The Cretaceous–Palaeogene boundary succession at Stevns Klint, Denmark: Foraminifers and stable isotope stratigraphy

High-resolution organic carbon isotope record across the Cretaceous–Tertiary boundary in south-central Alberta: implications for the post-impact recovery rate of terrestrial ecosystems and use of δ13C as a boundary marker

“…A shift in the δ 13 C composition of inorganic and organic matter across the Cretaceous-Tertiary (K-T) boundary, on the order of -1.0‰ to -3.0‰, has been reported in numerous marine sections around the world (e.g., Zachos et al 1992;Keller et al 1995;D'Hondt et al 1998;Sial et al 2001;Hart et al 2005). These δ 13 C shifts are thought to be related to, at least in part, the geologically sudden cessation of primary productivity (plankton) in the surface ocean, which resulted in the collapse of the carbon isotope gradient between surface and deep-ocean waters (see Hsü and McKenzie 1985;Zachos et al 1992;D'Hondt et al 1998).…”

Environmental change prior to the K–T boundary inferred from temporal variation in the morphology of cheilostome bryozoans

“…The shift to the production of smaller zooids just prior to the boundary may, however, be indicative of changes in oxygen conditions that are not driven by temperature. Anoxic events have been inferred to occur on a global scale prior to the boundary as a result of environmental perturbations from Deccan volcanism (see Glasby and Kunzendorf, 1996), and indeed the boundary clay in the Danish Basin has been suggested to represent an anoxic event (Kajiwara and Kaiho, 1992;Hart et al, 2005). What's more, alternating bioturbated and laminated chalks in other parts of the Danish basin imply the regular occurrence of dysoxic events during the Maastrichtian (Damholt and Surlyk, 2004), although no laminations were observed at Nye Kløv.…”

Morphogroups and small sized tests in Pseudotextularia elegans (Rzehak) from the Late Maastrichtian succession of Meghalaya, India as indicators of biotic response to paleoenvironmental stress

“…However, others proposed that the Chicxulub bolide impact at or close to the CretaceousPaleogene boundary might have more effect or consequence on environment and biota (Arz et al, 1999;Arenillas et al, 2000Arenillas et al, , 2006. Most of the Late Maastrichtian marine deposits from Egypt, Israel, Tunisia, Spain, Italy, France, Bulgaria, Kazakhstan, Texas, Alabama, and Drill Holes in the Pacific and Atlantic record the prevalence of high stressed depositional environment and biotic changes (Hofker, 1978;Yassini, 1979;Rosenfeld et al, 1989;Keller, 2004;Canudo et al, 1991;Liu and Olsson, 1992;D'Hondt and Keller, 1991;Olsson, 1997;Li and Keller, 1998b;Arz et al, 1999;Strong 2000;Arenillas et al, 2000;Adatte et al, 2002;Hart et al, 2004Hart et al, , 2005Alegret et al, 2004;Galal, 2006). In the studied sections as in these, the stressed environment during CF4-CF2 has been indicated by abnormalities in the associated planktonic foraminifera, occurrence of Guembelitria spp., incidence of PGE anomaly bearing brown claystone representing two phases of Deccan eruption, and dense suspension of clay-silt detritus and microspherules.…”