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Mineral and Power Resources Class 8 Notes Social Science Geography Chapter 3
CBSE Class 8 Geography Chapter 3 Notes Understanding the Lesson
1. Rocks on this earth have several materials mixed in term that are called minerals and minerals are scattered throughout the earth’s rocky crust.
2. Mineral is a naturally occurring substance that has a definite chemical composition.
3. Minerals are formed in different types of geological environments under varying conditions created by natural processes without any human interference.
4. Mineral can be identified on the basis of the physical properties such as colour, density, hardness and chemical property such as solubility.
5. There are over three thousand different minerals and they are classified on the basis of composition and are classified mainly as metallic and non-metallic minerals.
6. Metallic Minerals
- Contain metal in raw form.
- Metals are the hard substances that conduct heat and electricity and have characteristics lustre or shine.
- Metallic minerals may be ferrous or non-ferrous.
7. Ferrous Minerals
- Like iron ore, manganese and chromites contains iron.
8. Non-ferrous Minerals
- Does not contain iron.
- May contain other metals such as gold, silver, copper or lead.
9. Non-metallic Minerals
- Do not contain metals.
- Limestone, mica and gypsum are examples of such minerals.
- The mineral fuels like coal and petroleum are also non-metallic minerals.
- Minerals can be extracted by mining, drilling or quarrying.
10. Mining are of two types:
- Open-cast mining
- Shaft mining
11. Mining is the process of taking out minerals from rocks buried under the earth’s surface.
12. Open-cast mining is when minerals that lie at shallow depths are taken out by removing the surface layer and deep bores called shafts have to be made to reach mineral deposits that lie at great depths and this process is called shaft mining.
13. Drilling is when petroleum and natural gases occur far below the earth’s surface are taken out by deep bored wells.
14. Quarrying is the process in which minerals that lie near the surface are simply dug out.
15. Minerals occur in different types of rocks and these are found in igneous rocks, metamorphic rocks and some occur in sedimentary rocks.
- China and India have large iron ore deposits and the continent produces more than half of the world’s tin.
- Asia also has deposits of manganese, bauxite, nickel, zinc and copper.
- Leading producer of iron ore in the world.
- Minerals deposits of copper, lead, zinc, manganese and nickel are found in eastern Europe and European Russia.
18. North America
- The mineral deposits in North America are located in three zones:
- the Canadian region north of the Great Lakes.
- the Appalachian region.
- the mountain ranges of the west.
19. Western Cordilleras have vast deposits of copper, lead, zinc, gold and silver.
20. South America
- Brazil is the largest producer of high-grade iron ore in the world.
- Chile and Peru are leading producers of copper.
- Brazil and Bolivia are among the world’s largest producers of tin.
- South America also has large deposits of gold silver, zinc, chromium, manganese, bauxite, mica, platinum, asbestos and diamond.
- Rich in mineral resources.
- World’s largest producer of diamonds, gold and platinum.
- South Africa, Zimbabwe and Zaire produce a large portion of the world’s gold.
- Oil is found in Nigeria, Libya and Angola.
- Largest producer of bauxite in the world.
- Leading producer of gold, diamond, iron ore, tin and nickel.
- Kalgoorlie and Coolgardie areas of western Australia have the largest deposits of gold.
- Geology of Antarctica is sufficiently well known to predict the existence of variety of mineral deposits, some probably large.
- Significant size of deposits of coal in the Transantarctic Mountains and iron near the Prince Charles Mountains of East Antarctica is forecasted.
24. Distribution in India
- Deposit of high grade iron ore in India.
- The mineral is mainly found in Jharkhand, Odisha, Chhattisgarh, Madhya Pradesh, Goa, Maharashtra and Karnataka.
- Major bauxite producing areas are Jharkhand, Odisha, Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra and Tamil Nadu.
- Mica deposits mainly occur in Jharkhand, Bihar, Andhra Pradesh and Rajasthan. India is the largest producer and exporter of mica in the world.
- Mainly produced in Rajasthan, Jharkhand, Madhya Pradesh, Karnataka and Andhra Pradesh.
- Deposits lie in Maharashtra, M.P, Chattisgarh, Odisha, Karnataka and Andhra Pradesh.
- Major producing states in India are Bihar, Jharkhand, Odisha, M.P, Chattisgarh, Rajasthan, Gujarat and Tamil Nadu.
- Kolar in Karnataka has deposits of gold in India.
- These mines are among the deepest in the world making the mining of this ore a very expensive process.
- Obtained from sea, lakes and rocks.
- India is one of world’s leading producers and exporters of salt.
33. Uses of Minerals
- Minerals are used in many industries. Those used in gems are usually hard. Silicon is obtained from quartz and Aluminium is obtained from its ore bauxite.
