4-year PhD in carbonate triple oxygen isotope geochemistry

The Institute of Geology, Mineralogy and Geophysics, Faculty of Geosciences, Ruhr-University Bochum, Germany, has a PhD position available.

We are inviting applications for PhD position (m/f/d) for four years (75% TV-L E13).

Application deadline: 01.04.2024

The Project: The position is funded by the European Research Council (ERC) within the framework of a Consolidator Grant to entitled: "The kinetic oxygen cycle in chemical sediments" (KinO). Temperature is probably the most fundamental environmental parameter, but vigorously debated for most of Earth's history. Temperature derived from carbonate 18O/16O isotope ratios can be biased by i) kinetic effects, ii) alteration, or iii) late precipitation of secondary carbonates. Each of these mechanisms is expected to follow a different trajectory in 18O/16O vs. 17O/16O space. These characteristic slopes may allow to correct for the respective bias and to attain absolute paleo-temperatures. Exploring this concept for the diverse range of carbonates both experimentally and for natural samples is the main goal of the project. A similar concept will be explored for sulfates.

Isotope excursions in carbon (13C/12C) and oxygen (18O/16O) are generally observed together, e. g. during mass extinction events, implying that perturbations in the global carbon cycle always go along with paleo-temperature fluctuations. Sometimes, the magnitude of the 18O/16O excursion is interpreted to reflect a real temperature variation. In other cases, especially if the observed 18O/16O curve would imply temperature fluctuations in the order of tens of °C, the isotopic record is considered to be biased (e. g. by alteration). Using triple oxygen isotope systematics, it can be tested which process causes the isotope excursion providing reliable constraints both on the real temperature fluctuation and on the processes that have affected 18O/16O. This example illustrates how additional 17O/16O analyses can aid in reconstructing paleoenvironments.

Responsibilities and requirements: The primary objective of this and further positions is to tests the above concepts and to improve our quantitative understanding of triple oxygen isotope fractionation with respect to carbonates and sulfates. This can be achieved by conducting carbonate precipitation experiments, by analyzing natural samples and by theoretical modelling. While there is a planned work-schedule, this can be adjusted to fit the skills of the researchers, who are expected to contribute to the success of the project with their own research ideas. The researchers are expected to present results on national and international conferences, as well as publish in peer-reviewed journals. For these tasks, demonstrated experience in scientific writing and communication in English is a must.

The PhD candidate must have a MSc degree in natural sciences. Please see the parallel advert for a postdoc if you already hold a PhD degree. A background in isotope geochemistry and/or carbonate/sulfate chemistry and/or isotope modelling is desirable, but not mandatory. The ideal candidate is highly motivated to explore this new research field. The expected isotopic variations are subtle, and high precision analyses require tedious work. Some of the methods will be further improved within the framework of this project, which requires technical skills, ideally including programing. This high-risk high-gain project will involve some unexpected setbacks, which will require a certain resilience towards project delays. We are thus seeking for candidates that are eager to stubbornly work towards high profile publications.

What we offer: The position is based at the Ruhr-University Bochum, Germany. The Faculty of Geosciences has moved into brand new buildings just a few years ago. The Institute of Geology, Mineralogy and Geophysics at Bochum has an exceptionally good laboratory facility for inorganic carbonate geochemistry and extensive experience in carbonate sedimentology, diagenesis and geochemistry. Besides the triple oxygen isotope analyses it is intended to apply the full range of conventional and state-of-the-art proxies in carbonate petrography to unravel all relevant processes. The research will be conducted in close collaboration with the University of Göttingen, the University of Cologne and the University of Frankfurt, which provide complementary expertise and allows absolute state of the art analyses of the full range of stable isotope ratios (δ13C, δ18O, Δ17O, Δ47, Δ48, δ26Mg, δ44Ca) in carbonates.

Prof. Daniel Herwartz recently joined the Sedimentology and Isotope Geology department within the Institute (Prof. Adrian Immenhauser and his group), which has a long-standing focus on carbonates. By joining forces, we seek to create a vibrant, diverse, creative, social, communicative, and highly productive working environment. You will be part of a larger group with in total six permanent staff members (two professors, one lab manager, two technical assistance, one electronics engineer) and at least as many non-permanent researchers at the PhD and Postdoc level many of which focus on carbonates. We aim to create ideal conditions for using these synergies for conducting high profile research. At the same, we actively support a family friendly working environment.

The position at the Ruhr-University, in the Institute of Geology, mineralogy and Geophysics is available from 01.04.2024 or later. The duration of the project is 48 months for the PhD. The salary is in accordance with ERC rules. For details and further information, please contact Prof. Daniel Herwartz (Daniel.Herwartz@rub.de).

Interested applicants should email their application in pdf format to cornelia.schaefer@rub.de (cc to Daniel.Herwartz@rub.de) by 01.04.2024 at the latest.

Please provide a single pdf including:

  • 1-2-page cover letter outlining your academic background and skillset, the reasons you are interested in the project, and other points of relevance
  • CV and academic transcript (a copy of your M.Sc. and PhD degree certificates and any other relevant documents)
  • Contact details of one or two former advisors or supervisors (referees)

Once shortlisted, we will arrange for a videoconference or in-person interview.


posted: 26 February 2024     Please mention EARTHWORKS when responding to this advertisement.