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Licensed Unlicensed Requires Authentication Published by De Gruyter November 30, 2016

Hydrothermal mineral replacement reactions for an apatite-monazite assemblage in alkali-rich fluids at 300–600 °C and 100 MPa

  • Wladyslaw B. Betkowski EMAIL logo , Daniel E. Harlov and John F. Rakovan
From the journal American Mineralogist

Abstract

Mineral replacement reactions are common in the various environments where rocks have undergone re-equilibration with geologic fluids. Replacement reactions commonly take the form of fluid-aided, coupled dissolution-precipitation and often result in pseudomorph formation. One class of environment that frequently shows significant examples of mineral replacements is hydrothermal ore deposit systems. The goal of this study was to test the simultaneous reactivity of fluorapatite and monazite in Na- and Si-rich hydrothermal fluids, which partially mimic the mineralogy and fluid chemistry of the Llallagua tin deposit in Bolivia. A series of experiments were performed at 300 to 600 °C and 100 MPa, utilizing various combinations of monazite, fluorapatite, and H2O + Na2Si2O5. Reaction products were evaluated using scanning electron microscopy, electron microprobe analysis, and single-crystal X-ray diffraction. The results of this experimental study show that fluorapatite and monazite are differentially reactive under the conditions studied. The reaction products, pathways, and kinetics have a large temperature dependence. The 300 and 400 °C experiments show variable amounts of monazite replacement and only minor, if any, dissolution or reactivity of fluorapatite. The high-temperature 500 and 600 °C experiments are characterized by massive replacement of monazite by vitusite and britholite. Exclusively at 600 °C, monazite alteration takes the form of symplectite development at the reaction front as vermicular intergrowths of vitusite and britholite. The higher-temperature experiments also show substantially more reactivity by fluorapatite, which is partially pseudomorphically altered into britholite. This is an example of regenerative mineral replacement where both fluorapatite and britholite share the same atomic structure and are crystallographically coherent after the partial replacement. The britholite replacement is characterized by the presence of oriented nanochannels, which facilitate fluid-based mass transfer between the bulk solution and the reaction front. The fluorapatite replacement is enhanced by monazite alteration through a self-perpetuating, positive feedback mechanism between these two reactions, which enhance the REE mobility in alkali-bearing fluids and further drives bulk re-equilibration. These results have potential geochronologic implications and may be significant in the evaluation of monazite and fluorapatite as potential solid nuclear waste forms. They also give us deeper insights into the mechanism of mineral replacement reactions and porosity development.


Special collection papers can be found online at http://www.minsocam.org/MSA/AmMin/special-collections.html.


Acknowledgments

We thank Dieter Rhede of the GeoForschungsZentrum, Potsdam, for his expertise with the electron microprobe and helpful comments. Richard Edelman and Mat Duley are thanked for assistance with the SEM. We thank Jaroslaw Majka and an anonymous reviewer for their insightful comments on an earlier version on this manuscript. Support for this work was provided by the National Science Foundation through grant EAR-0952298 to J.R. We also thank Tresa Foster and Brian Kosnar for the Llallagua monazites used in these experiments.

References cited

Andersen, T., and Sørensen, H. (2005) Stability of naujakasite in hyperagpaitic melts, and the petrology of naujakasite lujavrite in the Ilímaussaq alkaline complex, South Greenland. Mineralogical Magazine, 69, 125–136.10.1180/0026461056920240Search in Google Scholar

Betkowski, W., Rakovan, J., and Harlov, D. (2015) Monazite, xenotime and apatite chemistry and textures: Clues to understanding geochronologic discrepancies in the Llallagua Tin Deposit, Bolivia. Goldschmidt Abstracts p. 283.Search in Google Scholar

Bhowmik, S.K., Wilde, S.A., Bhandari, A., and Basu Sarbadhikari, A. (2014) Zoned monazite and zircon as monitors for the thermal history of granulite terranes: An example from the Central Indian Tectonic Zone. Journal of Petrology, 55, 585–621.10.1093/petrology/egt078Search in Google Scholar

Budzyń, B., Harlov, D.E., Williams, M.L., and Jercinovic, M.J. (2011) Experimental determination of stability relations between monazite, fluorapatite, allanite, and REE-epidote as a function of pressure, temperature, and fluid composition. American Mineralogist, 96, 1547–1567.10.2138/am.2011.3741Search in Google Scholar

