Back to Search
Start Over
Presumed magnetic biosignatures observed in magnetite in derived from abiotic reductive alteration of nanogoethite
- Source :
- Comptes Rendus Géoscience, Comptes Rendus Géoscience, Elsevier, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩, Comptes Rendus Géoscience, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩, Comptes Rendus Géoscience, Elsevier Masson, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩
- Publication Year :
- 2017
- Publisher :
- HAL CCSD, 2017.
-
Abstract
- 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.<br />This work was supported by the “Agence nationale de la recherche” (France) under project 2010-BLAN-604-01. Dennis Kent and Joshua Feinberg are thanked for their constructive reviews. This is IPGP contribution 3826.<br />Final draft post-review
- Subjects :
- Nano-goethite
Goethite
010504 meteorology & atmospheric sciences
Magnetotactic bacteria
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
Magnetosome
Mineralogy
010502 geochemistry & geophysics
01 natural sciences
Magnetite
chemistry.chemical_compound
Biosignature
0105 earth and related environmental sciences
Bergfræði
Global and Planetary Change
Inorganic alteration
Diagenesis
Chemical engineering
chemistry
Steingervingafræði
visual_art
visual_art.visual_art_medium
Magnetism-based biosignature
General Earth and Planetary Sciences
Magnetosomes
Geology
Magnetofossil
Biomineralization
Subjects
Details
- Language :
- English
- ISSN :
- 16310713
- Database :
- OpenAIRE
- Journal :
- Comptes Rendus Géoscience, Comptes Rendus Géoscience, Elsevier, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩, Comptes Rendus Géoscience, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩, Comptes Rendus Géoscience, Elsevier Masson, 2017, 349 (2), pp.63-70. ⟨10.1016/j.crte.2017.02.001⟩
- Accession number :
- edsair.doi.dedup.....9792286fb57298761f9126179664e013