Reactive Fe(II) layers in deep-sea sediments

Iris König*, Matthias Haeckel, Matthias Drodt, Erwin Suess, Alfred X. Trautwein

*Corresponding author for this work
22 Citations (Scopus)


The percentage of the structural Fe(II) in clay minerals that is readily oxidized to Fe(III) upon contact with atmospheric oxygen was determined across the downcore tan-green color changed in Peru Basin sediments. This latent fraction of reactive Fe(II) was only found in the green strata, where it proved to be large enough to constitute a deep reaction layer with respect to the pore water O2 and NO3-. Large variations were detected in the proportion of the reactive Fe(II) concentration to the organic matter content along core profiles. Hence, the commonly observed tan-green color change in marine sediments marks the top of a reactive Fe(II) layer, which may represent the major barrier to the movement of oxidation fronts in pelagic subsurface sediments. This is also demonstrated by numerical model simulations. The findings imply that geochemical barriers to pore water oxidation fronts form diagenetically in the sea floor wherever the stage of iron reduction is reached, provided that the sediments contain a significant amount of structural iron in clay minerals.

Original languageEnglish
JournalGeochimica et Cosmochimica Acta
Issue number10
Pages (from-to)1517-1526
Number of pages10
Publication statusPublished - 01.05.1999


Dive into the research topics of 'Reactive Fe(II) layers in deep-sea sediments'. Together they form a unique fingerprint.

Cite this