Notes of structure and physiography - Geography - Class 11th 'Humanities'

HANDWRITTEN NOTES 

CLASS 11TH 'HUMANITIES' GEOGRAPHY 

STRUCTURE AND PHYSIOGRAPHY 

Three broad geological regions of India:-

1] The peninsular block: - The peninsular block is quite diff. from Himalayan mountains in respect of geological structure and physiography. It extends from Kuchchh along western flank of Aravali range to near Delhi and roughly parallel to Ganga and Yamuna River. The karbi-anglong and Meghalaya in north east and Rajasthan in west are extension of this block. Malda fault separates Meghalaya and karbi-anglong from chhotanagpur plateau. In west Rajasthan block comprises desert and other desert like features overlay this block.

       The peninsula is formed by ancient genesis and granites. Peninsula is rigid block except for some western part is submerged in sea.

2] The Himalayas and other peninsular mountains: - These are young, weak and flexible in their geological structure. These are tectonic in origin, dissected by youth fast flowing rivers. These are still subjected to interplay of exogenic and endogenic forces results in development of faults, folds and thrust plains.

3] Indo-Ganga-Brahmaputra plain: - These plains are formed by river Ganga, Brahmaputra and Indus. It was a geo-synclinal depression which was filled by sediments brought by Himalayan and peninsular rivers.

[Average depth of alluvial deposits: - 1000-2000m]

·      PHYSIOGRAPHY: - Physiography of an area is the outcome of structure, process and stage of development.

SIX PHYSIOGRAPHIC DIVISIONS OF INDIA ARE:-

1] The northern and north-eastern mountains: - It consists Himalayas and N-E hills. The Himalayas are new folded mountain and consist series of parallel mountain ranges. Great Himalayan range which include great Himalayas and Shiwalik.

·      Approximate length: - 2500km

·      Wideness: - 160-400km

·      Kailash, Ladakh, Zaskar, Peerpanjal, Dholadhar

·      Shiwalik are famous mountain ranges in Himalaya.

·      Himalayas are not only physical barrier they are also climatic, drainage and cultural divide.

Himalaya can be divided into following sub-divisions:-

A] Kashmir or N-W Himalayas: - This position comprises series of Karakorum, Ladakh, Zaskar, and Peerpanjal ranges.

·      North western part of Kashmir Himalayas is cold desert which lies between greater Himalayas and Karakorum Range.

·      Kashmir valley and Dal Lake lies between greater Himalayas and peerpanjal range.

·      Baltoro and siachen glaciers lie in this region.

·      These are famous for karewas formation [thick deposits of glacial clay]. These are useful for cultivation of saffron.

Important passes of this region are:-

1] Zozila on the great Himalayas.

2] Banihal on pirpanjal

3] Photu la on Zaskar

4] Kar dung la on ladakh range

·      Fresh water lakes- Dal, Wular

Salt water lakes- Pangong Tso, Tso Moriri

·      River draining this region- Indus, Jhelum, Chenab

·      Places of worship- Vaishno Devi, Amaranth cave, Charar-e-Sharif.

·      Southern part of this region has longitudinal valleys-duns- Jammu-dun, Pathankot-dun

B] The Himachal and Uttarakhand Himalayas:- It lies approximately between Ravi in west and kali[a tributary of Ghaghara river] in east.

·      Rivers- Indus[Ravi, Beas, Satluj], ganga[Yamuna, Gomti, Ghaghara]

·      Ladakh cold desert which lies in Spiti is the northern most part of Himachal Himalayas.

·      This region consists of grater Himalayas and lesser Himalayas. Lesser Himalayas are locally known as dholadhar in HP, Nagtibha in Uttarakhand and shiwalik range from north to south.

·      Important hill stations: - Dharamshala, Massorie, Shimla, Kaosoni, Ranikhet etc.

·      Important dunes of this region: - Chandigarh- Kalkadun, Nalagarh Dun, Dehra Dun, Harike Dun and Kota dun etc.

Dehradun- largest [length-35-45, width-22-25km]

·      Bhotia communities inhibit these regions.

·      Valleys of flowers are there.

·      Places of pilgrimage: - Gangotri, Yamunotri, Kedarnath, Badrinath and Hemkund sahib.

·      World famous five prayags are also there.

C] The Darjling and Sikkim Himalayas:-

Extension:- Nepal Himalayas in west and Bhutan Himalayas in east.

·      Fast flowing river- Tista

·      High mountain peaks- Kanchenjunga and deep valleys.

·      Lepcha tribe inhibited this region; southern part particularly has mixed Nepalis, Bengalis population.

·      Tea plantation due to moderate slope, thick soil and rainfall throughout the year.

·      Absence of shiwalik formation, Duar formations are there. Scenic beauty, orchids.

D] The Arunachal Himalayas:-

Extension: - Bhutan in east and Dhiphu pass in west.

·      General orientation is from south west to north east.

·      Important mountain peaks- Kangtu, Namcha Barwa. These ranges are dissected by fast flowing rivers from north to south, forming deep gorges.

