Earth orbital rhythms links timing of deccan trap volcanism phases and global climate change

At the end of the Cretaceous, the massive Deccan trap (DT) volcanic eruptions are regarded as the primary driver of global climate deterioration. Accurate age models are key to unravel the sequence of events related to DT vol- canism onset and effects on the global climate system. We establish a direct geochemical link between DT volca- nism as recorded in marine osmium isotopic data and global climate change documented in benthic foraminifera carbon and oxygen isotope records. Based on our state-of-the-art astronomically calibrated age model, two major shifts in marine 187Os/188Os at 66.49 and 66.28 million years ago are contemporaneous with major eruption phas- es of the DT and disruptions of the global carbon cycle. Geochemical records and modeling suggest larger erupted volumes with high volatile emissions for the early phase of DT volcanism and point to differing emissions of SO2 and CO2 during the observed marine osmium shifts with diverse effects on the global climate system.