1 Summary Geography Class 36 ## A brief discussion of the Previous Class (5:11 PM) ## Mapping(5:25 PM) - Sikkim and Meghalaya share a border with only one state. - Sikkim shares a border with West Bengal only. Meghalaya Shares a border with Assam only. - Telangana doesn't share a border with Odisha. - Madhya Pradesh doesn't share a border with Jharkhand. - Yamuna flows through Himachal Pradesh as well. ## Physiography of India (7:53 PM) ## Subcontinent - Subcontinent is the large landmass i.e. part of the continent but is considered separate from the rest of the continent. - For example, the Indian subcontinent, Alaskan Subcontinent, etc. - Reasons for considering India as a subcontinent. - (a) ==Geographical reasons== - Geographically, the Indian subcontinent has well-defined physical boundaries, such as the Himalayas and the Hindukush in the north, Purvanchal in the east, and the Indian Ocean in the South. - (b) ==Geological reasons== - The countries of the Indian subcontinent share common geological history, such as the formation of the Himalayas, northern plains, etc. - (c) ==Common climatic conditions== - All these countries experience monsoon types of climate. - (d) ==Political reasons== - They share a common political identity i.e. South Asia. - (e) ==Historical and Cultural reasons== - They share a common history, ruled by large empires such as Mauryan, Mughal, etc. - They also share a common culture of language, festivals, etc. ## Mountains of India (6:05 PM) ## Himalayas - **Origin of the Himalayas** - (Discussed in the Plate tectonic Class. Please refer to the notes of those classes.) - ==Different stages in the formation of the Himalayas== - The Himalayas were formed in three different phases, - (a) First Stage between 120-70 million years ago - During this stage, great Himalayas were formed. - (b) Second stage between 30-25 million years ago. - This resulted in the formation of the middle Himalayas. - (c) Third stage between 20-2 million years ago - This resulted in the formation of the Shivaliks. - ==Syntaxial Bending== - It refers to a deep knee bent, with the strike of the ridges suddenly turning at right angles. - It is due to the maximum push offered at both ends of the Indian Peninsula during its northward drift. - In the northwest direction, the Aravalis and in the northeast the Assam ranges acted as two extended arms, while the central area sagged giving an arcuate shape. - ==Evidence to prove that the Himalayas are still rising== - (a) Frequent earthquakes - (b) Recent adjustment in the height of Himalayan peaks. - (c) Frequent disturbance in the topographies. - (d) The rivers of the Himalayas, are in the youthful stage over a long time. - (e) Drying up of lakes of Tibet, which shows that the Tibetan plateau is still rising. - (Kindly refer to the diagram drawn by the faculty in the class for understanding the Fracture Zones of the Himalayas) ## Regional Division of Himalayas(7:17 PM) - The Himalayas are divided by rivers. This classification is called regional division. The main classifications are: - (a) ==Kashmir Himalayas== - Between the river Sutlej and Indus - (b) ==Kumaon Himalayas== - Between the river Sutlej and Kali - (c) ==Nepal Himalayas== - Between the river Kali and Teesta - (d) ==Assam Himalayas== - Between the river Teesta and Brahmaputra. - | | | | --- | --- | | **Western Himalayas** | **Eastern Himalayas** | | It includes Punjab and Kumaon Himalayas. | It includes Sikkim and Arunachal Himalayas. | | It is between River Indus and River Kali. | It is between River Teesta and the Brahmaputra. | | These are wider. | These are narrower. | | Middle Himalayas and Shivaliks are separate. | These have merged in the eastern Himalayas. | | These are taller. | These are comparatively shorter. | | These rise gradually. | These rise abruptly. | | The temperature of the western Himalayas is comparatively higher. | The temperature of the eastern Himalayas is comparatively higher. | | Coniferous type of vegetation. | Evergreen and deciduous types of vegetation. | | Lower biodiversity. | Higher biodiversity | | Lower precipitation. | Higher precipitation. | | Snowline at the lower altitude | Snowline at the higher altitude. | ## Longitudinal Division ## (7:36 PM) - (a) ==Trans Himalayas== - Karakoram range, Zaskar range, Ladakh range and Kailash range. - (b) ==Great Himalayas== - It extends from Nanga Parbat to Namcha Barwa. - These are also known as Himadri. - (c) ==Middle Himalayas/ Lesser Himalayas/ Himachal== - These are discontinuous ranges. - Pir Panjal range, Dhauladhar range, Mahabharat range, etc. - the average height is 4000 m. - (d) ==Shivaliks== - The average height is just 1000m. - Dafla, Mirim Abhor, and Mishmi are parts of the Middle Himalayas and Shivaliks. - (e) ==Purvachal== - These are hills of the northeast. - It includes Mizo hills, Tripura Hills, Naga Hills, etc. ## The Topics for the Next Class: Mountains of India (Continued)