Cámara, F., Ottolini, L., Devouard, B., Garvie, L.A.J., and Hawthorne, F.C. (2006) Sazhinite-(La), Na3LaSi6O15(H2O)2, a new mineral from the Aris phonolite, Namibia: Description and crystal structure. Mineralogical Magazine, 70, 405–418.10.1180/0026461067040343Search in Google Scholar

Chew, D.M., and Spikings, R.A. (2015) Geochronology and thermochronology using apatite: time and temperature, lower crust to surface. Elements, 11, 189–194.10.2113/gselements.11.3.189Search in Google Scholar

De Lucas, A., Lourdes, R., Sanchez, P., Carmona, M., Romero, P., and Lobato, J. (2004) Comparative study of the solubility of the crystalline layered silicates α-Na2Si2O5 and δ-Na2Si2O5 and the amorphous silicate Na2Si2O5. Industrial and Engineering Chemistry Research, 42, 1472–1477.10.1021/ie0303909Search in Google Scholar

Dietrich, A., Lehmann, B., and Wallianos, A. (2000) Bulk rock and melt inclusion geochemistry of Bolivian tin porphyry systems. Econimic Geology, 95, 313–326.10.2113/gsecongeo.95.2.313Search in Google Scholar

Elliott, J.C. (2013) Structure and Chemistry of the Apatites and Other Calcium Orthophosphates. Elsevier.Search in Google Scholar

Ewing, R.C., and Wang, L. (2002) Phosphates as nuclear waste forms. In M.L. Kohn, J. Rakovan, and J.M. Hughes, Eds., Phosphates, 48, p. 673–699. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America, Chantilly, Virginia.10.2138/rmg.2002.48.18Search in Google Scholar

Finch, A.A., and Fletcher, J.G. (1992) Vitusite—An apatite derivative structure. Mineralogical Magazine, 56, 235–239.10.1180/minmag.1992.056.383.10Search in Google Scholar

Grant, J.N., Halls, C., Sheppard, S.M.F., and Avila, W. (1980) Evolution of the porphyry tin deposits of Bolivia. Mining Geology, Special Issue, 8, 151–173.Search in Google Scholar

Harlov, D.E. (2015) Apatite: A fingerprint for metasomatic processes. Elements, 11, 171–176.10.2113/gselements.11.3.171Search in Google Scholar

Harlov, D.E., and Förster, H.-J. (2002) 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. Journal of Petrology, 43, 801–824.10.1093/petrology/43.5.801Search in Google Scholar

Harlov, D.E., and Förster, H.-J. (2003) Fluid-induced nucleation of (Y+REE)-phosphate minerals within apatite: Nature and experiment. Part II. Fluorapatite. American Mineralogist, 88, 1209–1229.10.2138/am-2003-8-905Search in Google Scholar

Harlov, D.E., and Hetherington, C.J. (2010) Partial high-grade alteration of monazite using alkali-bearing fluids: Experiment and nature. American Mineralogist, 95, 1105–1108.10.2138/am.2010.3525Search in Google Scholar

Harlov, D.E., and Wirth, R. (2012) Experimental incorporation of Th into xenotime at middle to lower crustal P-T utilizing alkali-bearing fluids. American Mineralogist, 97, 641–652.10.2138/am.2012.3865Search in Google Scholar

Harlov, D.E., Wirth, R., and Förster, H.-J. (2005) An experimental study of dissolution–reprecipitation in fluorapatite: fluid infiltration and the formation of monazite. Contributions to Mineralogy and Petrology, 150, 268–286.10.1007/s00410-005-0017-8Search in Google Scholar

Harlov, D.E., Wirth, R., and Hetherington, C.J. (2010) Fluid-mediated partial alteration in monazite: the role of coupled dissolution–reprecipitation in element redistribution and mass transfer. Contributions to Mineralogy and Petrology, 162, 329–348.10.1007/s00410-010-0599-7Search in Google Scholar

