Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Clay Minerals Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Clay Minerals; June 2008; v. 43; no. 2; p. 213-233; DOI: 10.1180/claymin.2008.043.2.06
© 2008 Mineralogical Society of Great Britain and Ireland
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 Similar articles in ISI Web of Science
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 DE BONA, J.
Right arrow Articles by DE ROS, L. F.
GeoRef
Right arrow GeoRef Citation

Research Paper

Dickite in shallow oil reservoirs from Recôncavo Basin, Brazil: diagenetic implications for basin evolution

J. DE BONA1, N. DANI1, J. M. KETZER2 and L. F. DE ROS1,*

1 Institute of Geosciences, Federal University of Rio Grande do Sul, UFRGS, Porto Alegre, RS, Brazil, and 2 Pontifical Catholic University of Rio Grande do Sul, PUC-RS, Porto Alegre, RS, Brazil

* E-mail: lfderos{at}inf.ufrgs.br

(Received 11 February 2007; revised 6 November 2007)

Fluvial and aeolian sandstones of the Sergi Formation are the most important reservoirs of the Recôncavo Basin, Brazil. Optical and scanning electron microscopy, X-ray diffraction and infrared spectroscopy revealed the occurrence of dickite, a clay mineral indicative of deep burial conditions (T >100°C), in the shallow Buracica (630–870 m) and Água Grande (1300–1530 m) oilfields. Vermicular dickite replaces K-feldspar and plagioclase grains, and fills intra- and intergranular pores. Its vermicular habit is a product of pseudomorphic kaolinite transformation during burial. The presence of dickite is in accordance with the intensity of compaction, post-compactional quartz cementation and {delta}18O values of calcite cements (T up to 109°C). These petrological features of deep burial, as well as apatite fission-track analyses, indicate that uplift and erosion of at least 1 km, and probably >1500 m, affected the central part of the Recôncavo Basin and possibly the entire region. This uplift has not been detected previously by conventional structural and stratigraphic models.

KEYWORDS: diagenesis, sandstones, reservoirs, dickite, uplift, Recôncavo Basin, Brazil






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Mineralogical Society of Great Britain and Ireland