A Mössbauer spectroscopic study of the iron redox transition in eastern Mediterranean sediments

Zee, Claar van der; Slomp, Caroline P.; Rancourt, Denis; Lange, Gert J. de; Raaphorst, Wim van

doi:10.1016/j.gca.2004.07.003

Cited by 36 publications

(18 citation statements)

References 53 publications

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“…Such pattern is not visible in the Mössbauer spectrum of the Ah horizon. Very small crystallites of goethite, however, are superparamagnetic at RT and then show only a quadrupole doublet with a splitting of about 0.52 mm s −1 (van der Zee et al 2005). Cases in which goethite at RT exhibits a broadened magnetic pattern resulting from relaxation phenomena intermediate between the slow relaxation (sextet) and the fast relaxation (doublet) limit have also been observed (Ganguly et al 1994;Govaert et al 1976;Murad and Cashion 2004).…”

Section: Mössbauer Spectroscopymentioning

confidence: 95%

Iron oxide mineralogy and stable iron isotope composition in a Gleysol with petrogleyic properties

et al. 2011

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Purpose Properties of Fe oxides are poorly understood in soils with fluctuating water tables and variable redox conditions. The objective of this research was to (a) characterize the mineralogical composition of Fe oxides and (b) determine the relationship to the stable Fe isotope ratio in a soil with temporally and spatially sharp redox gradients. Materials and methodsThe lowland Gleysol (Petrogleyic) is in Northwest Germany and consists of oximorphic soil horizons (Ah 0-15, Bg 15-35, and CrBg 35-70 cm) developed from Holocene fluvial loam overlaying glaciofluvial sand with reductomorphic properties (2Cr horizon, +70 cm). Field measurements during the course of 28 months included the monitoring of groundwater table, soil redox potential, and analysis of the soil solutions. Solid Fe phases were studied by room temperature and cryogenic 57 Fe Mössbauer spectroscopy, and stable Fe isotope compositions by multiple collector inductively coupled plasma mass spectrometry. Results and discussion The groundwater table ranged from −83 cm below to +8 cm above soil surface (median −27 cm). Permanent reducing conditions occurred in the 2Cr horizon with dissolved Fe concentrations of 44.8 mg L −1 (median). The duration of oxidizing conditions increased in the order CrBg < Bg < Ah. Total Fe increased from 50 (Ah) over 316 (Bg) up to 412 g kg −1 (CrBg) and was lowest in the 2Cr horizon (7 g kg −1 ). Ferrihydrite (51% of total Fe) was dominant over goethite (24%) in the Ah horizon. Conversely, nanogoethite dominated both the Bg (94%) and CrBg (86%) horizons. Iron in siderite amounted to 7% in the CrBg horizon. Iron isotope compositions yielded a range of δ 57 Fe values from +0.29‰ (Ah horizon) to −0.30‰ (Bg horizon). In contrast to the overlying CrBg (δ 57 Fe=−0.19‰) and Bg horizons, the 2Cr horizon is characterized by a relatively high δ 57 Fe value of +0.22‰. Conclusions Lasting water saturation and frequent reducing conditions lead to the enrichment of goethite in subsoil. Once formed, goethite remains stable compared to ferrihydrite because it is less available for microbial mediated reductive dissolution. High δ 57 Fe values in the topsoil primary result from fast ferrihydrite precipitation during aeration immediately after reducing conditions. In contrast,

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Section: Mössbauer Spectroscopymentioning

confidence: 95%

Iron oxide mineralogy and stable iron isotope composition in a Gleysol with petrogleyic properties

et al. 2011

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“…Therefore, we suggest that sinking MnO x particles act as nuclei for the precipitation of amorphous Fe-oxyhydroxides (FeOOH) as pseudomorphs either by direct oxidation of upward diffusing Fe 2+ by either oxygen or MnO x (e.g., Hartmann, 1985) causing irregular FeOOH coatings on MnO x particles. If Fe 2+ is directly oxidized by MnO x , rather than by oxygen or nitrate (e.g., van Cappellen and Wang, 1996;van der Zee et al, 2005), the textural similarities may be explained by the stepwise replacement of Mn(IV) by Fe(III). A similar process was proposed, e.g., by Danielsson et al (1980) and Hartmann (1985) for anoxic brines of the Red Sea.…”

Section: Formation and Fate Of The Mn-fe-p-shuttlementioning

confidence: 99%

A new particulate Mn–Fe–P-shuttle at the redoxcline of anoxic basins

Dellwig

Leipe

März

et al. 2010

Geochimica et Cosmochimica Acta

242

179

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“…The Fe (II) doublet may correspond to Fe in phyllosilicates (e.g. isomorphic substitution in illite) and the Fe(III) doublet may correspond to Fe in oxyhydroxides or to Fe in clay minerals (Mitra, 1992;Drodt et al, 1997;Van der Zee et al, 2004).…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

“…The presence of Fe(III) and Fe(II) in high spin state are easily distinguished by the large difference in their isomer shifts (Rancourt, 1998;Van der Zee et al, 2004); nevertheless, Fe(II) in pyrite is in a low spin state with similar isomer shift to those from high spin Fe (III). Therefore, 5.…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

Geochemistry of iron and manganese in soils and sediments of a mangrove system, Island of Pai Matos (Cananeia — SP, Brazil)

Ferreira²,

et al. 2009

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A Mössbauer spectroscopic study of the iron redox transition in eastern Mediterranean sediments

Cited by 36 publications

References 53 publications

Iron oxide mineralogy and stable iron isotope composition in a Gleysol with petrogleyic properties

Iron oxide mineralogy and stable iron isotope composition in a Gleysol with petrogleyic properties

A new particulate Mn–Fe–P-shuttle at the redoxcline of anoxic basins

Geochemistry of iron and manganese in soils and sediments of a mangrove system, Island of Pai Matos (Cananeia — SP, Brazil)

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