Occurrence and fate of fatty acyl biomarkers in an ancient whale bone (Oligocene, El Cien Formation, Mexico)
Highlights • Fatty acids preserved in an Oligocene whale bone were analysed. • The fatty acid content of the fossil was in the permil range vs. a recent whale vertebra. • Ca. 80% of the n-C16 and n-C18 alkyl moieties were extractable, ca. 20% being bound to kerogen. • Endogenous fatty acids were lar...
| Published in: | Organic Geochemistry |
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| Main Authors: | , , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Elsevier
2014
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| Subjects: | |
| Online Access: | https://oceanrep.geomar.de/id/eprint/24345/ https://oceanrep.geomar.de/id/eprint/24345/1/Thiel%20et.al.pdf https://doi.org/10.1016/j.orggeochem.2013.12.006 |
| Summary: | Highlights • Fatty acids preserved in an Oligocene whale bone were analysed. • The fatty acid content of the fossil was in the permil range vs. a recent whale vertebra. • Ca. 80% of the n-C16 and n-C18 alkyl moieties were extractable, ca. 20% being bound to kerogen. • Endogenous fatty acids were largely of microbial origin (sulfate reducers, actinobacteria). Abstract The taphonomic and diagenetic processes by which organic substances are preserved in animal remains are not completely known and the originality of putative metazoan biomolecules in fossil samples is a matter of scientific discussion. Here we report on biomarker information preserved in a fossil whale bone from an Oligocene phosphatic limestone (El Cien Fm., Mexico), with a focus on fatty acyl compounds. Extracts were quantitatively analysed using gas chromatography–mass spectrometry (GC–MS) and, to identify macromolecular-linked remains, demineralised extraction residues were subjected to catalytic hydropyrolysis (HyPy). To better recognise potential authentic (i.e. animal-derived) lipids, the data from the ancient bone were compared with those obtained from (i) the adjacent host sediment of the fossil and (ii) a recent whale (Phocoena phocoena) vertebra. In addition, the spatial distribution of organic and inorganic species was observed at the μm level by imaging MS (time-of-flight-secondary ion mass spectrometry, ToF-SIMS). Our results revealed a rather even distribution of hydrocarbon-, O- and N-containing ions in the trabecular network of the ancient bone. A different, more patchy arrangement of organic compounds was evident in the former marrow cavities that were partly cemented by clotted micrites of putative microbial origin. The concentration of fatty acids (FAs) in the ancient bone was in the permil range of the amount extracted from the recent whale vertebra. Endogenous compounds, including monoenoic n-C16 and n-C18 as well as branched FAs, were identified in the fossil bone by comparison with the host sediment. Ca. 80% of the prevalent ... |
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