Prof. apl. Dr. Jens Fiebig

Stable Isotopes Working Group / AG Stabile Isotope

Research Interests

  • Dual clumped isotope thermometry of carbonates 48 and Δ47)
  • Traditional stable isotopes
  • Carbonate (bio)mineralization
  • Reconstruction of paleoenvironmental conditions
  • Geochemistry of volcanic gases
  • Origin of hydrocarbons in hydrothermal systems
  • Fluid-rock interactions
  • Development of new techniques for stable isotope analysis of geo-materials


  • Einführung in die Isotopengeochemie - PDFs: 1 Theorie, 2 Kohlenstoff, 3 Sauerstoff, 4 Schwefel
  • Geochemie der stabilen Isotope bzw. Isotopen- und Spurenelementanalytik I
  • Isotopen- und Spurenelementanalytik II
  • Materialanalytische Methoden


  • Redox and temperature conditions governing chemical and isotopic equilibration of CO2 and CH4 in volcanic hydrothermal systems (2005-2008; FI-948/1-1)
  • Assessing the geochemical signatures of abiogenically dominated methane sources (2008-2011; FI-948/2-1)
  • Carbonation of porous rocks by interaction with magmatic and hydrothermal fluids - a case study on Unzen volcano (2009-2012; FI-948/3-1)
  • Clumped isotope thermometry applied to bivalve mollusks (2010-2014; FI-948/4-1)
  • Bulk carbon and clumped isotope composition of N-alkanes in volcanic-hydrothermal emissions (2013-2015; FI-948/6-1)
  • Empirical and experimental calibration of a clumped isotope (paleo)thermometer for bioapatites (2014-2015; FI-948/7-1)
  • Clumped isotopes in Brachiopods as an indicator of seawater and diagenetic temperatures (2015-2018; ESR08, ITN Baseline Earth, Horizon 2020, EU) Link
  • Hydrocarbons in Icelandic volcanic-hydrothermal discharges: An inventory of concentrations and preliminary bulk carbon, radiocarbon and clumped isotope data (2015-2018; FI-948/8-1)
  • Identifying the processes that govern the hydrogen isotopic composition of H2 and CH4 in fumarolic emission: a case study from Nisyros, Greece (2017-2019; FI-948/9-1)
  • Pushing the limits of bioapatite clumped isotope analysis: resolving endo- from ectothermy in mosasaurs (since 2020, FI-948/11-1)
  • Reliable sea surface temperatures and latitudinal temperature gradients for determining late Cretaceous and Paleogene polar amplification (since 2020, Project A1, VeWA, LOEWE)
  • Dual clumped isotope thermometry of carbonates: resolving the effects of temperature from kinetics and diagenesis for accurate reconstruction of Earth’s surface temperature (since 2021, FI-948/13-1; Reinhart Koselleck project)

Working Group Members

Former Working Group Members

  • Dr. Ulrike Wacker (Thermo Fisher Scientific)
  • Dr. David Bajnai (Uni Göttingen)
  • Dr. Niklas Löffler (VeWa Project)
  • MSc. Tanja Rutz
  • MSc. Christoph Schreiber
  • MSc. Vanessa Schlidt