标题：Elemental and organic carbon proxies for redox conditions of the Oligocene formations in the Ropa Tectonic Window (Outer Carpathians, Poland): palaeoenvironmental implications
摘要：The Oligocene Grybów Succession is recognized as a counterpart of the anoxic Menilite Formation. Itscomprehensive geochemical investigations are made in the key sections of the Ropa Tectonic Window (theGrybów Unit, Polish Outer Carpathians). The maceral assemblages, dominated by land-plant liptinite, vitriniteand intertinite, correspond to kerogen types II and III. A Tmax vs. HI diagram shows terrestrial kerogen type II withvarious additions of type III and algal kerogen type I. A variation in 13Corg. (from –25.21 to –27.38‰) may haveresulted from variations in the composition of organic matter (the content of terrestrial vs. marine organic matter),controlled by depositional setting (turbidite vs. hemipelagic). The highest TOC contents are associated with anenhanced influx of land-derived organic matter. The redox-sensitive trace elements positively correlate with TOCand TS contents. Redox conditions varied between oxic and anoxic, as was concluded from TOC-TS, V/(V+Ni)and U/Th. The turbidity currents might have ventilated the bottom waters, especially more efficiently in theproximal zone of turbidite sedimentation. Moreover, oxygenated bottom waters may have also affected the concentration of trace metals, owing to migration of the redox interface downward within the sediments.
