Multiple mechanisms of remagnetization involving sedimentary greigite (Fe3S4)

Roberts, Andrew P.; Weaver, R. M.

doi:10.1016/j.epsl.2004.11.024

Cited by 191 publications

(219 citation statements)

References 45 publications

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“…Greigite appears to form via the maturation of mackinawite, which is metastable with respect to greigite (34,43,44,50,52,56). Greigite is more resistant to dissolution than mackinawite under acidic conditions (50,61), and a decrease in 0.5 M HCl-extractable Fe(II) occurred in GBSRB4.2 cultures amended with 1 Fe(II):0 Fe(III) (Fig.…”

Section: Formation Of Magnetic Fes Phasesmentioning

confidence: 99%

“…The exact mechanisms of, and optimal conditions for greigite formation from "amorphous" FeS or mackinawite remain unclear (50). Greigite is a Fe(II)-and Fe(III)-containing mineral phase, so it has been suggested that some oxidant [e.g., O 2 or S(0)], is necessary for mackinawite transformation to greigite (34,44,50,52,56). However, the transformation of mackinawite to greigite has been reported in the absence of oxidant and may be enhanced by low pH and/or excess sulfide (24,50,67).…”

Section: Formation Of Magnetic Fes Phasesmentioning

confidence: 99%

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Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

Bertel

Peck

Quick

et al. 2012

Appl Environ Microbiol

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The mineralogical transformations of Fe phases induced by an acid-tolerant, Fe(III)-and sulfate-reducing bacterium, Desulfosporosinus sp. strain GBSRB4.2 were evaluated under geochemical conditions associated with acid mine drainage-impacted systems (i.e., low pH and high Fe concentrations). X-ray powder diffractometry coupled with magnetic analysis by first-order reversal curve diagrams were used to evaluate mineral phases produced by GBSRB4.2 in media containing different ratios of

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Section: Formation Of Magnetic Fes Phasesmentioning

confidence: 99%

Section: Formation Of Magnetic Fes Phasesmentioning

confidence: 99%

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

Bertel

Peck

Quick

et al. 2012

Appl Environ Microbiol

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“…Roberts & Weaver 2005;Rowan et al 2009). Roberts & Weaver (2005) describe five mechanisms of CRM acquisition in greigite.…”

Section: Other Remagnetization Mechanismsmentioning

confidence: 99%

Remagnetization and chemical alteration of sedimentary rocks

Elmore

Muxworthy

Aldana

2012

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Chemical remagnetization is a very common phenomenon in sedimentary rocks and developing a greater understanding of the mechanisms has several benefits. Acquisition of a secondary magnetization is usually tangible evidence of a diagenetic event that can be dated by isolation of the chemical remanent magnetization and comparison of the pole position to the apparent polar wander path. This can be important because diagenetic investigations are frequently limited by the difficulty in constraining the time frames in which most past events have occurred. Remagnetization can commonly obscure a primary magnetization; developing a better understanding of remagnetization could improve our ability to uncover primary magnetizations. Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (orogenic, basinal and hydrocarbons), burial diagenetic processes (clay diagenesis and maturation of organic matter) or other processes. This paper summarizes our current knowledge of these chemical remagnetization mechanisms, with a focus on examples where there is a connection with chemical alteration.

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“…These magnetic sulphide minerals are usually ephemeral, however, and thus cannot provide reliable historical records. Moreover, they sometimes develop as a result of late diagenetic processes that occur some metres below the sediment/water interface, and therefore do not reflect the environment in which the sediments were deposited (Lui et al, 2004;Roberts and Weaver, 2005).…”

Section: Magnetic Properties Of Sedimentsmentioning

confidence: 99%

Historical records of coastal eutrophication-induced hypoxia

Jorissen²,

et al. 2009

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Abstract. Under certain conditions, sediment cores from coastal settings subject to hypoxia can yield records of environmental changes over time scales ranging from decades to millennia, sometimes with a resolution of as little as a few years. A variety of biological and geochemical indicators (proxies) derived from such cores have been used to reconstruct the development of eutrophication and hypoxic conditions over time. Those based on (1) the preserved remains of benthic organisms (mainly foraminiferans and ostracods), (2) sedimentary features (e.g. laminations) and (3) sediment chemistry and mineralogy (e.g. presence of sulphides and redox-sensitive trace elements) reflect conditions at or close to the seafloor. Those based on (4) the preserved remains of planktonic organisms (mainly diatoms and dinoflagellates), (5) pigments and lipid biomarkers derived from prokaryotes and eukaryotes and (6) organic C, N and their stable isotope ratios reflect conditions in the water column. However, the interpretation of these indicators is not straightforward. A central difficulty concerns the fact that hypoxia is strongly correlated with, and often induced by, organic enrichment caused by eutrophication, making it difficult to separate the effects of these phenomena in sediment records. The problem is compounded by the enhanced preservation in anoxic and hypoxic sediments of organic microfossils and biomarkers indicating eutrophication. The use of hypoxiaCorrespondence to: A. J. Gooday (ang@noc.soton.ac.uk) specific proxies, such as the trace metals molybdenum and rhenium and the bacterial biomarker isorenieratene, together with multi-proxy approaches, may provide a way forward. All proxies of bottom-water hypoxia are basically qualitative; their quantification presents a major challenge to which there is currently no satisfactory solution. Finally, it is important to separate the effects of natural ecosystem variability from anthropogenic effects. Despite these problems, in the absence of historical data for dissolved oxygen concentrations, the analysis of sediment cores can provide plausible reconstructions of the temporal development of humaninduced hypoxia, and associated eutrophication, in vulnerable coastal environments.

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Multiple mechanisms of remagnetization involving sedimentary greigite (Fe3S4)

Cited by 191 publications

References 45 publications

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

Remagnetization and chemical alteration of sedimentary rocks

Historical records of coastal eutrophication-induced hypoxia

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