Loess

Loess is a fine‐grained terrestrial sediment derived from wind‐blown dust. Most loess deposits consist predominantly of silt‐sized particles but their content of sand and clay may increase or decrease their median and modal grain sizes. The surface morphology of loess deposits can take a variety of forms depending upon the underlying topography, including rolling hills, plateaux, and steep‐sided loess‐covered valleys. Many ocean sediments preserve significant accumulations of dust. Ice cores also retain a record of dust accumulation, usually derived from long‐range transport. Unlike lacustrine or marine sediments that contain records of dust accumulation, few loess deposits preserve palaeoecological indicators such as pollen, phytoliths, diatoms, ostracods, foraminifera, or radiolaria, which have been used to reconstruct past environmental conditions in lacustrine and marine settings. Loess and dust also pose health concerns for human and animal health e.g. through pneumoconiosis, or non‐industrial silicosis, resulting from exposure to mineral dust concentrations of silica‐rich particles of respirable size