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Projekt Druckansicht

Mikrobieller und diagenetischer Ursprung von Eisenmineralen in gebänderten Eisenformationen

Fachliche Zuordnung Paläontologie
Förderung Förderung von 2011 bis 2015
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 203718275
 
Erstellungsjahr 2016

Zusammenfassung der Projektergebnisse

The Precambrian chemical sediments, Banded iron formations (BIFs), are the primary repositories of information on the surface environment and biosphere at the time of deposition. Archean BIFs are likely to be formed by anoxygenic photosynthetic bacteria oxidizing Fe(II) ("photoferrotrophs") prior to atmospheric O2, but the low amounts of organic carbon associated with BIFs argued against a strong microbial influence. In this project we showed that BIF mineral assemblages, i.e. magnetite and siderite, are consistent with a photoferrotrophic origin and subsequent diagenesis (moderate heat and pressure) of cells and Fe(III) (oxyhydr)oxides. The mechanisms have been evaluated under Precambrian ocean conditions and compared to the mineral assemblages of BIFs. Trace element analysis (TE; e.g. Mo, Co, Cu, Zn, Ni) aided in evaluating a microbial origin. We used microspectroscopic and spectromicroscopic analyses to quantify trace elements incorporated in photoferrotrophic organic matter vs. minerals after diagenesis. The trace element signature of BIF minerals, partitioning coefficients into sulfide and Fe(III) (hydr)oxide minerals have been determined and used to determine the trace element concentrations of the Precambrian ocean, and to infer which microbial metabolisms were supported.

Projektbezogene Publikationen (Auswahl)

 
 

Zusatzinformationen

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