Geochemical characterization of extraterrestrial impact events recorded in sedimentary rocks

Speaker: Dott.ssa Honami Sato (Dipartimento di Geoscienze, Università degli studi di Padova) Thursday, 4th november – 4:30 PM | Aula Arduino


More than three decades have passed since the discovery of anomalies in the abundance of platinum group elements (PGEs: Os, Ir, Ru, Rh, Pt, Pd) across the sections of Cretaceous-Paleogene (K-Pg) strata from Gubbio (Italy) and Caravaca (Spain), which have been attributed to a bolide impact.

This remains one of the most significant findings in the field of Earth science. After the discovery, the PGE anomaly at the K-Pg boundary has been confirmed from more than 120 sites. Bolide impacts are not limited to the K-Pg boundary, but occurred throughout Earth’s history.

Pelagic deep-sea sediments are repositories of information regarding impact events over geologic time because they preserve long-duration continuous records with low sedimentation rates. This seminar introduces geochemical studies reporting evidence for a large impact event in the Upper Triassic. Geochemical data on PGEs and radiogenic osmium (Os) isotope ratios in the sedimentary rocks provide information regarding the type and size of impactor.