Tectonics - a branch of geology that studies the structure of the crust and the movement of lithospheric plates.But it is so versatile, it plays a significant role in many other Earth sciences.It is used in architecture, tectonics, geochemistry, seismology, the study of volcanoes and many other areas.
Science
Tectonics tectonics - a relatively young science, she has been studying the movement of lithospheric plates.For the first time the idea of moving plates voiced theory of continental drift Alfred Wegener in the 20-ies of XX century.But its development it has received only in 60-ies of XX century, after the research of the relief on the continents and the ocean floor.The resulting material was allowed to take a fresh look at previously existing theories.The theory of lithospheric plates appeared as a result of the ideas of continental drift, geosyncline hypothesis and contractions.
tectonics - the science that studies the strength and nature of the forces that shape the mountains, rock crushes into the folds, stretch the crust.It is the basis of all geological processes occurring on the planet.
contraction hypothesis
contraction hypothesis was put forward by geologist Elie de Beaumont in 1829 at a meeting of the Academy of Sciences of France.It explains the processes of mountain formation and folding of the earth's crust under the influence of reducing the volume of the Earth due to cooling.The basis of the hypothesis formed representation of Kant and Laplace on the primary fiery liquid earth and its further cooling.Therefore, the processes of mountain formation and folding explained the processes of compression of the crust.In the future, cooling down, the Earth has reduced its volume and crushes into the folds.
The contraction tectonics, which confirms the new definition of the doctrine of geosynclines explains the uneven structure of the crust, has become a solid theoretical basis for the further development of science.
geosyncline
existed at the turn of the late XIX and early XX centuries.It explains the tectonic processes cyclic oscillatory movements of the earth's crust.
Attention was drawn to the geologists that the rocks may lie horizontally and deployed.Flat-lying rocks carried to the platforms, and deployed - to the fold region.
According geosyncline, in the initial stages because of active tectonic processes occurs deflection, lowering the earth's crust.This process resulted in the destruction of precipitation and the formation of a thick layer of sediment.In the future, the process of mountain formation and the appearance of folding.On the estimate of geosynclinal regime comes platform, which is characterized by small tectonic movements with the formation of a small thickness of sedimentary rocks.The final stage - a stage of formation of the continent.
Almost 100 years dominated geosynclinal tectonics.Geology at the time was experiencing a shortage of factual material accumulated data later led to the creation of a new theory.
theory of lithospheric plates
Tectonics - is one of the areas of geology, which formed the basis of the modern theory of the movement of lithospheric plates.
According to the theory of lithospheric plates of the Earth's crust - lithosphere plates that are in constant motion.Their movement occurs relative to each other.In areas of crustal extension (mid-ocean ridges and continental rifts), a new oceanic crust (zone spreydinga).In zones dipping crustal blocks are absorbed old bark, and dive under the continental oceanic (subduction zone).Also in the framework of the theory explains the causes of earthquakes, mountain building and volcanic activity.
global plate tectonics includes such key concepts as geodynamic setting.It is characterized by a set of geological processes, within the same territory, in a certain period of geologic time.For the same geodynamic situation characterized by the same geological processes.
structure globe
Tectonics - a branch of geology that studies the structure of the planet Earth.Earth roughly has the shape of a flattened ellipsoid and consists of several shells (layers).
The structure of the world are the following layers:
- crust.
- Mantle.
- kernel.
crust - it's hard outer layer of the Earth, it is separated from the mantle boundary, which is called a surface Mohorovicha.
Mantle, in turn, is divided into upper and lower.The boundary separating the layers of the mantle is a layer of Golitsyn.The earth's crust and upper mantle asthenosphere up are the Earth's lithosphere.
The core is the center of the world, separated from the mantle boundary Gutenberg.It is separated into solid and liquid outer inner core, between them there is a transition zone.
Crustal structure
On the structure of the earth's crust has a direct bearing on the science tectonics.Geologic studies not only the processes occurring in the bowels of the Earth, but also its structure.
crust - it is the upper part of the lithosphere is the outer solid shell of the Earth, it is composed of rocks of different physical and chemical composition.On physical and chemical parameters of the existing division into three layers:
- Basalt.
- granite-gneiss.
- sedimentary.
There is also a division in the structure of the crust.There are four major types of the earth's crust:
- Continental.
