The Definition of the mountain

The Definition of the mountain

The mountain is what higher of the Earth's surface and elongate higher exceeded the hill. And geographically is Relief more elevated than him and exceeded taller relative of 600 m, and there is a view say 300 m, and the peak area smaller than the area of ​​the base, and the bottom severe declines, Tkhadddh valleys and indivisible. And the mountain top of the hill, and the hill top of the hill, and the hill higher than the mound are the lowest ones. The so-called mountain Tala, hill and mountain has and Bedouin transcended.

Types of mountains

Mountains of the world are organized into three types: individual mountains and mountain ranges, and mountain belts.

Abound mountains individual in volcanic regions, and in the Bekaa exposed to erosion, and the mountain ranges are bars long stretch tens and hundreds of kilometers, while composed belts mountain chains connected and stretching thousands of kilometers, the largest belt alpine Alheimalaúa, belt Andean, belt chains Central Asia, The margins Pacific belt.

And tend to the mountains chains and belts distributed on the margins of the continents and their coastlines, in the Arab world is the most important mountains on the shores of the Mediterranean, such as the mountains of the Levant and the Atlas in the Maghreb and on both sides of the Red Sea and Gulf of Aden, then the Oman Mountains, and in the Australian stretch Australian Alps coasts East In America South West coasts, and in North America on the western and eastern coasts, and in Asia Minor on the southern and northern coasts. Not about the Alps and Alberanh in Europe from the seas a lot, but keep pace with the Italian Coast and the Balkans. And there is an important mountain ranges within continents especially in أوراسية like the Carpathian Mountains and the Urals and the Caucasus and Central Asia and the chains on the Tibetan Plateau and its extension to South East Asia, and in Africa there are mountain blocks in the heart of the desert, such as stone and Tibesti Mountains.

Progeny or genesis

Continents contain two types of structural units, the first block of ancient rocks, dating back to the pre-Cambrian, consisting of rocks Asthalah and wounds sometimes associated with sedimentary rocks, is the initial nucleus of the continents and continental shields known continental shields. It has been observed to contain armor continental structures lava Alosaúdah pillow lavas associated with the 'deposits' flint chemical origin, which indicates that the primary rocks of the continents formed from volcanic eruptions under the sea.

The second type, consists of sedimentary formations and volcanic wounds and, composed mostly rising mountain blocks surrounding continental shields, the more recent move away towards the sea.

Mountains vary in origin and the size and nature of the rock, and difficult to classify. And can, depending on its individual associated with the causes of evolution, be classified in three groups: the volcanic mountains volcanic mountains and mountains of the blocks Alsdeih fault block mountains (or mountains Alvagayh or refractive) and mountains torsional fold mountains (or folds mountain) (Figure -1). The mountains of folding the most important types of mountains and widespread, and arise from the longitudinal compression Belts and advancement, and had the advantage of structural bodies and joint appearances suggest that they may have passed in identical historical stages, and called mountain systems.

Theories are mountain systems

Acquired development systems mountains and formed the attention of scientists, and was the subject of many studies, which included several theories most important theories: the first is old, and assume the development of the mountains in the geological geosynclines accumulate sediments many, with a gradual decline in the bottom, followed by the subject to movements side pressure, They then assume a vertical movements (vertical) and the other side, in the earth's crust, the first gravitational cause land subsidence and second expansion joints stressful, causing disfigurement and advancement, and was first described Dana Dana world in 1813 in the course of his study of the Appalachian Mountains. This was consistent with the theory intellectual trend that is supposed to continents and oceans old and fixed bodies of the earth's crust.

The second theory is modern and comprehensive analytical, developed according to recent studies and data concepts of plate tectonics [t] that explain the historical stages of the evolution of continents and oceans. The rise systems mountain is closely linked to the movement of plates lithosphere, which is within the scope of margins collision, where landing these margins under a sheet of continents to Tngrz on the coat, and consists of landing ocean trenches that become an area of ​​sediment accumulation over the tapes longitudinal downside of the Earth's crust called belts kinetic mobile belts.

