Loess Deposits of the Eastern Shore of Maryland

Abstract

AbstractA silty mantle on the upper Eastern Shore of Maryland was studied to determine its origin and characteristics. Thickness of the silts was studied by selecting traverses in an east‐west direction from the Chesapeake Bay and also scattered borings between traverses. These deposits are believed to be loess; they are characterized by 50 to 75% silt‐sized particles. The material is also carbonatefree, nonstratified, and yellowish brown in color. In addition, the silty mantle shows a reduction in thickness and particle size with increasing distance from the Chesapeake Bay, which was the probable source area. In areas of thin loess (< 90 cm), increasing amounts of sand were apparently incorporated into the loess at the time of deposition. Based on 14C date of a 11A1b horizon of a buried paleosol below the loess, deposition of the silts took place after 10,520 ± 240 years B.P. Profile characteristics of soils developed in the loess show moderately well expressed argillic horizons with the soil in this study having an increase of 9% clay from the A to the B2t horizon or a B2t/A clay ratio of 1.65.