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GEOREF RECORD

Textural relations and chemical composition of minerals from a pollucite+harmotome+chabazite nodule in the Vezna I Pegmatite, Czech Republic

Jiri Toman and Milan Novak
Textural relations and chemical composition of minerals from a pollucite+harmotome+chabazite nodule in the Vezna I Pegmatite, Czech Republic (in A tribute to Milan Novak, Radek Skoda (editor), Pietro Vignola (editor), Axel Mueller (editor) and Lee A. Groat (editor))
The Canadian Mineralogist (July 2018) 56 (4): 375-392

Abstract

Minerals and their textural relations from a pollucite + harmotome + chabazite nodule (PHC) enclosed in a volumetrically negligible albite-pollucite unit (1-2 dm (super 3) ) in the Vezna I beryl-columbite pegmatite were examined by EMP and XRD. The albite-pollucite unit consists of a dominant albite-lepidolite-topaz subunit (Ab + Qz + Kf + Ms + Lpd + Tpz) as a matrix surrounding minor nodular subunits: the examined PHC and triplite-apatite nodules. Small vugs with crystals of harmotome and chabazite growing from the PHC nodule and polylithionite with sokolovaite rims, albite, fluor-elbaite, and K-feldspar extending from the host albite-lepidolite-topaz subunit are locally developed at the margin. Several textural/paragenetic types of the individual minerals in the PHC were distinguished from center to margin of the nodule and vugs. The minerals exhibit very complicated textural relations varying from evident replacement of early pollucite by analcime to evident replacement of pollucite-analcime by late zeolites (harmotome+chabazite). However, the pollucite types have almost identical compositions and underwent strong analcimization along the contact with the albite-lepidolite-topaz subunit. Harmotome evolves from K-rich harmotome I (harmotome>phillipsite-K) via Ca,K-moderate harmotome II to Ca,K-poor and Ba-rich harmotome III and chabazite evolves from Ca-rich chabazite I via slightly K-enriched chabazite II to moderately K-enriched chabazite III (chabazite-Ca>chabazite-K) from center to margin and vugs, respectively. Pollucite was replaced by the assemblage harmotome+chabazite according to the simplified equation pollucite+Ba+2Ca+25H (sub 2) O=harmotome+chabazite. The temperatures of the processes leading to the assemblage pollucite+analcime+harmotome+chabazite in the PHC were inferred from the experimental and empirical P-T stabilities of the minerals: primary pollucite T> approximately 350 degrees C, analcimization T< approximately 150 degrees C, harmotome + chabazite T< approximately 100-150 degrees C.


ISSN: 0008-4476
EISSN: 1499-1276
Coden: CAMIA6
Serial Title: The Canadian Mineralogist
Serial Volume: 56
Serial Issue: 4
Title: Textural relations and chemical composition of minerals from a pollucite+harmotome+chabazite nodule in the Vezna I Pegmatite, Czech Republic
Title: A tribute to Milan Novak
Author(s): Toman, JiriNovak, Milan
Author(s): Skoda, Radekeditor
Author(s): Vignola, Pietroeditor
Author(s): Mueller, Axeleditor
Author(s): Groat, Lee A.editor
Affiliation: Masaryk University, Department of Geological Sciences, Czech Republic
Pages: 375-392
Published: 201807
Text Language: English
Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada
Meeting name: PEG2017; 8th international symposium on Granitic pegmatites
Meeting location: Kristiansand, NOR, Norway
Meeting date: 20170613June 13-15, 2017
References: 57
Accession Number: 2019-003874
Categories: Mineralogy of silicatesIgneous and metamorphic petrology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables
N49°26'52" - N49°26'52", E16°16'29" - E16°16'29"
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, copyright, Mineralogical Association of Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201902
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