost end meets the Sistema Ibérico and these mountains are a distinct physiographic province of the larger Alpine System physiographic division. The Cantabrian Mountains offer a range of trails for hiking. Skiing is possible in the ski resorts of Alto Campoo, Valgrande-Pajares, the Cantabrian Mountains stretch east-west, nearly parallel to the sea, as far as the pass of Leitariegos, extending south between León and Galicia. The ranges western boundary is marked by the valley of the river Miño, by the lower Sil, which flows into the Miño, and by the Cabrera River, Cantabrian mountains reach its south-western limit in Portugal. In some parts the coastal range rises sheer above the sea, the descent from the southern range to the high plateaux of Castile is more gradual, and several large rivers, notably the Ebro, rise here and flow to the south or west.
The breadth of the Cantabrian chain, with all its ramifications, increases from about 60 mi, many peaks are over 6000 ft high, but the greatest altitudes are attained in the central ridges on the borders of León, Asturias and Cantabria. A conspicuous feature of the chain, as of the adjacent tableland, is the number of its parameras, the Cantabrian Mountains make a sharp divide between Green Spain to the north, and the dry central plateau. The north facing slopes receive heavy rainfall from the Bay of Biscay. The Cantabrian Range has three distinct sections from west to east, The Asturian Massif and its foothills. Geologically it is a prolongation of the Galician Massif with Paleozoic folds. It is cut by deep east-west oriented canyons such as the Cares River valley, highest point Torre de Cerredo 2,648 m. They are composed of Carboniferous limestone and marl, the Paramo de Masa and La Lora grasslands are located in the south crossed by the Rudrón Valley. Other animals associated with the range include the Iberian wolf and the rebeco, some of the sites are included in the European Unions Natura 2000 network and Special Protection Areas for the Conservation of Wild Birds
The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. This Era is 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 and Cretaceous, which are further subdivided into a number of epochs. The Mesozoic was a time of significant tectonic 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, 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 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 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 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
The Carpathian Mountains or Carpathians are a mountain range system forming an arc roughly 1,500 km long across Central and Eastern Europe, making them the second-longest mountain range in Europe. The Carpathians and their foothills have many thermal and mineral waters, the Carpathians consist of a chain of mountain ranges that stretch in an arc from the Czech Republic in the northwest through Slovakia, Poland and Ukraine to Romania and Serbia. The highest range within the Carpathians is the Tatras, on the border of Slovakia and Poland, the second-highest range is the Southern Carpathians in Romania, where the highest peaks exceed 2,500 m. The divisions of the Carpathians are usually in three sections, Western Carpathians — Czech Republic and Slovakia. Eastern Carpathians — southeastern Poland, eastern Slovakia, Romania, the term Outer Carpathians is frequently used to describe the northern rim of the Western and Eastern Carpathians. The most important cities in or near the Carpathians are, Bratislava and Košice in Slovakia, Kraków in Poland, Cluj-Napoca and Braşov in Romania, and Uzhhorod in Ukraine.
In modern times, the range is called Karpaty in Czech, Slovak and Карпати in Ukrainian, Carpați in Romanian, Karpaten in German, Kárpátok in Hungarian and Karpati or Карпати in Serbian. Although the toponym was recorded already by Ptolemy in the 2nd century CE, for instance, Havasok was its medieval Hungarian name and Romanian chronicles referred to it as Hungarian Mountains. The archaic Polish word karpa meant rugged irregularities, underwater obstacles/rocks, the more common word skarpa means a sharp cliff or other vertical terrain. In late Roman documents, the Eastern Carpathian Mountains were referred to as Montes Sarmatici, the Western Carpathians were called Carpates, a name that is first recorded in Ptolemys Geographia. In the Scandinavian Hervarar saga, which relates ancient Germanic legends about battles between Goths and Huns, the name Karpates appears in the predictable Germanic form as Harvaða fjöllum, inter Alpes Huniae et Oceanum est Polonia by Gervase of Tilbury, has described in his Otia Imperialia in 1211.
