Hydrological conditions over the western Mediterranean basin during the deposition of the cold Sapropel 6 (ca. 175 kyr BP)

Enhanced rainfall in the Western Mediterranean during deposition of sapropel S1: stalagmite evidence from Corchia cave (Central Italy)

“…However, previous speleothem work from western Italy has shown that cave-temperature effects are likely to be counterbalanced by the influence of changing regional air temperatures on rainfall δ 18 O, which is estimated to be 0.2-0.3‰/°C (Bard et al, 2002). Hence, if a temperature increase alone occurred, it would have had an indistinguishable effect on speleothem δ 18 O at this site.…”

“…This is regarded as a principal mechanism driving variations in rainfall δ 18 O (and therefore drip-water and speleothem δ 18 O values) in the Mediterranean region (Bar-Matthews et al, 2000;Bard et al, 2002). In previously studied Corchia stalagmites, intervals of low δ 18 O correspond to wetter and warmer climatic periods (Drysdale et al, 2004;, suggesting that the amount effect is coupled to regional temperatures.…”

“…Kallel et al, 1997). Given that the Western Mediterranean supplies about 40% of the moisture reaching central-western Italy (Bard et al, 2002), a more 18 O-depleted sea surface would have caused a reduction in the δ 18 O of vapour, leading to a depletion in the isotopic composition of the recharge waters reaching the cave.…”

“…Speleothems are cave calcium carbonate deposits with a demonstrated capacity for preserving climate changes during Mediterranean sapropel events (Bar-Matthews et al, 2000;2003;Bard et al, 2002). In this paper, we present a precisely dated isotopic record from a speleothem collected from Antro del Corchia, central Italy, which displays direct evidence of increased rainfall in the region during the period of S1 deposition and provides an opportunity for correlation with nearby marineand lake-core records.…”

Early and mid-holocene environmental conditions in the eastern Adriatic recorded in speleotherms from Mala Špilja cave and Velika Špilja cave (Mljet island, Croatia)

“…We presume that δ 13 C c of analysed speleothems primarily reflects the density and/or type of vegetation cover and biogenic activity in the soil. Negative δ 13 (Bard et al 2002;Bar-Matthews et al 1999. However both δ 18 O c and δ 13 C c can be interpreted differently, depending on factors that at some point had a decisive influence on the isotopic signal.…”