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T he earth surface is being continuously subjected to by external forces originating within the earth atmosphere and by internal forces from within the earth. The external forces are known as exogenic forces and the internal forces are known as endogenic forces. The action of exogenic forces result in wearing down or basin on the earth surface. The phenomenal of wearing down of relief variations of the surface of the earth through erosion is known as gradation. The endogenic forces continuously elevate or build up parts of earth surface and hence the exogenic processes fails to even out the relief variation of the surface of the earth. So, variations remain as long as the opposition actions of exogenic and endogenic forces continue. Geomorphic Process The endogenic and exogenic forces causing physical stresses and chemical action on the earth materials bring about changes in the configuration of surface of the earth are known as geomorphic processes.Any exogenic element of nature, like water, ice, wind, etc capable of acquiring and transporting earth materials can be called geomorphic agent.Gravity is also important geomorphic processes. Gravity is the force that is keeping us in contact with the surface and it is the force that switches on the movement of all surface on the earth. All the movements either within the earth or on the surface of the earth occurs due to gradients- from higher levels to lower level, from high-pressure to low-pressure areas etc.Endogenic processesThe energy emanating from within the earth is the main force behind endogenic geomorphic processes. This energy is mostly generated by radioactivity, rotational and tidal friction and primordial heat from the origin of the earth.Diastrophism * moves, elevate or buildup portion of the earth crust.* Can be classified into three types: a. Orogenic process, b. Epeirogenic process, c. Earthquakes, d. Plate tectonics * Orogeny is a mountain building process whereas epeirogeny a continental building process.* Metamorphic rocks are result of all these processes.Volcanism * Movement of molten rock on two or towards earth surface* Which forms intrusive and extrusive volcanic formsExogenic processesThe exogenic processes drive their energy from atmosphere determined by the ultimate energy from the sun and also the gradients created by tectonic factors. All the exogenic geomorphic processes are covered under general term called denudation. Weathering, mass movements, erosion and transportation are included in denudation. Weathering Weathering is action of elements of weather and climate over earth materials. There are a number of processes within weathering which act either individually or together to affect the earth materials in order to reduce them to fragmental state. It is defined as a mechanical disintegration and chemical this composition of rocks through the action of various elements of weather and climate.There are three major groups of weathering process:i. Chemicalii. Physical or mechanicaliii. Biological weathering processesChemical weathering processesA group of weathering processes viz; Solution, carbonation, hydration, oxidation and reduction act on the rock to decompose, dissolve or reduce them to a fine clastic state through the chemical reaction by oxygen, surface and/or soil and other acid. Physical weathering processesPhysical or mechanical weathering processes depend on some applied forces. The flight forces would be:i. Gravitational forces such as overburden pressure, load and shearing stress.ii. Expense forces due to temperature changes, crystal growth or animal activity.iii. Water pressure control by waiting and drying cycles.Biological activity and weathering Biological withering is a contribution to for removal of minerals and irons from the weathering environment and physical changes due to growth for movement of organism. The decaying plant and animal matter help in production of humic , carbonic and other acid which enhance decay and solubility of some elements. Significance of weathering Withering process 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. Biomes and bio diversity is basically a result of forest and forests depend upon the depth of weathering mantles. Weathering of rocks and deposits help in the enrichment and concentration of certain valuable ores of iron, magnesium, aluminium, copper etc which are of great importance for the national economy.Mass movementsThese movements transfer the mass of rock degrees down the slopes under the direct influence of gravity. Mass movements are aided by gravity and no geomorphic agents like running water, glacier, wind waves and currents participate in the process of mass movement.Several activating causes precede mass movement.They are:i. Removal of support from below materials materials through national or artificial means.ii. Increase in gradient and height of slopes.iii. Overloading through addition of materials naturally or by artificial filling.iv. Overloading due to heavy rainfall, saturation and lubrication of slope material.v. Removal of material load from over the original slope surface.vi. Occurrence of earthquakes, explosions or machinery.vii. Excessive natural seepageviii. Heavy drawdown of water from lakes, reservoirs and rivers leading to slow outflow of water from under the slope or river banks.ix. Indiscriminate removal of natural vegetation. Landslides These are relatively rapid and perceptible movement. The materials involved are relatively dry. The size and shape of the detached masses depend on the nature of discontinuities in the rock, the degree of weathering and steepness of the slope.In India, debris avalanches and landslides occur very frequently in the Himalayas. There are many reasons for this. One, the Himalayas are tectonically active. They are mostly made up of sedimentary rocks and and consolidated and semi consolidated deposits. The slopes are very