REE-bearing petscheckite from Tiltvika, Nordland, Norway, and its heating products

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doi: 10.1127/0028-3649/2004/2004-0163
Authors:Tomasic, Nenad; Raade, Gunnar; Bermanec, Vladimir
Volume Title:Neues Jahrbuch für Mineralogie. Monatshefte
Source:Neues Jahrbuch für Mineralogie. Monatshefte, 2004(4), p.163-175. Publisher: E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Federal Republic of Germany. ISSN: 0028-3649
Publication Date:2004
Note:In English. 11 refs.; 4 tables
Summary:XRD powder diffraction study of a mineral from the Tiltvika granite pegmatite, Norway, shows the presence of a metamict phase with ferrocolumbite inclusions. On heating at 650°C for 21 hours, the diffraction pattern of petscheckite, a hexagonal mineral with idealized formula U4+Fe2+(Nb,Ta)2O8, is observed.The Tiltvika petscheckite is rich in REE and has the general formula (U,REE)(Fe2+Fe3+)(Nb,Ta)2(O,OH)8, with a 6.42, c 4.02 Å. Heating at 1000°C for 21 hours yields a phase with columbite-type structure and a pattern very close to that reported for heated 'wolframixiolite'. Assuming space group Pcan, this phase has a 5.005, b 14.05, c 5.64 Å. The high content of α-emitting uranium could explain the metamictization of a primary petscheckite. On the other hand, it is possible that an unknown primary mineral with complex composition has disintegrated into micro-exsolutions of phases with simple stoichiometry, which have recombined to petscheckite on heating at 650°C. For practical purposes, however, petscheckite as a metamict mineral species must be defined by its chemical composition and the characteristic XRD pattern that it gives on heating to 650°C. [R.A.H.]
Sections:Experimental mineralogy; Mineral data
Subsections:Non-silicates
Subjects:Electron probe data; Formula; Granites; Igneous rocks; Metals; Oxides; Pegmatite; Plutonic rocks; Rare earths; TGA data; Thermal properties; X-ray diffraction data; Europe; Nordland Norway; Northern Norway; Norway; Scandinavia; Western Europe; Petscheckite; Tiltvika Norway
Coordinates:N645500 N691800 E0181500 E0114500
Abstract Numbers:04M/1807
Record ID:2010054113
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe
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