Variazioni climatiche post-glaciali nei sedimenti lacustri del lago di Loclat (Neuchàtel, Svizzera): Evidenze sedimentologiche, palinologiche, mineralogiche, geochimiche ed isotopiche - Dati preliminari

Abstract

Sedimentoiogical, mineralogical, geochemical and isotopie analyses have been carried out on late-glacial to present-day lacustrine sediments of Lake Loclat (Neuchàtel, Switzerland). Two phases of lake history have been identified: the first one is dominated by detrital inputs; the second (beginning around 13,000 yr BP) is characterised by autochthonous biogenic carbonate deposition. Pollen analyses reveal a gradual succession in landscape reforestation, with sparse vegetation from the Oldest Dryas to various flora associations in post-glacial times. At the end of Bronze Age, anthropogenic indicator species appear. Stable isotope variations on authigenic carbonate sediments are similar to the trend reported from other late-glacial profiles of central Europe. Negative shifts in δ¹⁸O and δ¹³C isotopie values are interpreted as a return to colder climates, and are consistent with palynological data.