by Matthew Law

Used to describe sediments when discussing site formation processes, the adjective 'aeolian' means wind blown. In the UK, aeolian deposits are most commonly found dating from the Pleistocene, where they were laid down in periglacial tundra-like conditions, and particularly during the Devensian period; although the same processes of erosion and deposition by wind can occur today (English Heritage 2004: 6).

Pleistocene aeolian deposits commonly fall into two categories, determined by the dominant particle size:

1. Coversands. Coversands are the remnants of dune systems. They are usually formed of moderately well or well sorted sand sized material, comprising predominantly rounded to well rounded particles. If the material originated in a coastal environment, there may be fragments of marine shell present (English Heritage 2004: 7). The process by which coversands form is called saltation. During this process wind picks up exposed sediment - for example from the coast or from glacial outwash - and deposits it as the wind strength subsides. Subsequent gusts may repeat the process, allowing coversands to be transported in stages (Evans 1978: 72).
2. Loess. Loess deposits are commonly formed during glacial periods when the sea-level lowered, leaving large areas of fine-grained sediment exposed. They are predominantly formed of silt-sized material, although there may also be a large proportion of clay-sized material. Loess can be carried hundreds or thousands of miles. When loess is re-sorted and deposited by fluvial action (e.g. being carried in floodwaters), it gives rise to brickearth (English Heritage 2004: 7).

Holocene wind-blown deposits tend to derive from local conditions and only travel comparatively short distances (English Heritage 2004: 8)

References

English Heritage, 2004, 'Geoarchaeology: Using Earth Sciences to Understand the Archaeological Record', Eastney: English Heritage Centre for Archaeology.

Evans, J.G., 1978, 'An Introduction to Environmental Archaeology', London: Elek 

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