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Structure and Physiography (India - Physical Environment, Chapter-2)…

- - - - tectonic in origin, dissected by fast flowing rivers in their youthful stage
      - young, weak, flexible fold mountains unlike the mountains of the Peninsular Block
  - - - Originally a geo-synclinal depression, attained max. dev. during 3rd phase of Himalayan Mountain formation approx. 64 million years ago.
      - avg. dept of alluvial deposits in these plains - 1000-2000 metres.
  - - - In Rajasthan, desert and desert-like features overlay this block
      - Northeastern parts are separated by Malda fault in W.B from the Chhotanagpur Plateau
    - - Consists mostly of relict and residual mountains and hills such as Aravallis, Nallamalla, Javadi, Veliconda, Palkonda ranges
      - shallow river valleys
      - formed essentially of very ancient gneisses and granites, western coast partially submerged under the sea, earlier a part of Indo-Australian plate -> rift valleys of Narmada and Tapi
- - - - Bhabar
        
        8-10 km parallel to Shiwalik Hills at slope break up
        
        heavy river deposits of rocks and boulders with rivers often disappearing in this zone
      - Tarai
        
        10-20 km width where most streams re-emerge without any proper demarcated channel -> marshy and swampy conditions -> Tarai
      - Alluvial Plains
        
        Khadar
        
        new alluvial deposits
        
        Bhangar
        
        old alluvial deposits
        
        mature stage fluvial erosional and depositional features here- such as sand bars, meanders, ox bow lakes and braided channels
  - - - Deccan Plateau
        
        W- W.Ghats, E-E.Ghats, N-Satpura, Maikal and Mahadeo Hills
        
        W.Ghats
        
        Sahyadari (MH), Nilgiri (KTK), Cardomom and Anaimalai (Kerala)
        
        more elevated & continuous than E.Ghats
        
        avg. elevation- 1500 m wIth height increasing from N-S
        
        Anaimudi (2695m) highest & in Anaimalai Hills, Doddabetta(2637) in Nilgiri Hills
        
        most peninsular rivers originate in W.Ghats
        
        E.Ghats
        
        meet the W.Ghats at Nilgiri Hills
        
        some imp. ranges are Javadi, Palconda, Nallamalla, Mahendragiri
      - Central Highlands
        
        W- Aravalli, N- Satpura
        
        classic example of relict mountains highly denuded
        
        general elevation 700-1000 m & slopes towards N & NE
        
        Most of the tributaries of river Yamuna have origin in Vidhyan and Kaimur ranges, Banas( tributary of Chambal) originates in Aravali
        
        eastern extension- Rajmahal hills - south of it lies Chhotanagpur plateau- a large mineral reserve
      - Northeastern Plateau
        
        extension of penin. plateau formed during Himalayan origin after it got filled up with river deposits
        
        consists of Karbi Anglong and Meghalaya Plateau
        
        Meghalaya Plateau consists of Garo, Khasi, Jaintia Hills and is rich in mineral resources, max. rainfall from S.W monsoon and thus highly eroded
  - - - example of submerged plain thus ideal for development of natural ports
      - Divisions
        
        Kacch and Kathiawar coast- Gujarat
        
        Konkan Coast- MH
        
        Goan coast
        
        Malabar Coast- Kerala
        
        Has got Kayals (backwaters) which are used for fishing, inland navigation - Nehtru Trophy Vallamkalli (Boat race) held in Punnamada Kayal in Kerala
      - narrow in middle and broader towards north & south
    - - Broader than western coastal plains and example of emergent plain and lesser no. of ports due to large continental shelf of up to 500 kms
      - Well developed deltas found here formed by rivers draining in Bay of Bengal
  - - - Consists of 572 islands/islets situated b/w 6 N- 14 N and 92 E and 94 E, ( Major islet groups- Ritchie's Archipelago, Labyrinth Islands)
      - Andaman (North) and Nicobar (South) Islands
        
        Separated by ten degree channel
        
        these islands are elevated portions of submerged mountains, while some are volcanic in origin , have coral deposits and beaches
        
        Barren Island- only active volcano in India is situated in Nicobar Islands
        
        Some important peaks
        
        Saddle Peak ( 738 m) (North Andaman)
        
        Mount Diavolo (515 m) (Middle Andaman)
        
        Mount Koyob (460 m) (South Andaman)
        
        Mount. Thuiller (642 m) (Great Nicobar)
    - - Lakshadweep and Minicoy
        
        8-12 N and 71-74 E
        
        built of coral deposits
        
        11 out of 36 islands inhabited with Minicoy being the largest island
        
        Entire group of islands divided by Eleventh degree channel- North - Amini Islands and Sourth - Canannore Island.
        
        consist of storm beaches
  - - - Arunachal Himalayas
        
        some important rivers- Kameng, Subansiri, Dihang, Dibang, Lohit ( perennial with high rate of fall -> highest hydel power potential)
        
        dissected by fast flowing rivers from north to south - forming gorges -> Brahmaputra passes through a deep gorge after crossing Namcha Barwa
        
        Imp. Peaks - Kangtu and Namcha Barwa
      - Darjeeling and Sikkim Himalayas
        
        absence of Shiwalik formations but have 'duars' which are used for dev. of tea gardens
        
        Lepcha tribe- higher regions, while southern part, Darjeeling has mixed population of Nepalis, Bengalis and tribals from central India
        
        Known for Tista river and is a region of high mountain peaks such as Kanchenjunga and deep valleys.
        
        small but very significant part of Himalayas
        
        W- Nepal Himalayas, E-Bhutan Himalayas
      - Himachal and Uttaranchal Himalayas
        
        famous valley of flowers located here as well as Gangotri, Yamunotri, Badrinath, Kedarnath
        
        In Great Himalayan range, the valleys inhabited by Bhotia's who migrate to Bugyals ( summer grasslands in higher reaches) during summers and return to valleys during winters
        
        Duns and Shiwaliksfound here- Dehra dun is largest of all duns
        
        all 3 ranges of Himalaya prominent here too
        
        N-part extension of Ladakh cold desert
        
        lies b/w Ravi and Kali rivers & is drained by Indus and Ganga river systems
      - Kashmir Himalayas
        
        southernmost part of the region consists of Duns (longitudinal valleys)
        
        Srinagar - on banks of Jhelum, Jhelum still in youth stage and yet forms meanders
        
        famous for Karewa formations which are thick deposits of glacial clay and other minerals and are useful for cultivation of Zafran, a local saffron variety
        
        Kashmir Valley- b/w Great Himalayas and Pir Panjal
        
        NE- part- cold desert & lies b/w Great Himalayas and Karakoram
        
        Karakoram, Ladakh, Zaskar and Pir Panjal ( N-S)