A possible solar pacemaker for Holocene fluctuations of a salt-marsh in southern Italy

This study is aimed at verifying the possible influence of solar activity on the coastal vegetation development in the Tavoliere Plain (south Adriatic region, Italy) between 6350 and 4000 cal BP, when regular fluctuations of halophilic vegetation are recorded by pollen. A wavelet analysis, applied to the percentage values of glasswort vegetation is consistent with periodicities of solar activity and other palaeoenvironmental and palaeoclimate proxies in the literature. A comparison of salt-marsh pollen indicators (Salicornia type and Ruppia maritima) with the 10Be dataset from the Greenland ice core GISP2, on the basis of their independent chronologies, reveals a strong visual correlation, indicating that the minima of salt-marsh percentages match minima in the 10Be curve, corresponding to solar activity maxima, associated with warm and arid phases at the middle latitudes. The Tavoliere salt-marsh appears to have contracted during the arid/warm phases associated to maxima of solar activity and to have expanded during the wet/cold phases of solar minima. This coastal area, characterized by a very flat topography and arid climate, appears to have been very sensitive to even minor hydrological and climate changes. Changes of solar activity, determining extensive environmental transformations, were also possibly responsible for the abandonment of the human coastal settlements of one of the most important Neolithic archaeological districts of Italy.