·      Important rivers- Brahmaputra flows through deep gorge after passing through Namcha Barwa.

·      Kameng, Subanriri, Dihang, Dibang, Lohit.

·      Ethnic tribal communities: - Monpa, Daffla, Abor, Mishmi, Nishi, Nagas. Practice Jhumming cultivation.

·      Interaction through Duar region along Arunachal Pradesh and Assam border.

E] The eastern hills and mountains:-

·      General orientation:- north to south.

Their different names are Patkai bum, Naga Hills, the Manipur hills, Mizo or Lusai hills in south.

·      Low hills have any tribes practicing Jhumming cultivation.

·      Rivers- Barak- Manipur and Mizoram.

Loktak Lake[mountains on 3 sides]- Manipur.

Molasis basin - Mizoram.

Rivers of Nagaland: - tributary of Brahmaputra.

2] The northern plains: - These plains are formed by thick deposits brought by river- Indus, Ganga, and Brahmaputra.

Extension: - Punjab to Assam.

                     3200 km long and 150-300km wide and average height is 187m.

·      Fertile plains for variety of crops and density population.

·      Maximum depth of alluvial deposits:- 1000-2000m.

From north to south there are three major zones:-

A] Bhabhar: - It is a narrow belt ranging between 8-10km parallel to shiwalik foothills at the break-up of slope. At this, rivers coming from mountains deposits heavy rocky material and disappear in this zone.

B] Tarai:- south of Bhabhar is Tarai belt with width of 10-20km where most of rivers re-emerge without proper channel and creates swampy and marshy conditions known as Tarai.

C] Alluvial plains:- south of Tarai is belt consisting newer and old alluvium deposits known as khaddar and Bhangar. These have features of sand bars, meanders, ox-bow lakes, braided channels.

Famous rivers of plains: - Satluj, Ganga, Yamuna, Kosi, Gandak, Brahmaputra, son, Chambal, Betwa etc.

3] The peninsular plateau:- It is the irregular triangular landmass 150m above the river plains up to an elevation of 600-900m.

·      Delhi ridge in North West and the Rajmahal hills in east, Gir range in west and the cardamom hills in south constituent outer extent of peninsular plateau.

·      Its extension is also in north east in the form of Meghalaya and karbi-anglong plateau.

·      The peninsular India is made of series of Patland plateaus- Hazaribagh, Palamu, Ranchi, Malwa, Coimbatore and Karnataka plateau.

·      This is one of the oldest and most stable landmass of India .

·      General elevation of plateau is from west to east which can be proved by pattern of flow of rivers.

·       The western and north western part of plateau has presence of black soil.

·      The peninsular plateau has undergone recurrent phases of upliftment and submergence accompanied by crustal faulting and fractures.

·      The northern western part of plateau has complex relief of ravines and gorges.

Peninsular plateau is divided into three broad groups:-

A] The Deccan Plateau:- This is bordered by western Ghats in west, eastern Ghats in east, Satpura, Maikal range and Mahadeo hiils in north.

·      Local different names of Western Ghats: Sahyadri in MH, Nilgiri hills in Karnataka and Tamil Nadu and Anaimalai hills and cardamom hills in Kerala.

·      Their average elevation is about 1500m with height increasing from north to south.

·      Western Ghats higher in elevation than Eastern Ghats.

·      Anaimudi [2695] highest peak of south India located on Anaimalai hills. Dodabeta [2637m] second highest peak on Nilgiri hills.

·      Most peninsular rivers origins in Western Ghats, Eastern Ghats are highly eroded by Mahanadi, Godavari Krishna and Kaveri.

·      The Eastern Ghats and Western Ghats meet at Nilgiris hills.

·      It consist very hard and ancient rock- Igneous and metamorphic in this plateau.

B] The central highlands:- These are situated in middle of India and bordered by Aravali range as west and Vindhyan scraps on east.

·      Rift valley and Narmada rive forms southern boundary.

·      The entire region is forested and rocky.

·      The Aravali range, the east Rajasthan uplands, Maharashtra Bharat uplands and Bundelkhand from northern part of uplands while Malwa plateau, the Vindhyan scarp lands, the Vindhyan range and Narmada valley forms its southern part.

·      The general elevation of central highlands ranges between 700-1000m above mean sea level.

·      Gonds, Santhals, Bhils inhibit this region.

C] The north eastern plateau:- It is believed that due to north eastward movement of Indian plate at the time of Himalayan origin, a big fault was formed between rajmahal hills and Meghalaya plateau.

·      This fault was then filled by the deposition of numerous rivers originating from Himalayas.

·      Today mountain plateau and karbi-anglong plateau is separated from peninsular plateau.

The Meghalaya plateau is further divided into:

     i.            The Garo hills

  ii.            The Khasi hills

iii.            The Jaintia hills.

·      These are named after their tribes.

·      Karbi-anglong hills are also extension of peninsular plateau.

Meghalaya plateau is similar to chhotanagpur as:

1-Rich in minerals like coal, iron.

2-Receives maximum rainfall from south west monsoon winds.

