Deposits of loess (deposits of windblown dust of silt size) are widely distributed in mid- and high-latitude areas of North America, Europe, and Asia. They are a valuable geologic record of variations in Quaternary dust sources, transport pathways, and deposition. In combination with interbedded paleosols, they form one of the most complete terrestrial records of glacial-interglacial cycles, especially when loess-paleosol sequences can be dated using luminescence methods and correlated on regional and global scales using magnetostratigraphic techniques.

A recent issue of Quaternary Research (Volume 89 – Issue 3) is devoted to a series of article focused on aspects of loess research. The articles represent a selection of papers that originated from presentations and discussions at the 2016 INQUA LoessFest meeting held in Eau Claire, Wisconsin, USA.

A comprehensive review article (Schaetzl et al., 2018) that summarizes the variety of approaches and techniques applied to loess research and highlights recent studies of loess heads the collection of 13 articles. These articles discuss a wide range of topics of loess research including, but not limited to, chronology and stratigraphy, identification of sources of silt using isotopic, mineralogical and geochemical techniques, as well as case studies demonstrating the importance of the contributions of silt-sized material to soils in arid and humid environments. Refer to the table of contents for this volume for specific articles.

Some highlights of the Special Issue are summarized below.

The Chinese Loess Plateau is the largest (and thickest) area of loess deposits and has long been a key area for loess research. The area has provided a record of loess deposition spanning the Quaternary, but the source(s) of the silt-sized material is still debated. New techniques, including zircon U-Pb ages and geochemical and mineralogical analyses are beginning to constrain the likely sources, emphasizing the importance of fluvial transport of material from the Tibetan Plateau by the Yellow River (Fenn et al., 2017).

The importance of the loess deposits in Central Asia is increasingly recognized. Their deposition in a topographically-complex region makes stratigraphic correlations challenging and the results of older studies have been re-evaluated using modern techniques, including luminescence dating and analysis of digital elevation models (Sprafke et al., 2018).

In many parts of the world, the contributions of aeolian silt to soils marginal to major loess depositional areas, as well as to soils in desert margins are now being identified using geochemical and mineralogical approaches in combination with detailed studies of soil morphology (Reheis et al., 2017; Wah et al., 2018; Waroszewski et al., 2017).

Loess sequences in areas proximal to ice sheets can provide important information on past wind regimes (Schaetzl et al., 2017), as well as changes in source areas, reflecting fluctuations the extent of late Pleistocene ice sheet margins (Nash et al., 2017) and glaciers (Muhs et al., 2018).

Today, loess deposits provide the parent material for many of the world’s most productive agricultural soils. The significance of loess deposits as favorable locations for past agriculture and human settlements in Central Asia is illustrated by their connection to branches of the Silk Road and to their sensitivity to environmental change in the region (Owczarek et al., 2017).

 

 

Featured articles from Special Issue

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