All Title Author
Keywords Abstract

Mineral Chemistry of REE-Rich Apatite and Sulfur-Rich Monazite from the Mushgai Khudag, Alkaline Volcanic-Plutonic Complex, South Mongolia

DOI: 10.4236/ijg.2016.71003, PP. 20-31

Keywords: Fluorapatite, Hydroxyl-Bearing Fluorapatite, Sulfur-Rich Monazite, Mushgai Khudag

Full-Text   Cite this paper   Add to My Lib


The Mushgai khudag volcanic-plutonic complex consists of four REE mineralization zones: carbonatite zone, apatite zone, magnetite zone, and monazite zone. REE mineralization occurs within peripheries of alkaline magmatic rocks which consist of porphyritic syenite, microsyenite and quartz syenites. Three types of LREE-rich apatite can be found in the carbonatite, apatite, and monazite zones. Crystal-1 type of apatite exists as hexagonal prismatic shape and is mostly found in the apatite zone, and in syenite. Crystal-2 type of apatite can be exposed also at the apatite zone, and carbonatite zone as brecciated massive crystalline aggregate. Crystal-3 type of apatite demonstrates the compositional zoning texture with monazite as inter-zoning, and is only found in monazite zone. The LREE-bearing apatites from the Mushgai khudag complex are mostly fluorapatite to hydroxyl-bearing fluorapatite with variable REE content. Apatites from the monazite zone present individual sulfur-rich monazite grain, and are formed by comprehensive substitutions.


[1]  Dorjpalma, E. (2014) Mineralogical and Geochemical Study of the Mushgai Khudag Deposit. Master Dissertation, Department of Earth and Environmental Science, Korea University, Seoul.
[2]  Baatar, M., Ochir, G., Kynicky, J., Iizumi, S. and Comi-Ciaramonti, P. (2013) Some Notes on the Lugiin Gol, Mushgai-Khudag- and Bayan-Khoshuu Alkaline Complexes, Southern Mongolia. International Journal of Geosciences, 4, 1200-1214.
[3]  Harlov, D.E. and Forster, H.J. (2003) Fluid-Induced Nucleation of (Y+REE)-Phosphate Mineral within Apatite: Nature Experiment. Part II. Fluorapatite. American Mineralogist, 88, 1209-1229.
[4]  Harlov, D.E., Forster, H.J. and Schmidt, C. (2003) High P-T Experimental Metasomatism of a Fluorapatite with Significant Britholite and Fluorsellestadite Components: Implications for LREE Mobility during Granulite-Facies Metamorphism. Mineralogical Magazine, 67, 61-72.
[5]  Samoilov, V.C., Ivanov, V.G., Senge, D. and Kovalenko, V.I. (1983-1984) Prognostic Evaluation of Mushgia Rare Earth’s Deposit. Report.
[6]  Pan, Y. (1997) Zircon and Monazite Forming Metamorphic Reactions at Manitawadge Ontaria. Canada, Mineral, 35, 105-119.
[7]  Harlov, D.E., Forster, H.J. and Nijland, T.G. (2002) Fluid-Induced Nucleation of (Y + REE) Phosphate Minerals in Apatite: Nature and Experiment. Part I. Chlorapatite. American Mineralogist, 87, 245-261.
[8]  Pan, Y. and Fleet, M.E. (2002) Compositions of the Apatite-Group Minerals: Subtitution Mechanisms and Controlling Factors. Reviews in Mineralogy and Geochemistry, 48, 13-49.
[9]  Chakhmouradian, A.R. and Mitchell, R.H. (1999) Niobianilmenite, Hydroxylapatite and Sulfur-Rich Monazite: Alternative Hosts for Incompatible Elements in Calcite Kimberlite from Internatsional’Naya, Yakutia. The Canadian Mineralogist, 37, 1177-1189.
[10]  Bayarsaikhan, T. and Bayardalai, S. (2010) Exploration Report of the Mushgai Khudag Deposit. Report. (In Mongolia)
[11]  Watt, G.R. (1995) High-Thorium Monazite-(Ce) Formed during Disequilbrium Melting of Metapelties under Granulite-Facies Conditions. Mineralogical Magazine, 59, 735-743.
[12]  Pan, Y. and Fleet, M.E. (1995) Site Preference of Rare Earth Elements in Fluorapatite. American Mineralogist, 80, 329-335.
[13]  Pan, Y. and Fleet, M.E. (1993) Oriented Monazite Inclusions in Apatite Porphyroblasts from the Hemlo Gol Deposit, Ontaria. Canada, Mineral, Mag, 57, 697-707.
[14]  Chakhmouradian, A.R. and Mitchel, R.H. (1998) Lueshite, Pyrochlore and Monazite-(Ce) from Apatite-Dolomite Carbonatite, Lesnaya Varaka Complex, Kola Peninsula, Russia. The Canadian Mineralogist, 62, 769-782.
[15]  Rose, D. (1980) Barbanatite, CaTh(PO4)2, a New Mineral of the Monazite Group. Neues Jahrbuch für Mineralogie-Monatshefte, 247-257.
[16]  Jaroslav, P., Martin, O., Peter, B. and Bartosz, B. (2010) Methamorphic-Hydrothermal REE Minerals in the Bacuch Magnetite Deposit, Western Carpathias, Slovakia: (Sr, S)-Rich Monazite-(Ce) and Nd-Dominant Hingganite. The Canadian Mineralogist, 48, 81-94.
[17]  Giere, R. (1993) Transport and Deposition of REE in H2S-Rich Fluids: Evidence from Accessory Mineral Assemblages. Chemical Geology, 110, 251-268.
[18]  Palmer, M.A. (1998) Rare Earth Element Speciation in Geothermal Fluids from Yellowstone National Park, Wyoming, USA. Geochimica et Cosmochimica Acta, 62, 657-663.
[19]  Michard, A. (1989) Rare Earth Element Systematics in Hydrothermal Fluids. Geochimica et Cosmochimica Acta, 53, 745-750.
[20]  Banks, D.Y. (1994) REE Composition of an Aqueous Magmatic Fluid: A Fluid Inclusion Study from the Captain Pluton, New Mexico. Chemical Geology, 113, 22.
[21]  Wood, A. (1990) The Aquesous Geochemistry of the Rare-Earth Elements and Yttrium. Theoretical Predictions of Speciation in Hydrothermal Solutions to 350?C at Saturation Water Vapor Pressure. Chemical Geology, 88, 99-125.
[22]  Brookins, D. (1989) Aqueous Geochemistry of Rare Earth Elements, in Geochemistry and Mineralogy of the Rare Earth Elements. Reviews in Mineralogy, 21, 201-225.
[23]  Ahrland, S. (1968) Thermodynamics of Complex Formation between Hard and Soft Acceptors and Donors. Structure and Bonding, 5, 118-149.


comments powered by Disqus