Contribution of the mineralogy of sands to the study of the palaeoenvironments of mouste-Rian and upper palaeolithic occupations of the abri mochi (Italian Liguria)

摘要

The mineralogical study of the Abri Mochi sands (Grimaldi, italian Liguria), and in particular the heavy mineral analysis has allowed a sedimentary and palaeoclimatic distinction to be made between the Mousterian and Upper Palaeolithic of the liguro-mentonnais coastline. The Mousterian sediments are very rich in metamorphic and plutonic minerals amongst which garnet, stau-rolite and sphene are predominant. Their origin is derived from the detritic sedimentary formations, which are abundant within the shelter's immediate vicinity of which the first are the Paleogene sandstone of the Menton syncline. Their component materials were transported in a continental environment by water run off under a probably cold and wet climate. The Upper Palaeolithic sediments are distinguished from the Mousterian sediments by a diminution in the proportion of garnet, staurolite and sphene and an important increase in the percentage of zoisite as well as by the presence of volcanic origin minerals: green amphibole and denticulated pyroxenes with shock traces. The volcanic minerals are derived from the andesitic pyroclastites of the Cap d'Ail. Taking into account their morphology, the regional and local topographic constraints during the Quaternary, it is possible to envisage an aeolian transport under a cold dry climate for these latter minerals.