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Partial resetting of U–Pb ages during experimental fluid-induced re-equilibration of xenotime

Identifikátory výsledku

  • Kód výsledku v IS VaVaI

    <a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F19%3A00509442" target="_blank" >RIV/67985831:_____/19:00509442 - isvavai.cz</a>

  • Výsledek na webu

    <a href="https://www.sciencedirect.com/science/article/pii/S0024493719303202?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0024493719303202?via%3Dihub</a>

  • DOI - Digital Object Identifier

    <a href="http://dx.doi.org/10.1016/j.lithos.2019.105163" target="_blank" >10.1016/j.lithos.2019.105163</a>

Alternativní jazyky

  • Jazyk výsledku

    angličtina

  • Název v původním jazyce

    Partial resetting of U–Pb ages during experimental fluid-induced re-equilibration of xenotime

  • Popis výsledku v původním jazyce

    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.

  • Název v anglickém jazyce

    Partial resetting of U–Pb ages during experimental fluid-induced re-equilibration of xenotime

  • Popis výsledku anglicky

    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.

Klasifikace

  • Druh

    J<sub>imp</sub> - Článek v periodiku v databázi Web of Science

  • CEP obor

  • OECD FORD obor

    10505 - Geology

Návaznosti výsledku

  • Projekt

  • Návaznosti

    I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Ostatní

  • Rok uplatnění

    2019

  • Kód důvěrnosti údajů

    S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Údaje specifické pro druh výsledku

  • Název periodika

    Lithos

  • ISSN

    0024-4937

  • e-ISSN

  • Svazek periodika

    346-347

  • Číslo periodika v rámci svazku

    December

  • Stát vydavatele periodika

    NL - Nizozemsko

  • Počet stran výsledku

    16

  • Strana od-do

    346-347

  • Kód UT WoS článku

    000488335600022

  • EID výsledku v databázi Scopus

    2-s2.0-85070637261