Spuren von Asteroideneinschlägen auf der Erde. Neue Erkenntnisse aus chemischen Analysen alter Sedimentgesteine

Abstract

The observation of a large enrichment of platinum metals in sediments at the Cretacous/Tertiary boundary together with the fossils of many extinct species, e.g. dinosaurs, led to a world wide search for this anomaly. We analysed by neutron activation analysis samples from three locations containing the Cretaceous/Tertiary boundary. Results for Os, Ir and Au as well as other trace and major elements are presented. We investigated also very old sediments from the People’s Republic of China enclosing the Cambrium/Precambrium boundary. Our results are compared with the ones obtained by other groups for different geological boundaries.
Mechanisms leading to the observed enrichments are discussed and their consequences revealed. It is tempting to speculate on possible connections of the coinciding extinctions of fauna and flora with the enrichments of noble metals for several geological boundaries.