SYNTHESIS OF BIOSTRATIGRAPHIC AND PALEOENVIRONMENTAL INTERPRETATIONS OF MIOCENE SEDIMENTS FROM THE SHALLOW SUBSURFACE OF ONSLOW BAY, NORTH CAROLINA CONTINENTAL SHELF
Published:June 02, 1988
Scott W. Snyder, 1988. "SYNTHESIS OF BIOSTRATIGRAPHIC AND PALEOENVIRONMENTAL INTERPRETATIONS OF MIOCENE SEDIMENTS FROM THE SHALLOW SUBSURFACE OF ONSLOW BAY, NORTH CAROLINA CONTINENTAL SHELF", Micropaleontology of Miocene Sediments in the Shallow Subsurface of Onslow Bay, North Carolina Continental Shelf, Scott W. Snyder
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The Miocene Pungo River Formation in Onslow Bay represents three episodes of deposition, each with an estimated duration of approximately 1 million years. The Frying Pan Section is middle Burdigalian in age (18.4 to 17.4 Ma), the Onslow Bay Section spans the Langhian (15.9 to 14.9 Ma), and the Bogue Banks Section is middle Serravallian in age (13.0 to 12.0 Ma). Each section approximates a third-order seismic sequence within second-order supercycle TB2 of Haq and others (1987).
Pungo River Formation sediments were deposited in a middle sublittoral to upper bathyal bathymetric setting. The Frying Pan Section in southern Onslow Bay contains phosphorites which accumulated in nutrient-enriched, oxygen-poor waters introduced by marine up-welling. To the north, clastic sediments accumulated in more oxygen-enriched bottom waters. The Onslow Bay Section comprises prograding clinoforms of siliciclastic sediments that accumulated in high-energy, well oxygenated bottom conditions. Phosphorites in the Bogue Banks Section of central Onslow Bay coincide with a minor upwelling event, whereas mixed phosphorite-siliciclastic sediments in northern Onslow Bay correspond with the introduction of colder, well oxygenated waters, possibly from a northerly source.