Element contents, sulfur and oxygen isotopes, and molecular biomarkers of phosphatic crust samples from the Chimbote Platform of the shelf off Peru

DOI

Authigenic phosphatic laminites enclosed in phosphorite crusts from the shelf off Peru (10°01' S and 10°24' S) consist of carbonate fluorapatite layers, which contain abundant sulfide minerals including pyrite (FeS2) and sphalerite (ZnS). Low d34Spyrite values (average -28.8 per mill) agree with bacterial sulfate reduction and subsequent pyrite formation. Stable sulfur isotopic compositions of sulfate bound in carbonate fluorapatite are lower than that of sulfate from ambient sea water, suggesting bacterial reoxidation of sulfide by sulfide-oxidizing bacteria. The release of phosphorus and subsequent formation of the autochthonous phosphatic laminites are apparently caused by the activity of sulfate-reducing bacteria and associated sulfide-oxidizing bacteria. Following an extraction-phosphorite dissolution-extraction procedure, molecular fossils of sulfate-reducing bacteria (mono-O-alkyl glycerol ethers, di-O-alkyl glycerol ethers, as well as the short-chain branched fatty acids i/ai-C15:0, i/ai-C17:0 and 10MeC16:0) are found to be among the most abundant compounds. The fact that these molecular fossils of sulfate-reducing bacteria are distinctly more abundant after dissolution of the phosphatic laminite reveals that the lipids are tightly bound to the mineral lattice of carbonate fluorapatite. Moreover, compared with the autochthonous laminite, molecular fossils of sulfate-reducing bacteria are: (1) significantly less abundant and (2) not as tightly bound to the mineral lattice in the other, allochthonous facies of the Peruvian crusts consisting of phosphatic coated grains. These observations confirm the importance of sulfate-reducing bacteria in the formation of the phosphatic laminite. Model calculations highlight that organic matter degradation by sulfate-reducing bacteria has the potential to liberate sufficient phosphorus for phosphogenesis.

Supplement to: Arning, Esther T; Birgel, Daniel; Brunner, B; Peckmann, Jörn (2009): Bacterial formation of phosphatic laminites off Peru. Geobiology, 7, 295-307

Identifier
DOI https://doi.org/10.1594/PANGAEA.755217
Related Identifier https://doi.org/10.1111/j.1472-4669.2009.00197.x
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.755217
Provenance
Creator Arning, Esther T; Birgel, Daniel; Brunner, B ORCID logo; Peckmann, Jörn ORCID logo
Publisher PANGAEA
Publication Year 2009
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 3 datasets
Discipline Earth System Research
Spatial Coverage (-79.072W, -10.409S, -78.805E, -10.031N)
Temporal Coverage Begin 2000-06-16T00:00:00Z
Temporal Coverage End 2000-06-21T21:13:00Z