How Mountains are Formed - Lesson - TeachEngineering
Mountain formation is related to plate tectonics. Folding with a slope of 4°-6°. ( The relation between slope and viscosity falls under the topic of angle of repose.) . What tectonic plates formed the Appalachian mountains? jle c po._. Answered . Describe the relationship between tsunami and plate tectonic? The collision of. Concepts include the composition and structure of the Earth's tectonic plates and Explain the connection between tectonic plates and mountain formation.
Sometimes, the two tectonic plates press up against each other, causing the land to lift into mountainous forms as the plates continue to collide. Another possibility is that one plate pushes on top of the other, sending it downward into the Earth! We call this a subduction zone. The mountains formed from this powerful compressive process are called complex mountains.
Given these options, how do we know which possibility will occur? It depends on the composition of the tectonic plates involved in the collision. Tectonic plates are either made up of oceanic crust or continental crust. Oceanic crust is mainly made of basaltic rocks, and continental crust is mainly made of felsic rocks. Basaltic rocks are denser than felsic rocks; therefore, oceanic crust is denser than continental crust.
So, if an oceanic tectonic plate collides with a continental plate, the denser oceanic plate is likely to sink beneath the continental plate, creating a subduction zone.
If, however, two continental plates therefore of similar density smack into one another, they, instead, lift up against one another. Let's look at some diagrams. By paper handout or overhead projection, show students what happens in the various plate convergence scenarios, as shown in the attached Tectonic Plates Convergence Handout-Overhead. Now that we have talked about complex mountains, let's briefly touch on two other types of mountains. Fault-block mountains are formed by an entirely different process.
These mountains are produced when tectonic plates are stretched to the point that they crack and slide. These cracks, or vertical faults, are fractures in the continental crust. Crust is then squeezed upward between the two parallel lines, resulting in mountains!
And finally, the term erosional mountain describes mountains that are formed due to the erosion of uplifted rocks in the Earth's geography. This process occurs when rivers, over time, carve away at a region of uplifted geography.
But bumps and hills are all over this planet — so what constitutes a mountain? Mountains are landforms that extend above their surrounding areas in a limited area.
That is a very general definition! No required elevation exists for a mountain to be called a mountain, so what makes a mountain different from a hill? Mountains are generally considered to be higher and steeper than a hill, but the definitions ultimately depend on local custom. A hill to some is a mountain to others, and visa versa! These tunnels in Nevada enable traffic on US interstate highway 80 to continue through a mountain of rock instead of going around it.
Geotechnical engineers study mountains and the movement of tectonic plates for a variety of purposes. They observe plate movements to design technologies to measure the movement of tectonic plates and mountain formation in order to predict earthquakes and how to best protect people from them.
Using these technologies, they develop processes and rules for developing communities and roadways around tectonic plate movement adding extra support requirements to structures on an earthquake fault line.
They also use the information to develop technologies that predict locations at which geothermal, oil, natural gas and coal resources may be located. Sometimes geotechnical engineers work with other engineers to turn the geological formations themselves into res ources for humans, such as mountain tunnels, dams and roads.
Lesson Background and Concepts for Teachers The Earth's internal structure makes the land and oceans prone to mountain formation. The lithosphere, Earth's rigid top layer of rock, floats on the asthenosphere, Earth's hot, malleable layer beneath the lithosphere.
The rigid lithosphere layer is about km 60 miles thick and makes up the Earth's enormous moving rocks called tectonic plates; 14 major tectonic plates and 38 minor plates are identified.
Tectonic plates are further classified into two major groups based upon their composition: Typically, a single tectonic plate can contain both oceanic and continental crust.
plate tectonics | Definition, Theory, Facts, & Evidence | dubaiairporthotel.info
Oceanic crust is mainly comprised of basaltic rocks, whereas continental crust is largely made up of felsic rocks, which are lower in density. Map of the Earth's tectonic plates. Because the lithosphere essentially floats on the asthenosphere, movement in the asthenosphere gets transferred to the lithosphere, causing the Earth's tectonic plates to move in different directions.
