Loess

Article By:

Maher, Barbara A. Centre for Environmental Magnetism and Palaeomagnetism, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.388900

Deposits of windblown fine-grained angular particles that are produced by the breakdown of larger particles at desert or glacial margins. Suspension and transport by the wind produces particularly homogenous and well-sorted loess upon deposition. Loess is dominated by silt-sized (2–63 micrometers in diameter) particles of quartz, with smaller amounts of feldspars, calcium carbonate, and clay minerals, and can form successive, blanketing layers of thickness from centimeters to hundreds of meters, as in the Loess Plateau region of north-central China (Fig. 1). Loess occurs globally, encompassing the pampas of Argentina, the central and east European and Russian steppe, and the midcontinent United States, to name some locations. It is porous and unconsolidated, making it a valuable agricultural resource. Loess is highly erodible in wet conditions, although often mechanically strong when dry because calcium carbonate and clay aggregates bind the silt particles together. See also: Calcite; Clay minerals; Depositional systems and environments; Eolian landforms; Feldspar; Quartz

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