Geomorphic Process

• The endogenic and exogenic forces causing physical stresses and chemical actions on earth materials and bringing about changes in the configuration of the surface of the earth.

Endogenic Process

• Endogenic (Internal force from within the earth) – land building forces.

Diastrophism

• All processes that move, elevate or build up portions of the earth’s crust
• Orogenic (Horizontal Movement) – Mountain building.
• Epeirogenic (Vertical Movement) – Continental Building Process.
• Earthquakes – Minor Movement.
• Plate tectonics – Horizontal Movement.

Volcanism

• The movement of molten rock (magma) onto or toward the earth’s surface and also formation of many intrusive and extrusive volcanic forms.

Exogenic Forces

• Exogenic (External force originating within the earth atmosphere) – land wearing forces.
• All the exogenic geomorphic processes are covered under a general term, denudation.
• Weathering - Gravitational/ Molecular Stresses and/or Chemical Action
• Mass Movements - Gravitational Forces.
• Erosion/ Transportation - Kinetic Energy
• Deposition.
• Any exogenic element of nature (like water, ice, wind, etc.,) capable of acquiring and transporting earth materials - Geomorphic agent.
• Force applied per unit area – Stress.

Weathering

Weathering is defined as mechanical disintegration and chemical decom position of rocks through the actions of various elements of weather and climate.

• Chemical Weathering -  Chemical reaction on various minerals
• Physical or Mechanical Weathering – Depend on some applied forces.
• Gravitational forces
• Expansion forces
• Water pressures controlled by wetting and drying cycles.
• Biological Weathering
• Biological weathering is contribution to or removal of minerals and ions from the weathering environment and physical changes due to growth or movement of organisms.
• Earthworms, termites, rodents etc.,

Exfoliation (Special Effects of Weathering)

• It is a result but not a process. Exfoliation can occur due to expansion and contraction induced by temperature changes.

Significance

• Weathering processes are responsible for breaking down the rocks into smaller fragments and preparing the way for formation of not only regolith and soils, but also erosion and mass movements.

Mass Movement

• These movements transfer the mass of rock debris down the slopes under the direct influence of gravity. Mass movements are aided by gravity and no geomorphic agent like running water, glaciers, wind, waves and currents participate in the process of mass movements.
• Slow (Based – Rate of Movement)
• Creep
• Solifluction
• Rapid (Based – Size, Texture, Nature of Rock)
• Mudflow
• Earthflow
• Avalanche
• Debris
• Snow
• Land Slides - The materials involved are relatively dry.
• Slump – It is slipping of one or several units of rock debris with a backward rotation.
• Debris Slides – Rapid rolling or sliding of earth debris without backward rotation of mass.
• Rock Slide – Sliding of individual rock masses down bedding, joint or fault surfaces.
• Rock Fall – It is free falling of rock blocks over any steep slope keeping itself away from the slope.