DEPOSITI EOLICI E DI VERSANTE AL MARGINE DEI TRAVERTINI DI CARVANNO(Val Degagna,Brescia): SEDIMENTAZIONE E PEDOGENESI TRA IL PLEISTOCENE SUPERIORE E L'OLOCENE

Loess and slope deposits at the edge of the Carvanno Travertine(Val Degagna-Brescia).Sedimentary processes and soil development between the Upper Pleistocene and the Holocene.The Au-thors describe a sequence some 4 metres thick composed of slope and loess deposits which lies at analtitude of 360 metres,20 metres above the Torrente Agna.The series belongs to a polyciclic soil compo-sed of 4 lithostratigrapbic units which,from the bottom to the top,are as follows:—slightly weathered loess(Ⅳ C1);—red clayey soil sediments(Ⅲ B2)resulting from the erosion of a more ancient paleosol of《TerraRossa》type,developed during the Middle Pleistocene at the top of the Carvanno Tarvertine;—undisturbed loess and loess displaced by gelifluction(Ⅱ B21t/Ⅱ B23t);—recent colluvial deposits(A1+B1).The sequence was deposited between the Upper Pleistocene and the Holocene.During the Upper Pleisto-cene the loess deposition,alternated with colluvial and gelifluction phases,was caused by cold-humidclimatic conditions.During the postglacial,the loess was affected by weathering which lead to the deve-lopment of an alfisol.The mieromorphological analysis evidenced several stages in the postglacial soilforming process.First,in unstable geomorphological conditions,complex cutans(scheletans-matransiltans)covered the walls of the soil pores.In a later period,as a result of landscape stability,laminated andbirefringent ferri-argillans were mainly deposited.The deposition of the upper colluvial cover(A1+B1)and the coarse fills of tlie underlying horizons were produced by a degradational phase due to the defore-station of the area in historical times.The undisturbed argillans of the A1+B1 horizons indicate thatthe clay illuviation is still active in the area.