Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
European Journal of Mineralogy Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP FEEDBACK/COMMNET SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
European Journal of Mineralogy; April 2008; v. 20; no. 2; p. 199-204; DOI: 10.1127/0935-1221/2008/0020-1806
© 2008 E. Schweizerbart'sche Verlagsbuchhandlung Science Publishers
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
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
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Kameda, J.
Right arrow Articles by Kogure, T.
GeoRef
Right arrow GeoRef Citation

Articles

Textures and polytypes in vermiform kaolins diagenetically formed in a sandstone reservoir: a FIB-TEM investigation

Jun Kameda1,*, Kazuko Saruwatari1, Daniel Beaufort2 and Toshihiro Kogure1

1 The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
2 Université de Poitiers, CNRS, HydrASA, 40 Av. du Recteur Pineau, Poitiers, 86022, France

* Corresponding author, e-mail: kameda{at}eps.s.u-tokyo.ac.jp

Focused ion beam (FIB) sample preparation was applied to vermiform kaolin minerals to investigate by TEM the morphological evolution and mechanisms of kaolinite-to-dickite transformation during burial diagenesis. A core sample of a K-feldspar bearing arkosic sandstone, collected from the Brent Group sediments of the Froy hydrocarbon reservoir, Norwegian continental shelf, North Sea, was studied. Two types of vermiform aggregates were analyzed: 1) porous aggregates of fine lamellar crystals or intercalations of blocky and lamellar crystals, and 2) aggregates of densely packed hexagonal crystals. Electron diffraction (ED) revealed that aggregates of the first type are composed of pure one-layer kaolinite, whereas those of the second type consist of pure two-layer dickite. The two polytypes never coexist within the same aggregate. Furthermore, ED patterns of kaolinite and dickite are almost streak free, indicating a very low density of stacking faults. These observations suggest that the kaolinite-to-dickite transition in the pores of sandstone reservoir during burial diagenesis takes place by a dissolution-precipitation process rather than by a solid-state process. Blocky kaolinite, grown epitaxially on the (001) surface of muscovite, was also found in the specimen.

Key-words: vermiform kaolins, kaolinite-to-dickite transition, polytype, FIB, TEM.






JOURNAL HOME HELP FEEDBACK/COMMNET SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by E. Schweizerbart'sche Verlagsbuchhandlung Science Publishers