Q. Consider the following pairs:
Geographical Terms——————–Definitions
1.Avulsion———————— A significant length of a river or stream channel which no longer conveys fluvial discharge as part of an active fluvial system.
2.Sand dikes ————– A seam of sedimentary material that fills an open fracture in and cuts across sedimentary rock strata or layering in other rock types.
3.Paleochannel——————- The process in which river flows are diverted out of an established channel into a new course at a lower elevation on the adjacent surface.
How many of the above pairs are correctly matched?
Answer: A
Notes:
Explanation –
- Avulsion is the rapid abandonment of a river channel and the formation of a new river channel. This process occurs when a river changes its course abruptly, often during large floods or due to the buildup of sediment that elevates the riverbed above the surrounding floodplain.
- A sand dike, also known as a clastic dike, is a seam of sedimentary material that fills an open fracture and cuts across sedimentary rock strata or other rock types. These dikes form when sediment is injected into cracks due to fluid pressure or when sediment falls into open cracks from above.
- A paleochannel is a significant length of a river or stream channel that no longer conveys fluvial discharge as part of an active fluvial system. These channels are remnants of ancient rivers and can be preserved as surface features or buried by younger sediments.
Source: The Hindu
