Download Physical India - WordPress.com

FORMATION OF HIMALAYAS
•
Among the most dramatic and visible creations of plate-tectonic forces are
the lofty Himalayas, which stretch 2,900 km along the border between India
and Tibet. This immense mountain range began to form between 40 and 50
million years ago, when two large landmasses, India and Eurasia, driven by
plate movement, collided. Because both these continental landmasses have
about the same rock density, one plate could not be subducted under the
other. The pressure of the impinging plates could only be relieved by
thrusting skyward, contorting the collision zone, and forming the jagged
Himalayan peaks.
About 225 million years ago, India was a large island still situated off the
Australian coast, and a vast ocean (called Tethys Sea) separated India from
the Asian continent. When Pangaea broke apart about 200 million years
ago, India began to forge northward. By studying the history -- and
ultimately the closing-- of the Tethys, scientists have reconstructed India's
northward journey. About 80 million years ago, India was located roughly
6,400 km south of the Asian continent, moving northward at a rate of about
9 m a century. When India rammed into Asia about 40 to 50 million years
ago, its northward advance slowed by about half. The collision and
associated decrease in the rate of plate
Formation of Himalaya
•
•
•
•
•
The oldest landmass was a part of the Gondwanaland ( India, Australia, South Africa
and South America)
The convectional currents split the crust into number of pieces, thus drifting of the
Indo-Australian plate after being separated from the Gondwanaland, towards North.
The northward drift resulted in the collision of plate with the much larger Eurosian
plate.
Due to this collision the sedimentary rocks which were accumulated in the
geosyncline known as the Tethys were folded to form the Himalaya mountain.
FORMATION OF NORTHERN PLAINSHimalaya uplift out of Tethys sea and subsidence of the northern flank of peninsular
plateau resulted in the formation of a large basin. In the course of time this
depression, gradually got filled with deposition of sedimentation by the rivers flowing
from the mountians in the north and the plateau in the south. A flat land of extensive
alluvial deposits led to the formation of the northern plains of India.
• Ext. – From Kashmir to Arunachal Pradesh.
(Indus – Brahmaputra)
• Length- 2500 km Width- 150-400 km
• Three ranges of Himalaya
• 1. The Great or Inner Himalaya or Himadari
• # Most continuous
• # Consisting of loftiest peaks with average
height of 6000m.
•
•
•
•
•
•
•
•
•
Kanchanjunga – India – 8598m
Makalu –
Nepal – 8481m
Dhaulagiri Nepal – 8172m
Nanga Parbat India - 8176m
Annapurna
Nepal – 8078m
Nanda Devi
India - 7817m
Kamet
India - 7756
Namcha Bharwa India – 7756
Gurla Mandhata Nepal - 7728
Features
•
•
•
•
The folds are asymmetrical in nature
Core is made up of granite
Perennially snow bound
A number of glaciers
•
•
•
•
•
Most rugged mountain system
Altitude – 3700-4500m
Width – 50 km
Longest range – The Pir Panjal
Other ranges-The Dhaula Dhar and The
Mahabharat.
• Valleys- Kashmir, the Kangra and Kullu
• Altitude – 900-1100m
• Width – 10-50 Km
• Composed of unconsolidated sediments
brought down by rivers from main Himalayan
ranges.
• These valleys are covered with thick gravel and
alluvium.
• Longitudinal valley lying between lesser
Himalayas and Shiwalik is known as dun.
• Eg. Dehra Dun, Patli Dun and Kotli Dun.
Division of Himalayas
• Division of Himalayas on the basis of region
from west to east• Part of Himalayas lying between Indus and
Satluj – Punjab Himalaya- Kashmir and
Himachal Himalaya
• Between Satluj and Kali – Kumaon Himalaya
• Between Kali and Tista – Nepal Himalaya
• Between Tista and Dihang – Assam Himalaya
• Eastern most boundary – Brahamaputra
• Purvanchal or The Eastern hill or
mountains
• Running through the north-eastern states
• Composed of strong sandstone
• Covered with dense forest
• Parallel ranges and valleys
• Patkai hills, Naga Hills, Manipur hills, Mizo
hills
• HOW IT IS FORMED
• By interplay of the Ganga,the Brahmaputra and the
Indus.
• Formed of alluviul soil
• Area – 7 lakh sq.km.
• Length – 2400 km
• Width – 240-320 km
• Adequate water supply, favourable climate
• Many riverine islands are formed in the lower course due
to less velocity.
•
 THREE SECTIONS
 1. PUNJAB PLAIN – western part –
formed by Indus and its tributaries.
 Large part of this plain- in Pakistan which
is formed by Indus and its tributaries –
The Jhelum, the Ravi, The Beas etc.
 This part is dominated by Doab
 2. GANGA PLAIN- Extends between
Ghaggar and Teesta river
 It covers Haryana, Delhi, U.P., Bihar,
partly Jharkhand .
 3. BRAHMAPUTRA PLAIN- In Assam
 Note- These vast plains have various relief
features. According to variations in relief
features the Northern Plains can be
divided into 4 regions.
 1. Bhabar Belt- Lying parallel to the slopes
of the Shiwalik
 Width- 8-16 Km, a narrow belt of pebbles
 All the streams disappear in this belt.
 2. Terai – South of Bhabar, the streams
and rivers re-emerge and create a wet
swampy and marshy region. This was
thickly forested.
 Dudhwa National Park in this region.
 3. Bhangar – Formed of older alluvium
 Lie above the flood plains of the rivers and
present a terrace like feature.
 Here soil contains calcareous (kankar)
 4. Khadar – The newer, younger deposits o
fthe flood plains are called Khadar.
 They are renewed every year so ideal for
intensive agriculture.
A tableland of the crystalline, igneous and
metamorphic rocks.
 Formed due to the breaking and drifting of
the Gondwana land.
 Has broad and shallow valleys and
rounded hills.
 The Narmada valley divides it into 2 parts
– The Central Highland in the North and
the Deccan Plateau in the South.

