Late Pleistocene eolian features in southeastern Maryland and Chesapeake Bay region indicate strong WNW–NW winds accompanied growth of the Laurentide Ice Sheet

Abstract

Inactive parabolic dunes are present in southeastern Maryland, USA, along the east bank of the Potomac River. More elongate and finer-grained eolian deposits and paha-like ridges characterize the Potomac River–Patuxent River upland and the west side of Chesapeake Bay. These ridges are streamlined erosional features, veneered with eolian sediment and interspersed with dunes in the low-relief headwaters of Potomac- and Patuxent-river tributaries. Axis data for the dunes and ridges indicate formation by WNW–NW winds. Optically stimulated luminescence and radiocarbon age data suggest dune formation from ∼ 33–15 ka, agreeing with the 30–13 ka ages Denny, C.S., Owens, J.P., Sirkin, L., Rubin, M., 1979. The Parsonburg Sand in the central Delmarva Peninsula, Maryland and Delaware. U.S. Geol. Surv. Prof. Pap. 1067-B, 16 pp. suggested for eolian deposits east of Chesapeake Bay. Age range and paleowind direction(s) for eolian features in the Bay region approximate those for late Wisconsin loess in the North American midcontinent. Formation of midcontinent loess and Bay-region eolian features was coeval with rapid growth of the Laurentide Ice Sheet and strong cooling episodes (δ18O minima) evident in Greenland ice cores. Age and paleowind-direction coincidence, for eolian features in the midcontinent and Bay region, indicates strong mid-latitude WNW–NW winds for several hundred kilometers south of the Laurentide glacial terminus that were oblique to previously simulated anticyclonic winds for the last glacial maximum.

Synthesis on Quaternary aeolian research in the unglaciated eastern United States

“…1c,(6)(7)(8)(9)(10)(11)(12)(13)(14)16c,17). They also occur on relatively-broad, flat uplands or interfluves (Hack, 1955;Daniels et al, 1969;Markewich and Markewich, 1994;Ivester et al, 2001;Markewich et al, 2009b) (Fig. 15) and adjacent to shallow, generally flat-bottomed, circular-to-elliptical, raised-rim basins (Section 4.3.2.)…”

“…Non-glacial regional rivers, such as the Potomac ( Fig. 1b and d), drained high-elevation (>900 m) areas of Pleistocene periglacial activity (Clark, 1968(Clark, , 1992Whittecar and Ryter, 1992;Litwin et al, 2004;Markewich et al, 2009b). Inland aeolian sand deposits occur both east and west of Chesapeake Bay (e.g., Fig.…”

“…Inland aeolian sand deposits occur both east and west of Chesapeake Bay (e.g., Fig. 2 in Markewich et al 2009b;dunefield area 11 on Figs. 1a, c, d, 16c, d, and 17 in this article).…”

“…Many remnant dune fields within river valleys and on uplands have been modified or completely removed by fluvial or anthropogenic processes (urbanization, farming, etc.) (Markewich et al, 2009b). Although the current extent of ACP aeolian sand deposits has not been determined, sum of estimates for some morphologically identifiable dune fields and the Parsonsburg Sand (the Parsonsburg) (Table 1; Figs.…”

“…Feathers et al (2006) report OSL ages from $27 ka into the early Holocene for aeolian sand at the Cactus Hill archaeologic site within the Nottoway River valley. Markewich et al (2009bMarkewich et al ( , 2010a reported 23À16.5 ka OSL ages for aeolian sand from the Rubis Pearsall archaeologic site, located several kilometers downstream from the Cactus Hill site. The combined age data suggest that the dominant period of aeolian activity in the Nottoway River valley was from $27 to 18 ka (Fig.…”