Composition of sediments samples spanning the Cretaceous-Tertiary boundary at ODP Site 207-1259 ...

• Main Authors: MacLeod, Kenneth G, Whitney, Donna L, Huber, Brian T, Koeberl, Christian
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2007
• Subjects: Composite Core; Drilling/drill rig; Leg207; Joides Resolution; Ocean Drilling Program ODP; Macleod; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.719608; https://doi.pangaea.de/10.1594/PANGAEA.719608

Ocean Drilling Program (ODP) Leg 207, on the Demerara Rise in the western tropical North Atlantic, recovered multiple Cretaceous-Paleogene boundary sections containing an ejecta layer. Sedimentological, geochemical, and paleontological changes across the boundary closely match patterns expected for a mass extinction caused by a single impact. A normally graded, ~2-cm-thick bed of spherules that is interpreted as a primary air-fall deposit of impact ejecta occurs between sediments of the highest Cretaceous Plummerita hantkeninoides foraminiferal zone and the lowest Paleogene P0 foraminiferal zone. There are no other spherule layers in the section. In addition to extinction of Cretaceous taxa, foraminiferal abundance drops from abundant to rare across the boundary. Ir concentrations reach a maximum of ~1.5 ppb at the top of the spherule bed, and the Ir anomaly is associated with enrichment in other siderophile elements. We attribute the unusually well-preserved and relatively simple stratigraphy to the fact ... : Supplement to: MacLeod, Kenneth G; Whitney, Donna L; Huber, Brian T; Koeberl, Christian (2007): Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic. Geological Society of America Bulletin, 119(1-2), 101-115 ...