- Minerals are non-renewable resources that takes thousands of years for the formation and concentration of minerals. The rate of formation is much smaller than that of its consumption.
- To conserve mineral resources it is necessary to reduce wastage in the process of mining and with the recycling of metals is another way in which the mineral resources can be conserved.
34. Power resources
- Science and technology changes the lifestyles very fastly.
- Power or energy plays vital role in our lives.
- Power resources are broadly categorised as conventional and non-conventional resources.
35. Conventional sources
- These are those energies which have been in common use for a long time.
- Firewoods and fossil fuels are the two main conventional energy.
|Widely used for cooking and heating.||Remains of plants and animals which were buried under the earth for millions of years got converted by the heat and pressure into fossil fuels.|
36. Fossil Fuel
- The reserve of these minerals are limited.
- Rate at which they are consumed due to rapid growth in population might be the reason that they get exhausted soon.
- Most abundantly found fossil fuel.
- Electricity from coal is called thermal power.
- Coal is referred to as buried sunshine because coal which is used today was formed millions of years ago when giant ferns and swamps got buried under the layers of earth.
- It is found between the layers of rocks and is drilled from oil fields located in off-shore and coastal areas. Then this is sent to refineries which process the crude oil and produce a variety of products.
- Petroleum and its derivatives are called Black Gold because they are very valuable.
39. Natural gas
- Found with petroleum deposits and is released when crude oil is brought to the surface.
- Very few countries of the world have sufficient natural gas reserves of their own.
40. Hydel Power
- Rainwater or river water stored in dams is made to fall from heights. The falling water flows through pipes inside the dam over turbine blades placed at the bottom of the dam and the moving blades then turn the generator to produce electricity. This is called hydroelectricity.
- One-fourth of the world’s electricity is produced by hydel power.
41. Non-Conventional Sources of Energy
- The increasing use of fossil fuels is leading to its shortage. It is estimated that if the present rate of consumption continuous, the reserves of these fuel will get exhausted.
- There is need for using non-conventional sources such as solar energy, wind energy, tidal energy the energy which can be renewed.
42. Solar Energy
- Solar energy trapped from the sun can be used in solar cells to produce electricity.
- The technology of utilizing solar energy benefits a lot of tropical countries that are blessed with abundant sunshine.
43. Wind Energy
Wind an inexhaustible source of energy. Windmills have been used for grinding grain and lifting water since times immemorial. In modem time windmills, the high-speed winds rotate the windmill which is connected to a generator to procedure electricity.
44. Nuclear Power
- Obtained from energy stored in the nucleic of atoms of naturally occurring radioactive elements like uranium and thorium.
- These fuels undergo nuclear fission in nuclear reactors and emit power.
- The greatest producers of nuclear power are U.S.A and Europe.
- In India Thorium is found in large quantities in Monazite sands of Kerala.
- The nuclear power stations in India are located in Kalpakkam in Tamilnadu, Tarapur in Maharashtra Ranapratap Sagar near Kota in Rajasthan, Narora in Uttar Pradesh and Kaiga in Karnataka.
45. Geothermal Energy
- Heat energy obtained from the earth is called geothermal energy.
- The temperature in the interior of the earth rises steadily as we go deeper and some times this heat energy may surface itself in the form of hot springs. This heat energy can be used to generate power.
- USA has the world’s largest geothermal power plants.
- In India, geothermal plants are located in Manikaran in Himachal Pradesh and Puga Valley in Ladakh.
46. Tidal Energy
- Energy generated from tides is called tidal energy.
- Tidal energy can be harnessed by building dams at narrow openings of the sea. During high tide the energy of tides is used to turn the turbine installed in the dam to produce electricity.
- Russia, France and the Gulf of Kachchh in India have huge tidal mill farms.
- Organic waste such as dead plant and animal material, animal dung and kitchen waste can be converted into a gaseous fuel called biogas.
- The organic waste is decomposed by bacteria in biogas digesters to emit biogas which is essentially a mixture of methane and carbon dioxide.
- Energy exists on our earth in several forms but saving energy rather than wasting it is more compulsory because the energy saved is the energy generated.
Mineral and Power Resources Class 8 CBSE Notes Important Terms
Mineral: a naturally occurring substance that has a definite chemical composition is a mineral.
Rock: An aggregate of one or more minerals but without definite composition of constituent of mineral.
Ore: Rocks from which minerals are mined are known as ores.
Mining: The process of taking out minerals from rocks buried under the earth’s surface is called mining.
Quarrying: Minerals that lie near the surface are simply dug out, by the process known as quarrying.
Petroleum: It is derived from Latin words – Petra meaning rock and oleum meaning oil. So petroleum means rock oil.
Geothermal Energy: Heat energy obtained from the earth is called geothermal energy.
Tidal Energy: It is the energy generated from the tides.