The Cretaceous-Tertiary Boundary on the Cape Fear Arch, North Carolina, U.S.A.

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

The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium

The glauconite-rich Diest Formation in central and north Belgium contains sands in the Campine subsurface and the hilly Hageland area that can be distinguished from each other. The Hageland Diest Sands member contains no stratigraphically relevant fossils while in the Campine subsurface dinoflagellate cysts are common and show a stratigraphic range covering the entire Tortonian stage. K-Ar dates were determined for glauconite from 13 selected samples spread over both areas. A glauconite date corresponding to the earliest Tortonian indicates newly formed glauconite was incorporated into a greensand at the base of the Diest Formation in the central Campine area. All other dates point at reworked glauconite and can be organized in two groups, one reflecting a Burdigalian age and another reflecting a Langhian age. These data and the thickness and glauconite content of the Diest Formation imply massive reworking of older Miocene deposits. The paleogeographic implications of these data lead to the tentative recognition of two Tortonian sedimentary sequences. An older one corresponding to dinoflagellate biochron DN8 comprises the Deurne Member, part of the Dessel Member, the Hageland Diest member, the eastern Campine Diest member and some basal sands of the Diest Formation in the central Campine. A younger sequence corresponding to dinoilagellate biochrons DN9 and 10 was strongly influenced by the prograding proto-Rhine delta front in the Roer Valley Graben to the northeast. The subsiding Campine basin was filled from east to west during this second cycle

On the nature and chronostratigraphic position of the Rupelian and Chattian stratotypes in the southern North Sea basin

The nature and chronostratigraphic position of the Rupelian-Chattian boundary (Early-Late Oligocene) unconformity in its historical type region (Belgium) is examined using biostratigraphy, strontium isotope dating of benthic foraminifera and K-Ar dating of glauconites. The duration of this unconformity is derived from the absence of the globally synchronous Svalbardella dinocyst event associated with the important mid-Oligocene Oi2b cooling that occurred in the middle and upper part of chron C9n. This hiatus represents a gap in the rock record of about 500,000 years. Two 87Sr/86Sr dates from the upper Rupelian Boom Formation and two from the lower part of the Chattian Voort Formation suggest that the boundary lies between 28.6Ma and27.2 Ma. Although there is some inconsistency in the K-Ar glauconite dates, those considered correct from the upper part of the Boom Formation and from lower part of the Voort Formation suggest that the boundary lies between 29.2 Ma and 27.0 Ma. Sr and K-Ar dating indicate the top of the Rupelian not to be older than 29 Ma and the basal Chattian not younger than about 27 Ma. The recently proposed GSSP in the Apennines with an estimated date of 28.2±0.2 Ma therefore honours the position of the historically defined Rupelian-Chattian boundary.status: publishe

Geology and mineral resources of the Florence, Beaufort, Rocky Mount, and Norfolk 1©� x 2©� NTMS quadrangles : National Uranium Resource Evaluation Program /

On cover: "GJBX-197(82).""DPST-81-141-16."Title on half t.p.: Summary geology of the Florence, Beaufort, Rocky Mount, and Norfolk 1©� x 2©� NTMS quadrangles."Publication Date: August 1982."Includes bibliographical references (pages 71-83).Prepared for the U.S. Department of Energy under contract no. :Mode of access: Internet

The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium

The glauconite-rich Diest Formation in central and north Belgium contains sands in the Campine subsurface and the hilly Hageland area that can be distinguished from each other. The Hageland Diest Sands member contains no stratigraphically relevant fossils while in the Campine subsurface dinoflagellate cysts are common and show a stratigraphic range covering the entire Tortonian stage. K-Ar dates were determined for glauconite from 13 selected samples spread over both areas. A glauconite date corresponding to the earliest Tortonian indicates newly formed glauconite was incorporated into a greensand at the base of the Diest Formation in the central Campine area. All other dates point at reworked glauconite and can be organized in two groups, one reflecting a Burdigalian age and another reflecting a Langhian age. These data and the thickness and glauconite content of the Diest Formation imply massive reworking of older Miocene deposits. The paleogeographic implications of these data lead to the tentative recognition of two Tortonian sedimentary sequences. An older one corresponding to dinoflagellate biochron DN8 comprises the Deurne Member, part of the Dessel Member, the Hageland Diest member, the eastern Campine Diest member and some basal sands of the Diest Formation in the central Campine. A younger sequence corresponding to dinoflagellate biochrons DN9 and 10 was strongly influenced by the prograding proto-Rhine delta front in the Roer Valley Graben to the northeast. The subsiding Campine basin was filled from east to west during this second cycle.status: publishe