weathering and erosion by ahmed bin khalil

MADE BY:- AHMED BIN KHALILCLASS:-VIII B DATE:- 9TH FEBRUARY 2015SUBJECT:-GEOGRAFYTOPIC:- WEATHERING AND EROSION

WEATHERING AND EROSION

Weathering

It refers to the general process where by rocks distintegate and decompose at or near the Earths surface.

Nature of rocksIt refers to what the rocks are made up of like

some rocks are made up of soft minerals e.g gypsum and calcitthat takes a shorter time to break down than granite which is made up of hard minerals and took longer time to break down.

Natural agentsTemperature and rainfall are the two most

influences in weathering.Plants and animals also aid in the breaking

down of rocks

Types of weatheringFollowing are the types of weathering:-

1.Physical weathering

2.Chemical Weathering

3.Biological Weathering

Types of physical weatheringAlterante expension and contraction of rocks:It occurs mainly in arid regionswhere days are hot and nights are coldso the rocks expand in day and contract at night.this continous process causes the rocks to break down.

Freeze an thaw action of ice

It occurs mainly in cold region.cold temperature causesthe water to freeze in the rocks.When the temperature falls the water melts. This contineous process causes the rocks to break down.

Release of pressure within the rocks

When the upper surface of rock marerials is removed by erosion,the pressure is released.the stress is buildup which causes the fracture to form parallel to the surface.this will than peel off over time.

Chemical weatheringIt refers to the process whereby rocks are brokendown through decomposition.

TYPES OF CHEMICAL WEATHERING1.Oxidation: It is a chemicalweathering process where the ferrous oxide in rocks reacts with rain water or oxygen in the atmosphere and turn reddish-brown.

2.CarbonationIt is the chemical weathering process ehere the calcium carbonate in rocks reacts eith rainwater and becomes weakened in structures

3.Biological weatheringIt refers to the process whereby rocks are broken down through the action of plants and animals.Plants: They sink their roots into cracks of rocks and weakens itAnimals: Burrowing animals burrow in the ground abd make tunnels in the ground.Oxygen and water enter the tunnels and rwact with minerals and breakdown the rocks.

ErosionIt refers to the removal of weathered materials from the areas where weathering had taken place.

Agents of erosionFlowing water WindsSea waves

Positive impacts:1.Weathering forms soil which supports farming activities.2.Weathered rocks materials providesraw materials e.g rocks for construction.3.Wrathering and erosion creates new landforms which promote tourism

Negative impacts:1.Erosion by flowing water by floods auses extensive damage to lives andproperties of people.2.Wind erosion causes damage in deserts.3..Mildy acidic rainwater damages buildings.

REFERENCES1.Text book 2.Google images

All the information is used for educational purpose only!

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