End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change

Abstract

The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8±3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.

Intermittent euxinia in the high-latitude James Ross Basin during the latest Cretaceous and earliest Paleocene

“…Large-scale blooms of the dinoflagellate cyst Impletosphaeridium clavus in the LBF have been linked to the decay of ephemeral sea ice during short-lived 'cold snaps' (Bowman et al, 2013) correlated to isotopic evidence for cool ocean temperatures (Tobin et al, 2012;Petersen et al, 2016). Others have suggested that these blooms are related to periods of higher continental nutrient influx and eutrophication, without the need to invoke sea ice formation (Amenábar et al, 2014).…”

“…Climate warming in the late Maastrichtian has also been suggested, based on faunal (Bowman et al, 2013;Bowman et al, 2014) and geochemical (Tobin et al, 2012;Petersen et al, 2016) proxies. An apparent peak in warming located in the~70 m of the LBF stratigraphically below the K-Pg boundary, correlated to magnetochron C29R, has been linked to the main phase eruptions of the Deccan Traps LIP (Tobin et al, 2012;Renne et al, 2015;Petersen et al, 2016).…”

“…Additionally, clumped isotope estimates of water δ 18 O may imply a measurable input of terrestrial meteoric water to the local depositional environment (Petersen et al, 2016).…”

“…Fully assessing the applicability of this model to the terminal Cretaceous requires a detailed understanding of potential environmental deterioration leading up the extinction horizon. Changes in temperature resulting from Cretaceous climate evolution or the Deccan Traps eruptions and associated greenhouse gases may have been especially prevalent in the environmentally sensitive high latitudes (Tobin et al, 2012;Petersen et al, 2016).…”

Hazards and disasters in the Anthropocene: some critical reflections for the future

“…For example, the age of dinosaurs ended as a consequence of a likely combination of extraordinary planetary volcanism coupled with major asteroid/comet impact that triggered planetary-wide (climate) change. The end of the dinosaurs and many other species at the Cretaceous-Tertiary boundary approximately 65 million years ago (Kaiho et al 2016;Petersen et al 2016), opened up a space that ultimately led to the evolution of mammals and of course, Homo sapiens. There have been other significant evolutionary jumps and radiations of species after global catastrophes that would not have been possible without the opportunity and space created by those disasters (Goswami et al 2016).…”