SEDIMENTOLOGICAL AND FORAMINIFERAL INDICATIONS OF HOLOCENE ENVIRONMENTAL CHANGE IN PAMLICO SOUND, NORTH CAROLINA

The Quaternary geophysical, sedimentological, and chronostratigraphic framework of North Carolina's sounds and barrier islands is being defined. Previous works have demonstrated a complex evolutionary history over the past several thousand years including a period of barrier island collapse and normal salinity conditions within Pamlico Sound. To obtain a broader view of this history of Holocene environmental change, thirteen (1.93m to 7.19m long) vibracores that cover much of central Pamlico Sound, North Carolina are being studied. Sedimentologic and foraminiferal data indicate a change from terrestrial to estuarine conditions in the early Holocene as the rising sea level flooded into paleo-Pamlico Creek. The Pleistocene-Holocene contact is indicated by an orange iron-stained interval at the top of the Pleistocene “basement.” Within the Holocene sequence, finer-grained units containing agglutinated or mixed calcareous and agglutinated foraminiferal assemblages indicate estuarine conditions. Sandier units containing stenohaline foraminiferal assemblages indicate periods of time when Pamlico Sound was subject to a more open marine influence. These results confirm the findings of several other sedimentologic/foraminiferal studies in the Pamlico Sound/Outer Banks region that document periodic collapse of North Carolina's barrier islands during the Holocene, especially during the Medieval Warm Period, most likely as the result of major storm events. This study provides a greater understanding of the spatial and temporal extent of former barrier island collapse, and the response of the coastal system to climatic forcing mechanisms.