Documentation of the first stable isotopic records of the North Pyrenean foreland basin

Sébastien Castelltort – University of Geneva, Switzerland
Charlotte Fillon – TOTAL, CSTJF, Pau, France 
Eric Lasseur – BRGM, Orléans, France

Major Results

The geochemical record obtained in this work allows to define the stratigraphic position of the Paleocene-Eocene Thermal Maximum in Lussagnet (North Pyrenean foreland basin). Furthermore, this study highlights the possibility to get reliable information about past extreme climate events from sediments successions deposited within active tectonic


The Paleocene-Eocene thermal maximum (PETM; ~56 Ma) is characterized by a global warming and a significant perturbation of the carbon cycle. The large release of carbon associated with the development of the North Atlantic Igneous Province (NAIP) is suspected to be one of the mechanisms which triggered this abrupt climate upheaval. Mercury (Hg) anomalies can be used as a marker of volcanism and can therefore provide hints on the possible relationship between the development of NAIP and the PETM. The data obtained in Lussagnet reveal the occurrence of two main Negative Carbon isotopic Excursions (NCIEs).


The largest NCIE is interpreted as the PETM and the second, and smaller one, as the Pre-Onset Excursion. This geochemical record allows us to define a robust isochronous line on the North Pyrenean foreland basin. The two NCIEs are both systematically associated with important Hg anomalies (Figure 1). These results show that pulses of volcanism, associated to the emplacement of the NAIP, contributed to the onset and to the long duration of the PETM.

Evolution of 13C values and mercury concentrations in Lussagnet (LUG-101)