End-Cretaceous extinction in Antarctica linked to both Deccan Traps volcanism and bolide impact
Year: 2015
Type: conference-paper
Abstract: The cause of the end-Cretaceous (KP) mass extinction is still under debate. Some suggest that the eruption of the massive Deccan Traps volcanic province in India caused species extinction through negative effects of volatiles emitted during the eruption (e.g. CO2, SO2) [Keller, 2012]. Others cite the impact of the massive Chicxulub meteorite as the cause [Alvarez et al., 1980]. Recent work has suggested that the impactor triggered and accelerated eruption of the Deccan Traps [Richards et al., 2015], further complicating the cause-effect relationship. We present a record of high latitude ocean temperature and Ow from Seymour Island that covers the last few million years of the Cretaceous and crosses the KP boundary (~69-65.5 Ma). Seymour Island, Antarctica (6417’S, 5645’W) is particularly well-suited to studying the KP boundary interval due to its expanded section, continuous sedimentation, and abundant, exceptionally preserved macrofossils, including some species and genera that survive across the KP boundary [Macellari, 1988; Zinsmeister and Macellari, 1988]. We find an ~8C warming prior to the KP boundary that aligns with the onset of Deccan Traps volcanism and a pre-KP extinction event identified by [Tobin et al., 2012], directly tying extinction at this site to the volcanic trigger event through climate change. A second extinction event at the KP boundary coincides with a second warming pulse, the time of meteorite impact, and additional Deccan Traps volcanism. The bivalve shells were each measured at two positions: the umbo (hinge) and the ventral margin (back edge). We consistently find large differences in measured parameters between the two positions on the same shell (>5C, many ‰ in C and Ow). We suggest these differences are due to different seasonal aliasing early and late in the life cycle of the bivalve. In addition, the coldest temperatures recorded suggest the presence of sea ice and potentially continental glaciers at higher elevations, which is contrary to most assumptions of the Cretaceous as an ice-free world.
Institution: University of Michigan
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
OpenAlex ID: W2207452598