The Himalayan rivers have antecedent drainage because –a)They are sti...
Antecedent drainage in the Himalayan rivers
Antecedent drainage refers to the existence of rivers that flow across mountain ranges, in a direction opposite to the general slope of the land. In the case of the Himalayan rivers, the correct answer to why they have antecedent drainage is option 'C' - they cut gorges. Let's explore this answer in detail:
1. Formation of gorges:
The Himalayan rivers have antecedent drainage because they have cut deep gorges in their path. As these rivers flowed across the rising mountain range, they slowly eroded the land, cutting through the hard rocks and forming deep gorges. These gorges act as natural channels through which the rivers continue to flow.
2. Geological processes:
The Himalayas are a young mountain range, formed by the collision of the Indian and Eurasian plates. The tectonic forces involved in this collision caused the upliftment of the land and the formation of folds and faults. The rivers that existed in the region prior to the formation of the Himalayas were able to maintain their course by cutting through the rising landmass, resulting in antecedent drainage.
3. Youth stage:
While it is true that the Himalayan rivers are still in their youth stage, this alone does not fully explain their antecedent drainage. The youth stage is characterized by the presence of steep gradients, high erosive power, and the formation of rapids and waterfalls. However, these factors do not necessarily lead to the formation of antecedent drainage. It is the cutting of gorges that is the primary reason for antecedent drainage in the Himalayan rivers.
4. Direction of Himalayan folds:
The direction of the Himalayan folds, i.e., the orientation of the mountain ranges, is not directly responsible for the antecedent drainage of the Himalayan rivers. While the folds do influence the overall topography of the region, it is the cutting of gorges that allows the rivers to maintain their flow in a direction opposite to the general slope of the land.
In conclusion, the primary reason for antecedent drainage in the Himalayan rivers is the cutting of gorges by these rivers as they flow across the rising mountain range. This phenomenon is a result of the geological processes associated with the formation of the Himalayas.
The Himalayan rivers have antecedent drainage because –a)They are sti...
An antecedent stream is a stream that maintains its original course and pattern despite the changes in underlying rock topography. A stream with a dendritic drainage pattern, for example, can be subject to slow tectonic uplift. However, as the uplift occurs, the stream erodes through the rising ridge to form a steep-walled gorge.
The Himalayan Rivers are great examples of antecedent origin. These rivers originated well before the Himalayan region was uplifted. The rivers Indus, Brahmaputra, Sutlej, Kosi and Subansiri originated on Tibetan side and now traverse the existing mountain ranges, cutting deep gorges.