Chalcophile elements and Ir in continental Cretaceous-Tertiary boundary clays from the western interior of the USA

Element profiles and Ir concentration of Cretaceous-Tertiary (K-T) boundary layers at Medetli, Goelpazari, northwestern Turkey

“…Concentrations of and Co (29-43 ppm) for the goethite-rich layers in this study are in the range of those for the well-known marine K-T boundary sediments (66-1370 ppm for Ni and 7-230 ppm for Co) (e.g., Gilmour and Anders, 1989). Also high concentrations of chalcophile elements, such as As, Sb and Zn, are documented at many K-T boundary sites (e.g., Kyte et al, 1980;Smit and Ten Kate, 1982;Strong et al, 1987;Gilmour and Anders, 1989;Schmitz, 1992). The concentrations of As in the goethite-rich layers of this study (307-851 ppm) are much higher than those in the K-T sediments of the world (7-256 ppm).…”

“…Generally ferric hydroxide such as goethite and jarosite are considered to represent weathered pyrite or re-precipitated iron from dissolved pyrite (Schmitz, 1992). The ferric hydroxides are also common along small cracks and root channels in the sedimentary rocks, and are considered to anoxically scavenge As and Sb from sea water (e.g., Peterson and Carpenter, 1986).…”

“…Goethite is a common mineral in K-T boundary sediments worldwide (e.g., Kyte et al, 1980;Schmitz, 1992;Gilmour and Anders, 1989). Generally ferric hydroxide such as goethite and jarosite are considered to represent weathered pyrite or re-precipitated iron from dissolved pyrite (Schmitz, 1992).…”

Trace element concentrations in the Mexico‐Belize ejecta layer: A link between the Chicxulub impact and the global Cretaceous‐Paleogene boundary

“…6) in the lower part of the spheroid bed in Albion Island is, however, consistent with characteristics of K/T boundary layer elsewhere (e.g., Spain, Denmark, and New Zealand). Various explanations have been provided for the enrichment of the non-meteoritic elements As, Sb, and Zn from the distal K/T boundary layer (Smit and ten Kate 1982;Strong et al 1987;Schmitz 1992;Martinez-Ruiz et al 1999). Although elevated values of As and Sb are not ubiquitous at the K/T boundary (Ebihara and Miura 1996), the anomalies are distributed to such an extent that they are most likely linked to a global dispersal event.…”

“…Enrichment in Ni, Co, Cr, and in the non-meteoritic elements As, Sb, Se, and Zn also characterizes the global boundary layer (e.g., Smit and ten Kate 1982;Schmitz 1985Schmitz , 1992Schmitz et al 1988;Gilmour and Anders 1989;Ebihara and Miura 1996;Strong et al 1987;Martinez-Ruiz et al 1999. However, the exact relation of the Chicxulub impact to the 65 Myr old K/T boundary sediments is still debated.…”