In Core KC19C 19.6 m long , recovered in the abyssal plain between Crete and Cyprus in the eastern Mediterranean, a Ž . large number of organic-rich layers sapropels occur, which correlate to maxima in the insolation curve. In contrast to other Ž . sites in the eastern Mediterranean, porewaters contain sulfide below a few meters below seafloor mbsf . Geochemical Ž . analyses were performed on the porewaters ammonium, alkalinity, sulfate, manganese, iron, bisulfide, chloride, Eh, pH and Ž . sediments organic carbon, barium, total sulfur, total iron, manganese, pyrite, dithionite-extractable iron . In addition, a Ž . series of magnetic parameters and ratios NRM, ARM, IRM, x , ARMrIRM, S-ratio, ARM rARM were deter-in 20mT in Ž . mined. In the top of the sediments, Fe and Mn hydr oxides occur at the oxic–suboxic boundary just above the youngest Ž . sapropel Si2; these hydr oxides appear to be more easily demagnetized by means of alternating fields than deeper Ž . hydr oxides which presumably are of detrital origin. The transition from suboxic to anoxic sediments is located at ; 2 mbsf. Sulfide is produced, possibly during sulfate reduction through anoxic methane oxidation, at ; 17.5 mbsf. From 17.5 mbsf sulfide migrates upward, titrating reactive Fe, resulting in pyrite formation in the entire sediment column up to ; 2 Ž . mbsf. At this depth, the upward sulfide flux has been totally consumed by reaction with solid phase Fe and dissolved Fe II diffusing downward from the suboxic zone above. From ; 2 mbsf downward magnetic intensities are significantly reduced, indicating reductive dissolution of Fe-oxide minerals and pyrite formation. As a consequence, no reliable NRM data can be obtained in the lower half of the core. q 1998 Elsevier Science B.V. All rights reserved.