The Glacial–Interglacial transition and Holocene environmental changes in sediments from the Gulf of Taranto, central Mediterranean

Abstract

An extensive, high-resolution, sedimentological–geochemical survey was done using geo-acoustics, XRF-core scans, ICP-AES, AMS 14 C-dating and grain size analyses of sediments in 11 cores from the Gulf of Taranto, the southern Adriatic Sea, and the central Ionian Sea spanning the last 16 cal. ka BP. Comparable results were obtained for cores from the Gallipoli Shelf (eastern Gulf of Taranto), and the southern Adriatic Sea suggesting that the dominant provenance of Gallipoli Shelf sediments is from the western Adriatic mud belt. The 210 Pb and 14 C-dated high-accumulation-rate sediments permit a detailed reconstruction of climate variability over the last 16 cal. ka BP. Although, the Glacial–Interglacial transition is generally dry and stable these conditions are interrupted by two phases of increased detrital input during the Bølling–Allerød and the late Younger Dryas. The event during the Younger Dryas period is characterized by increased sediment inputs from southern Italian sources. This suggests that run-off was higher in southern- compared to northern Italy. At approximately ~ 7 cal. ka BP, increased detrital input from the Adriatic mud belt, related to sea level rise and the onset of deep water formation in the Adriatic Sea, is observed and is coincident with the end of sapropel S1 formation in the southern Adriatic Sea. During the mid-to-late Holocene we observed millennial-scale events of increased detrital input, e.g. during the Roman Humid Period, and of decreased detrital input, e.g., Medieval Warm Period. These dry/wet spells are consistent with variability in the North Atlantic Oscillation (NAO). A negative state of the NAO and thus a more advanced penetration of the westerlies into the central Mediterranean, that result in wet conditions in the research area concord with events of high detrital input e.g., during the Roman Humid Period. In contrast, a positive state of the NAO, resulting in dry conditions in the Mediterranean, dominated during events of rapid climate change such as the Medieval Warm Period and the Bronze Age. • A sedimentological–geochemical, basin-wide survey in the Gulf of Taranto • High Holocene sedimentation rates (~ 0.5 mm/yr) • A humid Younger Dryas in southern Italy, in contrast with northern Italy • Millennial-scale events of increased detrital input (e.g., Roman Humid Period) • Dry/wet spells reflecting the North Atlantic Oscillation (NAO)