Imaging of Vanadium in Microfossils: A New Potential Biosignature

Journal Article · Wed Nov 01 00:00:00 EDT 2017 · Astrobiology

DOI:https://doi.org/10.1089/ast.2017.1709· OSTI ID:1436103

Marshall, Craig P. ^[1]; Marshall, Alison Olcott ^[1]; Aitken, Jade B. ^[2]; Lai, Barry ^[3]; Vogt, Stefan ^[3]; Breuer, Pierre ^[4]; Steemans, Philippe ^[5]; Lay, Peter A. ^[2]

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1. Univ. of Kansas, Lawrence, KS (United States)
2. The Univ. of Sydney, NSW (Australia)
3. Argonne National Lab. (ANL), Argonne, IL (United States)
4. Saudi Aramco, Dhahran (Saudi Arabia)
5. Univ. of Liege, Liege (Belgium)

Being able to distinguish unambiguously the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from non-biological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This too, is important for the search for life on Mars; either by in situ analyses via rovers, or sample return missions for future analysis here on Earth. Here, we report the application of synchrotron X-ray fluorescence imaging of vanadium, within thermally altered organic-walled microfossils of bona fide biological origin. From our data, we demonstrate that vanadium is present within microfossils of undisputable biological origin. It is well known in the organic geochemistry literature, that elements such as vanadium are enriched and contained within crude oils, asphalts, and black shales that have been formed by diagensis of biological organic material. It has been demonstrated that the origin of vanadium is due to the diagenetic alteration of precursor chlorophyll and heme porphyrin pigment compounds from living organisms. Here, we propose that taken together, microfossil-like morphology, carbonaceous composition, and the presence of vanadium could be used in tandem as a biosignature to ascertain the biogenecity of putative microfossil-like structures.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: Australian Research Council; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1436103
• Journal Information: Astrobiology, Vol. 17, Issue 11; ISSN 1531-1074
• Publisher: Mary Ann Liebert, Inc.
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Biosignature
Microfossils
Synchrotron micro-X-ray fluorescence
Tetrapyrrole
Vanadium