An Ephemeral Inlet from the Virginia Barrier Island Chain: Stratigraphic Sequence and Preservational Potential of Infilled Sediments

Abstract

Stratigraphic sequence, character, and preservation potential of inlet sediments were determined from five vibracores in an ephemeral inlet. Bungalow Inlet, an ephemeral inlet located within the Virginia barrier island chain, is presently closed but was open during the period 1929–1969. Because permanent inlets along this coastal sector do not migrate laterally, ephemeral inlets may be important locales for the accumulation of abundant inlet-fill sands. The ephemeral inlet-fill sequence is well preserved. However, the channel bottom is only approximately 2.5 m below MSL. Shell and shell fragments lie disconformably over pre-existing muddy backbarrier sediments. Tan, fine grained, foreshore or washover sands conformably overlie the coarser grained inlet fill. The thickness of the inlet-fill decreases in a landward direction and toward the margins of the former inlet. Washover sediments are recognized in the more landward cores. Previous studies point to the preservation of inlet-filling sands from the episodic opening and/or lateral migration of inlets along a lengthy barrier spit or island. The infilling sands are deposited below wave base and represent a significant percentage of the material preserved within barrier systems of these types. However, the different morphology, antecedent topography, and associated hydrodynamics of barrier island chains, relative to a long barrier island or spit, result in the development of deep stable and shallow temporary inlets with little or no subsequent abundant preservation of inlet-fill sands. The paucity of sandy inlet deposits in ancient barrier sediments may reflect the presence of a barrier chain.

Virginia Institute of Marine Science Contribution Number 1392.