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GEOREF RECORD

Pegmatites at the Okatjimukuju farm, Karibib, Namibia; Part 1, Phosphate mineral associations of the Clementine II pegmatite

P. Keller and O. Von Knorring
Pegmatites at the Okatjimukuju farm, Karibib, Namibia; Part 1, Phosphate mineral associations of the Clementine II pegmatite
European Journal of Mineralogy (August 1989) 1 (4): 567-593

Abstract

The Clementine II pegmatite has been intruded into dolomite marbles of the Karibib formation of the Upper Precambrian Damara sequence. It is phosphate-bearing and is moderately fractionated with a Li stage and is well zoned. An unusual feature is a zone, intercalated between the outer and inner intermediate zones, on both sides of the nearly symmetrical pegmatite body; this zone is interpreted as an 'early space filling.' Six different associations of phosphate minerals can be distinguished, each characterized by a specific primary phosphate mineral: members of the triphylite-lithiophilite series with six distinct Fe/(Fe + Mn) ratios, triplite/zwieselite, and amblygonite/montebrasite. For the primary triphylite-lithiophilite series, microprobe studies show the range 0.45 less than or equal to Fe/(Fe + Mn) less than or equal to 0.79; this ratio decreases from the intercalated zone to the inner intermediate zone. Unusual features of the phosphate mineralization include: 1) an assemblage of triplite/zwieselite, magnetite and triphylite; 2) arrojadite occurs as a common metasomatic mineral; 3) oxidized eosphorite and kryzhanovskite occur in unusually high amounts. The pegmatite is mined for beryl, Li-mica and columbite; beryl and columbite occur in the intercalated zone, whereas Li-mica has been mined from the replacement veins.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 1
Serial Issue: 4
Title: Pegmatites at the Okatjimukuju farm, Karibib, Namibia; Part 1, Phosphate mineral associations of the Clementine II pegmatite
Affiliation: Univ. Stuttgart, Inst. Mineral. Kristallchem., D-7000 Stuttgart 80, Federal Republic of Germany
Pages: 567-593
Published: 198908
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 50
Accession Number: 1993-015441
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 9 tables, geol. sketch map
S29°00'00" - S16°40'00", E11°30'00" - E25°15'00"
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom. Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe, Hanover, Germany
Update Code: 1993
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