Harrison, T.M., Catlos, E.J., and Montel, J.-M. (2002) U-Th-Pb dating of phosphate minerals. In M.L. Kohn, J. Rakovan, and J.M. Hughes, Eds., Phosphates, 48, p. 524–558. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America, Chantilly, Virginia.10.2138/rmg.2002.48.14Search in Google Scholar

Hughes, J.M., and Rakovan, J.F. (2015) Structurally robust, chemically diverse: Apatite and apatite supergroup minerals. Elements, 11, 165–170.10.2113/gselements.11.3.165Search in Google Scholar

Jarosewich, E., and Boatner, L.A. (1991) Rare-earth element reference samples for electron microprobe analysis. Geostandards Newsletter, 15, 397–399.10.1111/j.1751-908X.1991.tb00115.xSearch in Google Scholar

Jonas, L., John, T., King, H.E., Geisler, T., and Putnis, A. (2014) The role of grain boundaries and transient porosity in rocks as fluid pathways for reaction front propagation. Earth and Planetary Science Letters, 386, 64–74.10.1016/j.epsl.2013.10.050Search in Google Scholar

Kelly, W.C., and Turneaure, F.S. (1970) Mineralogy, paragenesis and geothermometry of the tin and tungsten deposits of the eastern Andes, Bolivia. Economic Geology, 65, 609–680.10.2113/gsecongeo.65.6.609Search in Google Scholar

Kempe, U., Lehmann, B., Wolf, D., Rodionov, N., Bombach, K., Schwengfelder, U., and Dietrich, A. (2008) U–Pb SHRIMP geochronology of Th-poor, hydrothermal monazite: An example from the Llallagua tin-porphyry deposit, Bolivia. Geochimica et Cosmochimica Acta, 72, 4352–4366.10.1016/j.gca.2008.05.059Search in Google Scholar

Kohn, M.J., and Vervoort, J.D. (2008) U-Th-Pb dating of monazite by singlecollector ICP-MS: Pitfalls and potential. Geochemistry, Geophysics, Geosystems, 9, 1–16.10.1029/2007GC001899Search in Google Scholar

Kontak, D.J., and Clark, A.H. (2002) Genesis of the Giant, Bonanza San Rafael Lode Tin Deposit, Peru: Origin and significance of pervasive alteration. Economic Geology, 97, 1741–1777.10.2113/gsecongeo.97.8.1741Search in Google Scholar

Kusiak, M.A., Williams, I.S., Dunkley, D.J., Konečny, P., Słaby, E., and Martin, H. (2014) Monazite to the rescue: U-Th-Pb dating of the intrusive history of the composite Karkonosze pluton, Bohemian Massif. Chemical Geology, 364, 76–92.10.1016/j.chemgeo.2013.11.016Search in Google Scholar

Obata, M. (2011) Kelyphite and symplectite: textural and mineralogical diversities and universality, and a new dynamic view of their structural formation. INTECH Open Access Publisher.10.5772/20265Search in Google Scholar

Pan, Y., and Fleet, M.E. (2002) Compositions of the apatite-group minerals: substitution mechanisms and controlling factors. In M.L. Kohn, J. Rakovan, and J.M. Hughes, Eds., Phosphates, 48, p. 13–49. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America, Chantilly, Virginia.10.1515/9781501509636-005Search in Google Scholar

Pirajno, F. (2013) Effects of metasomatism on mineral systems and their host rocks: alkali metasomatism, skarns, greisens, tourmalinites, rodingites, black-wall alteration and listvenites. In D.E. Harlov and H.O. Austrheim, Eds., Metasomatism and the Chemical Transformation of Rock, pp. 203–251. Springer.10.1007/978-3-642-28394-9_7Search in Google Scholar

Pöml, P., Menneken, M., Stephan, T., Niedermeier, D.R.D., Geisler, T., and Putnis, A. (2007) Mechanism of hydrothermal alteration of natural self-irradiated and synthetic crystalline titanate-based pyrochlore. Geochimica et Cosmochimica Acta, 71, 3311–3322.10.1016/j.gca.2007.03.031Search in Google Scholar

Putnis, A. (2002) Mineral replacement reactions: from macroscopic observations to microscopic mechanisms. Mineralogical Magazine, 66, 689–708.10.1180/0026461026650056Search in Google Scholar

