Professor LIU Qingsong and his team present magnetic, geochemical, and diffuse reflectance spectroscopy data from three sapropels that are representative of glacial (S6) and interglacial (S1, S5) conditions in the eastern Mediterranean Sea to assess environmental changes associated with sapropel formation.

They link short-lived dust abundance peaks within sapropels S1 and S6 to centennial-scale periods of enhanced bottom-water circulation reported previously for these sapropels. Although these sapropel interruptions are driven by high-latitude cooling events, their results indicate that such centennial-scale episodes of atmospheric reorganization affected not only the eastern Mediterranean northern borderlands, but also subtropical North Africa. Overall, their results point to a dominant low-latitude forcing on sapropel formation via boreal summer insolation maxima and intensification of the African monsoon.

Fig. 1. Stratigraphic log and variations in colour indices (L* and a*) and geochemical parameters for sapropel S1. (Image by LIU)

Fig. 2. Stratigraphic log and variations in colour indices (L* and a*) and geochemical parameters for sapropels S5 and S6. (Image by LIU)

Liu et al. New constraints on climate forcing and variability in the circum-Mediterranean region frommagnetic and geochemical observations of sapropels S1, S5 and S6. PalaeogeogrPalaeoclimatol Palaeoecol 2012, 333-334,1-12, doi:10.1016/j.palaeo.2012.02.036 (Download Here)