Akademik Veri Yönetim Sistemi
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, cilt.116, ss.71-101, 1995 (SCI-Expanded, Scopus)
Sapropel S1 occurs as 25-35 cm-thick black, weakly laminated muds in Aegean Sea cores. S1 was deposited between 9600 and 6400 yr B.P., during a period of isotopically depleted and relatively cool surface waters. Micro-faunal and -floral data indicate a major reduction in surface waters salinity during the deposition of S1, and oxygen isotopic data show a northerly fresh water source. Relatively light delta(13)C(org) and high pollen-spore concentrations in S1 suggest increased influx of terrestrial organic carbon, probably supplied by major rivers draining into the northern Aegean Sea. Benthic foraminifera indicate high-nutrient, low oxygen bottom waters for S1, and together with silt-sized hematite and manganese coatings suggest that during the deposition of S1 surface sediments were oxic. Visual and XRD evidence of pyrite in S1, together with enrichments in S, Cu, Zn, As, Ni, Cr and Fe suggest that subsurface conditions were sufficiently reducing for SO42- reduction to occur, probably by diffusion from surface oxic into subsurface anoxic sediments.