EOLIAN-DEPOSIT AGE, PALEOWIND, AND POLLEN DATA AS EVIDENCE FOR PERIODS OF ARIDITY AND STRONG WINDS IN THE U.S. MID-ATLANTIC AND SOUTHEASTERN COASTAL PLAIN DURING RAPID GROWTH OF THE LATE QUATERNARY LAURENTIDE ICE SHEET

Late Quaternary eolian landforms characterize much of the U.S. mid-Atlantic and southeastern Coastal Plain, a region where eolian processes have little discernible effect on modern landscape development. Luminescence and isotopic age data for eolian deposits in this region indicate that (a) eolian dune activity occurred during the late Pleistocene prior to 35 ka; (b) the largest areal extent of dune and sand sheet development occurred from 35 to 20 ka; and (c) eolian dune activity continued intermittently during the early Holocene (about 11.5 to 7 ka). The period of maximum dune and sand-sheet development was coeval with rapid growth of the Laurentide Ice Sheet, with accumulation of the Peoria Loess in the U.S. midcontinent and Lower Mississippi Valley, and with eolian dune formation in the central and southwestern U.S. Dune bedform orientations indicate northwesterly and westerly source winds for eolian ridges/dunes in southern Louisiana, Arkansas, Virginia, Maryland, and Delaware and west to southwesterly winds for dunes in Georgia and the Carolinas. Age data also suggest that initial eolian activity began in mid OIS3 and preceded the period of LIS rapid growth. Pollen data indicate that eolian activity occurred when the climate of the mid-Atlantic Coastal Plain was sufficiently cold to support periglacial features and when the climate of the southeastern Coastal Plain was significantly cooler and drier than present. Plots of paleowind directional data by age allow: (a) assessment of dominant regional wind direction; and (b) with other paleoclimate data, estimates for the position(s)/movement of the jet stream during the last glacial maximum. The combined palynologic, age, and directional data suggest a mismatch between these data and the model-simulated late Pleistocene climates predicted for the mid-Atlantic and southeastern U.S.