Résumé
The Last Interglacial (LIG or Marine Isotopic Substage 5.5, MIS5.5), which is comprised between similar to 129 and similar to 116 thousand years Before Present (hereafter ky BP), is poorly documented, especially in continental areas, owing to the scarcity of deposits attributable to this period, which corresponds to the Eemian in the chronostratigraphy of northwestern Europe. The scarcity of documentation is even more pronounced for the deglaciation that precedes the LIG, the MIS 6/5 Transition or Termination 2, which lasted about ten thousand years. In this context, the site of Waziers, in Western Europe (France), has an exceptional sequence of successive fine silty-limestone deposits covering the penultimate deglaciation (MIS 6/5) and peat rich in plant remains contemporary with the last interglacial (MIS 5.5). Oxygen isotope analysis of phosphate of tooth enamel from large herbivorous mammals (horse, Equus sp.; megaloceros, Megaloceros giganteus; roe deer, Capreolus capreolus) present in these deposits allows the reconstruction of air paleotemperatures during the lifetime of the animals. The results yield annual mean temperatures of 4.7 +/- 0.6 degrees C for an early phase of the deglaciation (5 teeth of a same individual), of 6.9 +/- 0.5 degrees C for a mid-phase of the deglaciation (1 tooth), and of 8.6 +/- 0.5 degrees C for a phase preceding the establishment of the last interglacial, the MIS5.5 (1 tooth). In deposits contemporary with the latter phase, human artifacts were discovered, as well as in those of MIS5.5. In agreement with the palynological data, the paleotemperatures illustrate a gradual warming during part of the glacial/interglacial transition, the MIS6/5 Transition. The difference of similar to 4 degrees C between the minimal and maximal temperature reconstructed in this study allows us to minimize the temperature difference between the MIS6.2 glacial period and the MIS5.5 interglacial period at the Waziers site.