Pyritization processes and greigite formation in the advancing sulfidization front in the upper Pleistocene sediments of the Black Sea

Neretin, Lev N.; Böttcher, Michael E.; Jørgensen, Bo Barker; Volkov, I. I.; Lüschen, Holger; Hilgenfeldt, Katharina

doi:10.1016/s0016-7037(03)00450-2

Cited by 163 publications

(97 citation statements)

References 66 publications

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“…The FeS is eventually transformed to pyrite and adds to the pyrite formed during the limnic, sulfate-limited stage >9800 yr ago . Originally Fe 2+ had probably been present in the entire limnic sediment, but as more sulfate became available with increasing salinity, it was trapped by sulfide production, and so the sulfidization front moved downwards after the Holocene/Pleistocene transition Neretin et al, 2004). This penetration of the sulfidization front was similar at all three sites, with sulfide depletion ca.…”

Section: Sulfate Dynamics and H 2 Smentioning

confidence: 89%

Regulation of anaerobic methane oxidation in sediments of the Black Sea

et al. 2009

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Abstract. Anaerobic oxidation of methane (AOM) and sulfate reduction (SRR) were investigated in sediments of the western Black Sea, where upward methane transport is controlled by diffusion. To understand the regulation and dynamics of methane production and oxidation in the Black Sea, rates of methanogenesis, AOM, and SRR were determined using radiotracers in combination with pore water chemistry and stable isotopes. In the Danube Canyon and the Dnjepr palaeo-delta AOM did not consume methane effectively and upwards diffusing methane created an extended sulfate-methane transition zone (SMTZ) that spread over more than 2.5 m and was located in brackish and limnic sediment. Measurable AOM rates occurred mainly in the lower part of the SMTZ, sometimes even at depths where sulfate seemed to be unavailable. The inefficiency of methane oxidation appears to be linked to the paleoceanographic history of the sediment, since in all cores methane was completely oxidized at the transition from the formerly oxic brackish clays to marine anoxic sediments. The upward tailing of methane was less pronounced in a core from the deep sea in the area of the Dnjepr Canyon, the only station with a SMTZ close to the marine deposits. Sub-surface sulfate reduction rates were mostly extremely low, and in the SMTZ were even lower than AOM rates. Rates of bicarbonate-based methanogenesis were below detection limit in two of the cores, but δ 13 C values of methane indicate a biogenic origin. The most δ 13 CCorrespondence to: N. J. Knab (knab@usc.edu) depleted isotopic signal of methane was found in the SMTZ of the core from the deep sea, most likely as a result of carbon recycling between AOM and methanogenesis.

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Section: Sulfate Dynamics and H 2 Smentioning

confidence: 89%

Regulation of anaerobic methane oxidation in sediments of the Black Sea

et al. 2009

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“…AVS/CRS ratio is in good correlation with SOC (R 2 = 0.71) and the lowest AVS/CRS ratio coincides with the lowest SOC concentration, indicating that formation of CRS, depends rather on the availability of organic matter for degradation by sulfate reduction than the availability of reactive Fe. Concentration of elemental S below 5 cm depth is similar or even larger than AVS concentration, indicating that the pyrite formation is driven by sulfide production and is formed rather by direct reaction of Fe hydroxides with H 2 S than by conversion of AVS to CRS by addition of elemental S (Lein et al, 2002;Neretin et al, 2004).…”

Section: Characterisation Of the Rupel Sedimentsmentioning

confidence: 95%

Determination of High Resolution Pore Water Profiles of Trace Metals in Sediments of the Rupel River (Belgium) using Det (Diffusive Equilibrium in Thin Films) and DGT (Diffusive Gradients in Thin Films) Techniques

Leermakers

Gao

Gabelle

et al. 2005

Water Air Soil Pollut

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Abstract. The techniques of diffusional equilibrium in thin films (DET) and diffusional gradients in thin films (DGT) were used to obtain high resolution pore water profiles of total dissolved and labile trace (mobilizable) metals in the sediments of the Rupel River, Belgium. DGT measures labile metal species in situ by immobilizing them on a resin gel after diffusion through a diffusive gel whereas for DET an equilibrium is established between the DET gel and the pore water. Concentrations of Pb and Zn obtained by DGT were in good agreement with the results obtained by centrifugation, and thus were well buffered by rapid equilibrium with the solid phase, whereas Fe, Mn and Cd were very tightly bound to the sediment phase and large differences were observed between the labile and the total metal concentrations. Cu, Zn, Co and Ni show intermediated behavior.Good correlations were found between the profiles of As and Fe and Mn and Co for DET as well as DGT showing a close link between the geochemical behavior of these elements. Cu, Zn, Pb and Cd are also influenced by the reductive mobilization of Fe and Mn oxides but are also closely linked to the bacterial degradation of organic matter in the surface sediments as to the precipitation of metal sulfides in the deeper layers.

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“…Sulfide concentrations were below detection limit at 480 cmbsf (core 755) and at 360 cmbsf (core 214). According to Jørgensen et al (2004), Neretin et al (2004), and Knab et al (2009), the depletion of H 2 S within Unit III is attributed to the formation of iron sulfides upon reaction with upward-diffusing Fe 2+ that is released from the limnic deposits.…”

Section: Depth Of the Sulfate-methane Transitionmentioning

confidence: 99%

Diagenetic barium cycling in Black Sea sediments – A case study for anoxic marine environments

Henkel¹,

Mogollón²,

Nöthen³

et al. 2012

Geochimica et Cosmochimica Acta

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High-resolution sedimentary records of major and minor elements (Al, Ba, Ca, Sr, Ti), total organic carbon (TOC), and profiles of pore water constituents (SO 2À 4 , CH 4 , Ca 2+ , Ba 2+ , Mg 2+ , alkalinity) were obtained for two gravity cores (core 755, 501 m water depth and core 214, 1686 m water depth) from the northwestern Black Sea. The records were examined in order to gain insight into the cycling of Ba in anoxic marine sediments characterized by a shallow sulfate-methane transition (SMT) as well as the applicability of barite as a primary productivity proxy in such a setting. The Ba records are strongly overprinted by diagenetic barite (BaSO 4 ) precipitation and remobilization; authigenic Ba enrichments were found at both sites at and slightly above the current SMT. Transport reaction modeling was applied to simulate the migration of the SMT during the changing geochemical conditions after the Holocene seawater intrusion into the Black Sea. Based on this, sediment intervals affected by diagenetic Ba redistribution were identified. Results reveal that the intense overprint of Ba and Ba xs (Ba excess above detrital average) strongly limits its correlation to primary productivity. These findings have implications for other modern and ancient anoxic basins, such as sections covering the Oceanic Anoxic Events which Ba is frequently used as a primary productivity indicator. Our study also demonstrates the limitations concerning the use of Ba xs as a tracer for downward migrations of the SMT: due to high sedimentation rates at the investigated sites, diagenetic barite fronts are buried below the SMT within a relatively short period. Thus, 'relict' barite fronts would only be preserved for a few thousands of years, if at all.

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Pyritization processes and greigite formation in the advancing sulfidization front in the upper Pleistocene sediments of the Black Sea

Cited by 163 publications

References 66 publications

Regulation of anaerobic methane oxidation in sediments of the Black Sea

Regulation of anaerobic methane oxidation in sediments of the Black Sea

Determination of High Resolution Pore Water Profiles of Trace Metals in Sediments of the Rupel River (Belgium) using Det (Diffusive Equilibrium in Thin Films) and DGT (Diffusive Gradients in Thin Films) Techniques

Diagenetic barium cycling in Black Sea sediments – A case study for anoxic marine environments

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