LIDDICOATITE AND ASSOCIATED SPECIES FROM THE MCCOMBE SPODUMENE-SUBTYPE RARE-ELEMENT GRANITIC PEGMATITE, NORTHWESTERN ONTARIO, CANADA

2005 ◽  
Vol 43 (2) ◽  
pp. 769-793 ◽  
Author(s):  
A. G. Tindle ◽  
J. B. Selway ◽  
F. W. Breaks
Keyword(s):  
Granitic Pegmatite ◽  
Rare Element ◽  
Northwestern Ontario ◽  
Associated Species

THE Ta-Nb-Sn-Ti OXIDE-MINERAL PARAGENESIS FROM LA VIQUITA, A SPODUMENE-BEARING RARE-ELEMENT GRANITIC PEGMATITE, SAN LUIS, ARGENTINA

2008 ◽  
Vol 46 (2) ◽  
pp. 379-393 ◽  
Author(s):  
M. A. Galliski ◽  
M. F. Marquez-Zavalia ◽  
P. Cerny ◽  
V. A. Martinez ◽  
R. Chapman
Keyword(s):  
Granitic Pegmatite ◽  
Rare Element ◽  
Mineral Paragenesis ◽  
Oxide Mineral ◽  
San Luis

scholarly journals Nb–Ta–(Ti–Sn) oxide mineral chemistry as tracer of rare-element granitic pegmatite fractionation in the Borborema Province, Northeastern Brazil

2007 ◽  
Vol 43 (2) ◽  
pp. 207-228 ◽  
Author(s):  
Hartmut Beurlen ◽  
Marcelo R. R. Da Silva ◽  
Rainer Thomas ◽  
Dwight R. Soares ◽  
Patrick Olivier
Keyword(s):  
Mineral Chemistry ◽  
Northeastern Brazil ◽  
Granitic Pegmatite ◽  
Rare Element ◽  
Oxide Mineral ◽  
Borborema Province

scholarly journals Rare-element granitic pegmatite of Miocene age emplaced in UHP rocks from Visole, Pohorje Mountains (Eastern Alps, Slovenia): accessory minerals, monazite and uraninite chemical dating

2014 ◽  
Vol 65 (2) ◽  
pp. 131-146 ◽  
Author(s):  
Pavel Uher ◽  
Marian Janák ◽  
Patrik Konečný ◽  
Mirijam Vrabec
Keyword(s):  
Late Miocene ◽  
Volcanic Rocks ◽  
Eastern Alps ◽  
Granitic Pegmatite ◽  
Fault System ◽  
Rare Element ◽  
Accessory Minerals ◽  
Precipitation Temperature ◽  
The Alps ◽  
Chemical Dating

Abstract The granitic pegmatite dike intruded the Cretaceous UHP rocks at Visole, near Slovenska Bistrica, in the Pohorje Mountains (Slovenia). The rock consists mainly of K-feldspar, albite and quartz, subordinate muscovite and biotite, while the accessory minerals include spessartine-almandine, zircon, ferrocolumbite, fluorapatite, monazite- (Ce), uraninite, and magnetite. Compositions of garnet (Sps48-49Alm45-46Grs + And3-4 Prp1.5-2), metamict zircon with 3.5 to 7.8 wt. % HfO2 [atom. 100Hf/(Hf + Zr) = 3.3-7.7] and ferrocolumbite [atom. Mn/(Mn + Fe) = 0.27-0.43, Ta/(Ta + Nb) = 0.03-0.46] indicate a relatively low to medium degree of magmatic fractionation, characteristic of the muscovite - rare-element class or beryl-columbite subtype of the rare-element class pegmatites. Monazite-(Ce) reveals elevated Th and U contents (≤11 wt. % ThO2, ≤5 wt. % UO2). The monazite-garnet geothermometer shows a possible precipitation temperature of ~495 ± 30 °C at P~4 to 5 kbar. Chemical U-Th-Pb dating of the monazite yielded a Miocene age (17.2 ± 1.8 Ma), whereas uraninite gave a younger (~14 Ma) age. These ages are comtemporaneous with the main crystallization and emplacement of the Pohorje pluton and adjacent volcanic rocks (20 to 15 Ma), providing the first documented evidence of Neogene granitic pegmatites in the Eastern Alps. Consequently, the Visole pegmatite belongs to the youngest rare-element granitic pegmatite populations in Europe, together with the Paleogene pegmatite occurrences along the Periadriatic (Insubric) Fault System in the Alps and in the Rhodope Massif, as well as the Late Miocene to Pliocene pegmatites in the Tuscany magmatic province (mainly on the Island of Elba).

Chemical evolution of Nb-Ta oxides and zircon from the Koktokay No. 3 granitic pegmatite, Altai, northwestern China

2004 ◽  
Vol 68 (5) ◽  
pp. 739-756 ◽  
Author(s):  
A. C. Zhang ◽  
R. C. Wang ◽  
H. Hu ◽  
H. Zhang ◽  
J. C. Zhu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Evolution ◽  
Electron Microprobe ◽  
The Other ◽  
Northwestern China ◽  
Granitic Pegmatite ◽  
Hydrothermal Conditions ◽  
Rare Element ◽  
Other Hand ◽  
Backscattered Electron

AbstractThe Koktokay No. 3 granitic pegmatite, Altai, northwestern China, is a strongly zoned rare-element granitic pegmatite, where the petrographic zones were distinguished into two groups: outer zones (I to IV) and inner zones (V to IX). Nb-Ta oxides and zircon are investigated in this paper by using quantitative electron-microprobe analyses (EMPA) and backscattered-electron (BSE) imaging. Columbite-tantalite and zircon occur in most textural zones, whereas tapiolite and uranmicrolite are mainly restricted to zone VII. Manganocolumbite and zircon from the outer zones (zones II and IV) are homogeneous except for a few exceptions, whereas manganotantalite and hafnian zircon from the inner zones (V–VII) are obviously heterogeneous and strongly zoned. Chemically, Ta/(Nb+Ta) in columbite-tantalite and Hf/(Zr+Hf) in zircon increase from the outer to the inner zones on one hand, and from core to rim in single zoned crystals on the other hand. Observations of intra-zonal variations of the chemical composition of Nb-Ta oxides and zircon in the Koktokay No. 3 granitic pegmatite may suggest that the outer zones crystallize under magmatic conditions, whereas the inner zones crystallize under fluid-rich magmatic conditions, and locally under hydrothermal conditions. The extreme enrichments of columbite-tantalite in Ta, and of zircon in Hf, as well as the occurrence of uranmicrolite and tapiolite, indicate an elevated evolution of the Koktokay No. 3 granitic pegmatite.

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