Skip to Main Content
Book Chapter

Volumetric Relations Between Dissolved Plagioclase and Kaolinite in Sandstones: Implications for Aluminum Mass Transfer in the San Joaquin Basin, California

By
Michael J. Hayes
Michael J. Hayes
Department of Geological Sciences, University of California, Santa Barbara, California 93106
Search for other works by this author on:
James R. Boles
James R. Boles
Department of Geological Sciences, University of California, Santa Barbara, California 93106
Search for other works by this author on:
Published:
January 01, 1992

Abstract:

Mass transfer of aluminum is investigated on a thin-section scale by comparing volumes of dissolved plagioclase and authigenic kaolinite in quartzofeldspathic sandstones from the San Joaquin Basin. Samples include Oligocene marine-shelf sandstones, which have been infiltrated by meteoric water, and Late Miocene turbidite sandstones, which contain diluted sea water. Other aluminum sources and sinks are volumetrically minor in these sandstones.

Dissolved plagioclase and kaolinite presently appear from 600 m to depth of sample control (30–70°C present temperature) in the meteoric zone and from 2,100 m to depth of sample control (75–130°C present temperature) in the marine zone. Leached plagioclase and kaolinite are rare in the matrix-rich or carbonate-cemented sandstones, but appear in more than 80% of the uncemented turbidite sandstones and in up to 60% of the uncemented sandstones in some meteoric-zone reservoirs.

Point-counted volumes of plagioclase porosity and kaolinite in all sandstones are compared with relative volumes calculated from a mass-balance reaction in which aluminum is conserved between An30 plagioclase and kaolinite (25 to 50% microporosity). Aluminum is conserved on a centimeter scale in shale-encased turbidite sandstones exposed to limited fluxes of marine pore water, despite enrichment in organic-acid anions, which potentially may mobilize aluminum in soluble complexes. The average marine-zone sandstone has a volume of kaolinite approximately equal to that calculated for plagioclase porosity, based on relative volumes of the mass-balance reaction.

In contrast, the average sandstone with meteoric pore water has a kaolinite shortfall of 0.4 ± 0.3 volume percent of total rock relative to plagioclase porosity. This average aluminum loss is 0.2 ± 0.1 gm/100 cm3 rock volume. Complementary zones of aluminum import are not found in the meteoric zone. A small amount of aluminum is mobilized beyond a centimeter scale in shelf sandstones flushed by low-temperature, dilute waters.

Plagioclase dissolution and kaolinite precipitation in sandstones from both porewater settings result in compositional shifts of less than 0.4 weight percent Al2O3, too small to discriminate from the natural bulk chemical variation of 1 to 2 weight percent Al2O3. Data from this study do not support models proposed for transfer of large masses of aluminum over significant distances.

You do not currently have access to this article.

Figures & Tables

Contents

SEPM Special Publication

Origin, Diagenesis, and Petrophysics of Clay Minerals in Sandstones

David W. Houseknecht
David W. Houseknecht
Department of Geological Sciences University of Missouri Columbia Missouri 65211
Search for other works by this author on:
Edward D. Pittman
Edward D. Pittman
Department of Geosciences University of Tulsa Tulsa Oklahoma 74104
Search for other works by this author on:
SEPM Society for Sedimentary Geology
Volume
47
ISBN electronic:
9781565761728
Publication date:
January 01, 1992

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal