Late Pleistocene upland stratigraphy of the western Delmarva Peninsula, USA

Abstract

New pedological, geological, archaeological, and geochronological data from the Miles Point site in eastern Maryland are compared with similar data from other nearby sites to develop a framework for interpreting the upland stratigraphy in the western Delmarva Peninsula. Our results indicate the presence of two different intervals of loess deposition. The earlier loess (Miles Point Loess) was deposited between 41 and 25 ka. A paleosol (Tilghman Soil) formed in this loess was initially developed in grasslands and boreal environments during a subsequent period of landscape stability between 25 and 18 ka. Between 18 and 12.8 ka, the Miles Point Loess and the Tilghman Soil were eroded in many areas as evidenced by diagnostic ca. 12.8 ka Clovis-age artifacts lying unconformably on the Tilghman Soil. Cores adjacent to the deep channel area of the Chesapeake Bay confirm this erosional unconformity prior to 12.7 ka. A relatively uniform terminal-Pleistocene loess (Paw Paw), deposited prior to the Early Archaic period, buried Clovis-age lag artifacts and other archaeological remains older than 13.2 ka. Stratigraphic evidence from the Late Pleistocene lower Susquehanna River Valley suggests that the Paw Paw Loess is the result of eolian redeposition and reworking of non-glacial eroded upland sediments that filled the valley between 12.7 and 11.5 ka.