Plate tectonics

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Plate tectonics:

Plate tectonics Topic 11

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plate tectonics - Is a set of ideas that describes and explains the global distribution of earthquakes, volcanoes, fold mountains and rift valleys. plate tectonics  —  the study of the  structure  of the earth's crust and mantle with reference to the theory that the earth's lithosphere is divided into large rigid blocks (  plates  ) that are floating on semifluid rock and are thus able to inter-act with each other at their boundaries, and to the associated theories of continental drift and seafloor spreading

Under and at the earth’s surface:

Under and at the earth’s surface The surface of the Earth is known as the crust. This is a collection of solid tectonic plates that join together like a jigsaw puzzle. Around the solid core at the centre of the Earth is a layer of molten magma. This is called the mantle. Through this layer flow convection currents. The plates float on the mantle. The convection currents move these plates away from or towards or alongside each other. These movements along plate boundaries give rise to earthquakes, volcanoes and fold mountains

Fold mountains:

Fold mountains Fold mountains  are mountains formed mainly by the effects of folding on layers within the upper part of the Earth's crust. In the time before either plate tectonic theory developed, or the internal architecture of thrust belts became well understood, the term was used for most mountain belts, such as the Himalayas. The term is still fairly common in physical geography literature but has otherwise generally fallen out of use except as described below. The forces responsible for formation of the fold mountains are called  orogenic  movements. The term orogenic  has derived from a Greek word meaning mountain building. These forces act at tangent to the surface of the earth and are primarily a result of plate tectonics.


Vocabulary crust -the brown, hard outer portion or  surface Molten - liquefied by heat; in a state of fusion;  melted Magma - Geology  . molten material beneath or within the earth's crust, from  which   igneous  rock is formed. any  crude   mixture  of finely divided mineral or organic matter.

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Convergent – a djective characterized by  convergence ; tending to come together; merging. Divergent - —  adj 1. diverging  or causing divergence 2.(of opinions, interests, etc) different 3. maths   (of a series) having no limit; not convergent 4. botany   (of plant organs) farther apart at their tops than at their bases Lithosphere - n oun   Geology  . 1. the solid portion of the earth (distinguished from  atmosphere ,  hydrosphere  ). 2. the crust and upper mantle of the earth.


asthenosphere the region below the lithosphere, variously estimated as being from fifty to several  hundred  miles

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