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Paleoclimate, paleoceanography and the role of orbital-forcing during the Cretaceous–Paleogene

Unravelling how climate, the carbon-cycle and the oceans interacted in warm climates of Earth’s deep past is paramount if we are to better understand both the modern and future carbon-cycle-climate system, particularly in the context of ongoing anthropogenic burning of fossil fuels.

Constraining the long-term paleoclimate and carbon-cycle dynamics of the ancient ‘greenhouse’ worlds of the Cretaceous and Early Paleogene (~145 to 34 million years ago), offers us the chance to explore a possible analogue for a much warmer future Earth. This enigmatic time period witnessed great changes in global climate, from the peak warmth of the mid Cretaceous ‘super-greenhouse’, to the cooler late Cretaceous and Paleocene, and on to the Early Eocene Climatic Optimum, where average temperatures in the Arctic may have surpassed a balmy 25°C and temperate forests blanketed Antarctica.

This period was also characterised by a dynamic carbon-cycle, with large volcanic provinces spewing out CO2 and other gasses, vast quantities of carbon-containing permafrost locked up in the ice-free poles, and unstable methane hydrates lurking in the warm oceans. Earth’s biota also experienced several shocks during this interval, from the mass extinction at the K-Pg boundary ~65 million years ago, which saw the end of the age of the dinosaurs, to the large-scale extinction of deep-sea-dwelling microfossils and the radiation of land mammals during the climatic upheaval of the Paleocene Eocene Thermal Maximum (PETM, ~55 million years ago).

Our research

The Cretaceous-Paleogene group, led by , seeks to better understand this mysterious time period. We address key questions regarding the role of ocean circulation in regulating and responding to climate and carbon-cycle perturbations, and how these coupled systems were influenced by cyclic orbital forcing. We apply cutting-edge geochemical (stable-isotopes, radiogenic-isotopes, organic biomarkers, trace-elements), and paleontological (benthic and planktic foraminifera) techniques to deep-sea sedimentary cores recovered by the International Ocean Discovery Program and its predecessors.