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(b) in carbonation

(c) in glacial regions

(c) Mass Translocation

Correct Answer is: (a) Attrition

Movement and transfer of rock debris in massive amount along a slope due to gravitational force is called Mass Translocation. The gravitational force is responsible for the rolling down of unorganized rock debris. Creeping down the slopes, the rock particles accumulate in the foothills. This accumulation or pile of rocks – flour is called Talus.

A cone – shaped accumulation of loose rocks is called Talus Cone.

On the basis of the amount and speed of creeping or rolling down of unorganized loose materials, mass translocation is classified into the following three groups:

1. Mass translocation with gradual flow: Due to less amount of moisture, the rocks – flour creeps slowly. The action of gradual flow occurs mostly in sub-polar cold regions. Earth Creep, Rock Creep, Talus Creep and Soil Creep are included under the action of gradual flow. 

2. Mass translocation with rapid flow: Due to the adequacy of water, the rocks – flour gets saturated and creeps rapidly. Earth flow, Mud flow and Sheet flow are included under rapid flow. Mud flow can be seen creeping on the walls of the river valleys. 

3. Mass translocation with extreme rapid flow: Moisture of water is not necessary for extreme rapid flow. Large rock fragments start falling suddenly by gravitational force. Landslide, Rock Slide, Rock Fall, Landslip and Debris Fall are included in extreme rapid flow.

The process by which the cover of rocks of the crust gets removed is called Denudation. This process of denudation completes the action of leveling by the medium of exogenetic forces. Denudation is regarded as the combined result of weathering, erosion and mass translocation. On this basis. 

It is classified into the following parts:

Weathering: Weathering is a spatial process in which the rocks break down by disintegration and decomposition at their own place. The process of weathering completes mainly in the form of physical, chemical and biological weathering. This process of weathering is affected by the structure and organization of rocks, slope of land, diversity in climate and vegetation. In this, the amount and periodicity of insolation, nature of glacier, structure of rocks and the effect of water and gases on them are included.

Erosion: The word Erosion is made from the Latin word ‘Erodere’, the meaning of which is to rub or to nibble. Erosion is a dynamic process in which rocks keep on disintegrating by being rubbed, eroded, translocated or transported through glaciers, underground water, waves, air and rivers. The process of erosion takes place due to corrasion, attrition, hydraulic action, corrosion, deflation, cavitation and plucking.

Mass Translocation: Movement and transfer of rock debris in massive amount along a slope due to gravitational force is called Mass Translocation. Gravitational force is responsible in rolling down of unorganized rock debris. Creeping down the slopes, the rock particles accumulate in the foothills. This accumulation or pile of rocks – flour is called Talus. On the basis of the amount of rolling or creeping of unorganized loose materials, the mass translocation is classified in the form of gradual flow, rapid flow and extreme rapid flow.

The process of the movement and transfer of rock debris in massive amount along a slope duetto gravitational force, is called Mass Translocation.

Mass Translocation is classified into three parts: mass translocation with gradual flow, with rapid flow and with extreme rapid flow.

Weathering is a spatial process in which the rocks break down by disintegration and decomposition at their own place.

Types of Weathering: The process of weathering takes place in various forms. Considering the various components as the basis. 

weathering is classified into the following types:

1. Physical Weathering: Process of disintegration in the rocks by insolation, frost, water and wind is called Physical Weathering. It has the following types:

(a) Block Disintegration: In hot desert regions, cracks occur in the rocks due to extreme daily range of temperature. Over time/these rocks disintegrate into large pieces. 

(b) Exfolation: Breaking of rocks in the form of shells when the upper layer of rocks remain heated and the inner layers cool down. 

(c) Frost Weathering: In extreme cold regions, the breaking down of rocks due to the freezing and melting of water in the cracks of rocks on regular basis.

(d) Pressure Release: When the removal of upper rocks reduces the pressure on the lower rocks, then the cracks start appearing in the rocks.

2. Chemical Weathering: When the rocks break, dissolve, decay and change into new compounds by the action of water and gas in a chemical process , it is called Chemical Weathering. 

It is classified into the following parts:

(a) Oxidation: The atmospheric oxygen dissolves in water to change rock minerals into oxides by which decomposition of the rocks takes place. 

(b) Carbonation: The atmospheric carbon – dioxide gas dissolves in water to form carbonic acid by which the lime-rocks dissolve. 

(c) Desilication: Process of separation of silica from rocks. 

(d) Hydration: Absorption of water in rock minerals is called Hydration. Rocks scatter by the process of absorption of water.

(e) Dissolution: Rainwater dissolves many types of acids and carbonic elements in the rockmaterials and creates new chemical compounds. This reaction is called Dissolution.

3. Biological Weathering: Biological weathering is the weakening and subsequent disintegration of rock by vegetation and living organisms. 

It has the following types:

(a) Weathering by vegetation: Roots of trees enter into the rocks and disintegrate them. 

(b) Weathering by animals: Disintegration of rocks by earthworm, termite, rats, etc. 

(c) Weathering by humans: Weathering taking place due to agricultural, mining and construction activities done by human beings.

Changes take place in the configuration of the earth’s surface due to the physical pressure and chemical processes by endogenetic and exogenetic forces.

Two types of forces work in the formation of the earth’s surface:

1. Endogenetic Forces 

2. Exogenetic Forces

Endogenetic forces originate from deep down the surface and work at a very slow speed. By this, mountains are formed and unevenness is created on the earth’s surface. Undesirable incidents also occur by some endogenetic forces like volcanic eruption, earthquake, etc. Exogenetic forces originate above the surface and work right opposite to the endogenetic forces, thereby trying to reduce the relief.

In this process, somewhere they do the work of erosion and somewhere accumulation. In this way, the unevenness of the earth’s surface reduces by exogenetic forces. Thus, these forces are also called ‘Level Establishing Force’. The opposite work of both the forces remains as long as the opposing action of endogenetic and exogenetic forces continue. In this way, it is said that the Earth is the playground of geomorphic processes of two opposing groups.

Important factors of the Activation of Mass Movement: 

The important factors providing activation to mass movement are as follows:

1. By natural and artificial agents, the removal of the base, which supports the materials at the top. 

2. Increase in the height and intensity of slope. 

3. Materials to be of heavy weight. 

4. Overload resulting due to the lubrication of saturated materials of slope by excessive rainfall. 

5. Removal of materials from the surface of original slope. 

6. Earthquake 

7. Vibrations caused by explosives or machines. 

8. Excess of natural leakage. 

9. Excessive exploitation of water from river, lake and other water reservoirs, and gradual flow of water from down the river banks and slopes. 

10.Indiscriminate exploitation of vegetation.

Weathering is a spatial process, in which the rocks disintegrate and decompose at their own place. Mainly, there are three types of weathering:

1. Physical Weathering: It is further classified into Block Disintegration, Exfolation, Frost Weathering and Pressure Release. 

2. Chemical Weathering: This type of weathering is further classified into Oxidation, Carbonation, Desilication, Hydration and Dissolution. 

3. Biological Weathering: This type of weathering is classified into weathering by vegetation, weathering by animals and weathering by humans.

American Geomorphologist, William Morris Davis propounded the concept of Cycle of Erosion in 1899. He explained, “During the period of Erosion Cycle, the uplifted terrain on being eroded, transforms into shape – less pedeplain.” For the presentation of Cycle of Erosion, Davis considered the three elements important: structure, process and stage. These three are known by the name of Trikoot of Davis. 

Their brief description is as follows:

1. Structure: First, rock structure develops on a terrain. After that, various landscapes form there. 

2. Process: In the development of landscapes or land forms, any of the transformational processes like river, wind, waves, glacier, underground water, etc. plays a vital role. 

3. Stage: Like human life, there is a certain period of time for the development of landscapes. In the Erosion Cycle, Davis considered the direct connection between uplift and erosion. According to him, one of the two processes of uplift and erosion takes place at a time. When there is uplift, there is no erosion; and when there is erosion, there is no uplift. Erosion begins only when the uplift ends. 

The Erosion Cycle of Davis is classified into the following three stages:

• Youth Stage 
• Mature Stage 
• Old Stage.

Youth Stage: In this stage, erosion begins after the ending of uplift. In this stage, the river flows along an uneven surface and there is intensive bottom erosion, the gradients are steep and the erosion is rapid. The rapid deepening of the channel leads to the formation of V-shaped valleys.

Mature Stage: In this stage, lateral erosion begins whereby the valleys begin to widen rather than deepen. In this stage, the velocity of rivers reduces due to gentle slope, and this decreases their transportation capacity. Most of the rivers get levelled according to the base surface of the erosion.

Old Stage: In this stage, unevenness of the earth’s crust reduces. The entire area transforms into a pedeplain. Absolute and relative relief both are minimized. The valleys become shallow and extremely broad, and their lateral slope is concave in shape.

(a) Spatial process

Davis classified the Cycle of Erosion into three main stages: 

1. Youth Stage 

2. Mature Stage 

3. Old Stage

1. Youth Stage: In this stage, the river flows along an uneven surface and there is intensive bottom erosion, the gradients are steep and the erosion is rapid. The rapid deepening of the channel leads to the formation of V – shaped valleys. 

2. Mature Stage: In this stage, river widens the valley by lateral erosion. The bottom is eroded by the lateral erosion in this stage, by which the V – shaped valleys usually converts into a U – shape. 

3. Old Stage: In this stage, unevenness of the earth’s crust reduces and the entire area transforms into a pedeplain. In this stage, the slope is almost non-existent and the water spreads around.

Water of glaciers uproots the rock fragments coming in their way and carries them along, this process is called Plucking. The process of plucking takes place in glacial regions.

