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|Title:||Sedimentologic architecture of the shoreface prism, relationship to profile dynamics, and relevance to engineering concerns: Duck, North Carolina|
|Authors:||Allegheny College (Meadville, Pa). Department of Geology|
Schwartz, Robert K.
Cooper, Derek W.
Etheridge, Paul H.
|Publisher:||Coastal and Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (U.S. Army Engineer Waterways Experiment Station) ; CHL-97-19.|
Forty-nine vibracores were collected along two shore-normal transects extending from the beach out to ~8-m water depth at the Coastal and Hydraulics Laboratory’s Field Research Facility at Duck, NC. Close vibracore spacing and detailed hierarchical sedimentologic analysis enabled "high-resolution" definition of the textural and structural architecture of the shoreface prism, which was then compared with biweekly survey data representing a 12+ year period. The shoreface prism erosionally overlies an inlet-0associated tidal complex. Maximum shoreface thicknesses of 3-4 m occur below the beach-through-middle profile with seaward thinning down to 30-40 cm between the 7.5- and 8.5-m water depth. The gravel-rich swash zone and swash-trough transition facies record episodic seaward progradation of beach-to-inner trough flank surfaces over cross-stratified finer sand of downflank and trough axis settings. Cross-stratified sand and gravel also occur in the lower half of the shoreface prism below bar, upper ramp, and middle platform sectors of the profile documenting the migration of relatively large three-dimensional ripples and bars in historical current-dominated trough settings. A horizontal-laminated fine-sand facies overlies the trough-associated facies, representing shoal zone buildup under high-velocity plane-bed conditions. A bioturbated, horizontal-laminated, fine-to-very-fine sand facies underlies the lower ramp sector of the profile, also indicating buildup under high-velocity conditions.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|
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|TR-CHL-97-19.pdf||11.13 MB||Adobe PDF|