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Geochemical proxies for paleoenvironmental reconstructions


Number of ECTS : 3


Lecturer and Manager : Professor Christophe Lécuyer (stable isotope geochemist, University Claude Bernard Lyon 1 & Institut Universitaire de France).


This lecture (~25h) is devoted to the various approaches and techniques used to quantify some key variables in the fields of paleoclimatology, paleoecology and paleobiology.

  1. Basic principles in stable isotope geochemistry of the light elements (H, B, C, N, O and S)
  2. H and O isotopic fractionations within Earth’s water cycle
  3. Conventional stable isotope thermometry and clumped isotopes: principles, applications and caveats
  4. Study of chemical and isotopic records of Phanerozoic marine and continental sedimentary deposits
  • Climate: latitudinal gradients, variations through time

- Mean air and sea surface temperatures and their seasonal variations

- Relative humidity

- Prevailing winds

  • Oceanic currents and water masses

        - Impacts on biomass and biodiversity

  • Thermophysiology of extinct vertebrates
  • Paleoecology of aquatic vertebrates: freshwater, brackish water and marine environments

Personal and small-group work. Most concepts introduced during case studies


Examples of case studies:

1) Calculation of seawater pH and atmospheric pCO2

2) Calculation of skeletal growth curves for invertebrates

3) Calculation of Jurassic sea surface temperatures and their seasonal variations

4) Identification of past oceanic currents and their impact on faunal migration

5) Calculation of past seawater salinity during the Miocene

6) Calculation of air temperatures and their seasonal variations during Pleistocene glacial stages

7) Estimation of past ice volumes during the Late Jurassic and an interglacial stage of the Pleistocene


Scientific rationale of a method:

- How to solve a problem by using theoretical, experimental and empirical approaches?

- How to choose an appropriate hypothesis?

- How to define the limits of a method and the meaning of data.


Students will also work with real scientific data and will learn how to prioritize observations and interpretations, and how to construct a scientific discussion.

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