On the basis of their causative factors, Biological Weathering is classified as follows: 

1. Weathering by Vegetation: Roots of different types of trees by entering into the rocks make their particles loose, due to which dis – integration in the rocks takes place. This is called weathering by vegetation. 

2. Weathering by Living Organisms: This weathering takes place when the rocks are disorganized by various living – organisms like earthworm, termite, rats and animals. 

3. Weathering by Humans: When the rocks are disorganized by various human activities like mining, agriculture, construction, atomic explosion, it is included in the weathering by humans.

(c) Erosion, Weathering and Mass Translocation

Structure, process and time (stage) are known as the Trikoot of Davis.

The denudation is a collective process of weathering, erosion and mass translocation.

The process by which the cover of rocks of the crust is eroded, is called denudation. This process enables the leveling of different land forms created by endogenetic forces. In this, after the fragmentation of uplifted landmass, its transportation, erosion, attrition and mass translocation take place. Eventually, by these processes, the uplifted terrain transforms into the lower terrain.

The disintegration of rocks by the action of physical factors like insolation, frost, water and wind pressure is called Physical Weathering.

The factors that affect weathering include the structure and organization of rocks, slope of land, diversity of climate and vegetation.

The rock fragments or rock particles when carried by the air, water and glacier, smash together and break into smaller particles. This process is called Attrition.

The absorption of water in rock minerals is called Hydration.

By the chemical action of water, when the minerals of rocks dissolve in water and flow away, it is called Corrosion. This process of corrosion promotes the process of erosion.

Physical Weathering: Process of disintegration in the rocks by insolation, frost, water and wind is called Physical Weathering. 

The process of physical weathering is classified into the following parts:

1. Block Disintegration: In this type of process, due to extreme daily range of temperature, cracks occur in the rocks and they disintegrate into large pieces. 

2. Exfolation: Breaking of rocks in the form of shells when the upper layer of rocks remain heated and the inner layers cool down. 

3. Frost Weathering: In extreme cold regions, the breaking down of rocks due to freezing and melting of water in the cracks of rocks on regular basis.

4. Pressure Release: When the removal of upper rocks reduces the pressure on the lower rocks, then cracks start appearing in the rocks. This process is called Pressure Release.

(c) Tropical and Humid

When the rocks break, dissolve, decay and change into new compounds by the action of water and gas by chemical process, it is called Chemical Weathering.

When the removal of upper rocks reduces the pressure on the lower rocks, then cracks start appearing in the rocks. This process is called Pressure Release.

Correct Answer is: (c) Weathering

The action of breaking down of rocks into the fragments by the fragmentation of organized rocks is called Disintegration.

Correct Answer is: (b) Exfolation

Frost Weathering occurs in extreme cold regions, when the rocks break down due to the freezing and melting of water in the cracks of rocks on regular basis.

(b) in humid tropics

When the atmospheric oxygen dissolves in water to change rock minerals into oxides, then this process is called Oxidation.

The atmospheric carbon dioxide gas (CO2) dissolves in water to form carbonic acid. On coming in contact with it, the lime – rocks dissolve rapidly. This process is called Carbonation.

Carbonation is a type of chemical weathering in which the atmospheric carbon – dioxide gas dissolves in water to form carbonic acid, which in turn erodes lime rocks rapidly.

Oxidation is a type of chemical weathering in which atmospheric oxygen dissolves in water to change rock minerals into oxides.

Erosion is a dynamic process in which rocks keep on disintegrating by being rubbed, eroded, trans – located and transported through glaciers, underground water, waves, wind and rivers.

Block Disintegration is a type of physical weathering, in which cracks occur in the rocks and they disintegrate due to extreme daily range of temperature.

The process of attrition takes place in erosion. In this process, the rock fragments or particles being carried by wind, river or sea waves smash together and break into smaller particles.

(d) Daily range of temperature is high

The process of gradual-flow mostly takes place in sub – polar cold regions.

The extreme rapid flow is seen mainly in the forms of Landslide, Rock Slide, Rock Fall, Landslip, Debris Fall and Slumping.

Correct Answer is: (d) Slumping

Forces which originate in the internal part of earth are called Endogenetic Forces. New terrains are formed on the earth’s surface by these forces.

Forces originating or acting on the surface of earth are called Exogenetic Forces. The process of leveling is done mainly by these forces.

1. Barchans are moon-shaped dunes. They are live dunes which advance steadily before winds that blow from a particular direction. 

2. They occurs transversely to the wind, so that their horns thin out and become lower in the direction of the wind. 

3. The windward side is convex and gently-sloping while the leeward side (being sheltered) is concave and steep.

River meanders are bends of longitudinal courses. S-shaped meanders which are common to most rivers result when a ^ channel-forms a curved path. These are the result of both erosion and deposition work of rivers. Meanders generally form under conditions of a gentle slope and sufficient water in rivers. The river flow is diverted by an obstruction allowing the river to do lateral erosion work