ABSTRACT
The horizontal samplers suffer from the risk of contamination of aeolian samples by sediment derived from other erosion processes, example slopewash material. The explanation of the particular form of a dune entails an understanding of its aeolian and sedimentary environment. The extent of aeolian contamination is best determined in soils and sediments derived from lithologies having distinctive mineralogy, such that foreign grains are readily recognisable. Sampling in ground-level collections should be restricted to controlled, short-period experiments when other erosion processes do not interfere. The use of a vertical collector fitted with a direction vane eliminates the need for the time-consuming reorientation that is necessary with the horizontal box samplers. All the devices for sampling airborne particulates draw a measured volume of air through the unit usually by means of a motor-driven vacuum pump. The two most frequent biogenetic components of dust—freshwater diatoms and opal phytoliths—can be used to identify the source area of airborne particles.
