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Partial resetting of U–Pb ages during experimental fluid-induced re-equilibration of xenotime
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SYSNO ASEP 0509442 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Partial resetting of U–Pb ages during experimental fluid-induced re-equilibration of xenotime Tvůrce(i) Budzyń, B. (PL)
Sláma, Jiří (GLU-S) SAI, RID, ORCIDČíslo článku 105163 Zdroj.dok. Lithos. - : Elsevier - ISSN 0024-4937
346-347, December (2019), s. 346-347Poč.str. 16 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. NL - Nizozemsko Klíč. slova Dissolution-reprecipitation ; mineral-fluid reactions ; geochronology ; secondary textures ; xenotime Vědní obor RIV DB - Geologie a mineralogie Obor OECD Geology Způsob publikování Omezený přístup Institucionální podpora GLU-S - RVO:67985831 UT WOS 000488335600022 EID SCOPUS 85070637261 DOI 10.1016/j.lithos.2019.105163 Anotace Experimentally metasomatized xenotime was investigated in terms of preservation of U–Pb ages during fluid-induced alterations at 250, 450, 550 and 650 °C. Starting materials for experiments included xenotime (38.4 ± 0.6 Ma), albite, K-feldspar, biotite, muscovite, garnet, SiO2, CaF2, Na2Si2O5 and H2O that roughly replicated metapelitic to granitic composition with high Na, Ca, Si and F activities in the fluid. Despite partial replacement of xenotime by secondary phases including (Y,REE)-rich fluorapatite to Y-rich fluorcalciobritholite in all runs, and an unnamed (Y,HREE)-rich silicate in 250 °C experiment, only two experiments at 550 °C, 800 MPa and 650 °C, 600 MPa resulted in development of faint to moderate patchy zoning in the xenotime. Experimental results indicate higher chemical-stability of xenotime at lower P-T conditions compared to those corresponding to amphibolite facies conditions. The xenotime domains metasomatized via coupled dissolution-reprecipitation reactions are characterized by depletion of U and Pb and younger 206Pb/238U dates of ca. 15–34 Ma, demonstrating preferential removal of Pb and thus the partial resetting of the age record. The U–Pb data for the first time experimentally confirm that xenotime may be affected by re-equilibration induced by fluid or melt with high Na, Ca and F activities via coupled dissolution-reprecipitation reactions that result in removal of radiogenic Pb under temperature conditions of 550–650 °C. These findings have important implications for U–Pb geochronology of igneous (particularly in pegmatites) and metamorphic processes in terms of preservation of U–Pb ages of xenotime that was affected by multiple thermal events in the presence of alkali-rich fluid and/or melt. Pracoviště Geologický ústav Kontakt Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Rok sběru 2020 Elektronická adresa https://www.sciencedirect.com/science/article/pii/S0024493719303202?via%3Dihub
Počet záznamů: 1