Unusually Y-rich monazite-(Ce) with 6–14 wt.% Y2O3 in a granulite from the Bohemian Massif: implications for high-temperature monazite growth from the monazite-xenotime miscibility gap thermometry

Abstract Accessory monazite-(Ce) with an extraordinarily high proportion of the xenotime component in solid solution of 21–42 mol.% (6.5–14 wt.% Y2O3, 6–11 wt.% HREE 2O3) was discovered in a retrogressed Variscan high-pressure, high-temperature granulite from the southern Bohemian Massif, Austria. The grains with the highest proportion of xenotime (XXno ~0.4) should have had a minimum formation temperature of ~1050°C, according to published monazite-xenotime miscibility gap thermometers. This high temperature is consistent with previous petrological studies on the south Bohemian granulites indicating ~1000°C/16 kbar for the peak metamorphic stage.

[1]  A. Gerdes,et al.  Resolving the Variscan evolution of the Moldanubian sector of the Bohemian Massif: the significance of the Bavarian and the Moravo-Moldanubian tectonometamorphic phases , 2012 .

[2]  A. Locock,et al.  A new garnet, {(Y, REE)(Ca, Fe2+)2}[(Mg,Fe2+)(Fe3+,Al)](Si3)O12, and its role in the yttrium and rare-earth element budget in a granulite , 2009 .

[3]  F. Finger,et al.  Two types of metamorphic monazite with contrasting La/Nd, Th, and Y signatures in an ultrahigh-pressure metapelite from the Pohorje Mountains, Slovenia: Indications for pressure-dependent REE exchange between apatite and monazite? , 2009 .

[4]  F. Finger,et al.  Detrital and newly formed metamorphic monazite in amphibolite-facies metapelites from the Motajica Massif, Bosnia , 2008 .

[5]  E. Grew,et al.  Aureoles of Pb(II)-enriched feldspar around monazite in paragneiss and anatectic pods of the Napier Complex, Enderby Land, East Antarctica: the roles of dissolution-reprecipitation and diffusion , 2008 .

[6]  R. Parrish,et al.  Clasts of Variscan high‐grade rocks within Upper Viséan conglomerates – constraints on exhumation history from petrology and U‐Pb chronology , 2007 .

[7]  F. Finger,et al.  Metamorphic formation of Sr-apatite and Sr-bearing monazite in a high-pressure rock from the Bohemian Massif , 2004 .

[8]  C. Pin,et al.  Deciphering the petrogenesis of deeply buried granites: whole-rock geochemical constraints on the origin of largely undepleted felsic granulites from the Moldanubian Zone of the Bohemian Massif , 2004, Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

[9]  R. Wirth,et al.  Experimental determination of Thorium partitioning between monazite and xenotime using analytical electron microscopy and X-ray diffraction Rietveld analysis , 2002 .

[10]  D. Harlov.  High-Grade Fluid Metasomatism on both a Local and a Regional Scale: the Seward Peninsula, Alaska, and the Val Strona di Omegna, Ivrea–Verbano Zone, Northern Italy. Part II: Phosphate Mineral Chemistry , 2002 .

[11]  F. Spear,et al.  Monazite–Xenotime–Garnet Equilibrium in Metapelites and a New Monazite–Garnet Thermometer , 2001 .

[12]  R. Cooke.  High-pressure/temperature metamorphism in the St. Leonhard Granulite Massif, Austria: evidence from intermediate pyroxene-bearing granulites , 2000 .

[13]  W. Heinrich,et al.  Monazite-xenotime thermobarometry: Experimental calibration of the miscibility gap in the binary system CePO4-YPO4 , 1997 .

[14]  W. Heinrich,et al.  Monazite–xenotime miscibility gap thermometry. I. An empirical calibration , 1997 .

[15]  G. Franz,et al.  Crystal chemistry of monazite and xenotime from Saxothuringian-Moldanubian metapelites, NE Bavaria, Germany , 1996 .

[16]  P. O'Brien,et al.  Tectonometamorphic evolution of the Bohemian Massif: evidence from high pressure metamorphic rocks , 1993 .

[17]  A. Rao,et al.  The geochemistry of monazite types from the Eastern Ghats granulite terrain, India , 1991 .

[18]  RnNE Gnarz .lNn,et al.  Monazite-xenotime thermobarometry: Experimental calibration of the miscibility gap in the binary system CePOo-YPOo , 2007 .

[19]  W. Carlson,et al.  Monazite and xenotime petrogenesis in the contact aureole of the Makhavinekh Lake Pluton, northern Labrador , 2005 .

[20]  W. Franke.  The mid-European segment of the Variscides: tectonostratigraphic units, terrane boundaries and plate tectonic evolution , 2000, Geological Society, London, Special Publications.

[21]  F. Spear,et al.  An empirical garnet (YAG) – xenotime thermometer , 2000 .

[22]  P. O'Brien.  The fundamental Variscan problem: high-temperature metamorphism at different depths and high-pressure metamorphism at different temperatures , 2000, Geological Society, London, Special Publications.

[23]  O. V. Breemen,et al.  Geochronological studies of the Bohemian massif, Czechoslovakia, and their significance in the evolution of Central Europe , 1982, Transactions of the Royal Society of Edinburgh: Earth Sciences.

[24]  G. Fuchs.  Zur Entwicklung der Böhmischen Masse , 1976 .