Stable isotopic and micropaleontological studies were made of selected sapropels (organic-rich sediments) deposited in the Mediterranean Sea during the last 5.0 m.y. to determine the processes responsible for their formation. Distinct isotopic and faunal changes occur across sapropels of late Pleistocene, early Pleistocene and latest Pliocene age, while smaller isotopic changes and more stable faunal assemblages are associated with the early and mid-late Pliocene sapropels. The large d18O depletions and euryhaline fauna associated with latest Pliocene-Pleistocene sapropels supports a density stratification model with a low salinity surface layer. In contrast, early Pliocene and mid-late Pliocene sapropels appear to have been formed as the result of sluggish circulation and low oxygen contents in bottom waters of the eastern Mediterranean due to the stable, warm climatic conditions of that time period.

Sediment depth is given in mbsf. For all of the early Pliocene samples used in this study, isotopic analyses were carried out on Globigerinoides obliquus due to the scarcity of Globigerinoides ruber.

Supplement to: Thunell, Robert C; Williams, Douglas F; Belyea, Paul R (1984): Anoxic events in the Mediterranean Sea in relation to the evolution of late Neogene climates. Marine Geology, 59(1-4), 105-134