Opin vísindi

Presumed magnetic biosignatures observed in magnetite derived from abiotic reductive alteration of nanogoethite

Presumed magnetic biosignatures observed in magnetite derived from abiotic reductive alteration of nanogoethite


Titill: Presumed magnetic biosignatures observed in magnetite derived from abiotic reductive alteration of nanogoethite
Höfundur: Till, Jessica L   orcid.org/0000-0002-6982-6973
Guyodo, Yohan
Lagroix, France
Morin, Guillaume
Menguy, Nicolas
Ona-Nguema, Georges
Útgáfa: 2017-03
Tungumál: Enska
Umfang: 63-70
Háskóli/Stofnun: Háskóli Íslands
University of Iceland
Svið: Verkfræði- og náttúruvísindasvið (HÍ)
School of Engineering and Natural Sciences (UI)
Deild: Jarðvísindastofnun (HÍ)
Institute of Earth Sciences (UI)
Birtist í: Comptes Rendus Geoscience;349(2)
ISSN: 1631-0713
DOI: 10.1016/j.crte.2017.02.001
Efnisorð: Magnetite; Magnetosomes; Inorganic alteration; Nano-goethite; Magnetism-based biosignature; Bergfræði; Steingervingafræði
URI: https://hdl.handle.net/20.500.11815/446

Skoða fulla færslu

Tilvitnun:

Till, J. L., Guyodo, Y., Lagroix, F., Morin, G., Menguy, N., & Ona-Nguema, G. (2017). Presumed magnetic biosignatures observed in magnetite derived from abiotic reductive alteration of nanogoethite. Comptes Rendus Geoscience, 349(2), 63-70. doi:https://doi.org/10.1016/j.crte.2017.02.001

Útdráttur:

The oriented chains of nanoscale Fe-oxide particles produced by magnetotactic bacteria are a striking example of biomineralization. Several distinguishing features of magnetite particles that comprise bacterial magnetosomes have been proposed to collectively constitute a biosignature of magnetotactic bacteria (Thomas-Keprta et al., 2001). These features include high crystallinity, chemical purity, a single-domain magnetic structure, well-defined crystal morphology, and arrangement of particles in chain structures. Here, we show that magnetite derived from the inorganic breakdown of nanocrystalline goethite exhibits magnetic properties and morphologies remarkably similar to those of biogenic magnetite from magnetosomes. During heating in reducing conditions, oriented nanogoethite aggregates undergo dehydroxylation and transform into stoichiometric magnetite. We demonstrate that highly crystalline single-domain magnetite with euhedral grain morphologies produced abiogenically from goethite meets several of the biogenicity criteria commonly used for the identification of magnetofossils. Furthermore, the suboxic conditions necessary for magnetofossil preservation in sediments are conducive to the reductive alteration of nanogoethite, as well as the preservation of detrital magnetite originally formed from goethite. The findings of this study have potential implications for the identification of biogenic magnetite, particularly in older sediments where diagenesis commonly disrupts the chain structure of magnetosomes. Our results indicate that isolated magnetofossils cannot be positively distinguished from inorganic magnetite on the basis of their magnetic properties and morphology, and that intact chain structures remain the only reliable distinguishing feature of fossil magnetosomes.

Leyfi:

© 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Skrár

Þetta verk birtist í eftirfarandi safni/söfnum:


Fletta

Um vefinn

Reikningurinn minn