Soil Rocks and Minerals

Category : 5th Class

SOIL ROCK AND MINERALS

 

 

FUNDAMENTAL

Lithosphere of the earth is mainly made up of rocks and soils (natural resources).

  • Rocks are made up of grains called minerals. One or more than one minerals are present in one kind of rock.
  • Minerals can be seen or can't be seen with naked eyes. Minerals contains ores, from which metals and non-metals can be obtained profitably.
  • Rocks are formed

            (i) Inside the earth under very high temperature.

            (ii) From mud and sand under high temperature and pressures.

  • There are three kinds of rocks.

            (i) Igneous                      (ii) Sedimentary                          (iii) Metamorphic

 

Comparison between different types of rocks

 

 

Figure

Igneous Rock

Formed as a result of volcanic eruptions when magma reach the surface of the earth due to high pressure and gets solidified e.g., Basalt.

 

Sedimentary Rock

Formed from materials swept into rivers, lakes and seas and deposited there. e. g. sandstone is formed from sand.

 

Metamorphic

Rock

Metamorphic means change. These rocks are actually igneous and sedimentary rocks which are chemically changed under high temperature and pressure inside the earth. e.g., high heat turns limestone into marble.

  • Granite rock is made up of Mica, quarts, feldspar.
  • Sand stone is made up of quartz.
  • Limestone is made up of calcites

 

Some important rocks:

 

S. No.

Rock Type

Example

Property

Uses

1.

Igneous

Basalt

Dense and dark fine grains

Used in construction

2.

Igneous

Granite

Light colored, large grains

Constructing building and roads, statues

3.

Igneous

Pumice

Light colored containing dissolved gas

Scrubber

4.

Sedimentary

Sandstone

Grains of sand cemented together

Building construction

5.

Sedimentary

Conglomerate

Mass of pebbles cemented together

Used in architecture, construction and medical industry.

6.

Sedimentary

Shale

Smooth made up of clay

Tiles and bricks

7.

Sedimentary

Limestone

Thick sediments of chalk

Cement and brick metallurgy

8.

Metamorphic

Slate

Low grade metamorphic rock

Slate, black board, building

9.

Metamorphic

Marble

Colorful, can polished and carved

Statues and building

10.

Metamorphic

Gneiss

Formed from granite

Ornamental stones

11.

Metamorphic

Quartzite

Made from metamorphic of sandstone

Construction of building

 

MINERALS

A mineral is composed of an element or a chemical combination of elements. Silica is a mineral consisting oxygen, silicon and small amount of other elements.

Gem stone is a naturally occurring beautiful and attractive mineral which has got immense demand in jewelry making. These minerals are cut and polished to make jewelry.

            e.g., Diamond, Ruby, Sapphire,

 

S. No.

Mineral

Rock

1.

Pure in state

Contain more than one mineral

2.

Look attractive

Not attractive

3.

Have definite shape

No definite shape

4.

Same color through cut

Different colors, as contains different minerals of different color

5.

Have single crystal

Not single crystal

6.

e.g. Bauxite

e.g., Basalt

 

COAL

            Is an organic rock sedimentary which is formed from dead plant- fossil fuel.

 

PETROLEUM

Are formed when plants and dead animals in the     sea form in the sea from a layer of sediment on after another. The process takes millions of years.

 

SOIL

Soil is the upper most layer of earth’s surface, which is made up of the particles of rocks humus air and water. Soil contains minerals and water for survival of plants. Soil is formed from rocks by weathering. It is very slow process.

 

COMPONENTS OF A SOIL

  • Living organism
  • Air and water
  • Inorganic matter
  • Organic matter
  • Humus
  • Minerals

 

TYPES OF SOIL

Clayey

Loamy

Sandy

Size of particle less than 0.002mm;

Particle size between 0.002-0.05mm;

Particle size greater than 0.05-0.10mm;

Water holding capacity is good;

Hold sufficient air and water;

Water holding capacity is less;

Little amount of air is passed

Best suited for plants growth;

Not suitable for plant growth

Not suitable for plant growth.

Consists of clay and humus in proper amount.

 

 

RESIDUAL SOIL                                                        

            Soil which remains at the place of its formation.     

 

TRANSPORTED SOIL

  • Colluvial soil: Formed due to gravity forces.
  • Alluvial- soil is transported by flowing water.

 

MOUNTAINOUS SOIL

            This type of soil is found in mountain regions formed by clay, shale, lime stone and sandstone.

SOIL EROSION          

            Removal of the upper fertile soil layer due to weathering is called soil erosion.

 

CAUSES OF SOIL EROSION

  • Heavy rain fall
  • Wind
  • Due to overgrazing of grass
  • Cutting down of trees (deforestation)
  • Deep ploughing

 

PREVENTION OF SOIL EROSION

  • Afforestation
  • By making embankment and dam.
  • Terrance faming
  • By strip farming
  • Contour ploughing
  • Excessive grazing prevention.

Other Topics

Notes - Soil Rocks and Minerals
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