Geomorphic Processes

Erosion is the breakdown of the soil or rock fragments by agents of denufdation like running water, wind, ice etc.

Salts chemically react with water; some dissolve in it and are easily affected by water.

Debris avalanche is the collapse from an unstable side of a volcano. It is grouped under rapid flow mass movements.

(i) Weathering is responsible for bio-diversity of the earth. The rock particles are broken into fine dust particles and are blown. The forest depends upon the depth on weathering mantles. Biomes and biodiversity is a result of forests and vegetation. Therefore weathering is responsible for the bio-diversity of the earth.

(ii) Mass movements transfer the rock particles down the slope under the influence of gravity. The mass movements that are real rapid and perceptible are as follows:-

• Earth flow

• Mud flow

• Landslide

(iii) Weathering, erosion, transportation, deposition are the various mobile and mighty exogenic geomorphic agents. These agents bring changes on the surface of the Earth.

(iv) Yes. Weathering is the pre-requisite for the formation of soils. It breaks the rocks into fine dust particles or smaller fragments and then the soil formation takes place.

(i) The earth’s crusty is dynamic, it moves vertically and horizontally. The differences in the internal forces operating within the earth’s crust which is responsible for the variation on the earth’s crust. The earth’s surface is continuous subjected to external forces included basically by energy. They are active through with different intensities. The earth’s surface is continuously subjected to external and internal pressure. The external forces are known as exogenic forces and the internal forces are called endogenic forces. The actions of exogenic forces result in wearing down of relief or elevations and filling up of basins/depressions on the earth surface. The endogenic forces continuously elevate or build up parts of earth’s surface. So variations remain as long as opposing actions of exogenic and endogenic forces continue.

(ii) Exogenic forces act on the surface of the earth. All these forces derive their energy from the sun. Sunlight causes air to move, water to evaporate, and ocean waves to rise. These moving waves like water, waves attack the solid surface and erode it and deposit at faraway places. Erosion involves acquisition and transportation of rock debris. The erosion and transportation of earth materials are brought about by the wind, running water, glaciers. The climate is decided by the energy of the sun.

All geomorphic processes derive their energy form the sun but the gravitational force of the earth is also responsible because it enables mobility.

(iii) Weathering is action of elements of weather and climate over earth materials and rocks. Physical and chemical processes are not independent of each other. They are inter-dependant. Physical weathering processes depend on some applied forces such as the gravitational force, stress water pressure controlled by wetting and drying cycles. While in chemical weathering processes like oxidation, hydration, reduction, act on the rocks to decompose, dissolver or erode them in small fragments by chemical reactions.

Chemical weathering process depends on the work of physical weathering process. The agents of physical weathering such as temperature change and freezing break the rocks and provide chemical weathering process. It makes the rocks decayed which are broken down by physical weathering processes.

(iv) The pre requisite of soil is weathering. It enables the rock particles to break into tiny granules or smaller fragments. Soil formation is responsible for the number of factors. Weathering is the first and prime important for soil formation. Then the colonisation of bacteria, lichen, mosses, and sheltering of other organisms in the soil help in formation of humus. Then other grasses, plants, twigs get mixed to it and make the soil fertile. As air gets into it, the soil gets nourished.

Soil forming factors control the formation of the soils. There are five steps:

• Parent material

• Topography

• Climate

• Biological activity

• Time

The climate and biological activities play very important role. The climatic elements involved in the soil development are moisture and temperature. Rain gives the soil moisture which makes the chemical and biological activities possible. Excess of water helps in the downward transportation of soil components through the soil and deposits the same below. Temperature acts in increasing or decreasing biological activity.

Biological activity includes the effects of vegetative cover, organisms and bacteria. The vegetative cover and organism help in adding organic matter, humus, moisture, nitrogen. Dead plants also provide humus. It makes the soil fertile.

I live in Kolkata. The following details are as follows:-

1. Climate- Tropical wet and dry climate with mean temperature is 32°C.

2. Soil - Kolkata has alluvial soil because of its deposits on the banks of river Ganga. Laterite soil is also common. Therefore agriculture flourishes in Kolkata and its surroundings.

3. Weathering process- The main weathering process in Kolkata is running water as there are lot of rivers like Damodar, Ganga etc. Wind transportation is also common.

The speed of the rotation of the earth is responsible for this. The difference in the internal forces operating from within the earth which built up the crust is responsible for the variations in the Earth’s crust.

The endogenic and exogenic forces on the Earth that are causing physical stress and chemical processes on the Earth’s surface are called geomorphic process. Running water, ground water, glacier, wind are known as geomorphic agents. These agents are important because they shape up various landforms of the earth.

Volcanism can be defined as the movement of the magma onto or towards the Earth’s surface leading to formation of intrusive and extrusive volcanoes.

Volcanoes are rupture in the crust of a planetary mass object which allows the magma and hot gases to escape from interior of the earth’s surface.

The slopes or gradients are created due to natural disaster like earthquake which forms earthquake slopes, tsunami e creates mountain folding. The pressure beneath the earth is the main reason. Sometimes the continental plates collides which leads to the formation of slopes or gradients.

The gravitational force of the Earth is the sole driving force behind all exogenic process.

Weathering is defined as the disintegration of rocks and other particles by the agents of denudation like moving water, wind, glaciers etc. It is not synonymous with transportation. The particles are carried by some agents.

Yes iron rusting is an example of chemical oxidation.

In chemical weathering process in rocks like feldspar, granite. When water comes in contact with these rocks, a chemical reaction takes places which erode the rocks thereby weakening it.

No it can’t dominate in water scarce hot deserts.

Mass wasting is the removal of rock debris or the material of earth under the gravity.

Mass wasting suits better than mass movement as this leads to removal of large amount of earth’s crust and also wastage of valuable rock/minerals over a surface. The mass movements also create large destruction over the place they occur. Hence the word wasting is appropriate.

Solidification occurs when the upper portion gets water saturated and material starts flowing in tongue shaped. This is a slow movement.

The course or velocity of the agents of denudation decides the area where the eroded materials will be landed. So if the speed is low it may land in the same area or if it is high it lands in a different area.

Rocks are hard formed by minerals so there isn’t a possible of erosion if the rock is not undergoing weathering.

No. Soil formation is responsible for the number of factors. Weathering is the first and prime important for soil formation. Then the colonisation of bacteria, lichen, mosses, and sheltering of other organisms in the soil help in formation of humus. Then other grasses, plants, twigs get mixed to it and make the soil fertile. As air gets into it, the soil gets nourished.

Soil formation or pedogenesis depends on weathering while soil forming factors act in union and affect the action of one another. In soil formation, it is this weathering mantle which is basic input for the soil to form and other factors play around it.

Time, topography, parent material are considered as passive control factors in soil formation because their effects are not immediately observed. They control soil development and formation.