DOI: 10.1073/pnas.051500898. Truncated hexa-octahedral magnetite crystals in ALH84001: Presumptive biosignatures

Truncated hexa-octahedral magnetite crystals in ALH84001: Presumptive biosignatures

10.1073/pnas.051500898

Crossref journal-article

Proceedings of the National Academy of Sciences

Proceedings of the National Academy of Sciences (341)

Abstract

McKayet al.[(1996)Science273, 924–930] suggested that carbonate globules in the meteorite ALH84001 contained the fossil remains of Martian microbes. We have characterized a subpopulation of magnetite (Fe3O4) crystals present in abundance within the Fe-rich rims of these carbonate globules. We find these Martian magnetites to be both chemically and physically identical to terrestrial, biogenically precipitated, intracellular magnetites produced by magnetotactic bacteria strain MV-1. Specifically, both magnetite populations are single-domain and chemically pure, and exhibit a unique crystal habit we describe as truncated hexa-octahedral. There are no known reports of inorganic processes to explain the observation of truncated hexa-octahedral magnetites in a terrestrial sample. In bacteria strain MV-1 their presence is therefore likely a product of Natural Selection. Unless there is an unknown and unexplained inorganic process on Mars that is conspicuously absent on the Earth and forms truncated hexa-octahedral magnetites, we suggest that these magnetite crystals in the Martian meteorite ALH84001 were likely produced by a biogenic process. As such, these crystals are interpreted as Martian magnetofossils and constitute evidence of the oldest life yet found.

Bibliography

Thomas-Keprta, K. L., Clemett, S. J., Bazylinski, D. A., Kirschvink, J. L., McKay, D. S., Wentworth, S. J., Vali, H., Gibson, E. K., McKay, M. F., & Romanek, C. S. (2001). Truncated hexa-octahedral magnetite crystals in ALH84001: Presumptive biosignatures. Proceedings of the National Academy of Sciences, 98(5), 2164â2169.

Authors 10

Kathie L. Thomas-Keprta (first)
Simon J. Clemett (additional)
Dennis A. Bazylinski (additional)
Joseph L. Kirschvink (additional)
David S. McKay (additional)
Susan J. Wentworth (additional)
Hojatollah Vali (additional)
Everett K. Gibson (additional)
Mary Fae McKay (additional)
Christopher S. Romanek (additional)

References 27 Referenced 143

10.1126/science.286.5437.90
10.1016/S0016-7037(00)00481-6
10.1029/JB080i029p04049
10.1016/S0006-3495(97)78132-3
10.1007/978-1-4615-3810-3_7
10.2138/am-1998-11-1228
10.1146/annurev.ea.17.050189.001125
10.1126/science.170679
10.1126/science.203.4387.1355
10.1007/978-1-4615-3810-3_3
10.1515/9781501509247-008
10.1016/0012-821X(90)90084-B
M H Carr Water on Mars (Oxford Univ. Press, New York, 1996). (10.1093/oso/9780195099386.001.0001) / Water on Mars by Carr M H (1996)
10.1126/science.288.5475.2330
10.1039/a709130c
10.1126/science.284.5415.794
10.1128/jb.170.2.834-841.1988
10.1016/0012-821X(82)90140-6
10.1146/annurev.mi.48.100194.003523
V Braun, K Hantke, W Koster Metal Ions in Biological Systems 35, 67–145 (1998). / Metal Ions in Biological Systems by Braun V (1998)
10.1029/1999GL008455
C Meyer Mars Meteorite Compendium., ). (1998). / Mars Meteorite Compendium. by Meyer C (1998)
10.1111/j.1945-5100.1991.tb01029.x
T Owen Mars, eds H H Kieffer, B M Jakosky, C W Snyder, M S Matthews (Univ. of Arizona Press, Tucson, AZ), pp. 818–834 (1992). / Mars by Owen T (1992)
C A Barth, A I F Stewart, S W Bougher, D M Hunten, S J Bauer, A F Nagy Mars, eds H H Kieffer, B M Jakosky, C W Snyder, M S Matthews (Univ. of Arizona Press, Tucson), pp. 1054–1089 (1992). / Mars by Barth C A (1992)
10.1029/JS082i028p04641
10.1073/pnas.040539497

Dates

Type	When
Created	23 years ago (July 26, 2002, 10:45 a.m.)
Deposited	1 year, 7 months ago (Jan. 4, 2024, 12:14 a.m.)
Indexed	3 weeks, 4 days ago (July 30, 2025, 11:12 a.m.)
Issued	24 years, 5 months ago (Feb. 27, 2001)
Published	24 years, 5 months ago (Feb. 27, 2001)
Published Online	24 years, 5 months ago (Feb. 27, 2001)
Published Print	24 years, 5 months ago (Feb. 27, 2001)

Funders 0

None

BibTeX

@article{Thomas_Keprta_2001, title={Truncated hexa-octahedral magnetite crystals in ALH84001: Presumptive biosignatures}, volume={98}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.051500898}, DOI={10.1073/pnas.051500898}, number={5}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Thomas-Keprta, Kathie L. and Clemett, Simon J. and Bazylinski, Dennis A. and Kirschvink, Joseph L. and McKay, David S. and Wentworth, Susan J. and Vali, Hojatollah and Gibson, Everett K. and McKay, Mary Fae and Romanek, Christopher S.}, year={2001}, month=feb, pages={2164–2169} }

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