Pore water composition, pyrite distribution and pyrite crystal morphology of sediments from salt marshes in the Eastern Scheldt, southwestern Netherlands, were examined from July 1984 to October 1986.Hydrology and marsh vegetation were the chief determinants of pyrite accumulation. In the bare sediments of pans in the low marsh, highly reducing conditions prevailed just below the surface. At ...

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Request PDF | Iron monosulfide accumulation and pyrite formation in eutrophic estuarine sediments | This study investigates iron (Fe) and sulfur (S) …

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Iron monosulfide accumulation and pyrite formation in eutrophic estuarine sediments. Peter Kraal. Edward Burton. Richard T. Bush. Peter Kraal. Edward Burton. Richard T. Bush. Related Papers. Decoupling between water column oxygenation and benthic phosphate dynamics in a …

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The rate of pyrite formation via the H 2 S pathway (99% of pyrite formation) was about two orders of magnitude greater than via the polysulfide pathway (1% of pyrite formation). These calculations were compared to rate estimates based on the AVS and FeS 2 profiles in the relatively homogeneous silt layer (0–40 cm depth) at site 6.

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An earlier model for the formation of pyrite spheres in gas bubbles ... the average accumulation rate of these shales was on the order of 1023 mm/yr. This figure is based on thickness of strati-graphic sections, conodont data (Ettensohn et al. 1989), and age calibrations

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This study investigates iron (Fe) and sulfur (S) cycling in sediments from the eutrophic Peel-Harvey Estuary in Western Australia, which is subject to localized accumulation of strongly reducing, organic- and sulfide-rich sediments. Sedimentary iron was mostly present in highly reactive form (on average 73% of total Fe) and showed extensive sulfidization even in surface sediments, despite ...

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1616–1960, average pyrite accumulation rate was 322 lmol m-2 day-1. In the subsequent years, its average accumulation rate decreased to 210 lmol m-2 day-1. Fluctuations of oxygenation of bottom water in the study area were manifested by highly variable degree of pyritization (36 ± 11%) and particulate organic carbon to pyrite sulfur ratio (2 ...

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Pyrite seldom forms in fresh-water environments. The formation of pyrite crystals depends mainly on the iron content of the sediment. The process of pyrite formation in sediments results from the action of bacteria, which reduce sulphate ions (dissolved in the pore water) to sulphide. If there is iron present, iron sulphide crystals begin to grow.

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Pyrite is the most abundant iron−sulfur mineral in sediments. Over geological times, its burial controlled oxygen levels in the atmosphere and sulfate concentrations in seawater. However, the mechanism of pyrite formation in sediments is still being debated. We show that lithotrophic microorganisms can mediate the transformation of FeS and H2S to FeS2 at ambient temperature if …

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Request PDF | Iron monosulfide accumulation and pyrite formation in eutrophic estuarine sediments | This study investigates iron (Fe) and sulfur (S) cycling in sediments from the eutrophic Peel ...

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The behavior of C1 could be trochemical behavior of CPE-pyrite mineral with high purity associated with an activation of the mineral surface due to the (98.8% pyrite) was determined and later the CPE-arsenopyrite accumulation of oxidized products on the electrode. mineral (content of 86.95% arsenopyrite, 11.84% pyrite) oxida- Figure 4 shows SEM ...

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specifically sulfate, in solution to promote pyrite accumulation. In the incubated cores, increased ferrous iron (Fe2+) input to the sediment had a much more positive effect on pyrite precipitation than the input of ferric iron (Fe3+) due to the different pyrite formation pathways between these two types of iron.

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Pyrite, an iron sulfide formed in the presence of bacteria, operates as a strong control on oxygen accumulation in Earth's oceans and atmosphere, but it turns out that control is highly localized.

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In-situ pyrite sulfur isotope measurements may distinguish between the hypotheses of varying ε mic and different degrees of sulfide accumulation as explanations for the variations in …

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Methane-driven sulfate reduction at depth causes a progressive formation of pyrite with a δ34S of up to +15.0‰. The S-isotopic composition of FeS2 evolves due to contributions of different ...

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12%An occurrence of pyrite oxidation in the anoxic regions of pyritic sediments indicates that pyrite formation and accumulation in the reducing environments are not dominant processes. Rather, pyrite is being oxidized as they are formed. Consequently, the process of bacterial sulfate reduction for pyrite formation in the anoxic zones of pyritic ...

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This may indicate that (i) pyrite formation via reaction between dissolved Fe (including Fe clusters) and H 2 S was limited by low availability of dissolved Fe or (ii) reaction kinetics of pyrite formation via the H 2 S pathway may be relatively slow in natural reducing sediments. We propose that rapid burial of the FeS under anoxic conditions ...

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