Planetary Group Seminar

Immense volcanism and extraterrestrial impact are the two main suspects in driving the Cretaceous-Palaeogene (K-Pg) mass extinction, but incontrovertible empirical evidence for how either caused ecological collapse has up to now been scant. In my talk I will present new boron isotope data revealing rapid fluctuations in ocean pH and atmospheric pCO2 at the K-Pg, indicating ocean acidification caused by impact, not volcanism, prompted marine mass extinction. Furthermore, by coupling with earth system models, our pH estimates allow us to solve a longstanding geological puzzle: what was the cause of the post-extinction collapse in surface-deep carbon isotope gradients in the ocean, and what does it convey about the Earth’s ecological recovery after the mass extinction event? [more]