Final answer:
Dunes are sedimentary features created by the movement of wind or water over sand, with subaerial dunes being common in deserts and coastal areas on Earth. Mars also has extensive dune fields formed by wind, demonstrating that aeolian processes are not limited to our planet.
Step-by-step explanation:
An example of dunes (aeolian landform) can be found in many deserts and coastal regions around the world. Subaerial dunes are the ones most people are familiar with, which are constructed by wind-blown sand, and can be vegetated in some cases. These are primarily found in desert landscapes like the ones in Algeria or in Coyote Gulch within the Canyons of the Escalante, Utah, where sedimentary features show cross-bedding from ancient sand dunes. On other planets, like Mars, wind also plays a significant role in shaping the landscape, creating extensive dune fields and erosional features such as yardangs, which are aligned with the dominant wind direction.
When considering the size and formation of dunes, the environment plays a key role. Larger structures typically indicate aeolian (wind) processes, while smaller ripples form in water. This differentiation is important when analyzing sedimentary structures on Earth as well as on other planetary bodies.