Extreme greenhouse episodes in the Cretaceous (145-66 Ma) and Eocene (56-34 Ma) may be suitable analogues for current global warming. During the hothouse conditions of the mid-Cretaceous (94 Ma), a sudden warming event led to the expansion of the oxygen minimum zone in the world’s oceans, imperilling marine ecosystems.
The application of the radiogenic neodymium isotope proxy to marine sediments enables us to identify and follow the behaviour of water masses though time. Ocean circulation likely played a major role in the distribution of heat over the planet, and in the ventilation of the deep ocean. In this seminar, I will present Nd-isotope results from the onset of the Cenozoic greenhouse conditions, as well as from the peak of the Cretaceous hothouse, and their implications for the ocean circulation. In cunjunction,cyclostratigraphic age models are developed from time-series analyses of climate-sensitive data, and are integrated with carbon-isotope, radio-isotopic,bio- and magnetostratigraphic data.