Achievement

Although abundant evidence exists for a massive asteroid impact coincident with the Cretaceous-Paleogene (K-Pg) mass extinction event (65 Myr ago) that killed off the dinosaurs and about 50% of all species, the relative importance of this impact as an extinction mechanism is still the subject of debate. On Seymour Island, Antarctica, IGERT trainee Tom Tobin (Earth & Space Sciences) and his advisor Peter Ward have studied one of the most expanded K-Pg boundary sections known. Using a new chronology from magnetostratigraphy, and isotopic data from carbonate-secreting fossils, they measured a high-resolution, high-latitude paleotemperature record spanning this extinction event. They found three prominent warming events synchronous with the three main phases of Deccan Traps flood volcanism, the second of which is contemporaneous with a local extinction that pre-dates the asteroid impact. What has been termed the K-Pg extinction is therefore likely the sum of multiple, independent events.