Late Glacial–Holocene ecostratigraphy of the south-eastern Aegean Sea, based on plankton and pollen assemblages

Contrasting patterns of climatic changes during the Holocene across the Italian Peninsula reconstructed from pollen data

“…5d-g). The pattern of warm early to mid-Holocene temperatures and cooler late Holocene climate in the north is supported by alkenone-based SST curves from both records (Gogou et al, 2007;Triantaphyllou et al, 2009b). Alkenone-derived SSTs range between 20 • and 23 • C in the North Aegean MNB3 record during the early to mid-Holocene and drop to 20 • C after 6000 cal yr BP (Gogou et al, 2007).…”

“…8000, 6500 and 4200 cal yr BP and they correspond to strong shifts in the humidity index reconstructed from the Aegean cores. The earliest event seems to correspond with the regional expression of the 8.2 kyr event (Alley et al, 1997) in the Mediterranean region (Magny et al, 2003Kotthoff et al, 2008Kotthoff et al, , 2011Pross et al, 2009;Triantaphyllou et al, 2009b). This event is commonly explained through atmospheric circulation changes induced by freshwater pulses that produced a weakening of the thermohaline circulation in the North Atlantic.…”

“…Alkenone-derived SSTs range between 20 • and 23 • C in the North Aegean MNB3 record during the early to mid-Holocene and drop to 20 • C after 6000 cal yr BP (Gogou et al, 2007). In contrast, the South Aegean record of core NS14 displays SSTs ranging from 17 • to 22 • C for the early to mid-Holocene, rising to ∼ 24.8 • C at about 5000 cal yr BP (Triantaphyllou et al, 2009b). Terrestrial biomarkers (n alkanes) indicate the dominance of warm species in the South Aegean during the mid-to late Holocene, confirming the pollen signal (Kouli et al, 2012) and agreeing with our pollen-based reconstructions.…”

“…7) shows a climatic partition during the Holocene that matches well with the pollen-based precipitation reconstructions: the mid-Holocene is characterized by dry summer conditions in northern Italy and the North Aegean Sea, while wet conditions are reconstructed in southern Italy, Sicily and South Crete. Warm and humid conditions that prevailed during the mid-Holocene are also apparent in the South Aegean marine NS14 record by the deposition of a distinguishable sapropel-like layer (Sapropel midHolocene: SMH, Triantaphyllou et al, 2009b). The trend of warm and humid conditions in the south reverses during the late Holocene, after 6000 cal yr BP.…”

Late Quaternary palaeoenvironmental changes in the Aegean Sea: interrelations and interactions between North and South Aegean Sea.

“…Core SK-1 recovered during the R/V Discovery cruise of 1982 in the north-central Aegean Basin (38° 80′ N and 23° 80′ E), at present day water depth of 1000 m. The core NS-40 recovered during the R/V Aegaio cruise of 1998, from a similarly deep site (1078 m depth), at the easternmost edge of the recent Aegean volcanic arc in south Aegean Sea (37° 01′ N and 26° 19′ E). Both cores consist of grey hemipelagic mud, intercalated with Santorini tephra layer Z2, the most recent sapropel S1 and turbidite layers (Zachariasse et al, 1997;Triantaphyllou et al 2009;Kontakiotis, 2012). The established chronology of the cores NS-40 and SK-1 has led to an expanded palaeoecological reconstruction of the Late Glacial-Holocene archive in the Aegean Sea, spanning approximately the last 30 kyr nc BP and 16 kyr nc BP respectively (Kontakiotis, 2012).…”