Aeolian Processes

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Lag deposits & desert pavement

desert pavement

The surface of Eureka Valley
is covered with lag deposits

In Eureka Valley we observed the lag deposits or desert pavement. Let's examine how this feature of aeolian environments is formed.

lag deposit (lag' de'-pos-it') A residual accumulation of coarse rock fragments on a surface after the finer material has been blown away by the winds. Also known as desert pavement

Lag deposits are created by deflation. The graphic below illustrates how deflation takes place. As we discussed earlier, the wind can hold very small particles aloft quite easily. So the finest silt and clay sized particles are removed by the wind. The sand-sized particles are also removed during periods of high wind. The result is that only the larger pebbles and stones are left on the surface, forming a 'pavement' which protects the finer material underneath from erosion.


How deflation works