STRATIGRAPHY BELOW A MIGRATING CAROLINA BAY

Carolina Bays are elliptical depressions found along the Atlantic Coastal Plain from northern Florida to southern New Jersey and are oriented NW-SE. Juniper Bay is a 296ha bay in Robeson County, NC. To determine the geological setting and natural history of this bay, 17 cores inside the bay, 4 cores on the rim, and 8 cores outside the bay were collected on an equilateral triangle grid, and extended to depths of 6 and 15m. Initial observations indicate a buried surface within the bay between 1 and 2.7m below the present surface. One core penetrated a stratum between 3.6 and 7.3m that contained fossilized shells from a marine unit, possibly the Yorktown or Duplin Formation (Pliocene). Layers of coarse sand or laminated clay also occurred near those depths throughout the bay. A wavy-flaser bedded unit, identified as the Black Creek Formation (Cretaceous), extended downward from depths between 6.8 and 7.3m. Outside the bay, the top of this unit occurred between 7.5 and 11.4m. Cores taken on the rim consisted of 4.9m of sand overlying finer-grained sediment. A 15m core on the rim penetrated a coarse sand unit below the finer textured material, suggesting there may have been a channel in this area formed on the Cretaceous/Pliocene erosion surface. Initial interpretations suggest that the bay is underlain by sediments of the Black Creek Formation which are overlain by an eroded member of the Yorktown or Duplin Formation. The bay depression formed on this surface, likely in a sand blanket that had covered the erosion surface. The depression was then shaped by wind and water and filled-in with alluvial and eolian material. Core data and supporting Ground Penetrating Radar data (reported elsewhere) indicates this process of bay infilling was complex and episodic. Observations from aerial photographs and core data suggest that this bay has migrated northward and is merging with another bay in a process similar to stream capture.