Articles by Bruno Bosselin

The multivariate treatment of long pollen sequences coming from peat bogs constitutes an easy and effective method of factorial regression for the semi-quantitative reconstruction of the Paleoclimates. The comparison of the results obtained for the upper Pleistocene with the isotopic profiles of sea- and ice-cores, then with the previous methods, confirms a structuralization of the last climatic cycle in four periods: the interglacial Riss/Wurm including the optimum Eemian, the lower pleniglacial, the Wurmian interpleniglacial and the upper pleniglacial, before the Holocene. A numbering system of these oscillations, correlated with the Dansgaard-Oeschger events recognized in the ice-cores of Greenland, is proposed. A final statistical treatment shows a cyclic evolution of the forest vegetation during the Eemian, an evolution which better translates the variations of the Paleoclimates (temperature and humidity) than the arboreal pollen rate (AP).

The results of several sea- and ice-cores and pollen sequences of peat bogs, for the last 40,000 years, permits today to give evidence of palaeoclimatic oscillations of this period. A method of palaeoenvironment reconstitution, based on transfert functions computation, issued from pollen diagrams, is proposed. The method is building a palaeotemperature curve and a palaeohumidity curve, allowing to separate and correlate the two climatic components. A complete example of the method is developed with the data of the peat bog of Tenaghi-Philippon (Macedonia, Greece). All the analysed sequences (Tenaghi-Philippon, la Grande Pile, Banyoles, etc.), compared to sea-cores (KET 8004) and ice-cores (GRIPSummit, Greenland) confirm the evidence of mild and humid oscillations, and cold and humid oscillations, in a three parts structured sequence: the interpleniglacial (up to 28,000 BP), the late pleniglacial (between 28,000 BP and 13,500 BP), and the tardiglacial (between 13,500 BP and 10,000 BP). A numbering system, avoiding usage of ancient interstadials still to valid in their eponym sites, is proposed.