2. GEOMORPHIC MOVEMENTS
• The formation and deformation of landforms on the surface of the earth are a continuous process
which is due to the continuous influence of external and internal forces. The internal and
external forces causing stresses and chemical action on earth materials and bringing about changes in
the configuration of the surface of the earth are known as geomorphic processes.
• EARTH MOVEMENTS
3. •The Large-scale Movements On The Earth’s Crust Or Its Surface Brought Down By The Forces Emanating From Deep Below The
Earth’s Surface Are Called As Endogenic Geomorphic Movements Or Simply Endogenic Movements (Endo: Internal; Genic: Origin;
Geo: Earth; Morphic: Form).
The Geomorphic Processes That Are Driven By The Forces Emanating From Deep Below The Earth’s Surface Are Called Endogenic
Geomorphic Processes (Folding, Faulting, Etc.).
The Ultimate Source Of Energy Behind Forces That Drive Endogenic Movements Is Earth’s Internal Heat.
Earth’s Internal Heat Is A Result Of Mainly Radioactive Decay (50% Of The Earth’s Internal Heat) And Gravitation (Causes Pressure
Gradients).
Differences In Temperature And Pressure (Temperature Gradients Or Geothermal Gradients And Pressure Gradients) Among
Various Layers Of The Earth Give Rise To Density Differences And These Density Differences Give Rise To Conventional
Currents.
Convectional Currents In The Mantle Drive The Lithospheric Plates (Crust And Upper Mantle) And The Movement Of The
Lithospheric Plates (Tectonics) Is The Cause Behind Endogenic Movements.
The Earth’s Rotation (Coriolis Effect) Can Influence Where Convection Currents Travel.
The Destination Of Convection Currents Determines The Nature And Location Of The Endogenic Movements.
FORCEBEHIND ENDOGENIC MOVEMENTS
4. CLASSIFICATION OF ENDOGENIC MOVEMENTS
• Endogenetic movements are divided into
Diastrophic movements and Sudden
Movements.
• Diastrophism refers to deformation of
Earth’s crust.
• Diastrophic movements are gradual and
might stretch for thousand of years.
• On the other hand, Sudden movements like
earthquakes and volcanic eruptions occur in
a very short period.
5. DIASTROPHISM
• Diastrophic movements are further classified
into Epeirogenic movements (continent
forming - subsidence and upliftment) and
Orogenic movements (mountain building –
folding and faulting).
Orogenic processes involving mountain
building through severe folding
Epeirogenic processes involving uplift or
warping of large parts of the earth’s crust
(simple deformation)
6. EXOGENIC GEOMORPHIC MOVEMENTS
• The geomorphic processes on the earth’s crust or its surface brought down by the forces emanating from above the
earth’s surface (wind, water) are called exogenic geomorphic process.
• Exogenic geomorphic process gives rise to exogenic geomorphic movements such as weathering and erosion.
• The effects of most of the exogenic geomorphic processes are small and slow but will, in the long run, affect the
rocks severely due to continued fatigue.
THEFORCEBEHIND EXOGENIC MOVEMENTS
• Exogenic processes derive their energy from atmosphere determined by ultimate energy from the sun and the
gradients created by tectonic forces.
7. EXOGENIC GEOMORPHIC PROCESS ARE COVERED UNDER A GENERAL TERM,
DENUDATION.
THE WORD ‘DENUDE’ MEANS TO STRIP OFF OR TO UNCOVER.
DENUDATION LEADS TO
WEATHERING
MASS MOVEMENT
EROSION/ TRANSPORTATION
DENUDATION
8. 1. WEATHERING
• Weathering is the disintegration of rocks, soil, and
minerals under the influence of physical and
chemical agents.
• As very little or no motion of materials takes place
in weathering, it is an in-situ or on-site process.
• Weathered material is carried farther away by
erosion.
• There are 3 major groups of weathering processes:
1. CHEMICAL;
2. PHYSICAL OR MECHANICAL;
3. BIOLOGICAL WEATHERING PROCESSES.
• All the types of weathering often go hand in hand.
2. MASS MOVEMENT
• Mass movement is also known as mass
wasting.
• It is the movement of masses of bodies of
mud, bedrock, soil, and rock debris,
because of the gravitational pull.
• Mass movements which are sliding of
huge amounts of soil and rock are seen in
mudslides, landslides, and avalanches.
• These are very active over weathered slopes
rather than over unweathered materials.
• Mass movements do not come under
erosion though there is a shift of materials
from one place to another.
• Recent case of Joshimath, Uttarakhand.
Settled on an old landslide zone.
9. 3. EROSION/ TRANSPORTATION
• Erosion is the process by which soil and rock
particles are worn away and moved elsewhere
by gravity, or by a moving transport agent –
wind, water or ice.
• Transport refers to the processes by which the
sediment is moved along
• – for example, pebbles rolled along a river-
bed or sea shore, sand grains whipped up by
the wind, salts carried in solution.
