Summary
Within the Nkombwa Hill carbonatite complex, bastnäsite-(Ce), (Ce,La)CO3F, has been identified as an abundant mineral in xenoliths hosted by late-stage ferrocarbonatite sills and dykes. Bastnäsite-(Ce) occurs as fibrous yellow crystals, about 1 µm in size, replacing monazite and in association with baryte, in a matrix of dolomite. In common with bastnäsite-(Ce) from other locations, the bastnäsite-(Ce) of Nkombwa Hill contains up to 70% RE2O3, almost entirely as light rare-earth oxides. However, Nkombwa Hill bastnäsite-(Ce) is relatively deficient in La and enriched in Pr and Nd.
Zusammenfassung
Im Karbonatit-Komplex von Nkombwa Hill kommt Bastnäsit-(Ce), (Ce-La) CO3F, als eine weitverbreitete Komponente in Xenolithen in späten Ferrokarbonatit-Lagergängen und Gängen vor. Bastnäsit-(Ce) bildet faserige gelbe Kristalle in einer Matrix aus Dolomit, die ungefähr 1 µm groß sind, Monazit verdrängen und mit Baryt assoziiert sind. Ähnlich wie Bastnäsit von anderen Lokalitäten, enthält auch dieser bis zu 70% RE2O3 fast ausschließlich als Oxide der Leichten Seltenen Erden. Der Bastnäsite-(Ce) von Nkombwa Hill ist jedoch relativ verarmt an La und an Pr und Nd angereichert.
Similar content being viewed by others
References
Alderton DHM, Pearce JA, Potts PJ (1980) Rare earth element mobility during granite alteration: evidence from southwest England. Earth Planet Sci Lett 49: 149–165
Andersen T (1986) Compositional variations of some rare earth minerals from the Fen complex (Telemark, Norway): implications for the mobility of rare earths in a carbonatite system. Mineral Mag50: 503–509
Appleton JD, Bland DJ, Nancarrow PH, Styles MT, Mambwe SH, Zambezi P (1992) The occurrence of daqinshanite-(Ce) in the Nkombwa Hill carbonatite, Zambia. Mineral Mag56: 419–422
Deans T, McConnell JDC (1955) Isokite, CaMgPO4F, a new mineral from Northern Rhodesia. Mineral Mag30: 681–690
Drew LJ, Meng Q, Sun W (1990) The Bayan Obo iron-rare-earth-niobium deposits, Inner Mongolia, China. Lithos26: 43–65
Glass JJ, Smalley RG (1945) Bastnäsite. Am Mineral30: 601–615
Heinrich EW (1966) The geology of carbonatites. Rand McNally, Chicago, 555 pp
Humphris SE (1984) The mobility of rare earth elements in the crust. In:Henderson P (ed) Rare Earth Element geochemistry. Elsevier, Amsterdam, pp 317–342
Jones AP, Wyllie PJ (1984) Low temperature glass from a synthetic rare earth carbonatite: implications for the origin of the Mountain Pass Deposit, California. Econ Geol78: 1721–1723
Le Bas MJ (1977) Carbonatite-nephelinite volcanism. Wiley and Sons, London, 347 pp
Le Bas MJ, Keller J, Kejie T, Wall F, Williams CT, Peishan Z (1992) Carbonatite dykes at Bayan Obo, Inner Mongolia, China. Mineral Petrol46: 195–228
Neary CR, Highley DE (1983) The economic importance of the rare earth elements. In:Henderson P (ed) Rare Earth Element geochemistry. Elsevier, Amsterdam, pp 423–466
Olson JC, Shawe DR, Pray LCM, Sharp WN (1954) Rare-earth mineral deposits of the Mountain Pass district, San Bernadino County, California. US Geol Surv, Prof Pap 261, 75 pp
Reeve WH, Deans T (1954) An occurrence of carbonatite in the Isoka district of Northern Rhodesia. Colonial Geol Min Res4: 271–281
Snelling NJ (1965) Age determination of three African carbonatites. Nature205: 492
Turner DC, Andersen LS, Punukollu SN, Sliwa A, Tembo F (1989) Igneous phosphate resources in Zambia. In:Notholt AJG, Sheldon RP, Davidson DF (eds) Phosphate deposits of the world, vol 2. pp 247–257
Van Wambeke L (1977) The Karonje rare-earth deposit, Republic of Burundi: new mineralogical-geological data and origin of mineralization. Mineral Deposita 12: 373–380
Zambezi P (1995) Geochemistry of the Nkombwa Hill Carbonatite Complex of Isoka District, Northeast Zambia, with special emphasis on economic minerals. Thesis, Free University of Amsterdam, 121 pp
Zhou Z, Li G, Sung T, Liu Y (1980) On the geological characteristics and genesis of the dolomites at Bayan Obo, Inner Mongolia. Geol Rev 26: 35–42
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Zambezi, P., Hale, M., Voncken, J.H.L. et al. Bastnäsite-(Ce) at the Nkombwa Hill carbonatite complex, Isoka District, Northeast Zambia. Mineralogy and Petrology 59, 239–250 (1997). https://doi.org/10.1007/BF01161861
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01161861