MICROPALEONTOLOGICAL EVIDENCE FOR MID-PLIOCENE WARMING FROM THE YORKTOWN FORMATION, VIRGINIA

The mid-Pliocene is widely recognized as a period of global warmth, but the causes remain disputed. The Yorktown Formation of southeastern Virginia and northeastern North Carolina is a major mid-Atlantic Coastal Plain stratigraphic unit that provides an especially complete record of paleoclimate trends and exceptionally high sea level. Microfossil data (pollen, planktic foraminifera) from the Eyreville Core are integrated with data from other outcrops of the Yorktown Formation to provide a biostratigraphic context for newly obtained core samples and regional estimates of terrestrial and marine paleoclimate conditions for the mid-Atlantic. Quantitative analysis of planktic foraminifera from the Yorktown Formation suggests decreased seasonality relative to present day conditions and mean annual sea surface temperatures 3°C greater than today. Pollen assemblages from the Yorktown Formation indicate mean annual atmospheric temperatures 2˚ - 2.5˚ C warmer with greater precipitation than today. Data from the Eyreville core have the potential to provide unprecedented insights into the amplitude and range of temperature variability during a sustained interval of global warmth.