Petrologic and faunal study of a 72.5m continuous corehole drilled in southeastern North Carolina has provided an opportunity to study a relatively uninterrupted vertical sequence across the Cretaceous-Tertiary boundary. The following stratographic sequence occurs; upper middle Maastrichtian Peedee Formation, –65.8m to –51.8m below sea-level (BMSL), upper middle Maastrichtian Rocky Point Member of the Peedee Formation, –51.8m to –27.4m BMSL, and middle to upper (?) Eocene Castle Hayne Limestone, –27.4m to 15.2m BMSL (base of casing).
The Peedee Formation consists of moderately indurated, very fine to fine, sandy foraminiferal biomicrite and sandy biomicrite. Silt-size zoned dolomite rhombohedra form up to 30% of the upper Peedee Formation and are most abundant where bioturbation is common. A diverse and well-preserved foraminiferal fauna indicates a middle to outer continental shelf environment.
The Rocky Point Member conformably overlies typical Peedee Formation lithology and consists of well-indurated sandy, fossiliferous biomicrite that grades upward into sandy, pelecypod biomicrosparite, and finally pelecypod biomicrudite. The Peedee Formation and the Rocky Point Member represent an overall shallowing-upward sequence with the upper surface forming the Cretaceous-Tertiary boundary.
The Castle Hayne Limestone disconformably overlies the Rocky Point Member and consists of lithoclast-bearing, bryozoan-molluscan biomicrudite grading upward into bryozoan biomicrudite. The Castle Hayne Limestone was deposited in an open, normal salinity environment between 30m and 100m in water depth.
Cretaceous-Tertiary boundary, Peedee Formation, Castle Hayne Limestone, Sedimentary petrography
©1986 Academic Press Inc. (London) Limited
Harris, W. Burleigh; Thayer, Paul A.; and Curran, H. Allen, "The Cretaceous-Tertiary Boundary on the Cape Fear Arch, North Carolina, U.S.A." (1986). Geosciences: Faculty Publications, Smith College, Northampton, MA.