Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
American Mineralogist RIMG advertisement
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
American Mineralogist; February 1999; v. 84; no. 1-2; p. 171-182
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Akai, J.
Right arrow Articles by Sasagawa, I.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Biologically induced iron ore at Gunma iron mine, Japan

Junji Akai, Kurumi Akai, Makoto Ito, Satoshi Nakano, Yonosuke Maki, and Ichiro Sasagawa

Niigata University, Department of Geology, Niigata, Japan

The mineralogy of sedimentary iron ores from the Gunma iron mine are described to evaluate the role of microorganisms and plants in ore formation. The iron ore is composed of nanocrystalline goethite, well-crystallized jarosite and very small amounts of strengite. The ore characteristically occurs as thick-bands of alternating goethite and jarosite bands, thin-bands of different goethite grain sizes, and fossil-aggregate ore rich in moss and/or leaves. Algal fossils are clearly preserved in the goethite bands in the thick-banded ore. Lattice imaging showed characteristic crystallographic orientations of the goethite nanocrystals. The thin-banded iron ores consist of micrometer-sized chestnut-burr-like goethite aggregates, probably formed by bacterial iron biomineralization. The bands may be attributed to biological or seasonal rhythms. Various products of biomineralization are found in the present-day pH 2-3, Fe (super 2+) -, and SO (super 2-) 4 -rich streams. Bacterial precipitation had variations from amorphous Fe-P-(S) precipitates near the outlet of mineral spring to Fe-P-S precipitates and to Fe-S-(P) (schwertmannite-like) precipitates in the midstream. Mosses and green algae are also collecting Fe precipitates in and around the living and dead cells. Comparison of the processes occurring in the present-day streams and the iron-ore specimens supports the interpretation of these ores as the product of biomineralization.

This record provided courtesy of AGI/GeoRef.




This article has been cited by other articles:


Home page
 American MineralogistHome page
R. M. Hazen, D. Papineau, W. Bleeker, R. T. Downs, J. M. Ferry, T. J. McCoy, D. A. Sverjensky, and H. Yang
Mineral evolution
American Mineralogist, November 1, 2008; 93(11-12): 1693 - 1720.
[Abstract] [Full Text] [PDF]

Home page
 Clays and Clay MineralsHome page
M. Ueshima, M. Ueshima, and K. Tazaki
POSSIBLE ROLE OF MICROBIAL POLYSACCHARIDES IN NONTRONITE FORMATION
Clays and Clay Minerals, August 1, 2001; 49(4): 292 - 299.
[Abstract] [Full Text] [PDF]

Home page
 Can MineralHome page
K. Sasaki and H. Konno
MORPHOLOGY OF JAROSITE-GROUP COMPOUNDS PRECIPITATED FROM BIOLOGICALLY AND CHEMICALLY OXIDIZED Fe IONS
Can Mineral, February 1, 2000; 38(1): 45 - 56.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Mineralogical Society of America