Summary
Bastnaesites of Ce and La and their OH-analogs were synthesized and their stability relations were determined atPf = 1 kbar andT = 400 to 900°C in a part of the system (Ce,La)-F-H-C-0. The initial fluid compositions were such that\(P_{CO_2 } \approx \frac{1}{2}P_f \) and HF/(HF + H2O) ratios were 0 to 0.172. XRD and IR studies indicate that bastnaesites equilibrated in initial fluids low in HF are all F-enriched. The hydroxylbastnaesite-(La) is stable up to 810°C and the fluorbastnaesite-(La) is stable up to 860°C. Their condensed breakdown products are La2O2CO3 and LaOF, respectively. The stability of Ce bastnaesites is slightly\(f_{0_2 } \) dependent. The hydroxylbastnaesite-(Ce) is stable up to 660°C at the\(f_{0_2 } \) defined by the IQF buffer and up to 640°C by the MH buffer. The fluorbastnaesite-(Ce) is stable up to 800°C at the\(f_{0_2 } \) defined by the IQF and up to 760°C by the MH buffer. The condensed breakdown product for the hydroxyl end-member is simply CeO2 but for the fluorine one is a combination of CeO2, CeF3, and CeOF. Factors, such as OH vs F,\(f_{0_2 } \), and bulk composition, that affect the stability of individual species are discussed. Petrogenic implications resulting from the present study include that bastnaesites can be stable from hydrothermal to magmatic conditions, that F-enriched species can form in an environment relatively low in F content, and that OH-species are rare and occur only in low-temperature environments essentially devoid of F.
Zusammenfassung
Ce- und La-Bastnäsite, sowie deren OH-Analoga wurden synthetisiert und ihre Stabilitätsbeziehunger beiP f = 1 kbar undT = 400 bis 900°C wurden im System (Ce,La)F-H-C-O bestimmt. Die anfänglichen Flüssigkeitszusammensetzungen waren so, daß\(P_{CO2} \approx \frac{1}{2}P_f \) und die HF/(HF + H2O)-Verhältnisse 0–0.172 waren. Röntgenpulver- und Ultrarot-Untersuchungen zeigten, daß Bastnäsite, die mit anfänglich HF-armen Flüssigkeiten equilibriert wurden, alle an F angereichert sind. Hydroxilbastndsit-(La) ist bis 810°C und Fluorbastnäsit-(La) bis 860°C stabil. Ihre festen Zersetzungsprodukte sind La2O2O3, bzw. LaOF. Die Stabilität der Ce-Bastnäsite hängt etwas von\(f_{0_2 } \) ab. Hydroxilbastnäsit-(Ce) ist bei\(f_{0_2 } \) des Eisen-Quarz-Fayalit-Puffers bis 660°C stabil und mit Magnetit-Hämatit-Puffer bis 640°C. Das feste Zerfallsprodukt ist für das Hydroxil-Glied nur CeO2, für das Fluor-Glied eine Mischung aus CeO2, CeF3 und CeOF. Faktoren, welche die Stabilität der einzelnen Spezies beeinflussen, werden diskutiert, wie das Verhältnis OH zu F,\(f_{0_2 } \) und die Gesamtzusammensetzung. Petrogenetische Folgerungen aus der vorliegenden Studie schließen ein, daß Bastnäsite von hydrothermalen bis zu magmatischen Bedingungen stabil sein können, daß sich an F angereicherte Glieder in relativ F-armer Umgebung bilden können, und daß OH-Glieder selten sind und nur unter Bildungsbedingungen niedriger Temperatur und weitgehender Abwesenheit von F auftreten.
