4.earth movements

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Video Series on Geography (GS)


Earth Movements

Previous Video: Earth’s Interior

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Earth movements

Endogenetic

Diastrophism

Epeirogenic or Continent forming

Upward

Downward

Orogenic or Mountain building

Tension

Compression

Sudden movements

Earthquakes

Volcanoes

Exogenetic

Weathering

Physical

Chemical

Biological

Erosion

Ice

River Water

Sea

Wind

Underground Water

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Forces Responsible

Radioactivity in the core

Tectonics

Climatic Factors

Rotation of Earth

Isostacy

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Earth movements

Endogenetic

Diastrophism

Epeirogenic or Continent forming

Upward

Downward

Orogenic or Mountain building

Tension

Compression

Sudden movements

Earthquakes

Volcanoes

Exogenetic

Weathering

Physical

Chemical

Biological

Erosion

Ice

River Water

Sea

Wind

Underground Water

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slow bending, folding, warping and fracturing

All processes that move, elevate or build up portions of the earth’s crust


Endogenetic Forces - Diastrophism

Epeirogenic

Orogenic

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upheavals or depressions exhibiting long wavelengths and little folding

Broad undulations The broad central parts of

continents are called cratons, and are subject to epeirogeny

The movement may be one of subsidence toward, or of uplift from, the centre of the Earth.

The movement is caused by a set of forces acting along an Earth radius [isostasy and faulting]www.poormansfriend.org

Epeirogenic or continent forming movements

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Uplift

Raised beaches, elevated wave-cut terraces, sea caves and fossiliferous beds

Coringa near the mouth of the Godavari, Kaveripattinam in the Kaveri delta

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Rann of Kachchh The Andamans and

Nicobars have been isolated from the Arakan coast by submergence of the intervening land.

Gulf of Mannar and Palk Strait is very shallow and has been submerged in geologically recent times



Subsidence

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Tensions produces fissures and compression produces folds

Orogenic or the mountain-forming movements


EART

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mountain-forming movements act tangentially to the earth surface, as in plate tectonics

Orogenic or the mountain-forming movements


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Endogenetic Forces - Sudden Movements


Earthquakes Volcanoes

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Exogenetic Forces - Denudation


exogenic processes derive their energy from atmosphere determined by the ultimate energy from the sun

Internal stresses in rocks shear stresses gravitational

stress molecular stresses

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Denudation


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Exogenetic Forces - Weathering


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Carbonation Carbon dioxide in the presence of water, forms carbonic acid that acts as a weak acid.

Hydration Minerals take up water and expand. This induces stress.

Oxidation and Reduction Combination of a mineral with oxygen to form oxides or hydroxides. When oxidised minerals are placed in an environment where oxygen is absent, reduction takes place

Red colour of iron upon reduction turns to greenish or bluish grey

Chemical Weathering


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Chemical and Mechanical Weathering aided by various organisms.

Burrowing and wedging help in exposing the new surfaces to chemical attack and assists in the penetration of moisture and air.

Decaying plant and animal matter help in the production of humic, carbonic and other acids

Algae utilise mineral nutrients for growth and help in concentration of iron and manganese oxides.

Plant roots exert a tremendous pressure on the earth materials mechanically breaking them apart

Biological Weathering


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Physical or Mechanical Weathering


Granular Disintegration

Exfoliation Block Seperation

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Physical or Mechanical Weathering


Mass Wasting ShatteringFrost Wedging

Salt Weathering

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Effects and Significance of Weathering


Peneplane

Iselberg

TorsPatination

Soil Fromation

Enrichment

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4.earth movements

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