caa a22 4500 465790879 CHVBK 20180323112024.0 cr unu---uuuuu 170327e19901101xx s 000 0 eng 10.1007/BF01167286 doi (NATIONALLICENCE)springer-10.1007/BF01167286 Magmatic and hydrothermal R.E.E. fractionation in the Xihuashan granites (SE China) [Elektronische Daten] [Patricia Maruéjol, Michel Cuney, Laurent Turpin] The Xihuashan stock (South Jiangxi, China) is composed of cogenetic granitic units (granites Xe, γa, γc, γd and γb) and emplaced during the Yanshanian orogeny (153±0.2 Ma). They are two feldspars, Fe-rich biotite±garnet and slightly peraluminous granites. Primary accessory minerals are apatite 1, monazite, zircon, uranothorite±xenotime in granites Xe and γa, zircon, uranothorite, uraninite, betafite, xenotime 1; hydrothermal minerals are monazite altered into parisite and apatite 2, Y-rich parisite, yttroparisite, Y-rich fluorite and xenotime 2 in granites γc and γb. Petrographic observations, major element, REE, Y and Rb−Sr isotropic data point to a magmatic suite (granites Xe and γa → granites γc and γd → granite γb) distinct from hydrothermal Na-or K-alteration of γb. From granite Xe to granite γb, LREE, Eu, Th and Zr content are strongly depleted, while HREE, Y and U content increase. During K-alteration of γb, these variations are of minor importance. Major and accessory mineral evidences, geochemical and fluid inclusion results indicate two successive alteration fluids interacting with γb, (1) a late-magmatic F− and CO2−rich fluid and (2) a post-magmatic, aqueous and slightly saline fluid. The depletion of LREE and Th content and the increase in HREE, Y and U content correspond, in the magmatic suite to the early fractionation of monazite in the granites where there is no hydrothermal alteration (granites Xe and γe) and to the hydrothermal alteration of monazite into parisite and secondary apatite, intense new formation of yttroparisite, Y enrichment and U loss in the uranothorite and late crystallization of uraninite in the granites γc and γb. Moreover, simulated crystallization of monazite and temperature of monazite saturation show early fractionation of monazite from the magma in the less evolved granites (Xe and γe) and prevailing hydrothermal leaching of monazite in the most evolved granites (γc-γd and γb) related to a late-magmetic event. The slight variations of REE, Y, Th and U content in the K-altered granites compared to granite γb emphazes the distinct chemical nature of the successive hydrothermal fluids. Rb−Sr and Sm−Nd isotopic results point to a 30 Ma period of time between the late-magmatic and the post-magmatic fluid circulation. Springer-Verlag, 1990 Maruéjol Patricia Centre de Recherches sur la Géologie de l'Uranium, GS-CNRS-CREGU, BP 23, F-54501, Vandoeuvre-lès-Nancy Cedex, France aut Cuney Michel Centre de Recherches sur la Géologie de l'Uranium, GS-CNRS-CREGU, BP 23, F-54501, Vandoeuvre-lès-Nancy Cedex, France aut Turpin Laurent DCAEA/SEA, CEN-Valrho, BP 171, F-30205, Bagnols sur Cèze, France aut Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 668-680 0010-7999 104:6<668 1990 104 410 https://doi.org/10.1007/BF01167286 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01167286 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Maruéjol Patricia Centre de Recherches sur la Géologie de l'Uranium, GS-CNRS-CREGU, BP 23, F-54501, Vandoeuvre-lès-Nancy Cedex, France aut NATIONALLICENCE 700 1- Cuney Michel Centre de Recherches sur la Géologie de l'Uranium, GS-CNRS-CREGU, BP 23, F-54501, Vandoeuvre-lès-Nancy Cedex, France aut NATIONALLICENCE 700 1- Turpin Laurent DCAEA/SEA, CEN-Valrho, BP 171, F-30205, Bagnols sur Cèze, France aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 668-680 0010-7999 104:6<668 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer