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American Mineralogist

Journal of Earth and Planetary Materials

Ed. by Baker, Don / Xu, Hongwu / Swainson, Ian


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1945-3027
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Volume 102, Issue 7

Issues

Cathodoluminescence images and trace element compositions of fluorapatite from the Hongge layered intrusion in SW China: A record of prolonged crystallization and overprinted fluid metasomatism

Chang-Ming Xing
  • Corresponding author
  • Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510460, China
  • Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China
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  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Christina Yan Wang
  • Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510460, China
  • Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China
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Published Online: 2017-07-19 | DOI: https://doi.org/10.2138/am-2017-6028

Abstract

Cathodoluminescence (CL) and trace element analyses were performed for fluorapatite from the gabbro and Fe-Ti oxide ores in the upper zone of the Hongge Fe-Ti oxide-bearing, mafic-ultramafic layered intrusion in SW China. The fluorapatite is closely associated with Fe-Ti oxides and interstitial to plagioclase and clinopyroxene. The fluorapatite grains in one thin section vary from ~10 to 800 mm in width and ~50 to 1200 μm in length. Coarse-grained fluorapatite crystals (>200 in width) in the same thin section show both simple and complex CL images. The coarse-grained fluorapatite crystals with simple CL images show discontinuous, thin dark rims along grain boundaries, whereas those with complex images show clearly bright veinlets across the grains. On the other hand, fine-grained fluorapatite crystals (<200 μm in width) show complex CL images and can be divided into four types, i.e., concentric, chaotic, banded, and overall dark. The concentric type shows distinctly bright core surrounded by dark mantle that is irregularly zoned, whereas the chaotic type shows disordered bright and dark sectors in the interior with a thin dark rim. The banded type shows unevenly distributed bright and dark bands. The overall dark type shows a relatively dark and uneven image. Fluorapatite grains contain 1.84–2.74 wt% F, 0.07–0.19 wt% Cl, and 0.86–1.63 wt% OH. Coarse-grained fluorapatite grains have total rare earth elements (REE) concentrations ranging from 2278 to 3008 ppm and Sr/Y of 9 to 13. Fine-grained fluorapatite grains have relatively high REE (2242–4687 ppm) and low Sr/Y of 6 to 14 in the bright cores, sectors, and bands and relatively low REE (1881–2728 ppm) and high Sr/Y of 9 to 15 in the dark mantles, sectors, and rims under CL imaging. On the thin section scale, the bright sections under CL imaging for fine-grained fluorapatite have much higher REE contents than those for similar bright CL images for coarse-grained fluorapatite. The highly variable REE concentrations among fluorapatite grains and the sections within a single fluorapatite are attributed to a prolonged crystallization process and overprint by fluid metasomatism. The coarse-grained fluorapatite may have crystallized earlier than fine-grained fluorapatite. Then variable degrees of hydrothermal metasomatism released REE from the fine-grained fluorapatite so that diverse CL images developed in the crystals. This study reveals that magmatic apatite from a layered intrusion can be intensively modified by later-stage fluid-induced metasomatism in both trace element composition and CL image texture. Reconstruction of primary melt compositions using apatite from layered intrusions should therefore be treated with caution.

Keywords: Fluorapatite; cathodoluminescence image; trace element; fluid metasomatism; mafic-ultramafic layered intrusion

References cited

  • Barbarand, J., and Pagel, M. (2001) Cathodoluminescence study of apatite crystals. American Mineralogist, 86(4), 473–484.Google Scholar

  • Barnes, S.J. (1986) The effect of trapped liquid crystallization on cumulus mineral compositions in layered intrusions. Contributions to Mineralogy and Petrology, 93(4), 524–531.Google Scholar

  • Bindeman, I.N., Davis, A.M., and Drake, M.J. (1998) Ion microprobe study of plagioclase-basalt partition experiments at natural concentration levels of trace elements. Geochimica et Cosmochimica Acta, 62(7), 1175–1193.Google Scholar

  • Bonyadi, Z., Davidson, G.J., Mehrabi, B., Meffre, S., and Ghazban, F. (2011) Significance of apatite REE depletion and monazite inclusions in the brecciated Se-Chahun iron oxide-apatite deposit, Bafq district, Iran: insights from paragenesis and geochemistry. Chemical Geology, 281, 253–269.Google Scholar

