Figure 1.

Environmental changes coincident with phase II Deccan volcanism. Compilation of published Os isotope [39] (a), and δ¹⁸O-derived temperature [43–46] (b) records, alongside new (e,g) and published [39,47–51] (c,d,f,h) records of carbonate preservation in the lead up to the K–Pg boundary. Deccan emplacement is marked at the onset of Os isotope decline. In (b), the dashed line is a sixth-order polynomial fit through the data, and the black solid line is a cubic spline. Note wt.% CaCO₃ records from ODP site 690 are subject to intense bioturbation near the K–Pg boundary; this region is marked as a dashed line. Os isotope decrease towards the boundary from 66.1 Ma is due to down-core leaching of extra-terrestrial Os [39]. Age constraints for DSDP 577 [51] (h) are uncertain below the onset of magnetochron C29r. All data are plotted against time (in Ma); for details of the age models used, see electronic supplementary material.