Desert DNA

Desert landforms are unique in their structure and their formation. For these landforms to exist, other factors must first be discussed. Weathering and erosion must occur to allow for the movement and transportation of earth and sediment which form the desert landscape.

For many years it was believed that the dominant process involved in desert weathering was the mechanical breakdown of rocks due to the cycle of heating and cooling in the extreme environment. Commonly known as exfoliation or onion-skin weathering the daily variations in temperature stressed the rock causing it to fracture on the surface with the outer layers subsequently being ‘peeled’ away. More recent studies have identified that this particular method of weathering is not alone responsible for creating desert landscapes.

It is now commonly accepted that wind and water are also important processes, and led to the distinction that different processes are dominant in different areas. It became clear to scientists and researchers that areas which are typically very dry may have experienced a much different climate in history. Wind erodes the landscape through deflation and abrasion and transports the eroded material in several ways, including saltation, suspension and surface creep, similar to the processes found to occur in a river channel.

It would be important to notes to students that not all desert landscapes are the same and it would be interesting to begin a lesson by displaying a selection of photos of desert landscapes and asking students which they thought were deserts and which were not, emphasising that a desert landscape is not restricted to camels and sand dunes. Case studies such as the Grand Canyon (a deep gorge) and Death Valley (being immensely flat) in the US could be introduced. The Grand Canyon would be a great example of water erosion and how over a large time period the landscape can change dramatically. Case studies are an excellent way to place ideas into reality and students can only benefit from doing this.