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GEOREF RECORD

Dissolution of silica in nature and its implications

S. K. Ghosh
Dissolution of silica in nature and its implications (in Opportunities for the nineties; Canadian Society of Petroleum Geology 1991 convention; abstracts, Anonymous)
Bulletin of Canadian Petroleum Geology (June 1991) 39 (2): 212

Abstract

Quartz is the most stable natural form of silica, normally resisting weathering. However, Precambrian quartz arenites of the Roraima Group in Venezuela clearly show evidence of abundant quartz dissolution in a highly organic-rich, acidic to neutral meteoric environment. The Roraima sediments occur in flat-topped mesas (200 m high) in a tropical environment of heavy rainfall. The degree of weathering varies from highly indurated, unweathered quartz arenites, away from and deeper than the outcrop surfaces, to highly degraded, crumbly, extremely porous sandstones on the outcrops. Petrographically, the tight arenites show abundant grain welding as a result of pervasive syntaxial quartz cement and sutured grain contacts. In the weathered samples, by contrast, an excellent network of lamellar porosity has formed through the dissolution of quartz cement. The silica dissolution has mainly followed along the compromise boundaries of adjacent overgrowths. The extensive dissolution and mobility of silica may be related to organic acids produced during the biodegradation of terrestrial organic matter. These organic acids or compounds can react with dissolved silica, lowering the activity of silicic acid and accelerating the dissolution of quartz and other aluminosilicates.


ISSN: 0007-4802
Coden: BCPGAI
Serial Title: Bulletin of Canadian Petroleum Geology
Serial Volume: 39
Serial Issue: 2
Title: Dissolution of silica in nature and its implications
Title: Opportunities for the nineties; Canadian Society of Petroleum Geology 1991 convention; abstracts
Author(s): Ghosh, S. K.
Author(s): Anonymous
Affiliation: Petroscan Int. Petrol. Consult., Calgary, AB, Canada
Pages: 212
Published: 199106
Text Language: English
Publisher: Canadian Society of Petroleum Geologists, Calgary, AB, Canada
Meeting name: Canadian Society of Petroleum Geology 1991 convention
Meeting location: CAN, Canada
Meeting date: 19911991
Summary: Y
Accession Number: 1991-040298
Categories: Sedimentary petrology
Document Type: Serial Conference document
Bibliographic Level: Analytic
N00°45'00" - N12°10'00", W73°15'00" - W59°55'00"
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 1991
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