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This post was republished to IAS Help at 21:00:37 11/01/2010

Global Geography #9 | Study Material::General Studies | IAS Help

Category Global Geography

[ratings]

MOUNTAINS

Overview

A mountain is a large landform that stretches above the surrounding land in a limited area Mountains are sometimes referred to by the Greek name: montes or mons (singular) The highest mountain on earth is Mount Everest (8848 m) The highest mountain in the solar system is Olympus Mons on Mars (21,171 m) Mountains cover 24% of earths land mass The study of mountains is called Orology

Characteristics of mountains

Mountains are colder than lower ground because the Sun heats the Earth from the groundup.

When the Suns rays travel through the atmosphere and reach the ground, the earth absorbsthe heat. In general air closest to the earths surface is warmest

Air temperature usually decreases 1-2 C for every 300 m of altitude The flora and fauna in tall mountains tend to be isolated to one particular altitude zone.

These isolated ecological systems are called sky islands.

The peak shape of mountains is produced by glaciation and erosion through frost action As altitude increases, the atmospheric pressure decreases. Thus, although the percentage

of oxygen remains constant (21%), the amount of oxygen decreases.

Altitude sickness (aka Acute Mountain Sickness) is caused by lack of oxygen at high altitudes.Altitude sickness can lead to High Altitude Pulmonary Edema (HAPE) or High Altitude

Cerebral Edema (HACE)

Availability of oxygen decreases significantly over 3000 m (10,000 ft). for this reason, thecabin altitude in passenger aircraft is kept to 8000 ft

Higher altitudes also mean lesser protection to UV radiationFormation of mountains

Mountains are usually produced by the movement of lithospheric plates Major mountains tend to occur along long linear arcs, indicating tectonic plate boundaries Compressional forces in continental collisions cause the compressed region to thicken and

force the upper surface upwards

Meanwhile, in order to balance the weight, much of the compressed rock is forceddownwards as well, forming deep mountain roots. As a result, mountains form upwards

as well as downwards.

Types of mountains

Fold Mountains

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o Formed by the effects offolding on layers within the upper part of the earths crusto Fold mountains are generally formed on the less deformed areas adjacent to areas

strongly affected by thrust tectonics

o Most fold mountains are likely to relative young in geological terms since they willstart to erode as soon as they are formed

o Examples: Zagros mountains (Iran), Jura mountains (near the Alps i.e. France,Switzerland, Germany) Fault-block mountains

o Formed when large areas of bedrock are broken up by faults creating large verticaldisplacements of continental crust

o These mountains are formed by the crust being stretched and extended by tensionalforces

o The uplifted blocks are called block mountains or horsts. The intervening droppedblocks are called graben, and can form extensive rift valleys

o Examples: Vosges (northeast France), Basin and Range (western USA) Volcanic mountains

o Isolated mountains produced by volcanoeso Includes small islands that reach great heights beyond the ocean flooro Example: Mount Kilimanjaro (Tanzania)

Inselberg (or Monadnock)o They are isolated hills or small mountains that rise abruptly from a surrounding plaino They arise when a rock resistant to erosion is enclosed within a softer rock like

limestone. When the limestone erodes away to form the nearby plains, the resistant

rock is left behind as an island-mountain

o Example: sugarloaf mountain (Brazil), Pilot Mountain (USA)

The Seven Summits

The Seven Summits are the highest mountain peaks of each of the seven continents The Seven Summits are

o Africa: Mount Kilimanjaro Tanzaniao Antarctica: Vinson Massif British Antarctic Territoryo Australia: Kosciuszko Australiao Asia: Mount Everest Nepal, Tibeto Europe: Elbrus Russiao North America: Mount McKinley (Denali) Alaskao South America: Aconcagua - Argentina

Important Mountain ranges in the world

Mountain Range Location Length

(km)

Notes

Mid ocean ridge 65,000 Underwater mountain range

Longest mountain range in the world

Demarcates boundary b/w tectonic plates

Consists of seven ridges connected together: Gakkel

Ridge, Mid Atlantic, Southwest Indian, Central Indian,

Southeast Indian, Pacific Antarctic, East Pacific Rise

Andes SouthAmerica

7000 Longest continental mountain rangeHighest mountain range outside Asia

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Rocky North

America

4800

Himalayas Asia 3800 Highest mountain range on earth

Includes Karakoram, Hindu Kush

Separates Indian subcontinent from Tibetan plateau

Great DividingRange

Australia 3700

Transantarctic

Mountains

Antarctica 3500 Serve as division b/w East Antarctica from West

Antarctica

Important Mountain peaks in the world

Mountain peak Height

(m)

Mountain

Range

Location Notes

Mount Everest 8848 Himalayas Nepal/ Tibet Highest mountain on earth

K2

(Mt. Godwen-

Austen)

8611 Karakoram Pakistan/China Second highest mountain

Second highest fatality rate (25%)

Kangchenjunga 8586 Himalayas Nepal/India Highest in India

Annapurna 8091 Himalayas Nepal Highest fatality rate (40%)

Aconcagua 6961 Andes Argentina Highest mountain outside Asia

Mt. Kilimanjaro 5895 Kilimanjaro Tanzania Highest volcanic mountain

Highest in Africa

Mt Erebus 3794 Antarctica

(Ross Island)

Southernmost active volcano

Mt Chimborazo 6268 Andes Ecuador Point on surface most distant from

earths centre

Important Mountain ranges in India

Mountain range Location Notes

Himalayas

Aravalli Rajasthan, Haryana, Gujarat Were extremely tall in ancient

times, now completely worn

down due to weathering

Vindhyas Gujarat, Madhya Pradesh Earliest known fossil of

eukaryotes discovered here

(1.6 billion years)Satpura Gujarat, Maharashtra, Madhra

Pradesh, Chattisgarh

Sivalik Hills Sikkim, Nepal, Uttarakhand,

Kashmir, Pakistan

Southernmost and geologically

youngest of the Himalayan

system

Eastern Ghats West Bengal, Orissa, Andhra

Pradesh, Tamil Nadu

Discontinuous range of

mountains

Older than Western Ghats

Western Ghats Gujarat, Maharashtra,

Karnataka, Kerala, Tamil Nadu

60% of Western Ghats located

in Karnataka

Rivers from Western Ghatsdrain 40% of India

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One of worlds ten Hottest

Biodiversity Spots

Nilgiri Hills Tamil Nadu UNESCO World Heritage Site

Anamalai Hills

(Western Ghats)

Kerala, Tamil Nadu Under consideration for

UNESCO World Heritage Site

Cardamom Hills(Western Ghats)

Kerala, Tamil Nadu Under consideration forUNESCO WHS

Southwest Indian Ridge Indian Ocean Separates African Plate from

Antarctic Plate

Central Indian Ridge Indian Ocean Boundary between African

Plate and Indo-Australian Plate

Southeast Indian Ridge Indian Ocean Separates Indo-Australian Plate

from Antarctic Plate

Important Mountain peaks in India

Mountain peak Mountain range Location Notes

Kangchenjunga Himalayas Sikkim Highest peak in India

Third highest in the

world

Nanda Devi Himalayas Uttarakhand Highest peak entirely

within India

Anamudi Anaimalai Hills

(Western Ghats)

Kerala Highest peak in India

outside the

Himalayas

Mount Abu Aravalli Hills Rajasthan Highest peak in the

Aravallis

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