COLLAPSE OF THE OUTER BANKS, NORTH CAROLINA AS INDICATED BY HIGH RESOLUTION FORAMINIFERAL DATA FROM PAMLICO SOUND

High-resolution foraminiferal data taken from an 8.2 m vibracore in southeastern Pamlico Sound, North Carolina reveal two periods within the last 5,000 years when open shelf waters were present in what is now a large estuary. The presence of the benthic foraminifera Hanzawaia strattoni, Nonionella atlantica, Asterigerinata mamilla, and Bolivina lowmani, and the planktonic foraminifera Globigerinoides ruber, and Globorotalia menardii, indicate open shelf and Gulf Stream waters, respectively, in an otherwise estuarine sequence. Radiometric dating of the older open marine sequence (ca. 4000 years BP) indicates that it accumulated during the mid-Holocene hypsithermal. The younger open marine sequence accumulated just 1,000 to 500 years ago, during the Medieval Warm Period. The latter event indicates that the portion of the outer banks barrier islands, which formed around 3,000 years BP, collapsed, allowing Gulf Stream eddies, and their associated benthic and planktonic foraminiferal assemblages to occupy the Pamlico Basin. During these 500 years, this basin was an open bay rather than an estuary. The correlation of two periods during the last 5,000 years, when open shelf waters occupied the Pamlico Basin, with known warm intervals during the Holocene suggests that future collapse of the barrier islands might take place during future warm water intervals. Continued global warming and increased hurricane activity along the North Atlantic coast indicate that collapse is likely for the Outer Banks of North Carolina. With more than $13 billion dollars per year spent by vacationers to North Carolina, many to the Outer Banks, it is important to recognize that the Outer Banks barriers are ephemeral features.