steep. Compare to the Himalayas, the Nilgiris bordering Tamil Nadu, Karnataka, Kerala and the Western Ghats along with west coast a relatively tectonically stable and are mostly made up of very hard rocks. But still, debris avalanches and landslides occur though not as frequently as in the Himalayas. Many slopes are steeper with almost vertical clips and escarpments in the Western Ghats and Nilgiris. Mechanical weathering due to temperature changes and ranges is pronounced. They receive heavy amount of rainfall over short periods. So, there is almost direct rockfall quite frequently in these places along with landslides and debris avalanches.Erosion and Deposition Erosion involves acquisition and transportation of rock debris’s. When massive rocks break into smaller fragments through withering and any other process, erosional geomorphic agents like running water, groundwater, glaciers, wind and waves removes and transport it to the other places depending upon the dynamic of each of these agents. Operation by rock degrees carried by this geomorphic agents also add greatly in erosion erosion involves acquisition and transportation of rock debris‘s. When massive rocks break into smaller fragments through withering and any other process, erosional geomorphic agents like running water, groundwater, glaciers, wind and waves removes and transport it to the other places depending upon the dynamic of each of these agents. Abrasion by rock debris carried by this geomorphic agents also aids greatly in erosion.The deposition is a consequence of erosion. The erosional agents lose their velocity and hence energy on gentler slopes and the material carried by them start to settle themselves. Soil formation Soil is a dynamic medium in which many chemical, physical and biological activities go on constantly. Swann is a result of decay, it is also the medium for growth. It is a changing and developing body. It has many characteristics that fluctuate with the seasons. It may be alternatively cold and warm or dry and moist. Biological activity is slowed or stopped if the soil become too cold or too dry. Organic matter increases when leaves fall or glasses die.Process of soil formationWeathering is the first process of formation of soil.The without material or transport deposits are colonised by Victoria and other inferior plant bodies like mosses and lichens.also, several minor organism takes shelter within the mantle and deposits. The dead remains of organisms and plants help in human accumulation. Minor grasses and ferns may grow. Later, bushes and trees will start growing through the seeds brought in by birds and wind. Plant roots penetrate down, borrowing animals bring up particles, mass of material become porous and sponge-like, with a capacity to retain water and to permit passage of air. and finally a mature soil, a complex mixture of material and organic products forms.Soil forming factorsFive basic factors control the formation of soil:i. Parent materialii. Topography iii. Climateiv. Biological activity, and v. Time
T
he earth surface is being continuously subjected to by external forces originating within the earth atmosphere and by internal forces from within the earth. The external forces are known as exogenic forces and the internal forces are known as endogenic forces. The action of exogenic forces result in wearing down or basin on the earth surface. The phenomenal of wearing down of relief variations of the surface of the earth through erosion is known as gradation.
The endogenic forces continuously elevate or build up parts of earth surface and hence the exogenic processes fails to even out the relief variation of the surface of the earth. So, variations remain as long as the opposition actions of exogenic and endogenic forces continue.
Geomorphic Process
The endogenic and exogenic forces causing physical stresses and chemical action on the earth materials bring about changes in the configuration of surface of the earth are known as geomorphic processes.
Any exogenic element of nature, like water, ice, wind, etc capable of acquiring and transporting earth materials can be called geomorphic agent.
Gravity is also important geomorphic processes. Gravity is the force that is keeping us in contact with the surface and it is the force that switches on the movement of all surface on the earth. All the movements either within the earth or on the surface of the earth occurs due to gradients- from higher levels to lower level, from high-pressure to low-pressure areas etc.
Endogenic processes
The energy emanating from within the earth is the main force behind endogenic geomorphic processes. This energy is mostly generated by radioactivity, rotational and tidal friction and primordial heat from the origin of the earth.
Diastrophism
* moves, elevate or buildup portion of the earth crust.
* Can be classified into three types: a. Orogenic process, b. Epeirogenic process, c. Earthquakes, d. Plate tectonics
* Orogeny is a mountain building process whereas epeirogeny a continental building process.
* Metamorphic rocks are result of all these processes.
Volcanism
* Movement of molten rock on two or towards earth surface
* Which forms intrusive and extrusive volcanic forms
Exogenic processes
The exogenic processes drive their energy from atmosphere determined by the ultimate energy from the sun and also the gradients created by tectonic factors. All the exogenic geomorphic processes are covered under general term called denudation. Weathering, mass movements, erosion and transportation are included in denudation.
Weathering
Weathering is action of elements of weather and climate over earth materials. There are a number of processes within weathering which act either individually or together to affect the earth materials in order to reduce them to fragmental state. It is defined as a mechanical disintegration and chemical this composition of rocks through the action of various elements of weather and climate.
