Geography X NCERT chapter 5 key points

                      IAS Prelims Preparation 2018

Day # 31 (April 23, 2017)

Topics of the day: Geography X NCERT chapter 5 key points

CHAPTER 5 – MINERAL AND ENERGY RESOURCES

- Geologists define mineral as a ―homogenous, naturally occurring substance with a definable internal structure.‖

- Minerals are found in varied forms in nature, ranging from the hardest diamond to the softest talc.

- Rocks are combinations of homogenous substances called minerals.

- Minerals are usually found in ―ores‖. The term ore is used to describe an accumulation of any mineral mixed with other elements.

- Minerals generally occur in these forms:

(i) In igneous and metamorphic rocks minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are called lodes. In most cases, they are formed when minerals in liquid/ molten and gaseous forms are forced upward through cavities towards the earth‘s surface. They cool and solidify as they rise. Major metallic minerals like tin, copper, zinc and lead etc. are obtained from veins and lodes.

(ii) In sedimentary rocks a number of minerals occur in beds or layers. They have been formed as a result of deposition, accumulation and concentration in horizontal strata. Coal and some forms of iron ore have been concentrated as a result of long periods under great heat and pressure. Another group of sedimentary minerals include gypsum, potash salt and sodium salt. These are formed as a result of evaporation especially in arid regions.

(iii)Another mode of formation involves the decomposition of surface rocks, and the removal of soluble constituents, leaving a residual mass of weathered material containing ores. Bauxite is formed this way.

(iv)Certain minerals may occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called placer deposits‘ and generally contain minerals, which are not corroded by water. Gold, silver, tin and platinum are most important among such minerals.

(v)The ocean waters contain vast quantities of minerals, but most of these are too widely diffused to be of economic significance. However, common salt, magnesium and bromine are largely derived from ocean waters. The ocean beds, too, are rich in manganese nodules.

Ferrous Minerals

Ferrous minerals account for about threefourths of the total value of the production of metallic minerals.

They provide a strong base for the development of metallurgical industries. India exports substantial quantities of ferrous minerals after meeting her internal demands.

Iron Ore

 Iron ore is the basic mineral and the backbone of industrial

development.

 India is endowed with fairly abundant resources of iron ore.

 India is rich in good quality iron ores.

 Magnetite is the finest iron ore with a very high content of iron up to 70 per cent. It has excellent magnetic qualities, especially valuable in the electrical industry.

 Hematite ore is the most important industrial iron ore in terms of the quantity used, but has a slightly lower iron content than magnetite. (50-60 per cent).

 The major iron ore belts in India are:

(a) Odisha-Jharkhand belt: In Odisha high grade hematite ore is found in Badampahar mines in the Mayurbhanj and Kendujhar districts. In the adjoining Singbhum district of Jharkhand haematite iron ore is mined in Gua and Noamundi.

(b)Durg-Bastar-Chandrapur belt lies in Chhattisgarh and Maharashtra. Very high grade hematites are found in the famous Bailadila range of hills in the Bastar district of Chhattisgarh. The range of hills comprise of 14 deposits of super high grade hematite iron ore. It has the best physical properties needed for steel making. Iron ore from these mines is exported to Japan and South Korea via Vishakhapatnam port.

(c)Ballari-Chitradurga-Chikkamagaluru Tumakuru belt in Karnataka has large reserves of iron ore. The Kudremukh mines located in the Western Ghats of Karnataka are a 100 per cent export unit. Kudremukh deposits are known to be one of the largest in the world. The ore is transported as slurry

through a pipeline to a port near Mangaluru.

(d)Maharashtra-Goa belt includes the state of Goa and Ratnagiri district of Maharashtra. Though, the ores are not of very high quality, yet they are efficiently exploited. Iron ore is exported through Marmagao port.

Manganese

 Manganese is mainly used in the manufacturing of steel and ferromanganese alloy.

 Nearly 10 kg of manganese is required to manufacture one tonne of steel.

 It is also used in manufacturing bleaching powder, insecticides and paints.

 Odisha is the largest producer of manganese ores in India.

Non-Ferrous Minerals

India‘s reserves and production of non- ferrous minerals is not very satisfactory.

However, these minerals, which include copper, bauxite, lead, zinc and gold play a vital role in a number of metallurgical, engineering and electrical industries.

Copper

 India is critically deficient in the reserve and production of copper.

