|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | FEEDBACK/COMMNET | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Articles |
1 Department of Earth and Environmental Sciences, University of Veszprém, Veszprém, POB 158, H-8200 Hungary
2 Paleomagnetic Laboratory of the Eötvös Loránd Geophysical Institute, Budapest, Homonna u. 1., H-1118 Hungary
3 Department of Geophysics, Eötvös Loránd University, Budapest, Ludovika tér 1., H-1088 Hungary
4 Departments of Geological Sciences and Chemistry/Biochemistry, Arizona State University, Tempe, Arizona 85287–1404, USA
5 Department of Physics, California Polytechnic State University, San Luis Obispo, California 93407, USA
6 Department of Microbiology, Iowa State University, Ames, Iowa 50011, USA
* E-mail: posfaim{at}almos.vein.hu
This paper was presented at the "Biogenic Iron Minerals" symposium held in Tihany, Hungary (May 2000)
Sedimentary greigite (Fe3S4) can form either by "biologically controlled" or by "biologically induced mineralization" (BCM and BIM, respectively). In order to identify the origin of magnetic Fe sulfides, we studied and compared the sizes and morphologies of greigite crystals produced by a magnetotactic microorganism (previously described and referred to as the "many-celled magnetotactic prokaryote", MMP) and Fe sulfides from two specimens of Miocene sedimentary rocks (from Laka, in the foredeep of the Western Carpathians and from Michalovce, in the Transcarpathian Depression). Greigite grains from the MMP and the Laka rock show nearly Gaussian crystal-size distributions (CSDs), whereas the CSD is lognormal for Fe sulfides from the Michalovce rock. We simulated various crystal-growth mechanisms and matched the calculated and observed CSDs; crystals from the MMP and the Laka rock have CSDs that are consistent with random growth of crystal nuclei in an open system, whereas the CSD of the Michalovce Fe sulfides is consistent with surface-controlled growth followed by supply-controlled growth in an open system. On the basis of CSDs and characteristic contrast features in the transmission electron microscope, greigite in the Laka rock is likely of BCM origin, whereas the Fe sulfide crystals in the other rock sample were produced by BIM processes. Our results indicate that the methods we applied in this study may contribute to the identification of the origin of magnetic Fe sulfide minerals in sedimentary rocks.
Key-words: greigite, magnetotactic bacteria, biologically controlled mineralization, biologically induced mineralization, crystal size distribution.
This article has been cited by other articles:
|
|
 |
|
  R. Merinero, R. Lunar, L. Somoza, V. Diaz-del-Rio, and J. Martinez-Frias Nucleation, growth and oxidation of framboidal pyrite associated with hydrocarbon-derived submarine chimneys: lessons learned from the Gulf of Cadiz European Journal of Mineralogy, October 1, 2009; 21(5): 947 - 961. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Faivre, N. Menguy, M. Posfai, and D. Schuler Environmental parameters affect the physical properties of fast-growing magnetosomes American Mineralogist, February 1, 2008; 93(2-3): 463 - 469. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kasama, M. Posfai, R. K.K. Chong, A. P. Finlayson, P. R. Buseck, R. B. Frankel, and R. E. Dunin-Borkowski Magnetic properties, microstructure, composition, and morphology of greigite nanocrystals in magnetotactic bacteria from electron holography and tomography American Mineralogist, August 1, 2006; 91(8-9): 1216 - 1229. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Arato, Z. Szanyi, C. Flies, D. Schuler, R. B. Frankel, P. R. Buseck, and M. Posfai Crystal-size and shape distributions of magnetite from uncultured magnetotactic bacteria as a potential biomarker American Mineralogist, August 1, 2005; 90(8-9): 1233 - 1240. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | FEEDBACK/COMMNET | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
