The terminal Cretaceous iridium anomaly in the Red Deer Valley, Alberta, Canada

Abstract

Neutron activation analysis following fire-assay preconcentration in a nickel sulphide button allows processing of relatively large samples (25 g) for precision analysis of platinum group elements. Using this method, an iridium anomaly with maximum concentration of 3.36 ± 0.04 ppb has been located at the Cretaceous–Tertiary boundary at the base of the Nevis coal seam in the Red Deer Valley of Alberta. The iridium anomaly coincides with the disappearance of diagnostic late Cretaceous palynomorphs, including all but one species of Aquilapollenites.

The reciprocal interaction of angiosperm evolution and tetrapod herbivory

“…Most of the basal Paleocene palynofloras are fern-dominated (although see Lerbekmo and St. Louis, 1986), and the lowest megafloras are low diversity assemblages of lobed or stenophyllous leaves (Wolfe and Upchurch, in press). These data suggest that earliest Paleocene vegetation (within 10 1000yr following the boundary?)…”

“…Whatever its cause, the terminal Cretaceous event had a major effect on the vegetation of a large part of North America. Floras from the few cm just above the boundary are dominated by ferns (Orth et al, 1981;Tschudy et al, 1984;Nichols et al, 1986; although see Lerbekmo and St. Louis, 1986); in Colorado, U.S.A., the subsequent few meters of sediment preserve dispersed cuticle and megafossils that indicate early successional angiosperms (Wolfe and Upchurch, 1986, in press). Wolfe and Upchurch (1986, in press) suggest this records vegetational succession following regional devastation of Maestrichtian plant communities.…”

A multi-proxy geochemical investigation of the early Paleocene (Danian) continental palaeoclimate at the Fontllonga-3 site (South Central Pyrenees, Spain)

“…The Cretaceous-Tertiary transition has been extensively documented in the marine realm (Smit, 1990;Kaiho et al, 1999), but events in continental environments, such as the extinction of dinosaurs, extraterrestrial impact signals and isotopic anomalies at the CretaceousTertiary boundary (KTb) have only been studied in a few North American (Lerbekmo and St Louis, 1986), French (Jaeger and Westphal, 1989) and Chinese sections (Zhao et al, 1991). Therefore, the study of new continental sections across the KTb is important in order to derive an integrated vision of the mechanisms behind one of the major biological crisis known in the history of Earth.…”

The succession of Vertebratesand Plants across the Cretaceous-Tertiary boundary in the Tremp Formation, Ager valley (South-central Pyrenees, Spain)

“…This is the case in US Western Interior, the only continental area in the world were the K/T boundary crisis has been intensively documented (Tschudy et al 1984;Lerbekmo et al 1986;Smit et al 1987;Sheenan et al 1991;Archibald 1996). The abundant erosive episodes and the fossil content from presumably reworked channel-fill sediments, seriously flaw the interpretations of the palaeoenvironmental crisis.…”