I suppose the existence of these belts during the studies conducted on the Appalachian Mountains, it has been observed that the thickness of Rsupacha Albalyozoah exceed 12,000 meters, was also noted that this fine, gradually decreasing thickness towards the west direction within the continent, and low limits of approximately ten. And evidence Almsthathih indicates that most of them were placed in shallow marine environments, reaching thickness limit far exceeds the greatest bathymetric, so I suppose a decline in these parts of the earth's crust during the sedimentary accumulation, and the greater the decline occurred more accumulation.

There are many places of the earth's crust suit accumulation sedimentary nowadays, and there are other places in the past the scene of the accumulation, including the continents, but is limited to the development of belts motor near the edges of the continental shelves edges of continental shelves or near parentheses islands island arcs (Figures 2 and 3). In such places, the continents and islands arches role of the main sources of supply belts Kinetic Balrsupac. As the motor belts in mountain systems are the longitudinal bars of sedimentary and volcanic rocks deformed, the location must be located in the ranges of lithosphere plates collided, between continents and oceans and along arcs of islands.

Examples include, mentions that the presentation of the continental shelf east of North America has about 320 kilometers, which is covered with deposits up thick at its edge foreign to 5000 meters (Figure -3) and return to Hakba Almizzouzoa and Elkinozoa, consisting of rocks and sandy Clay and Clay Cefhah and calcareous , or the equivalent of rigid Rsupac, which resemble a whole with Rsupac the inner part of the Appalachian belt, except they are free of sandstone wedges. The fine, deep accumulated over the ocean crust, they are soft Clay tinged with coarse material rolled off the continental shelf, and the superiority of thick in some locations thickness of sedimentary cover over the continental shelf.

Falling belts kinetic: reduces landing gradual belts kinetic thickness of large parts of the accumulation sedimentary thick, and is attributed to the fact that rocks continental crust density less than rock coat lining them, then it is floating above it, and must be part riser them be subject to erosion فتقل thick and tends to promotion, and in turn tends part carrier deposits increased in thickness to decline, according to the principle of balance buoyancy floating balance or what is known Baltoazinah isostasy, and this accounts for landing belts kinetic increasingly act of gravity, with the increasing accumulation sedimentary, namely, that rate of decline commensurate with the rate of accumulation, and building , the corresponding part of the rock coat, falling under the earth's crust, must يزاح and pushing sideways to cause the advancement of neighboring parts.

This debate may be acceptable a few decades ago, but it is not acceptable at the present time. The Almatafa part supposed to dislodge heavily sediment is more dense than the downside. Therefore can not يزاح rock coat only part equivalent to the weight of the payload. Based on this, can not explain how great the fall in the motor belt fully downloaded sedimentary, it has to be the participation of other mechanical factors. Kinetic Valahzma is part of the lithosphere plates that are subject to decline and implantation in the coat due to the collision between the plates, so it pulls and pulls down factors differ from the balance of buoyancy. For example, parts of the earth's crust is between ocean trenches, island arcs in East Asian model of the outer part of the belt motor. And accounts for landing this part in the mechanism that causes decline in the earth's crust in the ocean trenches. Except that the expansion in the present causal on the inner part of sign in trouble. Valrv continental east of North America is probably an example of the inner part of the belt motor, it develops, away from the ocean trenches and arcs islands, the situation of the balance of buoyancy with coat lining him, and landing must be the product of other processes, Valrfov continental broad-covered deposits thick evolve At present on the edges of continental plates spaced, and to explain the reasons for landing must reflect on the following assumed geological events that lead to the open ocean.

While climbing stream hot from rock coat to the bottom crust continental, it leads to Tqubbha and Triqgaha heating and stretching, and ends tensile and laminating in part vaulted to cracks Pfwalq normal and falling parts along these faults (Figure 4: A and B), and accumulate in the valleys descending from many deposits resulting from erosion the blocks Alvagayh Mountains on its sides. However relay these events continental crust is broken into two parts apart, between them knew ridge to a new community, and takes this expansion of ocean volcanic eruptions generated ocean crust caused by partial melting in the hot rock coat free from pressure. Thus develops the inner part of the traction motor and belt laminating and downs along the normal faults on both sides of the plates Alaqaritin Almtbaeidtin (Figure 4 - b). With the continued expansion of cans the Almtoldtin Ocean on both sides of the custom and Tsadmanma with plates Alaqaritin Almtbaeidtin landing ocean crust below them and Tngrz in coat (Figure 5 - a).

