Cenozoic Shallow Marine Sands of North Carolina and South Carolina Sandhills Area

Suellen Cabe

Skolithos burrows occur in post-Cretaceous sands of the Sandhills region of the upper coastal plain of North Carolina and South Carolina. The burrows, about 15 cm tall and 1.5-2 cm in diameter, are the only fossils found in this tide-dominated, shallow marine deposit. The sediments are moderately sorted, medium quartz sands; most samples contain less than 10% silt and clay.

The major sedimentary structures are horizontal and cross-bedded alternating layers (1-2 cm thick) of clean and more clayey sand. Cross-bedded sets are 2-3 m thick and probably represent large sand waves. Some burrows are in the horizontally bedded layers, which also have wavy bedding.

This unit is transgressive-regressive. The lowermost sands are very clean, cross-bedded eolian sands. Overlying these are shallow marine sands (alternating clean and clayey layers), which grade upward into a massive sand layer with 20-25% silt and clay. Above the sharp truncation of the massive sand are layers of alternating clean and clayey sand. Interfingering with these sands near the top of the unit at one location, a lens of dark sand contains abundant wood fragments. Burrows also occur in a thin layer that dips gently away from this lens.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.