| Summary |
Pamlico Sound is a drowned river on the North Carolina continental margin, underlain by a regional depositional basin called the Albemarle Embayment. 850 km of highresolution single channel uniboom seismic data were acquired along 37 seismic profiles in the Pamlico Sound of North Carolina. Interpretation of data reveal the regional geologic framework, distribution and character of Pliocene and Quaternary depositional sequences, and associated incised paleodrainage systems. Deposits represent the updip component of transgressive and regressive sequences in a filling basin. Seven Type 1 and eight Type 2 sequence boundaries are observed and distinguished based on the presence of or lack of complex incised channelization respectively. At least 15 Quaternary depositional sequences have been identified within the basin. Quaternary sediments lie on a northward dipping unconformity that is identified as the top of the Pliocene, ranging from 85 meters below sea-level (mbsl) in the north to approximately 37 mbsl in the south. Data reveal a complex fill history characterized by multiple large (30+ meters deep, >2 km wide) incised valleys and numerous smaller incised channels within the Quaternary section. Paleochannels provide information concerning the locations, sizes, geometries, orientations and fill history of the fluvial systems that previously occupied the basin. Dominate clinoform progradation is to the east, with a few trending to the northwest. An antecedent high identified in the Central Pamlico Sound and named the Cape Hatteras High (CHH) is mid-Pleistocene in age. Northern Pamlico Sound sequences below this high tend to be thick, while sequences above are thin and onlap onto the high. The Southern Pamlico Valley is composed of numerous cut-and-fill channels and incises the southern flank of the CHH. Correlation from the Northern Pamlico Sound across the high with sequences in the Southern Pamlico Sound is difficult because of the extent of its subaerial erosion and the complex nature of the Southern Pamlico Sound. |
