Extent and Thickness of Last Glacial Aeolian Additions to Soils Across the Conterminous U.S.

The mapped extent of Last Glacial aeolian additions is frequently limited to areas where deposits are several meters thick (such as the Midwestern U.S.).  Previous research has identified specific locales east of the Midwestern U.S. where aeolian addition to soils has been substantiated, or strongly suggested, but not widely mapped.  We sought to identify and potentially map these soils and thus document the wider extent of Last Glacial aeolian influence on soil genesis in the conterminous United States.  We present a new model of the spatial extent and thickness of Last Glacial aeolian deposition based upon dissimilarities in particle size between upper 1.5 m soil profiles and parent materials underlying those soils.  Soil physical data from over 900 pedons in Pennsylvania was used to ascertain an aeolian signature and depth of influence across the state.  Results from this analysis were then used with a digital multilayer soil characteristics dataset for the conterminous United States (CONUS-SOIL) to derive the extent and thickness of aeolian additions across the conterminous U.S.  Our results indicate aeolian additions are far more widespread than previously noted and its potential affect on soil genesis in the eastern U.S. is likely as significant as it is in western U.S. models of soil genesis, which are driven by profile aggradation.  A rationale is also presented of some of the reasons that thin loess has not been reported in Pennsylvania.