 Being malleable, ductile and a good conductor, copper is mainly used in electrical cables, electronics and chemical industries.

 The Balaghat mines in Madhya Pradesh, Khetri mines in Rajasthan and Singhbhum district of Jharkhand are leading producers of copper.

 Bauxite Though, several ores contain aluminium, it is from bauxite, a clay-like substance that alumina and later aluminium is obtained.

 Bauxite deposits are formed by the decomposition of a wide variety of rocks rich in aluminium silicates.

 Aluminium is an important metal because it combines the strength of metals such as iron, with extreme lightness and also with good conductivity and great malleability.

 India‘s bauxite deposits are mainly found in the Amarkantak plateau, Maikal hills and the plateau region of Bilaspur-Katni.

 Odisha was the largest bauxite producing state in India.

 Panchpatmali deposits in Koraput district(odisha) are the most

important bauxite deposits in the state.

Non-Metallic Minerals

Mica

 It is a mineral made up of a series of plates or leaves.

 It splits easily into thin sheets.

 These sheets can be so thin that a thousand can be layered into a mica sheet of a few centimeters high.

 Mica can be clear, black, green, red yellow or brown.

 Due to its excellent di-electric strength, low power loss factor,

insulating properties and resistance to high voltage, mica is one of the most indispensable minerals used in electric and electronic

industries.

 Mica deposits are found in the northern edge of the Chota Nagpur plateau. Koderma Gaya – Hazaribagh belt of Jharkhand is the leading producer.

 In Rajasthan, the major mica producing area is around Ajmer.

 Nellore mica belt of Andhra Pradesh is also an important producer in the country.

Rock Minerals

Limestone

 It is found in association with rocks composed of calcium carbonates or calcium and magnesium carbonates.

 It is found in sedimentary rocks of most geological formations.

 Limestone is the basic raw material for the cement industry and essential for smelting iron ore in the blast furnace.

Coal:

 In India, coal is the most abundantly available fossil fuel.

 It provides a substantial part of the nation‘s energy needs.

 It is used for power generation, to supply energy to industry as well as for domestic needs.

 India is highly dependent on coal for meeting its commercial energy requirements.

 Lignite is a low grade brown coal, which is soft with high moisture content. The principal lignite reserves are in Neyveli in Tamil Nadu and are used for generation of electricity.

 Coal that has been buried deep and subjected to increased

temperatures is bituminous coal. It is the most popular coal in

commercial use. Metallurgical coal is high grade bituminous coal

which has a special value for smelting iron in blast furnaces.

 Anthracite is the highest quality hard coal.

 In India coal occurs in rock series of two main geological ages,

namely Gondwana, a little over 200 million years in age and in

tertiary deposits which are only about 55 million years old.

 The major resources of Gondwana coal, which are metallurgical coal, are located in Damodar valley (West Bengal-Jharkhand). Jharia, Raniganj, Bokaro are important coalfields.

 The Godavari, Mahanadi, Son and Wardha valleys also contain coal deposits.

 Tertiary coals occur in the north eastern states of Meghalaya, Assam, Arunachal Pradesh and Nagaland.

 Remember coal is a bulky material, which loses weight on use as it is reduced to ash. Hence, heavy industries and thermal power stations are located on or near the coalfields.

Petroleum

 Petroleum or mineral oil is the next major energy source in India after coal. It provides fuel for heat and lighting, lubricants for machinery and raw materials for a number of manufacturing industries.

 Petroleum refineries act as a ―nodal industry‖ for synthetic textile, fertiliser and numerous chemical industries.

 Most of the petroleum occurrences in India are associated with

anticlines and fault traps in the rock formations of the tertiary age.

 In regions of folding, anticlines or domes, it occurs where oil is

trapped in the crest of the upfold.

 The oil bearing layer is a porous limestone or sandstone through which oil may flow.

 The oil is prevented from rising or sinking by intervening non-porous layers.

 Petroleum is also found in fault traps between porous and nonporous rocks.

 Gas, being lighter usually occurs above the oil.

 About 63 per cent of India‘s petroleum production is from Mumbai High, 18 per cent from Gujarat and 16 per cent from Assam.

 Ankeleshwar is the most important field of Gujarat.

 Assam is the oldest oil producing state of India.

 Digboi, Naharkatiya and Moran-Hugrijan are the important oil fields in the state.

Natural Gas

 It is an important clean energy resource found in association with or without petroleum.

