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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

In: Geologica Carpathica, vol. 65, no. 2
Pavel Uher - Marian Janák - Patrik Konečný - Mirijam Vrabec
Detaily:
Rok, strany: 2014, 131 - 146
Jazyk: eng
Kľúčové slová:
granitic pegmatite, spessartine-almandine, columbite, zircon, fluorapatite, monazite, uraninite, age, Pohorje, Eastern Alps
O článku:
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—4Prp1.5—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) re- veals 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).
Ako citovať:
ISO 690:
Uher, P., Janák, M., Konečný, P., Vrabec, M. 2014. 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. In Geologica Carpathica, vol. 65, no.2, pp. 131-146. 1335-0552. DOI: https://doi.org/10.2478/geoca-2014-0009

APA:
Uher, P., Janák, M., Konečný, P., Vrabec, M. (2014). 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. Geologica Carpathica, 65(2), 131-146. 1335-0552. DOI: https://doi.org/10.2478/geoca-2014-0009
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