A stalactite overgrown by scleractinian corals was collected from a karstic cave located along the northwestern Sicilian coast between Trapani and San Vito Lo Capo at 100m above the sea level. The Custonaci coastal area consists of four major marine terraces identified by Antonioli et al. (2002), with the youngest terrace (about 16 m above sea level) attributed to MIS 5.5 on the basis of the Senegalese fauna (Strombus bubonius). The cave developed at the base of a marine paleo-cliff and its roof is also partly encrusted by coral growth. The speleothem section shows three hiatuses that are considered to represent three different sea level transgressions older than the coral overgrowth. Several pieces of the continental layers of the stalactite were analysed for 230Th/U using a multi-collector ICPMS NeptunePlus and all the ages resulted to be beyond the upper limit of the 230Th age range. Small fragments (3-5mg) of the thecal wall of three corals were analysed for 87Sr/86Sr ratio and the strontium ages were then calculated from the regression curves LOWESS look-up Table version 4: 08/04 (revised from McArthur et al., 2001). The age of the corals is 1.1±0.2Myrs (mean ± 2SD), supporting the 230Th/U ages of the continental layers beyond the upper limit of the U-series chronometer. We measured the δ18O of the continental layers at 1 mm spatial resolution and the comparison with marine and continental records suggests that the calcite of the stalactite was precipitated during MIS 27-31. The stalactite from Custonaci thus represents a unique paleoclimatic and paleo sea level archive together with the Bahamas flowstone (Lundberg and Ford 1994) and the Argentarola speleothems (Dutton et al., 2009).
|Stato di pubblicazione||Published - 2012|