Advancement systems mountains

Characterized margins collision lithosphere many types of activities, including two types are of particular importance in the advancement of the mountains; types first thermal activity resulting from implantation ocean crust inside the coat and the high temperature and the occurrence of

 Partial fusion generator for leisurely (Almagma) that pushes on the surface volcanic activities. The second type is a mechanical activity to decline ocean crust, and Ingrazha lead to deeper deposits concave geological, Andgatha, distorted Balti and reverse faults and impossibility, which gradually leads to advancement in the form of mountain systems. And to return to the current development of the oceans, the Atlantic is still in the process of expansion, and thus increases the depth of burial of sediment accumulated in geological Mqarath along its continental borders. We have started the development of this Almqarat along the eastern shores of North America 200 million years ago, but its development along the eastern shores of the South أمريكة was too late, because the openness of the Atlantic Ocean was gradually progresses from north to south. Since landing ocean crust under this Almqarat pull Sediments down as pushed toward the continental margin and makes them vulnerable to distortion, the deeper parts of these deposits are gradually impossibility, and give the types of rocks Alhestah and Algnaessah (Figure 5 - b). With increasing heating rocks continental deep gets the melting partially generated from leisurely (Magma) Riulietah (similar in composition granite) ascend slowly upwards due to viscosity high, not that soon harden into rocks that ravaged the body Mdsusat Batholat huge (Figure 5 - h ),

Great Valichohat and impossibility and the maximum and the advancement of fusion, are that make up the core of the mountain system that corresponds with the deeper geological concave parts (Figure 5 - d and 5 - e). The sedimentary cover on the shelf Continental Vindguet and cornered between the mass of the continent and the deep rock mass awakening involves distorted and rises also, to be the marginal area of ​​new mountain system (Figure 5 - e). In many parts of the world there are parts of the lithosphere plates under conflicting sheets with, and there are systems in the process of promoting mountain, including the Andes in western South.

Vsfihh Ocean Almngrzh is Nazca Nazca plate and continental plate colliding with are South أمريكة, ocean trench above the trench scope Alangraz is Peru, Chile, and the rising mountain system is the Andes dotted with volcanic activity. It is believed that this volcanic activity occurring constantly on the continental side of the collision are playing a key role in the evolution of this mountain system. The Himalayas and the Alps, one of the most famous mountain systems in the world, coming-Vtaatcef very steep terrain and towering peaks and located within the continents. The inception began stages since 200 million years, and back advancement to the collision sheets continental فجبال Himalayan rose from the collision plate Indian subcontinent with a mass Tibet Asian, as I got up the Alps plate African continent with plate European, and led to the closure perimeter Altaths old.

The Appalachian that lived in fulfilling mountains are currently situated in the west of Europeanization, believed that evolution was in the concave geologist follow ocean-Atlantic older than the current few hundred million years, when moved plate European continent to collide with North America, and has led this collision to the advancement system mountain in Albaanjieh continent Pangaea, and then broke the Appalachian Mountains west of Europeanization, while broken this ancient continent and diverged parts. It is also believed that the ancient mountain systems located within the Asian continent, Kjebal Urals dating sedimentary formations to Albalyozoa times, has risen from continental collisions, those that may be collected parts of the continent (Albaanjieh).

And give feedback ancient continental shields indications contain a bygone mountain systems, much older than Albalyozoa, so scientists believe that the lithosphere plates movements were taking place since ancient geologic time, resulting in a fusion of continental blocks and split multiple times.

Finally it can be said, without confirmation, that these movements follow successive stages of history, ending each verbal new Hmlanah cells inside the coat, which, he believes, defended President to break the lithosphere and platelet move its parts