ENDOGENETIC AND EXOGENETIC FORCES LAND FEATURES UGC NET GEOGRAPHY
Origin of Words
- Catastrophic & Diastrophic Forces
- Epeirogenetic Movements
- Orogenetic Movements
- Compressional Movements
- Tensional Movements
- Degradational Forces
- Aggradational Forces
Endogenetic and Exogenetic Forces
Endo means Inside
Exo means Outside
Genic means Origin
The forces which acts inside (interior) of the earth are called Endogenetic/Endogenic Forces.
- g.- Earthquake and Volcano
The forces which acts on the surface of the earth are called Exogenetic/Exogenic Forces.
- g.- River, Wind, Glacier Work.
- These forces originate from deep inside the earth.
- They create irregularities on surface on the earth.
- They Classified into two type: (i) Catastrophic Forces (ii) Diastrophic Forces
(i) Catastrophic Forces / Sudden Forces:
- These are the endogenetic forces.
- These forces are the result of long period of preparation deep inside the Earth.
- Their appearance is sudden and brings major changes on the surface of the Earth.
- g. – Earthquake , Volcanoes
(ii) Diastrophic Forces / Slow Movements:
- These are the endogenetic forces.
- These forces are slow and gradual, working deep inside the Earth to produce changes which become perceptible over millions of years on the surface of Earth.
- These effects are visible after thousands of years.
- Himalayas hieght increasing 10 cm/year
- Rise in coast of Baltic sea 1.3 meter in a century
- They are further classified into two type (a) Epeirogenetic movements (b) Orogenetic movements
- Eperogenetic is derived from two Greek word – Epeiros means land and Genesis means Origin, so its means origin of the land.
- Epeirogenetic movements are vertical movements.
- Depending on their direction they can either be upward or downward forces.
- Horizontal arrangement remains undisturbed.
- A portion may elevated or large area may depressed
- So, they cause upliftment / emergence and subsidence/submergence of continental and oceanic masses respectively.
- Upliftment/emergence are upward movements and subsidence/submergence are downward movements.
- Orogenetic is derived from two Greek word – Oros means Mountain and Genesis means Origin, so its means origin of the mountain.
- They are horizontal movements.
- Mountain building forces.
- They are also known as horizontal or tangential movements.
- These are further divided into two type (i) Compressional Movements (ii) Tensional Movements
(i) Compressional Movements
- These movements are face to face movements working in same direction.
- They produce folding and warping of rocks.
(ii) Tensional Movements
- These movements occur in opposite directions to each other.
- Tensional movements create rupture, fracture and faults in the rocks.
- Exogenetic Forces
- These forces originate under the influence of atmospheric and climatic conditions.
- They are engaged in planation of irregularities on the surface of Earth.
- They are classified into two type (i) Degradational (ii) Aggradational forces
(i) Degradational Forces
- They work under the influence of atmospheric and climatic processes to reduce irregularities on the surface by erosion, weathering and mass movement.
(ii) Aggradational Forces
- These forces, working under the influence of atmospheric and climatic processes raise the level of land to reduce surface irregularities by deposition of sediments.
- Depositional material is accumulated where the supply of sediment is greater than the amount of transported sediments.
- The sediments cause the land to elevate and level. The ideal environment for aggredation includes deltas, alluvial fans etc.