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Into the Icehouse -
Ocean temperatures from CLumped Isotopes in Benthic and planktic foraminifera across the Eocene-­Oligocene climate transition

Final Report Summary - CLIMBP (Into the Icehouse -<br/>Ocean temperatures from CLumped Isotopes in Benthic and planktic foraminifera across the Eocene-­Oligocene climate transition)

Analysis of the geologic record shows that Earth’s temperature raised suddenly, and plunged precipitously, many times in its history. These abrupt climate transitions presumably occurred because tipping points in the climate system were exceeded. What is the nature of these tipping points? The major goal of CLImBP is to investigate such climate transitions through the application of a new and powerful paleo-thermometer: clumped isotopes in carbonates. Such temperature reconstructions can be used to test climate model simulations and improve our understanding of tipping points in the climate system, which is important for the comprehension of modern global climate change.

The main focus since the beginning of the project has been on the improvement of the clumped isotope measurement technique for small samples. In an collaborative effort within the clumped isotope group at ETH Zürich, a new correction scheme was designed and implemented using a set of newly produced carbonate standards. A further primary objective of CLImbP was the establishment of a clumped isotope thermometer calibration that can be applied on benthic foraminifera. Within the framework of CLImBP and in collaboration with other research projects, different calibration datasets were produced, based on natural as well as synthetic samples. The newly developed method and correction scheme as well as the new calibrations have been applied in a range of different paleoclimate studies. These datasets document for example the huge temperature response in the interior of North America during a natural carbon cycle perturbation during the Early Eocene. Such information is very important, since these events are considered as potential analogues for the modern anthropogenic perturbation of the carbon cycle.

The expected impact of the results that were achieved within the framework of CLImBP is large, since they provide an important fundamental basis for ongoing and future applications of the carbonate clumped isotope thermometer. Such applications do not only touch upon fundamental paleoclimate research, but also reside in the field of hydrocarbon reservoir and geothermal energy resources research.