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GEOREF RECORD

Sector-zoned tourmaline from the cap rock of a salt dome

Darrell J. Henry, Brenda L. Kirkland and Douglas W. Kirkland
Sector-zoned tourmaline from the cap rock of a salt dome (in Tourmaline 97, Milan Novak (convener) and Frank C. Hawthorne (convener))
European Journal of Mineralogy (April 1999) 11 (2): 263-280

Abstract

Sector zoned tourmaline, showing striking compositional variations in pyramidal sectors, is described from the cap rock of the salt dome associated with the Challenger Knoll, Gulf of Mexico. Trace amounts of fine-grained (10-80 mu m) euhedral authigenic tourmaline are included in calcite forming part of the carbonate-rich portion of the cap rock. Compositional, textural and geological data are consistent with an authigenic origin of the tourmaline in bedded halite under oxidizing conditions prior to incorporation into the cap rock. The cap rock tourmaline commonly has a tabular morphology, with optical and chemical zoning, this tourmaline is magnesian but surprisingly rich in Fe (super 3+) , poor in Ca and deficient in Al, and is best described as a solid solution between ferrian 'oxy-dravite' and povondraite. Four discrete pyramidal sectors display chemical sector zoning of a magnitude rarely recorded in minerals. The influence of surface energies at distinct faces of cap rock tourmaline apparently dramatically affects cation incorporation at the relatively low T of formation (< 150 degrees C). This 'oxy-dravite'-povondraite solid solution trend is similar to that developed in other ferrian tourmalines from oxidized meta-evaporites, meta-arkoses, quartz-tourmaline veins, stockwork veins associated with granite porphyry metal deposits and hydrothermal veins in metasediments.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 11
Serial Issue: 2
Title: Sector-zoned tourmaline from the cap rock of a salt dome
Title: Tourmaline 97
Author(s): Henry, Darrell J.Kirkland, Brenda L.Kirkland, Douglas W.
Author(s): Novak, Milanconvener
Author(s): Hawthorne, Frank C.convener
Affiliation: Louisiana State University, Department of Geology and Geophysics, Baton Rouge, LA, United States
Pages: 263-280
Published: 199904
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
Meeting name: Tourmaline 97
Meeting location: Nove Mesto na Morave, CZE, Czech Republic
Meeting date: 199707July 1997
References: 69
Accession Number: 1999-035206
Categories: Mineralogy of silicates
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: University of Texas at Austin, USA, United States
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199912
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