Duration of S1, the most recent sapropel in the eastern Mediterranean Sea, as indicated by accelerator mass spectrometry radiocarbon and geochemical evidence

Abstract

Abstract. Slowly accumulated (<5 cm kyr '1) and rapidly accumulated (5-20 cm kyr -1) sediments have been compared to define the initiation and termnation times of the most recent sapropel (S1) in the eastern Mediterranean Sea. The Ba/A1 ratio has been employed as a more persistent index of productivity than C•g. Accelerator mass spectrometry radiocarbon dating of pelagic foraminifera indicates a maximum duration for increased Ba/A1 levels in S 1 from -9500-6000 (uncorrected radiocarbon convention years B.P.) in the rapidly accumulated sediments and -9500-5300 years B.P. in the slowly accumulated sediments. This difference is ascribed to bioturbation affecting the slower accumulated S1 sediments. In the two most rapidly accumulated S1 units, from the Adriatic and Aegean Seas, there is a "saddle" of lower values centered on 7500 years B.P. in the Corg and Ba/AI profiles, so that the visual S 1 unit appears as a doublet. Geochemical evidence indicates that this intervening period is best interpreted as an episode of increased ventilation and bottom water oxygenation during the period of sapropel accumulation.

Abnormal carbonate diagenesis in Holocene–late Pleistocene sapropel-associated sediments from the Eastern Mediterranean; evidence from Emiliania huxleyi coccolith morphology

“…Moreover, within S1, we observed partial erosion and mechanical breakage of coccoliths (Plate II, figure 6) that together can be used as a proxy for coccolith dissolution (Ziveri et al, 1999a,b). The upper part of sapropel S1 has been subject to post-depositional downward oxidation that affected its original organic carbon and carbonate content (De Lange et al, 1989;Van Santvoort et al, 1996;Thomson et al, 1999;Mercone et al, 2000). However, the dark and oxidised portion of the sapropel is characterized by a similar abundance of the different LM morphotypes.…”

“…On the right side, the ''Diagenetic'' intervals D1 -D5. Sapropel is traced on the base of estimated age of bottom of S1 and top of oxidised S1 calculated for low sedimentation rate cores by Mercone et al (2000) (5.3 and 9.5 ka, respectively). A hypothetic Holocene tephra layer is also evidenced.…”

“…Selected works included detailed analyses of calcareous nannofossils assemblages within the youngest sapropel S1 (f 6-9 ka, Mercone et al, 2000) (Violanti et al, 1991;Castradori, 1992Castradori, , 1993aAksu et al, 1995a;Negri et al, 1999a;Negri and Giunta, 2001;Giunta et al, 2003;Principato et al, 2003). However, important aspects of the taxonomy applied to these assemblages have remained poorly defined, with key taxa being referred to informal groups or assigned to species which are usually confined to the Pliocene (Table 1).…”

A Late Glacial to Holocene record of environmental change from Lake Dojran (Macedonia, Greece)

“…Despite this increasing humidity during the early Holocene, which incidentally coincides partly with the formation of sapropel 1a between ca. 10 000 and 8200 cal yr BP in the Mediterranean Sea (Emeis et al, 2000;Mercone et al, 2000;Kotthoff et al, 2008b;Schmiedl et al, 2010), K and Fe imply decreasing catchment erosion until 9000 cal yr BP. Less input from the catchment could be due to denser vegetation in the littoral areas and catchment, which while filtering clastic material might cause greater delivery of more allochthonous OM to the lake, as indicated by increasing TOC/TN.…”

Warfare in Late Neolithic\Early Chalcolithic Pisidia, southwestern Turkey. Climate induced social unrest in the late 7th millennium calBC

“…The duration of the first of these is well established at 5 to 6 centuries (Mercone et al 2000;Casford et al 2007), and it evidently forms part of a repeating RCC pattern during the Holocene. The GISP2 data ( Fig.…”