Loess in Ohio in Relation to Several Possible Source Areas: II. Elemental and Mineralogical Composition

Abstract

AbstractThis study presents the elemental and mineralogical composition of thin loessial deposits eastward of three rivers in Ohio. In general, elemental contents (Ca, Fe, K, Ti, and Zr) of medium and coarse silts of the Late Wisconsin‐age loesses were of the same magnitude in each area. These elements showed remarkably slight weathering profiles which were essentially comparable among areas. Weathering profiles of Fe were more strongly expressed than those of K and Ca; depth‐distributions of Zr and Ti were most uniform. Contents of Ca within a Loveland loess paleosol were remarkably constant with depth and notably low, especially in the coarse silt fraction (mean of 0.06%). Mineralogy did not reflect bedrock lithologies among the different assumed loess source areas. Clay fractions from the parent loess in the first two transects were dominated by mica followed by vermiculite and quartz with less expandables and kaolinite. Clay fractions of surface and subsurface horizons in these transects contained about equal amounts of mica, vermiculite, and quartz with less expandables and kaolinite. In the third transect, weathered loessial materials generally contained less mica and more interstratified 10–14Å components. Clay‐free particle‐size distribution was the most sensitive parameter of parent material uniformity; total Zr and Ti in silt fractions, and Ti/Zr ratios were less sensitive in that order.