Thirteenth- to fifteenth-century Hungarian documents named the mountains Thorchal, Tarczal or less frequently Montes Nivium, the northwestern Carpathians begin in Slovakia and southern Poland. They surround Transcarpathia and Transylvania in a semicircle, sweeping towards the southeast. The total length of the Carpathians is over 1,500 km, the highest altitudes of the Carpathians occur where they are widest. The Carpathians cover an area of 190,000 km2 and, after the Alps, although commonly referred to as a mountain chain, the Carpathians do not actually form an uninterrupted chain of mountains. Rather, they consist of several orographically and geologically distinctive groups, the Carpathians at their highest altitude are only as high as the middle region of the Alps, with which they share a common appearance and flora. The Carpathians are separated from the Alps by the Danube, the two ranges meet at only one point, the Leitha Mountains at Bratislava. The river separates them from the Balkan Mountains at Orşova in Romania, the valley of the March and Oder separates the Carpathians from the Silesian and Moravian chains, which belong to the middle wing of the great Central Mountain System of Europe
The Armenian Highlands is the central-most and highest of three land-locked plateaus. that together form the northern sector of the Middle East. To its west is the Anatolian plateau which rises slowly from the lowland coast of the Aegean Sea, to its southeast is the Iranian plateau, where the elevation drops rapidly by about 600 metres to 1,500 metres above sea level. The Caucasus extends to the northeast of the Armenian Highlands, to the southwest of the Armenian Highlands is Upper Mesopotamia. During the Middle Ages, Turkmens settled in numbers in the Armenian Highlands. The region was mainly inhabited by Armenians, and minorities of Georgians and Assyrians. The Christian population of the Western half of the region was exterminated during the Armenian Genocide of 1915, the region is mainly inhabited by Armenians, Azerbaijanis and Georgians. Their total area is about 400,000 km2, the Armenian Highlands have been the scene of great volcanic activity. The Armenian Highlands are rich in water resources, most of the Armenian Highlands is in eastern Turkey, and includes northwestern Iran, all of Armenia, southern Georgia, and western Azerbaijan.
Its northeastern parts are known as Lesser Caucasus, which is a center of Armenian culture. From 4000 to 1000 BC, tools and trinkets of copper and iron were produced in this region. It is believed to be one of the possible locations of the Garden of Eden. The Armenian Plateau has been called the epicenter of the Iron Age, in the Early Iron Age, the Kingdom of Van controlled much of the region, until it was overthrown by the Medes and Orontid dynasty. In Gilgamesh, the land of Aratta is placed in a space that could be describing the Armenian plateau. From the early era and on, the region came directly under Safavid Iranian rule. The apricot was known by the Romans as the prunus armenicus and was brought to Europe from the Armenian plateau, history of Armenia Geography of Armenia Hewsen, Robert H. Armenia, A Historical Atlas
It forms the western section of the Hindu Kush Himalayan Region. It divides the valley of the Amu Darya to the north from the Indus River valley to the south, the eastern end of the Hindu Kush in the north merges with the Karakoram Range. Towards its southern end, it connects with the Spin Ghar Range near the Kabul River, the Hindu Kush range were a historically significant center of Buddhism with sites such as the Bamiyan Buddhas. The range and communities settled in it hosted ancient monasteries, important trade networks, Buddhism declined, after Islam arrived in the region. The Hindu Kush range has been the passageway during the invasions of the Indian subcontinent and this collision created the Himalayas, including the Hindu Kush. The Hindu Kush range remains geologically active and are still rising, the origins of the name Hindu Kush are uncertain, with multiple theories being propounded by different scholars and writers. The Persian-English dictionary indicates that the word koš is derived from the verb, the word and suffix -kush means kill, death.
In his travel memoirs about India, the 14th century Moroccan traveller Muhammad Ibn Battuta mentioned crossing into India via the passes of the Hindu Kush. In his Rihla, he mentions these mountains and the history of the range in slave trading, to Arab geographers, states Allan, Hindu Kush was the frontier boundary where Hindustan started. According to McColl, yet another possibility is that the name may be from the ancient Avestan language, the mountain range was called Paropamisadae by Hellenic Greeks in the late first millennium BC. Some scholars remove the space, and refer to Hindu Kush as Hindukush, the mountains have historical significance in the Indian subcontinent and China. The Hindu Kush range was a center of Buddhism with sites such as the Bamiyan Buddhas. It has been the passageway during the invasions of the Indian subcontinent, a region where the Taliban and Al Qaeda grew, Buddhism was widespread in the ancient Hindu Kush region. Ancient artwork of Buddhism include the giant rock carved statues called the Bamiyan Buddha and these statues were blown up by the Taliban Islamists.
One of the early Buddhist schools, the Mahāsāṃghika-Lokottaravāda, was prominent in the area of Bamiyan, the Chinese Buddhist monk Xuanzang visited a Lokottaravāda monastery in the 7th century CE, at Bamiyan, Afghanistan. Some manuscripts are in the Gāndhārī language and Kharoṣṭhī script, while others are in Sanskrit, after the Islamic conquest of the region and Islam becoming the state religion, Buddhism vanished and locals became Muslims. The significance of the Hindu Kush mountain range has been recorded since the time of Darius I of Persia, alexander the Great entered the Indian subcontinent through the Hindu Kush as his army moved past Bactria into the Afghan valley in the spring of 329 BCE. He moved towards the Indus valley river region in 327 BCE, the region became a part of the Kushan Empire in centuries around the start of the common era
The Caucasus Mountains are a mountain system in Eurasia between the Black Sea and the Caspian Sea in the Caucasus region. The Caucasus Mountains include the Greater Caucasus in the north and Lesser Caucasus in the south, the Greater Caucasus runs west-northwest to east-southeast, from the Caucasian Natural Reserve in the vicinity of Sochi on the northeastern shore of the Black Sea nearly to Baku on the Caspian Sea. The Lesser Caucasus runs parallel to the Greater about 100 km south, the Greater and Lesser Caucasus ranges are connected by the Likhi Range, and to the west and east of the Likhi Range lie the Colchis Plain and the Kur-Araz Lowland. The Meskheti Range is a part of the Lesser Caucasus system, in the southeast the Aras River separates the Lesser Caucasus from the Talysh Mountains which straddle the border of southeastern Azerbaijan and Iran. The highest peak in the Caucasus range is Mount Elbrus in the Greater Caucasus, Mountains near Sochi hosted part of the 2014 Winter Olympics.