The area having black soil is known as
Deccan Trap.
CENTRAL HIGHLANDS






It has three parts- Malwa Plateau, the small
plateau of Bundelkhand and the Chotanagpur
plateau.
In South – The Vindhyan range
In Northwest – The Aravalis
Westward – desert
Important rivers- the Chambal, the Sind, the
Betwa and Ken – from southwest to northeast.
Wider in west and narrower in the east.
DECCAN PLATEAU
This triangular landmass lies to the south
of the river Narmada.
 North- Satpura range
 East – The Mahadev, the Kaimur hills and
the Maikal hills.
 Higher in the west and slopes eastward
 Other names – The Meghalaya, KarbiAnglong and North Cachar








THE 2 GHATS Mark the western and eastern edges of
the Deccan Plateau.
Western Ghats - lie the parallel to the western coast.
They are continuous and can be crossed through passes
only.
Average elevation- 900-1600 it increases from north to
south.
They cause orographic rain by facing the moist winds to
rise along western slopes.
Anai Mudi(2695m) and Doda Beta(2637) are the highest
peaks.
Shevroy Hills and the Javedi Hills- Southeast of the
Eastern Ghats.
EASTERN GHATS1. They stretch from Mahanadi valley to the
Nilgiris in south.
2. They are discontinuous and irregular and
dissected by rivers draining into Bay of
Bengal.
3. Mahendragiri (1501m) is the highest
peak.
•
•
•
•
•
•
•
•
LAKSHADWEEP- (1973)
LYING CLOSE TO MALABAR COAST OF KERALA
COMPOSED OF SMALL CORAL ISLANDS
OTHER NAMES- LACCADIVE, MINICOY AND
AMINDIVE
AREA- 32 sq km.
Adm. Headquarters- Kavaratti
Great diversity of flora and fauna
Pitti island – bird sanctuary
ANDAMAN AND NICOBAR ISLAND
• LOCATION- Bay of Bengal
• These are an elevated portion of
submarine portion
• Has equatorial climate and variety of flora
and fauna.
INDIAN DESERT
► LOCTION-
Western margins of the Aravali Hills.
► Covered with sand dunes.
► Rain fall- 150 mm
► Arid climate – low vegetation.
► Seasonal rivers.
► Luni- large river
► Barchans( crescent shaped dunes)- Jesalmer
► Longitudinal dunes are near Indo-Pakistan
Boundary.