Barium in Illinois Surface Soils

Abstract

AbstractThe mean total Ba content determined in 174 upland, surface soil samples was 610 mg kg−1 and the contents of the samples formed a normal distribution. An isopleth map of Ba contents was produced from programs calculating contours on a grided surface overlaid on a base map of Illinois. The isopleths are related to loess isopachs in southern Illinois and uniformly decrease from about 700 mg kg−1 near the Mississippi River to near 500 mg kg−1 at the eastern boundary of the state. This change in Ba content may reflect both weathering intensity and aeolian sorting of Ba‐bearing minerals. In northwestern Illinois where loess is also an important parent material, Ba contents are rather invariant in the range 600 to 650 mg kg−1. Where loess is very thin or nonexistent, surface soils of northeastern Illinois contain about 500 mg kg−1, a content thought to reflect the concentration in the tills of this area.