Arrange the following stages in the development of a desert oasis resulting from wind action in the correct sequential order from earliest to latest.
- 1Persistent wind deflation scours and removes loose, dry sand particles from a localized arid surface depression.
- 2Continued wind scouring deepens the depression progressively toward the subterranean water table.
- 3Groundwater moisture reaches the surface of the hollow floor, binding soil grains and halting further wind deflation.
- 4Vegetation colonizes around the exposed water source, establishing a fertile desert oasis.
Answer
The correct sequence begins with persistent wind deflation scouring away dry sand, followed by the continuous deepening of the hollow down to the water table level. Exposure of groundwater moisture halts further wind deflation, enabling vegetation to colonize and form an oasis.
Wind deflation acts as the primary excavation mechanism, removing dry surface sand to create a depression. As the hollow deepens, it eventually meets the subterranean water table. Moisture from the water table acts as a natural limit to aeolian erosion because damp sand cannot be lifted by wind currents. Once water is available at the surface, vegetation takes root, completing the formation of a desert oasis.
Step-by-Step Solution
Key Concept
Formation of deflation hollows and oases by aeolian processes