A LATE-PLEISTOCENE PHASE OF SAHARAN DUST DEPOSITION IN THE HIGH APENNINE MOUNTAINS (ITALY) .

Abstract

The presence of Late Pleistocene hexogen quartz-rich loess on Apennine massifs, formed by limestone rocks, has been reported since the 90s of the 20th century, and indicates that the dust must come from outside areas. The thickness of the aeolian deposits decrease from south to north, becoming null north of the latitude of 42° N; thus indicating that the dust come from South. The study of new exposures on Mount Matese, where the loess is interbedded with tephra layers and in proglacial lake sediments, have led to a more detailed chronology of the phases of sedimentation. Specifically, we have established that the loess deposition was contemporaneous with the Late Pleistocene phases of intense Saharan dust sedimentation in maar lakes in Italy, and in the Mediterranean Sea. The geochemical characterization and the recognition of three tephra layers have enabled us to establish that the end of the loess sedimentation occurred at the transition between the Oldest Dryas stadial (or Greenland stadial GS-2) and the Bölling/Alleröd Interstadial (or Greenland Interstadial Gl-1), simultaneously with the start of the African Humid Period. We hypothesize, therefore, that the quartz-rich loess in the Apennines was formed by the sedimentation of Saharan dust. The greater amount of dust, brought by southerly winds, would have been sedimented during periods of increased aridity in North Africa which were coeval with the Apennines Last Glacial Maximum and stadial phases.