Étude des matières organiques du sol d’occupation acheuléen de l’unité archéostratigraphique UA 27 de la grotte du Lazaret

Abstract

Geochemical analyzes of organic matter were conducted by GC/MS and ESI/MS on 30 samples from the unit archeostratigraphic UA 27 of the cave of Lazaret, dated about 160,000 years. These analyzes highlight the relative proportions of animals and plants fats in various areas of the Acheulean surface occupation. The dominants organic components in all samples are C16:0 (palmitic saturated fatty acid), C18:0 (stearic or octadecanoic saturated fatty acid), C18:1 (unsaturated octadecenoic fatty acid or oleic acid), nonanoic acid and dodecanoic acid. Other compounds appear only in some spectra as vanillin, oleamide, cholesterol and behenyl alcohol. The concentration of organic matter is much greater in the hearth level and appears to have a mostly animal origin such as cholesterol and oleamide. Others ground occupation areas essentially contain molecules of plants as behenyl alcohol appears to be the result of the degradation of marine and terrestrial grasses that fed litter origin.