Consider the following statements on Northern Plains of India:1. It w...
- India's third geological division comprises the plains formed by the river Indus, the Ganga and the Brahmaputra Originally.
- It was a geo-synclinal depression that attained its maximum development during the third phase of the Himalayan mountain formation approximately 64 million years ago.
- Since then, it has been gradually filled by the sediments brought by the Himalayan and Peninsular rivers Average depth of alluvial deposits in these plains ranges from 1,000 to 2,000 m.
Geosyncline - It is a linear trough of subsidence of the Earth's crust within which vast sediment accumulate.
- The filling of a geosyncline with thousands or tens of thousands of feet of sediment is accompanied in the late stages of deposition by folding, crumpling, and faulting of the deposits, the intrusion of crystalline igneous rock and regional uplift along the axis of the trough generally complete the history of a particular geosyncline, which is thus transformed to a belt of folded mountains,
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Consider the following statements on Northern Plains of India:1. It w...
Statement 1: It was a geo-synclinal depression.
The first statement is correct. The Northern Plains of India were formed as a result of the subsidence of the ancient Tethys Sea, which was a part of the supercontinent Gondwana. This subsidence created a large depression known as the Tethys geosyncline. Over time, this depression was filled with sediments, resulting in the formation of the Northern Plains.
Statement 2: It has been gradually filled by the sediments brought by Himalayan and Peninsular rivers.
The second statement is also correct. The Northern Plains have been formed by the deposition of sediments brought by the Himalayan and Peninsular rivers. The Himalayan rivers, such as the Ganges, Brahmaputra, and Indus, carry large amounts of sediment eroded from the mountains. These sediments are deposited in the plains as the rivers flow through them. Similarly, the Peninsular rivers, such as the Yamuna, Chambal, and Son, also contribute to the deposition of sediments in the Northern Plains.
Statement 3: Average depth of alluvial deposits in these plains ranges from 1 to 2 km.
The third statement is incorrect. The average depth of alluvial deposits in the Northern Plains is not as deep as mentioned in the statement. The alluvial deposits in these plains generally range from a few meters to a few hundred meters in depth. The thickness of the alluvial deposits varies across different regions of the plains.
Conclusion:
In conclusion, statements 1 and 2 are correct. The Northern Plains of India were formed as a result of a geo-synclinal depression and have been gradually filled with sediments brought by the Himalayan and Peninsular rivers. However, statement 3 is incorrect as the average depth of alluvial deposits in these plains does not range from 1 to 2 km.
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