Putnis, A. (2009) Mineral replacement reactions. In E.H. Oelkers and J. Schott, Eds., Thermodynamics and Kinetics of Water-Rock Interaction, 70, p. 87–124. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America, Chantilly, Virginia.10.1515/9781501508462-005Search in Google Scholar

Rakovan, J.F. (2002) Growth and surface properties of apatite. In M.L. Kohn, J. Rakovan, and J.M. Hughes, Eds., Phosphates, 48, p. 51–86. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America, Chantilly, Virginia.10.1515/9781501509636-006Search in Google Scholar

Rakovan, J.F. (2013) Apatite and other phosphates from Llallagua, Bolivia: An interesting story of hydrothermal mineralization and pseudomorphism. Rochester Mineralogical Symposium Program with Abstracts.Search in Google Scholar

Rakovan, J.F. McDaniel, D.K., and Reeder, R.J. (1997) Use of surface-controlled REE sectoral zoning in apatite from Llallagua, Bolivia, to determine a single-crystal Sm-Nd age. Earth and Planetary Science Letters, 146, 329–336.10.1016/S0012-821X(96)00226-9Search in Google Scholar

Rapp, R.P., and Watson, E.B. (1986) Monazite solubility and dissolution kinetics: implications for the thorium and light rare earth chemistry of felsic magmas. Contributions to Mineralogy and Petrology, 94, 304–316.10.1007/BF00371439Search in Google Scholar

Ronsbo, J.G., Khomyakov, A.P., Semenov, E.I., Voronkov, A.A., and Garanin, V.K. (1979) Vitusite—A new phosphate of sodium and rare earths from the Lovozero Alkaline Massif, Kola, and the Ilimaussaq Alkaline Intrusion, South Greenland. Journal of Mineralogy and Geochemistry, 137, 42–53.Search in Google Scholar

Schettler, G., Gottschalk, M., and Harlov, D.E. (2011) A new semi-micro wet chemical method for apatite analysis and its application to the crystal chemistry of fluorapatite-chlorapatite solid solutions. American Mineralogist, 96, 138–152.10.2138/am.2011.3509Search in Google Scholar

Sillitoe, R.H., Halls, C., and Grant, J.N. (1975) Porphyry tin deposits in Bolivia. Economic Geology, 70, 913–927.10.2113/gsecongeo.70.5.913Search in Google Scholar

Stormer, J., Pierson, M.L., and Tacker, R.C. (1993) Variation of F and Cl X-ray intensity due to anisotropic diffusion in apatite. American Mineralogist, 78, 641–648.Search in Google Scholar

Sugaki, A., Kojima, S., and Shimada, N. (1988) Fluid inclusion studies of the polymetallic hydrothermal ore deposits in Bolivia. Mineralium Deposita, 15, 9–15.10.1007/BF00204221Search in Google Scholar

Torab, F.M., and Lehmann, B. (2007) Magnetite-apatite deposits of the Bafq district, Central Iran: Apatite geochemistry and monazite geochronology. Mineralogical Magazine, 71, 347–363.10.1180/minmag.2007.071.3.347Search in Google Scholar

Tropper, P., Manning, C.E., and Harlov, D.E. (2013) Experimental determination of CePO4 and YPO4 solubilities in H2O–NaF at 800° C and 1 GPa: Implications for rare earth element transport in high-grade metamorphic fluids. Geofluids, 13, 372–380.10.1111/gfl.12031Search in Google Scholar

Williams, M.L., Jercinovic, M.J., Harlov, D.E., Budzyń, B., and Hetherington, C.J. (2011) Resetting monazite ages during fluid-related alteration. Chemical Geology, 283, 218–225.10.1016/j.chemgeo.2011.01.019Search in Google Scholar

Xia, F., Brugger, J., Chen, G., Ngothai, Y., O’Neill, B., Putnis, A., and Pring, A. (2009) Mechanism and kinetics of pseudomorphic mineral replacement reactions: A case study of the replacement of pentlandite by violarite. Geochimica et Cosmochimica Acta, 73, 1945–1969.10.1016/j.gca.2009.01.007Search in Google Scholar

Received: 2016-3-13
Accepted: 2016-7-25
Published Online: 2016-11-30
Published in Print: 2016-12-1

© 2016 by Walter de Gruyter Berlin/Boston

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