- Ocean.
- subcontinental.
- suboceanic.
Continental crust is represented by all three layers, its power ranges from 35 to 75 km.The upper, sediment, developed widely, but usually has a small capacity.The next layer, the granite-gneiss, has a maximum capacity.The third layer, basalt, composed of metamorphic rocks.
oceanic crust is represented by two layers - sedimentary and basaltic, the power of it is 5-20 km.
subcontinental crust, as well as continental, consisting of three layers.The difference is that the power of granite-gneiss layer subcontinental crust is much smaller.This type of crust is found on the border of the continent to the ocean in the area of active volcanism.
sub-oceanic crust is close to the ocean.The difference is that the thickness of the sedimentary layer can reach 25 km.This type of crust is timed to deep troughs Earth's crust (the inland sea).
lithospheric plates
Lithospheric plates - a major crustal blocks that are part of the lithosphere.Plates are able to move relative to each other on top of the mantle - asthenosphere.Plates separated from each other by deep trenches, mid-ocean ridges and mountain systems.A characteristic feature of the lithospheric plates is that they are able to keep the hardness, shape and structure for a long time.
Tectonics of the Earth says that the lithospheric plates are in constant motion.Over time they change their path - can crack or grow together.To date, it allocated 14 major lithospheric plates.
Plate tectonics
process of forming the appearance of the Earth, is directly related to plate tectonics.Tectonics of the world means that there is a movement not of continents and lithospheric plates.Facing each other, they form mountain ranges or deep oceanic trenches.Earthquakes and volcanic eruptions are the result of movement of lithospheric plates.Active geologic activity is confined mainly to the edges of these formations.
movement of lithospheric plates recorded by satellite, but the nature and mechanism of this process still remains a mystery.
Tectonics Oceanic
ocean processes of destruction and sedimentation are slow in nature, so the tectonic movements are well reflected in the landscape.Bottom topography is difficult dissected structure.Allocated tectonic structure formed by the vertical movements of the crust, and the structure obtained due to horizontal movements.
to the structure of the ocean floor are landforms such as abyssal plains, oceanic basins and mid-ocean ridges.In the area of depressions, usually observed tectonic calm environment in the area of mid-ocean ridges marked tectonic activity of the Earth's crust.
Tectonics Oceanic More includes structures such as trenches, oceanic mountains and Pierre Guyotat.
reasons to move plates
driving force is the geological tectonics of the world.The main reason why there is a movement of plates is mantle convection currents created teplogravitatsionnymi mantle.This occurs because the temperature difference on the surface and in the center of the Earth.Inside the rocks are heated, there is their expansion and decrease in density.Light fractions are beginning to emerge, and in their place dropped cold and heavy mass.The process of heat transfer occurs continuously.
On motion of plates are more pleased factors.For example, in areas of the asthenosphere updrafts is raised, and in the areas of immersion - lowered.Thus, a ramp, and the process of "gravity" slip lithospheric plate.And influence of the subduction zone, where the cold and heavy oceanic crust is delayed under the hot continental.
Power asthenosphere beneath the continents is much less and the viscosity is greater than under the oceans.Under the ancient part of the continents the asthenosphere is virtually absent, so in these places they do not move and stay in place.And as the lithospheric plate includes continental and oceanic part, the presence of ancient mainland will prevent the movement of plates.Movement purely oceanic plates faster than mixed, and the more continental.
mechanisms resulting in the movement of the plates, many shareware may be isolated in two groups:
- mechanisms that move under the influence of mantle flow.
- mechanisms associated with the application of forces to the edges of the plates.
set of processes driving forces reflects the overall geodynamic process that encompasses all layers of the Earth.
architecture and tectonics
Tectonics - is not only a purely geological sciences related to processes occurring in the Earth's interior.It is used in everyday life.In particular, it applies tectonics in architecture and construction of any structures, whether buildings, bridges or underground structures.Here lie the basis for the laws of mechanics.In this case, under the tectonics refers to the degree of strength and stability of the structure in this particular area.
theory of lithospheric plates does not explain plate movements due to deep processes.We need a theory that would explain not only the structure and movement of the lithospheric plates, but also the processes occurring inside the Earth.The development of such a theory is related to the association of professionals such as geologists, geophysicists, geographers, physicists, mathematicians, chemists, and many others.