 It is used as a source of energy as well as an industrial raw material in the petrochemical industry.

 Natural gas is considered an environment friendly fuel because of low carbon dioxide emissions and is, therefore, the fuel for the

present century. Large reserves of natural gas have been discovered in the Krishna- Godavari basin.

 Along the west coast the reserves of the Mumbai High and allied fields are supplemented by finds in the Gulf of Cambay.

 Andaman and Nicobar islands are also important areas having large reserves of natural gas.

 The 1700 km long Hazira-Vijaipur - Jagdishpur cross country gas pipeline links Mumbai High and Bassien with the fertilizer, power and industrial complexes in western and northern India.

 This artery has provided an impetus to India‘s gas production.

 The power and fertilizer industries are the key users of natural gas.

 Use of Compressed Natural Gas (CNG ) for vehicles to replace liquid fuels is gaining wide popularity in the country.

Electricity

 Electricity is generated mainly in two ways: by running water which drives hydro turbines to generate hydro electricity; and by burning other fuels such as coal, petroleum and natural gas to drive turbines to produce thermal power.

 Hydro electricity is generated by fast flowing water, which is a

renewable resource.

 India has a number of multi-purpose projects like the Bhakra Nangal, Damodar Valley corporation, the Kopili Hydel Project etc. producing hydroelectric power.

 Thermal electricity is generated by using coal, petroleum and natural gas. The thermal power stations use non-renewable fossil fuels for generating electricity.

Non-Conventional Sources of Energy

Nuclear or Atomic Energy

 It is obtained by altering the structure of atoms.

 When such an alteration is made, much energy is released in the form of heat and this is used to generate electric power.

 Uranium and Thorium, which are available in Jharkhand and the Aravalli ranges of Rajasthan are used for generating atomic or

nuclear power.

 The Monazite sands of Kerala is also rich in Thorium.

Solar Energy

 India is a tropical country.

 It has enormous possibilities of tapping solar energy.

 Photovoltaic technology converts sunlight directly into electricity.

 Solar energy is fast becoming popular in rural and remote areas.

 Some big solar power plants are being established in different parts of India which will minimise the dependence of rural households on firewood and dung cakes, which in turn will contribute to environmental conservation and adequate supply of manure in agriculture.

Wind power

 India has great potential of wind power.

 The largest wind farm cluster is located in Tamil Nadu from

Nagarcoil to Madurai.

 Apart from these, Andhra Pradesh, Karnataka, Gujarat, Kerala,

Maharashtra and Lakshadweep have important wind farms.

 Nagarcoil and Jaisalmer are well known for effective use of wind energy in the country.

Biogas

 Shrubs, farm waste, animal and human waste are used to produce biogas for domestic consumption in rural areas.

 Decomposition of organic matter yields gas, which has higher

thermal efficiency in comparison to kerosene, dung cake and

charcoal.

 Biogas plants are set up at municipal, cooperative and individual levels. The plants using cattle dung are known as Gobar gas plants‘ in rural India.

 Biogas is by far the most efficient use of cattle dung.

 It improves the quality of manure and also prevents the loss of trees and manure due to burning of fuel wood and cow dung cakes

Tidal Energy

 Oceanic tides can be used to generate electricity.

 Floodgate dams are built across inlets.

 During high tide water flows into the inlet and gets trapped when the gate is closed.

 After the tide falls outside the flood gate, the water retained by the floodgate flows back to the sea via a pipe that carries it through a power-generating turbine.

 In India the Gulf of Khambhat, the Gulf of Kuchchh in Gujarat on the western coast and Gangetic delta in Sunderban regions of West Bengal provide ideal conditions for utilising tidal energy.

Geo Thermal Energy

 Geo thermal energy refers to the heat and electricity produced by using the heat from the interior of the Earth.

 Geothermal energy exists because, the Earth grows progressively hotter with increasing depth.

 Where the geothermal gradient is high, high temperatures are found at shallow depths.

 Groundwater in such areas absorbs heat from the rocks and becomes hot.

 It is so hot that when it rises to the earth‘s surface, it turns into steam.

 This steam is used to drive turbines and generate electricity.

 There are several hundred hot springs in India, which could be used to generate electricity.

 Two experimental projects have been set up in India to harness

geothermal energy. One is located in the Parvati valley near

Manikarn in Himachal Pradesh and the other is located in the Puga Valley, Ladakh.