Climatic cycles as expressed in sediments of the PROMESS1 borehole PRAD1-2, central Adriatic, for the last 370 ka: 2. Paleoenvironmental evolution

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Abstract

[1] The multidisciplinary study of planktic and benthic foraminifera, alkenone SST, and O and C stable isotope records allowed reconstruction of the paleoenvironmental history of the central Adriatic basin over the last 360 ka B.P. In general, the main paleoclimatic changes documented in the central Adriatic appear in phase with climate change in the North Atlantic realm, except for intervals which correspond to the deposition of sapropel levels in the eastern Mediterranean. In particular, the interval between Marine Isotope Stage (MIS) 7.5 and MIS 5 appears to be strongly influenced by the monsoonal regime. The comparison with other Mediterranean records also suggests that the Adriatic Basin was affected by very low sea surface temperature (SST) (down to 2°C for MIS 2) during glacial intervals, which is uncommon for the Mediterranean Basin. In addition, the SST record indicates that this basin was unable to maintain warm interglacial/interstadial conditions for durations similar to the western Mediterranean. This fact can be explained by the landlocked position and shallow depth of this basin, which make it particularly exposed to atmospheric forcing (e.g., Siberian High) and to the strong influence of the nearby landmass during glacial intervals, producing a lag in the demise of glacial intervals. Moreover, the progressively higher values of the δ18O records of glacial intervals, alongside the SST record and the foraminifera assemblage, imply an increasing impact of the formation of cold and dense water since the penultimate glacial.

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