Geography [2 Mark Question Answer]

Rapid mass movement includes large amount of debris, soil, boulders and rock pieces etc, e.g. landslides and sheet erosion or displacement of the upper rock strata in large amount to uncover the rocks lying below.

Slow movements of mass wasting a be divided into two
main types — Creep and Solifluction.
Creep: The slow downhill movement of debris is called soil creep.
Solifluction: The water mixed with soil forms clay which moves as a thick viscous fluid.

Tropical climates are noted for distinct dry and wet season and high rate of evaporation. During the rainy season the oxides of iron and aluminium are dissolved in water and mix up with the soil to form laterite soils.

Loess and Alluvium: Alluvial soils are formed by the depositional activity of running water and loess by the wind. Alluvium contains high mineral and humus content, and loess is highly permeable.

Weathering and Denudation:
Weathering is a process 4 of the gradual disintegration of rocks by atmospheric or weather forces. Denudation is a process of wearing away of land and it includes weathering also.

The break-down but not removal of rocks is called weathering. It is a process of wearing away of land through forces of nature like weather, running water, ocean currents, etc. Weathering is a single process and takes place in the air.

Because it involves the physical disintegration of rocks. Physical disintegration is quickest when rock is already weakened by chemical weathering. So it is primarily known as mechanical weathering.

Weathering may be :

1. Mechanical : weathering is the disintegration of rocks by mechanical forces, without chemical changes.
2. Chemical : weathering is the gradual decomposition of the rock owing to the reaction and combination of the constituent minerals of the rock with oxygen or carbon dioxide present in the atmosphere. In Chemical weathering the presence of water is essential.

Sheet Erosion :

• Sheet Erosion causes washing out the upper layer of soil and vegetation cover due to heavy rainfall or floods.

Gully Erosion :

• Through gully erosion deep cuts, cracks and trenches are carved in the soil-bed, These tend to be deeper channels known as ‘gullies’.

Weathering and Denudation:
Weathering is a process 4 of the gradual disintegration of rocks by atmospheric or weather forces. Denudation is a process of wearing away of land and it includes weathering also.

The factors influencing the formation of soils are the parent rock, topography, vegetation, climate, and time span. Out of these climates is the most important because it controls the type of weathering the first step of the soil formation process.

According to the texture (sizes of the soil particles), the soil is divided into three main types i.e. Clay, loam (silt) and sandy loam (sand gravel), the diameter of soil particles ranges from .0002 mm to more than 2 mm. Soil structure refers to the physical arrangement of the soil.

Sheet Erosion :

• Sheet Erosion causes washing out the upper layer of soil and vegetation cover due to heavy rainfall or floods.

Gully Erosion :

• Through gully erosion deep cuts, cracks and trenches are carved in the soil-bed, These tend to be deeper channels known as ‘gullies’.

Mechanical Weathering :

• It is done by the change in temperature and action of ice which breaks the rocks into small pieces.

Chemical Weathering :

• It is done by oxidation hydration, carbonation, and solution, etc chemical processes which causes the breaking of rocks.

Weathering and Denudation:
Weathering is a process 4 of the gradual disintegration of rocks by atmospheric or weather forces. Denudation is a process of wearing away of land and it includes weathering also.

A highly dissected land surface is known as badland. In sloping areas, gully erosion results in soil erosion. These gullies develop a ravine land a badland topography. This topography consists of ridges, earth pillars, ravines, escarpments, etc. This topography is found in Chambal Valley of Madhya Pradesh in India

The following atmospheric gases help in the process of chemical weathering:

1. Oxygen
2. Hydrogen
3. Carbon dioxide

Equatorial region is noted for more active chemical weathering due to excess of temperature and water; the tropical region is remarkable for the formation of laterite soil by mixing of oxides of iron and aluminium in the soil due to change in heating and much evaporation.

Denudation is the process of wearing away of rock-strata by water, wind, and ice along with the change in weather and temperature.
Gradation is the process of leveling down the whole landform gradually to ground level by various agents of the change mainly water, (rivers), wind and ice (glaciers), etc.