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| Titel |
Biomineral formation as a biosignature for microbial activities Precambrian cherts |
| VerfasserIn |
Blanca Rincón Tomás, Dominik Mühlen, Michael Hoppert, Joachim Reitner  |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107462
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| Publikation (Nr.) |
 EGU/EGU2015-7166.pdf |
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| Zusammenfassung |
| In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite,
kutnohorite) derive mainly from the reduction of manganese(IV) compounds by microbial
anaerobic respiration. Small particles of rhodochrosite in stromatolite-like features in the
Dresser chert Fm (Pilbara supergroup, W-Australia), associated with small flakes
of kerogen, account for biogenic formation of the mineral in this early Archaean
setting. Contrastingly, the formation of huge manganese-rich (carbonate) deposits
requires effective manganese redox cycling, also conducted by various microbial
processes, mainly requiring conditions of the early and late Proterozoic (Kirschvink et
al., 2000; Nealson and Saffrani 1994). However, putative anaerobic pathways like
microbial nitrate-dependent manganese oxidation (Hulth et al., 1999), anoxygenic
photosynthesis (Johnson et al., 2013) and oxidation in UV light may facilitate manganese
cycling even in a reducing atmosphere. Thus manganese redox cycling might have
been possible even before the onset of oxygenic photosynthesis. Hence, there are
several ways how manganese carbonates could have been formed biogenically and
deposited in Precambrian sediments. Thus, the minerals may be suitable biosignatures
for microbial redox processes in many respects. The hyperthermophilic archaeon
Pyrobaculum islandicum produces rhodochrosite during growth on hydrogen and
organic compounds and may be a putative model organism for the reduction of
Mn(IV).
References
Hulth S, Aller RC, Gilbert F. (1999) Geochim Cosmochim Acta, 63, 49-66.
Johnson JE, Webb SM, Thomas K, Ono S, Kirschvink JL, Fischer WW. (2013) Proc Natl
Acad Sci USA, 110, 11238-11243.
Kirschvink JL, Gaidos EJ, Bertani LE, Beukes NJ, Gutzmer J, Maepa LN, Steinberger
LE. (2000) Proc Natl Acad Sci USA, 97, 1400-1405.
Nealson KH, Saffarini D. (1994). Annu Rev Microbiol, 48, 311-343. |
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