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The crosscutting theme "tephrochronology"

The crosscutting theme "tephrochronology" dealts on the analysis of volcanic tephra from stratigraphic records of Quaternary and Cretaceous series, with an application to sites located in the Mediterranean, Atlantic and southeastern Pacific regions.

The aim is to optimize the use of tephra to improve our understanding in a wide range of scientific issues in the fields of volcanology, geochronology and palaeoenvironmental reconstructions. A proper interpretation of the "tephra tool" requires a thorough knowledge of the volcanological context where they settled, their classification by geochemical analysis, the stratigraphic context in which these levels are and taphonomic processes affecting all stages of dispersion and deposition.

The members of this crosscutting theme offer an interdisciplinary orientation mainly combining the expertise of volcanology, geochemistry, geochronology (14C, K/Ar, Ar/Ar datings), mineralogy and stratigraphy as well as a range of important areas related to these studies. In addition, a network of associated national and international groups (LSCE, UPMC, Univ. Vrije-Amsterdam, Univ. Tohuku-Sendai, Univ. of Bari and Univ. of Pisa), provide access to key information on the sites of all the major volcanic provinces related to our investigations.

The aims of crosscutting theme tephrochronology are as follows:

  • Improve the chronology of volcanic events using traditional dating methods (Ar/Ar, K/Ar and 14C ).
  • Optimise the chronology of time scales (Cretaceous to Quaternary) and the intercalibration time scales (14C vs Ar/Ar and K/Ar).
  • Provide the exact timing of climate changes and their inter-hemispheric corrélations using tephra as a correlation tool.
  • Improve new geochemistry protocols on tephra through Analytical Development (LA MC ICPMS on single-point glass shards) to optimize a better discrimination of volcanic sources and tephra correlations.