Magnetic mineral study of the prehistoric site of caverna delle fate (finale, liguria, Italy) [?tude des minéraux magnétiques du site préhistorique de la caverna delle fate (finale, ligurie, savona, italie)]

摘要

The Fate cave (Caverna delle Fate) is an Upper Pleistocene prehistoric site located near Finale, in the province of Liguria, northern Italy. The magnetic study of the sedimentary deposit in the cave has allowed a better understanding of its characteristics. The lower part, made up of sandy layers deposited during an active karst period, (intercalated with clay and loamy layers), is characterized by low values of the magnetic parameters. The iron oxides present are essentially detrital and dominated by goethite and single domain magnetite. Fine, superparamagnetic, grains are rare except in the clayey layers, which have much higher magnetic parameters. The upper part of the deposit is marked by a halt in the active karst sedimentation and the beginning of a fossil karst regime. During this period the cave was occupied by prehistoric man. The different magnetic parameters indicate the presence of fine magnetic grains of low coercive force (magnetite, maghemite), and in a greater concentration than in the lower part.