3-Has eroded surface

4-Cherapunji devoid of vegetation.

4] The Indian desert:-

·      It lies in North West of Aravali hills.

·      It is a land of undulating topography dotted with longitudinal dunes and barchans.

·      This region receives less rainfall below 150m/year.  Hence, it has arid climate with low vegetation cover. So, it is called as Marusthali due to its features.

·      It is believed that it was under water/sea during Mesozoic era.

·      Its surface features are carved by physical weathering and wind actions.

·      Some of the well pronounced desertic features are:-

           -mushroom rocks

           -shifting dunes

           -oasis in southern part.

·      On the basis of orientation desert can be divided into two parts:-

§  The northern part sloping towards Sindh

§  The Rann of Kuchchh

·      Rivers- Luni River is most significant.

·      Low precipitation and high evaporation makes it water deficit region.

·      Some lakes or playas are also there.

5] The coastal plains:-

The western coastal plains

a)  It lies between Western Ghats and Arabian Sea.

b)Narrower than eastern coastal plains.

c)  Receives more rainfall.

d)Kathiawar and Kuchchh are two peninsulas.

e) Narmada and Tapti forms estuaries, no deltas.

f)   No sand dunes due to sufficient rainfall.

g) In Maharashtra, it is called as Konkan, in Karnataka as kanara and Malabar in Kerala.

h)Numerous backwaters- Kayals are situated.

·      [example of submerged coastal plain]

·      Ports- Kandla, Marmagao, Cochin etc.]

·      [Nehru trophy vallamkali[boat race] held in punnamada kayal in Kerala.]

The eastern coastal plains:-

a) It lies between eastern Ghats and bay of Bengal.

b)Wider than western coastal plains.

c)  Receives less rainfall

d)No peninsulas.

e) Mahanadi, Godavari, Krishna, Kaveri form deltas not estuaries.

f)   Sand dunes due to less rainfall.

g) In Andhra Pradesh and Tamil Nadu-coramandel coast, in Orissa as Utkai plain.

h)Chilika Lake and Pulicat lake are situated.

·      [no good ports due to emergent nature of coast]

 6] the islands:-

     I.            Bay of Bengal:- 572 islands, roughly situated between 6°N- 14°N and 92°E- 94°E.

·      Two principle group of islands:- Ritchie’s archipelago and labyrinth island.

·      The entire group of island is divided into two broad categories:-

-Andaman in north

-Nicobar in south

·      These are separated by 10°channel.

·      These islands are elevated portion of submarine mountains.

·      Some smaller islands are volcanic in origin. Barren island- the only active volcano in India situated in Nicobar islands.

·      Peaks- Mount Diavolo, Saddle peak, Mount Koyob, Mount Thuiller.

·      The coastline has some coral deposits and beautiful beaches.

·      These islands receive convectional rainfall and have equatorial type of vegetation.

II.            Arabian sea:-

The islands of Arabian Sea include Lakshadweep and Minicoy.

·      These are scattered between 8°N-12°N and 71°E-74°E longitude.

·      These islands are located at a distance of 280km-480km off the Kerala coast.

·      The entire island group is built of coral deposits.

·      36 islands- 11 are inhibited.

·      Minicoy is the largest island- 453sq. km.

·      The entire island group is divided by 11°channel.

·      Amini islands in north, Canannore in south.

·      The islands of this archipelago have storm beaches consisting of unconsolidated pebbles, cables etc. on eastern seaboard.

Western Himalayas	Eastern Himalayas
i.            These spread over j and k, up, Uttaranchal.	ii.            These spread over West Bengal, Sikkim, Bhutan.
iii.            Peaks- K2, Nanga Parbat.	iv.            Peaks- Mount Everest, Nagahills, Kanchenjunga, Patkaibum etc.
v.            Called as Kashmir Himalayas.	vi.            Called as Assam Himalayas.
vii.            River:- Satluj, beas, Ravi, Chenab, Jhelum, Indus, Yamuna.	viii.            River- Brahmaputra, Tista
ix.            Passes: Karakorum, Zozila, Bara Lancha La, Shipkila.	x.            Passes- Jelapa, Bandila.

                    

WESTERN COASTAL PLAIN IS DEVOID OF ANY DELTA BECAUSE:-

i.            These are built by hard rock’s which are not easily eroded.

ii.            The rivers flow with very fast speed in rift valley.

iii.            They are not capable of eroding too much.

iv.            Due to speed they do not deposit any sediments on mouth and drop sediments into the sea.

BADRINATH TO SUNDERBANS DELTA, COURSE OF RIVER GANGA- GEOMORPHOLOGICAL FEATURES ARE:-

     I.            Alluvial fans

  II.            Meanders and ox-bow lakes

III.            flood plains

IV.            delta

 V.            distributaries

COMPARISON BETWEEN ARABIAN SEA AND BAY OF BENGAL:-

Arabian sea	Bay of Bengal
More salinity in Arabian sea	Less salinity in BOB.
It is less warm.	It is warmer.
It contains rocky beach.	It contains sandy beach.

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