Late Quaternary depositional history of the Albemarle Embayment, NC
- East Carolina Univ., Greenville, NC (United States). Dept. of Geology
The depositional history of Albemarle Embayment documents deep fluvial incisement by the Roanoke River system during glacial episodes and subsequent infilling by fluvial-estuarine-barrier island sediment sequences during interglacial transgressions. Unraveling the Holocene time slice will help reconstruct complex Quaternary records of multiple incisement and backfilling. A network of drill holes, vibracores, and seismic data suggest a four-phase infill history over the last 12,000 years. (1) Lower Roanoke River: (a) Bedload-charged, braided fluvial systems deposited basal sequences of sand and gravel prior to [approximately]5,000 BP. (b) Aggradational, swamp-forest floodplains developed [approximately]5,000 BP and bound the modern incised channels characterized by minimal bedload sedimentation. (2) Albemarle sound: (a) In the central basin, the basal channel sand sequence is overlain by an open estuarine, highly interlaminated sand and mud sequence that accumulated between [approximately]12,000 BP and [approximately]2,000 BP. (b) Depositional patterns within this unit suggest multiple oscillations of Holocene sea level that caused channel reincisement and subsequent backfilling. (c) Present estuarine marsh sedimentation began in protected coastal areas [approximately]5,000 BP. (3) Outer banks: (a) Barrier islands first influenced sedimentation in the area after [approximately]5,000 BP producing a semi-enclosed Albemarle Sound. (b) Deposition within the central basin shifted to uniform organic-rich muds that grade eastward into overwash and inlet sands. (4) Modern man: (a) colonial development within the drainage basins in the early 1700's AD produced a wedge of orange mud in inner Albemarle Sound. (b) Dam construction in the 1950's terminated orange mud deposition and the central basin reverted to organic-rich mud sedimentation.
- OSTI ID:
- 6078050
- Report Number(s):
- CONF-9304188-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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