Eolian Settings: Loess

Abstract

The term loess comes from the German word Löss, meaning loose, which is reported to have been first used to describe friable, silty deposits along the Rhine Valley near Heidelberg (Pye 1995). Loess is a fine-grained sedimentary material resulting from the deposition of eolian dust, which extensively accumulated in some areas of the world during the Quaternary; it is also recorded in older geologic intervals (e.g., Pfeifer et al. 2021). Loess is defined as a sediment composed predominantly of silt-sized particles (50–2 μm) with subordinated amounts of clay (<2 μm) and sand (>50 μm) that has been entrained, transported, and accumulated by the wind (Muhs 2014). A more restrictive definition of loess, still regarded by some researchers, considers that loess is not simply eolian dust but the result of weathering and soil formation, a process called loessification (Pécsi 1990; Smalley et al. 2011). If primary loess has been modified by weathering, soil formation, and diagenesis,...