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References
Akhmanova MV, Orlova LP (1966) Investigation of rare-earth carbonates by infra-red spectroscopy. Geochem Intl 5: 444–451
Aleksandrov IV, Ivanov VI, Sin'kova LA (1965) ew information on bastnaesite. Zap. VMO, 2nd set., part XCIV, fasc. 3
Appleman DE, Evan HT (1973) Indexing and least-squares refinement of powder diffraction data. US Natl Tech Inform Serv PB-216-188
Burt DM (1989) Compositional and phase relationships among rare earth element minerals. In:Lipin BP, McKay GA (ed) Geochemistry and Mineralogy of Rare Earth Elements, Reviews in Mineralogy 21, pp 259–308
Chai BHT, Mroczkowski S (1978) Synthesis of rare-earth carbonates under hydrothermal conditions. J Cryst Growth 44: 84–97
Christensen AN (1973) Hydrothermal preparation of rare earth hydroxyl-carbonates. The crystal structure of NdOHCO3. Acta Chem Scand 27: 2973–2982
Day HW (1973) The high temperature stability of muscovite plus quartz. Amer Mineral58: 255–262
Donnay G, Donnay JDH (1953) The crystallography of bastnaesite, parisite, roentgenite, and synchisite. Am Mineral 38: 932–963
Evans BW (1965) Application of reaction-rate method to the breakdown equilibia of muscovite and muscovite plus quartz. Am J Sci 263: 647–667
Fleischer M (1978) Relative proportions of the lanthanides in minerals of the bastnaesite group. Can Mineral 16: 361–363
Garvey R (1985) LSUCRIPC, least square unit cell refinement and indexing with the personal computer. Powder Diff 1: 114
Glass JJ, Evans HT Jr, Carron MK, Hildebrand FA (1958) Cerite from Mountain Pass, San Bernadino County, California. Am Mineral 43: 460–475
Haschke JM (1975) The lanthanum hydroxide fluoride carbonate system: The preparation of synthetic bastnaesite. J Solid State Chem 12: 115–121
——Eyring L (1971) Hydrothermal equilibria and crystal growth of rare earth oxides, hydroxides, hydroxynitrates, and hydroxylcarbonates. Inorg Chem 10: 2267–2274
Holloway JR, Burnham CW, Millhollen GL (1968) Generation of H2O-CO2 mixtures for use in hydrothermal experimentation. J Geophys Res 73: 6598–6600
Hsu LC (1976) The stability of the wolframite series. Am Mineral 61: 944–955
Huang S, Wang Z, Zhang A, He S (1986) Experimental studies of the conditions of formation of bastnaesite. Acta Mineral Sinica 6: 157–160
Jones AP, Wyllie PJ (1986) Solubility of rare earth elements in carbonatite magmas, indicated by the liquidus surface in CaCO3-Ca(OH)2-La(OH)3 at 1 kbar pressure. Appl Geochem 1: 95–102
Kirillov AS (1964) Hydroxylbastnaesite, a new variety of bastnaesite. Doklady Akad Nauk SSSR 159: 93–95
Korzhinskiy MA (1981) Apatite solid solutions as indicators of the fugacity of HCl° and HF° in hydrothermal fluids. Geochem Intl 18: 44–60
Kutty TRN, Viswanathiah MN, Tareen JAK (1978) Hydrothermal equilibria in Nd2O3H2O-CO2 system. Proc Ind Acad Sci 87A: 69–74
Maksimovic Z, Panto G (1985) Hydroxyl-bastnaesite-(Nd), a new mineral from Montenegro, Yugoslavia. Mineral Mag 49: 717–720
Munoz JL, Eugster HP (1969) Experimental control of fluorine reactions in hydrothermal systems. Am Mineral 54: 943–959
Oftedal I (1931) Zur Kristallstruktur von Bastnasit (Ce,La-)FCO3. Z Krist 78: 462–469
Sawyer J, Caro P, Eyring L (1973) Hydroxyl-carbonates of lanthanide elements. Rev Chim Mineral 10: 93–104
Tareen JAK, Kutty TRN (1980) Hydrothermal phase equilibria in Ln2O3-H2O-CO2 systems. 1. The lighter lanthanides. J Cryst Growth 50: 527–532
Tuttle OF (1949) Two pressure vessels for silicate-water studies. Geol Soc Amer Bull 60: 1727–1729
Wakita H, Kinoshita S (1979) A synthetic study of the solid solutions in the system La2(CO3)3 · 8H2O-Ce2(CO3)3 · 8H2O and La(OH)CO3-Ce(OH)CO3. Bull Chem Soc Japan 52: 428–432
Williams-Jones AE, Wood SA (1992) A preliminary petrogenetic grid for REE fluorocarbonates and associated minerals. Geochim Cosmochim Acta 56: 725–738
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Hsu, L.C. Synthesis and stability of bastnaesites in a part of the system (Ce,La)-F-H-C-O. Mineralogy and Petrology 47, 87–101 (1992). https://doi.org/10.1007/BF01165299
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DOI: https://doi.org/10.1007/BF01165299