作者: Timothy W. Lyons , Robert A. Berner
DOI: 10.1016/0009-2541(92)90028-4
关键词: Sediment–water interface 、 Geology 、 Sedimentary rock 、 Water column 、 Sediment 、 Pyrite 、 Sulfur 、 Total organic carbon 、 Mineralogy 、 Turbidite
摘要: Abstract Box cores recovered during Leg 4 of the 1988 R/V “Knorr” Black Sea Oceanographic Expedition from deep-water regions basin were dominated by coccolith-rich, microlaminated (Unit 1) sediment and muddy, gray turbidite layers. Both organic carbon (OC) pyrite sulfur values for Unit 1 display narrow ranges, with mean concentrations 5.3 ± 1.1 (1σ) wt% 1.3 0.3 wt%, respectively. is not enriched in pyrite-S relative to sediments deposited under oxygenated bottom waters (normal marine sediments) comparable OC concentrations. Carbon-sulfur relationships (evaluated on a calcium carbonate-free basis avoid spurious correlations resulting dilution effects) demonstrate that are essentially decoupled. These observations, combined persistence elevated pore-water sulfide depth strong correlation between detrital Fe component argue strongly limitation formation availability reactive Fe. Unit-1 further indicated degree-of-pyritization (DOP) studies (a measure extent which original potentially has been transformed pyrite). show sulfidation ranging 57% 78%, DOP independent concentration. profiles suggest majority formed sulfidic water column and/or very close sediment-water interface. Pyrite-S 1, when compared particulate reduced fluxes measured time-series traps, compatible predominantly water-column formation. Because limitations supply associated comparatively high OC, characterized C/S ratios greater than those typical Holocene oxically sediments. The muds deep S (relative normal samples low (low ratios). This reflects anoxic-sulfidic bottom-water conditions probable upper-slope source region, as well transport final deposition. Intermediate turbidites, part product their rapid rate deposition, reveal ultimately factor should form burial. However, at forms suggests fundamental differences overall reactivities phases turbiditic signature anoxia regard sedimentary clearly levels muds. agrees similar conclusions based ancient rocks.