Project Details
Projekt
Water isotope analyser
Subject Area
Mineralogy, Petrology and Geochemistry
Term
Funded in 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 570491468
Oxygen, carbon, and hydrogen are the main elements of the hydrosphere, biosphere, lithosphere, and important components of the atmosphere. By studying the isotopic ratios of these elements in various material groups, it is possible to reconstruct processes (e.g., photosynthesis), conditions (e.g., temperature), and material flows (e.g., sources and sinks) in the present-day environment as well as throughout Earth's history. A general challenge with stable isotopes lies in their one-dimensional scale. The interpretation of 2H/1H, 13C/12C, and 18O/16O ratios is often ambiguous, as different processes may overlap. For instance, paleo-temperatures are reconstructed from measured 18O/16O ratios in carbonates. This is feasible when the carbonate forms in near-equilibrium with seawater. However, for many carbonates, this approach does not work because kinetic isotope fractionation processes distort equilibrium fractionation. Diagenesis can also alter the reconstructed temperatures. On the one-dimensional 18O/16O scale, these overlapping processes can often only be identified indirectly (e.g., using 13C/12C) and sometimes not at all. Additional 17O/16O analyses allow for resolving minute differences in purely mass-dependent fractionation processes. This second dimension of oxygen isotopes enables the identification, quantification, and correction of overlapping processes. Investigating such processes in carbonates, sulfates, phosphates and other chemical precipitates experimentally always requires analyzing the respective 18O/16O and 17O/16O ratios in water as well. Acquiring a respective instrument is the aim of this proposal. Some chemical sediments, such as gypsum, comprise water bound in the crystal lattice. This allows for reconstructing paleo-water compositions e.g. from the Messinian Salinity Crisis. Such paleo-water 18O/16O, 17O/16O and 2H/1H ratios then permit estimating paleo relative humidity. In another approach, the triple-O isotopic composition of body water is used to infer the physiology of animals. This approach is applied in an active project to quantify the water sources of Insects from dry desert environments. It is planned to extend this concept to study the physiology of Dinosaurs. For this purpose, it is planned to improve body water models of recent animals, which requires direct 18O/16O, 17O/16O and 2H/1H measurements on a variety of animal groups.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Wasser Isotopen Analysator
Instrumentation Group
1520 Meßgeräte für Gase (O2, CO2)
Applicant Institution
Ruhr-Universität Bochum
