Search

The Cape fear Formation rests on basement rocks in the Cape Fear River valley of the North Carolina Coastal Plain. It consists primarily of graded muddy sand-sandy mud couplets. A typical sequence each couple starts with a disconformity, followed by a basal gravelly sand megaclats of quartz and clay pebbles, cross-bedded sand, and finally a structureless mud bed. Fossils are absent. The sand fraction is sorted and the sediment has a clayey texture. Stucture and textures suggest that each couple is the product of a current warning from an upper flow regime, to the lower part of a lower flow regime. Turbidity current and fluvial origins are considered. Cross-bedding and texture criteria indicate that normal, low-density currents are responsible for at least part of the typical sequence. A normal fluvial origin is rendered less likely by the absence of mud cracking. Root casts, and textural criteria of a partitioned subaeria environment. Stratigraphic and geochemical considerations suggest that the formation may have been deposited in estuaries or coastal lagoons; if so, the stratification may record sedimentation during the periodic flushing of saline water by river floods. [ABSTRACT FROM AUTHOR]

Indicates that the type Lindsey Bridge Member of the Moorefield Formation of northeastern Oklahoma consists of massively cross-bedded limestone. Use of an hydrodynamic model developed in flume studies; Presence of three facies; Foresets; Toesets; Bottomsets; Occurrence of flow separation as currents crossed a pre-Moorefield topographic high and entered a basin on the downcurrent side.