The currents causing this movement in the asthenosphere are not entirely understood, but the Earth's internal heat engine is the hypothesized cause. Three types of tectonic pl ate boundaries exist: Mountains are formed by plate convergence.PLATE TECTONICS
Plate convergence describes tectonic plate movement that results in the collision of two plates. These slow-moving collisions shift the plates only a few centimeters a year, but are powerful enough to form large mountain ranges over time.
Plate convergence resulting in mountain formation occurs in several ways. First, two tectonic plates can be pressed up against each other until the land lifts and folds over itself. This subduction zone is also called Benioff zone.
Mountains: How Are They Formed? - Universe Today
The subduction of plate boundary causes lateral compressive force which ultimately squeezes and folds the sediments and materials of the margins of the plates and thus mountains are formed. The subducted part of the plate after reaching a depth of km or more in the mantle is liquefied and thus expands in volume because of conversion of the portion of plate into magma.
This expansion of molten materials causes further rise in the mountains. The convergence and consequent collision of plate boundaries occurs in three situations viz.: The best example of the formation of mountains due to collision of two oceanic plates is the situation of Japanese island arc.
It may be pointed out that all the mountains of Japan are of volcanic origin. Though Japanese mountains exhibit a number of characteristic features of folded mountains but they can no longer be regarded as Fold Mountains like the Alps and the Himalayas.
Honshu Island represents the most characteristic example of the situation of the convergence of two oceanic plates. Honshu is bordered by Japan Trench in the east and Japan Sea in the west.
The western part of the island is more frequented by volcanic activities than the eastern part. The island is characterized by two belts of metamorphic rocks on either side.
According to plate tectonic theory the subducted portion of plate after reaching a depth of km or more starts melting due to high temperature prevailing in the upper mantle. The magma, thus formed, ascends and appears as volcanic eruption about km away from the oceanic trench. Since Japan is very close to the Japan Trench and hence western part of Japan is more frequented by volcanic activities.
This process is still continuing as the Pacific plate is being continuously subducted under the oceanic crust along the Japan Trench. The eruption of volcano in the month of June, in Japan after a dormant period of about years and the eruption of Mt Pinatubo on June 9, in Manila, Phillippines, validate the authenticity of this theory of plate tectonics.
When two convergent plates composed of continental crusts collide against each other, the continental plate having relatively denser materials is subducted under the other continental plate having comparatively lighter materials than the former. There existed a long Tethys geosyncline between Eurasian plate in the north and African-Indian plate in the south during Mesozoic Era.
The geosynclinal sediments of Tethys sea were squeezed and folded into Alpine-Himalayan mountain chains due to lateral compressive forces caused by the convergence and collision of Eurasian and African-Indian continental plates during Cenozoic Era.
About million years ago there was an extensive geosyncline, known as Tethys geosyncline, in the place of the Himalayas.
Plate Tectonics and Mountain Building
Tethys geosyncline was bordered by Asiatic plate in the north and Indian plate in the south. Tethys geosyncilne began to contract in size due to movement of Indian and Asiatic plates together. About million years ago the Indian plate came very close to Asiatic plate. The Indian plate began to actively subduct under the Asiatic plate. The convergence and collision of Asiatic and Indian plates and consequent subduction of Indian plate under the former caused lateral compression due to which the sediments of Tethys geosyncline were squeezed and folded into three parallel chains of the Himalayas about million years ago.
It has been estimated that the crust has been shortened by km between Asiatic and Indian plates due to convergence of two plates and subduction of Indian plate. Alpine mountains of Europe were formed due to convergence and collision of European and African plates.
Since the collision of these two continental plates was very complex and hence the structure of the European Alpine mountains is also very complex.
The African plate is still moving northward and is being subducted under European plate to the south of Aegean arc. Similarly, Indian plate is also being continuously subducted under Asiatic plate. Evaluation of the Plate Tectonic Theory: In fact, the continental drift has now become a reality on the basis of evidences of palaeomagnetism and sea-floor spreading. Plate tectonic theory also satisfactorily explains the cyclic pattern of mountain building.