There are three major groups of weathering process:
i. Chemical
ii. Physical or mechanical
iii. Biological weathering processes
Chemical weathering processes
A group of weathering processes viz; Solution, carbonation, hydration, oxidation and reduction act on the rock to decompose, dissolve or reduce them to a fine clastic state through the chemical reaction by oxygen, surface and/or soil and other acid.
Physical weathering processes
Physical or mechanical weathering processes depend on some applied forces. The flight forces would be:
i. Gravitational forces such as overburden pressure, load and shearing stress.
ii. Expense forces due to temperature changes, crystal growth or animal activity.
iii. Water pressure control by waiting and drying cycles.
Biological activity and weathering
Biological withering is a contribution to for removal of minerals and irons from the weathering environment and physical changes due to growth for movement of organism. The decaying plant and animal matter help in production of humic , carbonic and other acid which enhance decay and solubility of some elements.
Significance of weathering
Withering process 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. Biomes and bio diversity is basically a result of forest and forests depend upon the depth of weathering mantles.
Weathering of rocks and deposits help in the enrichment and concentration of certain valuable ores of iron, magnesium, aluminium, copper etc which are of great importance for the national economy.
Mass movements
These movements transfer the mass of rock degrees down the slopes under the direct influence of gravity. Mass movements are aided by gravity and no geomorphic agents like running water, glacier, wind waves and currents participate in the process of mass movement.
Several activating causes precede mass movement.They are:
i. Removal of support from below materials materials through national or artificial means.
ii. Increase in gradient and height of slopes.
iii. Overloading through addition of materials naturally or by artificial filling.
iv. Overloading due to heavy rainfall, saturation and lubrication of slope material.
v. Removal of material load from over the original slope surface.
vi. Occurrence of earthquakes, explosions or machinery.
vii. Excessive natural seepage
viii. Heavy drawdown of water from lakes, reservoirs and rivers leading to slow outflow of water from under the slope or river banks.
ix. Indiscriminate removal of natural vegetation.
Landslides
These are relatively rapid and perceptible movement. The materials involved are relatively dry. The size and shape of the detached masses depend on the nature of discontinuities in the rock, the degree of weathering and steepness of the slope.
In India, debris avalanches and landslides occur very frequently in the Himalayas. There are many reasons for this. One, the Himalayas are tectonically active. They are mostly made up of sedimentary rocks and and consolidated and semi consolidated deposits. The slopes are very steep. Compare to the Himalayas, the Nilgiris bordering Tamil Nadu, Karnataka, Kerala and the Western Ghats along with west coast a relatively tectonically stable and are mostly made up of very hard rocks. But still, debris avalanches and landslides occur though not as frequently as in the Himalayas. Many slopes are steeper with almost vertical clips and escarpments in the Western Ghats and Nilgiris. Mechanical weathering due to temperature changes and ranges is pronounced. They receive heavy amount of rainfall over short periods. So, there is almost direct rockfall quite frequently in these places along with landslides and debris avalanches.
Erosion and Deposition
Erosion involves acquisition and transportation of rock debris’s. When massive rocks break into smaller fragments through withering and any other process, erosional geomorphic agents like running water, groundwater, glaciers, wind and waves removes and transport it to the other places depending upon the dynamic of each of these agents. Operation by rock degrees carried by this geomorphic agents also add greatly in erosion erosion involves acquisition and transportation of rock debris‘s. When massive rocks break into smaller fragments through withering and any other process, erosional geomorphic agents like running water, groundwater, glaciers, wind and waves removes and transport it to the other places depending upon the dynamic of each of these agents. Abrasion by rock debris carried by this geomorphic agents also aids greatly in erosion.
The deposition is a consequence of erosion. The erosional agents lose their velocity and hence energy on gentler slopes and the material carried by them start to settle themselves.
Soil formation
Soil is a dynamic medium in which many chemical, physical and biological activities go on constantly. Swann is a result of decay, it is also the medium for growth. It is a changing and developing body. It has many characteristics that fluctuate with the seasons. It may be alternatively cold and warm or dry and moist. Biological activity is slowed or stopped if the soil become too cold or too dry. Organic matter increases when leaves fall or glasses die.
Process of soil formation
Weathering is the first process of formation of soil.The without material or transport deposits are colonised by Victoria and other inferior plant bodies like mosses and lichens.also, several minor organism takes shelter within the mantle and deposits. The dead remains of organisms and plants help in human accumulation. Minor grasses and ferns may grow. Later, bushes and trees will start growing through the seeds brought in by birds and wind. Plant roots penetrate down, borrowing animals bring up particles, mass of material become porous and sponge-like, with a capacity to retain water and to permit passage of air. and finally a mature soil, a complex mixture of material and organic products forms.
Soil forming factors
Five basic factors control the formation of soil:
i. Parent material
ii. Topography
iii. Climate
iv. Biological activity, and
v. Time