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Using Figure 4 and your own knowledge, assess the relative importance of factors leading to the development of this landscape - AQA - A-Level Geography - Question 2 - 2021 - Paper 1
Question 2
Using Figure 4 and your own knowledge, assess the relative importance of factors leading to the development of this landscape. Note: The landforms in this landscape... show full transcript
Worked Solution & Example Answer:Using Figure 4 and your own knowledge, assess the relative importance of factors leading to the development of this landscape - AQA - A-Level Geography - Question 2 - 2021 - Paper 1
Step 1
Assess the factors contributing to the development of the landscape
Answer
In evaluating the factors contributing to the development of the landscape shown in Figure 4, it's important to consider the role of various environmental elements in the formation of barchan dunes.
Energy Sources
The primary source of energy in hot desert environments such as the Namib Desert comes from solar insolation, accompanied by strong winds. Winds play a crucial role in shaping the landscape by transporting and depositing sand, and they can have significant variations in direction and intensity.
Geomorphological Processes
Various geomorphological processes are also at play:
- Weathering: The absence of vegetation leads to minimal biological weathering, whereas physical weathering contributes to the breakdown of larger rocks into smaller sediments.
- Erosion: As winds blow consistently, they erode sediment from the surface, contributing to the formation of delicate barchans. Erosion processes like deflation and abrasion are particularly prominent, influencing the shape and size of these dunes.
Sediment Sources
The sediment supply is vital for the formation of the dune landscape. The Orange River, located several kilometres from the dunes, is a primary source of sediment. The river’s flow and sediment transport mechanisms ensure that there is a continuous supply of material for dune formation.
Role of the Wind
The wind's predictable patterns are critical. In this case, a predominantly regular direction allows for the consistent shaping of dunes. This flow pattern results in the formation of the crescent shape commonly observed in barchans, as the wind lifts and deposits sand.
Conclusion
Overall, the factors leading to the development of this landscape are interlinked. Solar energy drives wind patterns, which in turn erode and transport sediments sourced from the Orange River. Understanding these interactions provides insight into how barchan dunes have formed and evolved in this specific desert setting.
Step 2
Evaluate the relative importance of each factor
Answer
While each factor is significant, the relative importance can be assessed as follows:
- Wind Patterns (Most Important): The regular and dominant wind patterns dictate the shape and movement of the dunes, making wind the most crucial factor.
- Sediment Supply: The significant role of the Orange River in providing sediment is fundamental, yet it is the movement and deposition facilitated by wind that truly shapes the barchan dunes.
- Energy from Insolation (Less Important): Although solar energy is essential for creating the hot desert conditions, its role is indirect compared to the direct impact of wind and sediment transport.
In summary, while all factors contribute to the landscape's formation, wind and its interactions with sediment supply are the most instrumental in the development of barchans in the Namib Desert.