Possible complexity of the climatic event around 4300-3800 cal. BP in the central and western Mediterranean

This paper presents an event stratigraphy based on data documenting lake-level changes as well as volcanic eruptions over the period 4500-3500 cal. BP from sediment sequences of Lakes Accesa in Tuscany (north-central Italy) and Maliq (Albania) in the central Mediterranean. The available data make it possible to recognise a tripartite climatic oscillation between c. 4300-3800 cal. BP. A phase characterised by drier conditions at c. 4100-3950 cal. BP appears to have been bracketed by two phases marked by wetter conditions and dated to c. 4300-4100 and 3950-3850 cal. BP, respectively. The deposition of the Avellino tephra occurred during the first humid phase, slightly before 4300 cal. BP, and that of an interplinian tephra AP2-AP4 (or Pr1) around 4050 cal. BP during the dry intermediate phase. This dry median episode may be related to the so-called '4.2 ka event' observed in tropical areas as well as in northwestern Italy. A comparison of the Accesa lake-level record with palaeoclimatic terrestrial and marine records suggests that this complex climatic oscillation around 4300-3800 cal. BP affected the central and western Mediterranean area. The key position of the 4300-3800 cal. BP climatic oscillation at a crucial transition from mid to late Holocene in the Mediterranean and tropical areas, deserves major consideration in further investigations.