Details of Award

NERC Reference : NE/G001456/1

Evolution of seawater Mg/Ca ratios since the Cretaceous: New constraints from the carbonate 'clumped isotope' thermometer.

Principal Investigator:: Dr A Tripati, University of Cambridge, Earth Sciences
Grant held at:: University of Cambridge, Earth Sciences

ENRIs:: Global Change
Science Topics:: Palaeobiology; Biogeochemical Cycles; Land - Ocean Interactions; Climate & Climate Change

Abstract:: The chemical evolution of the oceans is fundamentally tied to climate change and biological evolution throughout Earth history. Few methods exist for directly reconstructing the past ionic composition of seawater, and thus empirical constraints on seawater magnesium to calcium ratios (Mg/Ca) are very limited. We propose to develop a record of seawater Mg/Ca for the Cretaceous to Pleistocene by combining temperatures reconstructed using the new carbonate 'clumped isotope' thermometer with measurements of benthic foraminiferal Mg/Ca ratios. This record of seawater Mg/Ca will be used to test several hypotheses: 1) We will test whether the Mg/Ca ratio and [Ca2+] of the oceans were much more dynamic than previously thought, as some authors have suggested. We will for the first time be able to precisely determine the timing and magnitude of changes in seawater Mg/Ca, data which are required for both carbon cycle models and Mg/Ca-based paleotemperature reconstructions. 2) We will test whether a major driving force for evolutionary change in biomineralization of marine organisms was secular variation in seawater Mg/Ca. We will compare our record of seawater Mg/Ca with the skeletal mineralogy of dominant reef-builders and sediment producers through time.

Authorised funds only

This grant award has a total value of £26,701

DI - Other Costs	Indirect - Indirect Costs	DA - Estate Costs	DI - Staff	DI - T&S	DA - Other Directly Allocated
£13,996	£4,394	£1,694	£3,499	£2,860	£256

If you need further help, please read the user guide.