Remarkably high arsenic (As) contents have been reported in numerous Cretaceous-Paleogene boundary (KPB) clays worldwide including those from Spain (at Caravaca and Agost) and New (N.) Zealand (at Woodside Creek). Two interpretations have been offered to explain this anomaly. The first one suggests that this As was generated by the combustion of fossil fuels (such as crude oil, coal or oil shales) near the Chicxulub impact site and the second interpretation proposes the post-impact combustion of the global biomass at the KPB. Both types of combustion were presumably triggered by the Chicxulub impactor. This report shows that the estimated surface densities of As in Spain and N. Zealand strongly contradict the fossil fuel hydrocarbons/biomass hypotheses. In addition, we also show that previously reported global abundances of As at KPB are greatly overestimated. The high abundances of iron (Fe) in the ejecta layers from Spain and N. Zealand lead us to a working hypothesis that a major fraction of their anomalous As was adsorbed from seawater by the Fe-oxides. These oxides were mainly derived of Fe from the vaporized carbonaceous chondrite impactor. These were originally deposited on the local (topographically high) oxic soils in Spain and N. Zealand and then laterally transported to the KPB sites by the impactinduced surface waters.
Premović, P. I. (2016). Cretaceous-Paleogene Boundary Clays from Spain and New Zealand: Arsenic Anomaly and the Deccan Traps. International Letters of Natural Sciences, 55, 1–8. https://doi.org/10.18052/www.scipress.com/ilns.55.1