Northeastern Section (39th Annual) and Southeastern Section (53rd Annual) Joint Meeting (March 2527, 2004)
Paper No. 5-3
Presentation Time: 9:00 AM-9:20 AM

HIGH-RESOLUTION GEOLOGIC EVIDENCE OF A FORMER, WAVE-DOMINATED TIDAL INLET SYSTEM: OLD CURRITUCK INLET, VIRGINIA/NORTH CAROLINA

MCBRIDE, Randolph A., Environmental Science & Public Policy, George Mason Univ, 4400 University Dr, Fairfax, VA 22030-4444, rmcbride@gmu.edu, BUYNEVICH, Ilya, Coastal & Marine Geology Program, U.S. Geol Survey, 384 Woods Hole Road, Woods Hole, MA 02543, and ROBINSON, Marci M., Geology and Earth Science Program, Environmental Science and Policy, George Mason Univ, Fairfax, VA 22030

The paleo-inlet channel and flood tidal delta of Old Currituck Inlet was investigated using ground-penetrating radar (GPR) imaging profiles, six vibracores, x-ray radiography, and aerial photography to determine the geological signature of a relict tidal inlet system. The former wave-dominated inlet is located at the Virginia-North Carolina state line along Currituck Spit, which forms the northern portion of the Outer Banks barrier island system. Based on historical documents, Old Currituck Inlet opened prior to 1585 A.D. and closed ~1731 A.D.

The paleo-inlet channel is ~400 m wide and up to 7 m deep. The preserved channel is characterized by a broad U-shaped cut-and fill structure that is skewed to the south. The channel fill exhibits a compound pattern dominated by a series of parallel, sigmoidal-shaped reflectors (beds) indicating lateral progradation from north to south overlain by less extensive accretionary reflectors. The prograded channel fill indicates the dominant direction of longshore sediment transport and inlet migration to the south. Inlet shoaling at Old Currituck Inlet caused the accretionary channel-fill pattern and most likely began when tidal prism was gradually captured by New Currituck Inlet, which opened in 1713 about 10 km to south. The accretionary channel fill represents the terminal position of Old Currituck Inlet before closure in 1731.

Landward of the paleo-inlet channel is a large, well-preserved, relict flood-tidal delta that protrudes into Knotts Island Bay as marsh-capped shoals. Based on vibracores and x-ray radiography, four sedimentary facies were identified and document the following sequence of depositional environments from bottom to top: estuary, active flood-tidal delta (subtidal), active to waning flood-tidal delta (intertidal), and marsh.

Overall, this study details the sand body geometry and stratigraphic characteristics of a former, wave-dominated tidal inlet system, hence providing additional recognition criteria for modern and ancient transgressive barrier island deposits.

Northeastern Section (39th Annual) and Southeastern Section (53rd Annual) Joint Meeting (March 2527, 2004)
General Information for this Meeting
Session No. 5
Former Tidal Inlets and Breaches along Modern and Ancient Coasts: Formation, Evolution, and Geologic Record
Hilton McLean Tysons Corner: Martinique's
8:00 AM-12:00 PM, Thursday, March 25, 2004

Geological Society of America Abstracts with Programs, Vol. 36, No. 2, p. 52

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