Geography Notes for SSC Exams - Part 2

Geography Notes for SSC Exams

Here We Listed all important Topics of Geography Hand Written Note down Points from which basic tricky questions were frequently asked in SSC, RAILWAY, NDA and Other Government Competitive Exams. Today is the 2nd Day of Geography where we covered the major types of Rocks, Volcanoes, Mountains, Etc. Major Mountain Ranges of the World and 5 Layers of Atmosphere. 

Rocks & Its Types

The solid part of Earth’s crust is known as Rocks. Generally Rocks are of three types i.e. Igneous Rock, Sedimentary Rock and Metamorphic Rock.

Igneous Rock – This type of rock solidified directly from the molten silicates (Magma). Here are some Igneous Rock.

Types	Acidic (High Silica Content)	Neither Basic Nor Acidic	Basic (High in Basic Oxides)
Intrusive/ Plutonic	Granite	Diorite	Gabbro
Extrusive/ Volcanic	Rhyolite	Andesite	Basalt

Sedimentary Rocks – This type of Rock is formed when Igneous rocks are eroded as a sediment under sea. Here are some Example of Sedimentary Rocks.

Sedimentation Type	Examples
Mechanically	Sandstone, mudstone(clay), Gravel (Sand)
Organically	Limestone, chalk, Peat, Lignite, coal, corals
Chemically	Gypsum, Rocksalt, Potash, Nitrate

Metamorphic Rocks - The nature of igneous and sedimentary rocks changes due to the effects of tremendous pressure or heat and new transformed rocks. Here are some Examples of Metamorphic Rocks.

Original Rocks	Metamorphic Rocks
Sandstone, Clay, Coal, Limestone, Granite, Shale	Quartzite, Slate, Graphite, Marble, Gneiss and Schist

Facts on Earthquakes

• It is the vibration in the earth’s crust. 
• The earth’s crust is made of different parts of various sizes (plates). 
• Movement of the plates is the main reason of earthquake. 
• Richter Scale and Mercally Scale are used to measure the magnitude and intensity of earthquake respectively. 
• The branch of Geology that deals with the study of earthquake is known as Seismology. 
• Circum Pacific Belt, Mid Atlantic Belt and Mid Continental Belt are the main zones of earthquake.

Facts on Volcanoes & Its Types

• It is the opening of earth’s crust and is connected by a conduit to an underlying magma chamber. 
• Molten Lava, volcanic gases, stream and other pyro-classic materials are ejected from the magma chamber. 
• There are three types of volcanoes.

Types	Examples
Active	It erupts frequently. Ex. Mt. St. Helens (USA), Stamboli and Mt. Etna (Mediterranean Sea) and Pinatubo (Philippines)
Dormant	Not erupted for quite sometime. Ex. Barren Island (India), Fujiyama (Japan)
Extinct	Not erupted several centuries. Ex. St. Arthur’s Seat (Edinburgh).

Facts on Mountains & Its Types

• The uplifted portion of Earth’s surface is known as hill or mountain.
• Mountains are classified into four types. i.e. Block Mountains, Fold Mountains, Volcanic Mountains and Residual Mountains.

Types of Mountain	Features with Examples
Block Mountains	When great blocks of earth’s crust are raised or lowered during the last stage of mountain-building, the block mountains are formed. Ex. Black Forest (Germany), Vosges (France), Satpura and Vindhyachal (India) and Salt Range   (Pakistan)
Fold Mountains	These are formed by folding of crustal rocks by compressive forces  under the influence of tectonic forces. Ex. Alps (Europe), Aravallis (India), Andes (South America)
Volcanic Mountains	These mountains are formed due to the accumulation of sand, soil, lava, rocks, etc. On the earth’s crust. Ex. Mt. Popa (Myanmar), Mt. Mauna Loa (Hawaii)
Residual Mountains	These mountains are formed as a result of weathering. Ex. Nilgiri, Parasnath, Hills of Rajmahal (India) and Siera (Spain)

Major Mountain Ranges of the World

Ranges	Length (Km) and Location
Andes	7200 and South America
Himalaya-Karakoram-Hindukush	5000 and South Central Asia
Rockies	4800 and North America
Great Dividing Range	3600 and East Australia
Atlas	1930 and North West Africa
Western Ghats	1610 and Western India
Caucasus	1200 and Europe
Alaska	1130 and USA
Alps	1050 and Europe

Major Mountain Peaks of the World

Peaks	Heights (m) and Location
Everest	8848 and Nepal
Godwin-Austin (K-2)	8611 and India
Kanchenjanga	8598 and India
Makalu	8481 and Nepal-China
Dhaulagiri	8172 and Nepal
Cho Oyu	8153 and Nepal
Nanga Parbat	8126 and India
Hidden Peak	8068 and India
Annapurna	8078 and Nepal
Nandadevi	7813 and India

Plateaus & Its Types

These are extensive upland areas characterized by the flat and rough top surface and steep walls, which rise above the neighbouring ground surface at least for 300 m.

Plateaus	Location
Plateaus of Alaska	North-West North America
Tibetan Plateau	Between Himalayas and Quinloo Mountains
Plateau of Bolivia	Andes Mountains
Plateau of Mexico	Mexico
Arabian Plateau	South-West Asia
Great Basin Plateau	South of Colombia Plateau, USA
Deccan Plateau	Southern India
Plateau of Colombia	USA
Colorado Plateau	South of Great Basin Plateau
Plateau of Brazil	Central-Eastern South America

Plains- It is a relatively low lying flat land surface with least difference between its highest and lowest points. 

Atmosphere- It is a mixture of a layer of gases enveloping the earth. The gases held to it by Gravitational Force. 

• The atmosphere extends to about 1000 Km from the surface of the earth but 99% of the total mass of the atmosphere is found within32 Km. 
• Composition of the atmosphere are Nitrogen (78.09%), Oxygen (20.95%), Argon (0.93%)and Carbon-Di-Oxide (0.03%) etc. 
• Carbon-Di-Oxide is an important constituent of air as it has the ability to absorb heat. As a result, the atmosphere becomes warm and the heat of the earth is balanced. 

5 layers of the atmosphere

Troposphere: 

• It contains 90% of gases.
• The temperature at Tropopause is about -57Degree Celsius.
• It is 18 Km at Equator and 8 Km at Poles.
• Vertical decrease in temperature at the rate of 6.4Degree Celsius/ 1000M.
• This layer has great significance for plants, animals, human and microorganisms.

Stratosphere:

• It lies above the Tropopause (50Km in Equator).
• It has Ozone Layers that absorbs ultraviolet rays.
• The temperature ranges between 57 Degree Celsius and 0 Degree Celsius.

Mesosphere:

• It lies above the Stratosphere.
• Its height is up to approximately 80 Km.
• The temperature decreases here with height and falls to about 100Degree Celsius at 80Km height.

Thermosphere:

• It extends from the top of Mesosphere to about 600 Km above the earth’s surface.
• The temperature increases greatly with height reaching up to 2000 Degree Celsius at the top of the layer.

Exosphere:

• It extends from the top of the thermosphere to about 10000 Km above the earth’s surface.
• The temperature in this region range from 300 Degree to 1650 Degree Celsius.
• Satellites orbit the earth in this layer.

You May also Like to Read: Part 1 - Geography Notes for SSC & Railway Exams