Questions and Answers
What geological regions broadly follow the physical features of the earth?
The Peninsular Block, The Himalayas and other Peninsular Mountains, Indo-Ganga-Brahmaputra Plain.
How old is the earth approximately?
4600 million years.
Which of the following forces have changed the physical environment of the Indian subcontinent?
What are some important consequences of the northward movement of the Indian plate?
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Which geological division primarily consists of relict and residual mountains?
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Name two examples of the rift valleys mentioned in the text.
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What type of mountains primarily constitute the Peninsula?
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Study Notes
Overview of Physiography
- Earth is approximately 4600 million years old, exhibiting a dynamic geological history.
- Current landforms are a result of endogenic (internal) and exogenic (external) forces over millions of years.
- Major physiographic divisions of India: Peninsular Block, Himalayas and other Peninsular Mountains, Indo-Ganga-Brahmaputra Plain.
The Peninsular Block
- Northern boundary is an irregular line from Kachchh, along the western Aravali Range, parallel to the Yamuna and Ganga to Rajmahal Hills.
- Contains extensions such as Karbi Anglong and Meghalaya Plateau in the northeast, and regions in Rajasthan.
- The block consists mainly of ancient gneisses and granites, forming a rigid geological structure since the Cambrian period.
- Some areas, like the western coast, are submerged beneath the sea, while others have experienced tectonic activity modifying the land.
- Vertical movements and block faulting have shaped the landscape, giving rise to rift valleys (e.g., Narmada, Tapi, and Mahanadi).
- Features residual mountains: Aravali, Nallamala, Javadi, Veliconda, and Mahendragiri hills.
Indo-Ganga-Brahmaputra Plain
- Represents the third geological division; formed by the river systems of Indus, Ganga, and Brahmaputra.
- River valleys in this region are characterized by shallow and low-lying features, highlighting significant sedimentary deposition over time.
- Originally formed as a geo-synclinal.
Dynamics of Plate Movements
- Historical context: Indian plate was south of the equator and larger earlier, later breaking into parts with the Australian plate.
- Ongoing northward movement of the Indian plate influences both the geological structure and the physical environment of the subcontinent.
- Important consequences of this movement include the formation of various geological features and the landscape's evolution.
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Description
This quiz covers the structure and relief of the Earth's physiographic divisions, including drainage systems and watersheds. Focus is given to Himalayan and Peninsular physiography, highlighting the geological history and physical features of the Earth. Test your knowledge on these essential concepts of physical geography.
