What is the term for sediment that is deposited by wind?

The term for sediment that is deposited by wind is loess. Loess is a specific type of sediment primarily composed of silt-sized particles that are typically carried by wind over long distances and then deposited when the wind speed decreases. This process creates significant deposits that can form extensive, thick layers of sediment.

Wind action is particularly effective at moving fine particles like silt because they can be suspended in the air and transported by wind currents. When conditions are right, loess deposits can accumulate and often result in fertile soils that are critical for agriculture, especially in regions like the Midwest of the United States.

In contrast, sand dunes refer specifically to sedimentary formations of sand that are shaped by wind action but do not encompass the broader category of wind-blown sediments like loess. Colluvium describes sediments that have accumulated at the base of slopes primarily due to gravity, while alluvium refers to sediments deposited by running water, such as in riverbeds or floodplains. Thus, loess is the most appropriate term for wind-deposited sediments in this context.