Formation of the Shelf-edge Cretaceous-Tertiary contact off the southeastern U.S. Coast

• Published in: Palaeogeography, palaeoclimatology, palaeoecology Vol. 57; no. 2; pp. 117 - 135
• Main Authors: Poppe, L.J., Hathaway, J.C., Hall, R.E., Commeau, R.F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1986; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Marine; Petrology of sedimentary rocks except quaternary rocks; Sedimentary rocks; Stratigraphy; ASW, USA; Mesozoic; Paleogene; Sand; Mineral assemblages; Atlantic Ocean; Paleocene; SEM data; Clastic sediments; Middle Paleocene; Sedimentary rocks; North American Atlantic; Maestrichtian; Continental margin sedimentation; Silt; North Atlantic; Upper Cretaceous; Carbonates; Borehole cross-section; Tertiary; Discordance; Borehole sections; Cores; Coccoliths; Foraminifers; Unconformities; Trace elements
• ISSN: 0031-0182; 1872-616X
• DOI: 10.1016/0031-0182(86)90010-6

Submarine erosion, associated with changes in position of the proto-Gulf Stream, was the dominant mechanism controlling the formation of the Cretaceous-Tertiary unconformity in AMCOR borehole 6004. Paleontologic evidence indicates that this unconformity, which is marked by a gravelly-sand enriched in glauconitic and phosphoritic concretions, represents a hiatus of about 7 m.y. Both Cretaceous and Paleocene sediments contain middle-outer neritic foraminiferal assemblages that become more diverse with distance from the contact. Of the elemental abundances measured, Al, Ba, Co, Fe, Ga, K, Mg/Ca, Mo, Ni, P, Sr/Ca, V, Y, and Zn show a strong positive correlation with proximity to the contact, probably as a result of the concentration of authigenic and heavy minerals present as lag sediments on the erosion surface.