Geologically, the Caucasus Mountains belong to a system that extends from southeastern Europe into Asia, the Greater Caucasus Mountains are mainly composed of Cretaceous and Jurassic rocks with the Paleozoic and Precambrian rocks in the higher regions. Some volcanic formations are found throughout the range, on the other hand, the Lesser Caucasus Mountains are formed predominantly of the Paleogene rocks with a much smaller portion of the Jurassic and Cretaceous rocks. The Caucasus Mountains formed largely as the result of a plate collision between the Arabian plate moving northwards with respect to the Eurasian plate. As this happened, the rocks that had been deposited in this basin from the Jurassic to the Miocene were folded to form the Greater Caucasus Mountains. This collision caused the uplift and the Cenozoic volcanic activity in the Lesser Caucasus Mountains, the entire region is regularly subjected to strong earthquakes from this activity. While the Greater Caucasus Mountains have a mainly folded sedimentary structure, the Javakheti Volcanic Plateau in Georgia and the surrounding volcanic ranges which extend well into central Armenia are some of the youngest features of the region.
The Kazbek is no active, but the Elbrus erupted in postglacial times. Contemporary seismic activity is a prominent feature of the region, reflecting active faulting, clusters of seismicity occur in Dagestan and in northern Armenia. Many devastating earthquakes have been documented in historical times, including the Spitak earthquake in December 1988 which destroyed the Gyumri-Vanadzor region of Armenia, europes highest mountain is Mount Elbrus 5,642 m in the Caucasus Mountains. Elbrus is 832 m higher than Mont Blanc, the highest peak in the Alps at 4,810 m, the Caucasus Mountains are defined as the continental divide between Asia and Europe for the region between the Black and Caspian Seas. The table below lists some of the highest peaks of the Caucasus, with the exception of Shkhara, the heights are taken from Soviet 1,50,000 mapping. There are higher and more prominent, but nameless, peaks than some of the peaks included below, the climate of the Caucasus varies both vertically and horizontally.
Temperature generally decreases as elevation rises, average annual temperature in Sukhumi, Abkhazia at sea level is 15 °C while on the slopes of Mt. Kazbek at an elevation of 3,700 metres, average annual temperature falls to−6.1 °C
The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Westerham Heights, at the edge of the North Downs, near Bromley. The North Downs lie within two Areas of Outstanding Natural Beauty, the Surrey Hills and the Kent Downs, the North Downs Way National Trail runs along the North Downs from Farnham to Dover. Downs is from Old English dun meaning, amongst other things, the word acquired the sense of elevated rolling grassland around the fourteenth century. These hills are prefixed north to distinguish them from the morphologically similar range of hills - the South Downs - which run parallel to them. The narrow spine of the Hogs Back between Farnham and Guildford forms the western extremity of the North Downs, whilst the cliffs between Folkestone and Deal terminate the ridge in the east, there are two distinct aspects, the steep south-facing escarpment and the gentle north-facing dip slope. The southern boundary is defined by the foot of the escarpment which gives way to the flat, the northern boundary is less apparent but occurs where the chalk submerges below the more recent Paleocene deposits.
The Downs are highest near the Kent-Surrey border, often reaching heights in excess of 200 m above sea level at the crest of the escarpment, the highest point is Botley Hill in Surrey at 269 metres. The County top of Kent at Betsoms Hill, with a height of 251 metres is located nearby, east of the Medway Valley the Downs become broader and flatter, extending as far as the Isle of Thanet. The ridge is intersected by the valleys of a series of rivers and these drain much of the Weald to the south, the western ones are tributaries of the Thames, they carve steep valleys through the chalk and provide natural corridor routes. Except for the valleys and wind gaps, the crest of the escarpment is almost continuous along its length. The dip slope is dissected by small dry valleys, and in the broad eastern part in Kent. Leith Hill is sometimes referred to as part of the North Downs but is located on the parallel Greensand Ridge. The Chalk Group, composed almost entirely of chalk, a kind of soft fine-grained limestone.
It is formed of three parts, the Upper Chalk, which has many flints, the Middle Chalk, with flints. The chalk is most commonly exposed on slopes or as cliffs, the buried upper surface of the chalk beneath the acidic strata is often eroded into pipes and pinnacles, sometimes visible in road cuttings and quarries. The Upper Greensand Formation, a whitish, limy sandstone, often used for building, the Upper Greensand of the North Downs is a thin bed of one or two metres thickness, and it is rarely visible at the surface. The Upper Greensand marks the edge of the Downs, being underlain by