  • Broska, I., Ravna, E.J.K., Vojtko, P., Janák, M., Konečný, P., Pentrák, M., Bačik, P., Luptáková, J., and Kullerud, K. (2014) Oriented inclusions in apatite in a post-UHP fluid-mediated regime (Troms⊘ Nappe, Norway). European Journal of Mineralogy, 26(5), 623–634.Google Scholar

  • Cawthorn, R.G. (1994) Formation of chlor- and fluor-apatite in layered intrusions. Mineralogical Magazine, 58, 299–306.Google Scholar

  • Cawthorn, R.G. (2013) Rare earth element abundances in apatite in the Bushveld Complex—A consequence of the trapped liquid shift effect. Geology, 41(5), 603–606.Google Scholar

  • Filippelli, G.M., and Delaney, M.L. (1993) The effects of manganese (II) and iron (II) on the cathodoluminescence signal in synthetic apatite. Journal of Sedimentary Research, 63(1), 167–173.Google Scholar

  • Harlov, D.E. (2015) Apatite: a fingerprint for metasomatic processes. Elements, 11(3), 171–176.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(8-9), 1209–1229.Google Scholar

  • Harlov, D.E., Förster, H.-J., and Nijland, T.G. (2002a) Fluid-induced nucleation of (Y+REE)-phosphate minerals within apatite: Nature and experiment. Part I. Chlorapatite. American Mineralogist, 87(2-3), 245–261.Google Scholar

  • Harlov, D.E., Andersson, U.B., Förster, H.-J., Nyström, J.O., Dulski, P., and Broman, C. (2002b) Apatite-monazite relations in the Kiirunavaara magnetite-apatite ore, northern Sweden. Chemical Geology, 191(1), 47–72.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(3), 268–286.Google Scholar

  • Harlov, D.E., Meighan, C.J., Kerr, I.D., and Samson, I.M. (2016) Mineralogy, chemistry, and fluid-aided evolution of the Pea Ridge Fe oxide-(Y+ REE) deposit, southeast Missouri, USA. Economic Geology, 111(8), 1963–1984.Google Scholar

  • Hart, S.R., and Dunn, T. (1993) Experimental cpx/melt partitioning of 24 trace elements. Contributions to Mineralogy and Petrology, 113(1), 1–8.Google Scholar

  • Holness, M.B., Tegner, C., Nielsen, T.F., Stripp, G., and Morse, S.A. (2007) A textural record of solidification and cooling in the Skaergaard intrusion, East Greenland. Journal of Petrology, 48(12), 2359–2377.Google Scholar

  • Kempe, U., and Götze, J. (2002) Cathodoluminescence (CL) behaviour and crystal chemistry of apatite from rare-metal deposits. Mineralogical Magazine, 66(1), 151–172.Google Scholar

  • Li, X., and Zhou, M.-F. (2015) Multiple stages of hydrothermal REE remobilization recorded in fluorapatite in the Paleoproterozoic Yinachang Fe-Cu-(REE) deposit, Southwest China. Geochimica et Cosmochimica Acta, 166, 53–73.Google Scholar

  • Lisowiec, K., Słaby, E., and Götze, J. (2013) Cathodoluminescence (CL) of apatite as an insight into magma mixing in the granitoid pluton of Karkonosze, Poland. Conference on Raman and Luminescence Spectroscopy in the Earth Sciences, p. 67–68. University of Vienna, Austria.Google Scholar

  • Liu, Y., Hu, Z., Gao, S., Günther, D., Xu, J., Gao, C., and Chen, H. (2008) In situ analysis of major and trace elements of anhydrous minerals by LA-ICP-MS without applying an internal standard. Chemical Geology, 257(1), 34–43.Google Scholar

  • Ma, Y., Ji, X.T., Li, J.C., Huang, M., and Kan, Z.Z. (2003) Mineral Resources of the Panzhihua Region. Sichuan Science and Technology Press, Chengdu. 275 pp. (in Chinese).Google Scholar

  • McDonough, W.F., and Sun, S.-S. (1995) The composition of the Earth. Chemical Geology, 120(3), 223–253.Google Scholar

  • Meurer, W., and Meurer, M. (2006) Using apatite to dispel the “trapped liquid” concept and to understand the loss of interstitial liquid by compaction in mafic cumulates: an example from the Stillwater Complex, Montana. Contributions to Mineralogy and Petrology, 151(2), 187–201.Google Scholar

  • Murray, J.R., and Oreskes, N. (1997) Uses and limitations of cathodoluminescence in the study of apatite paragenesis. Economic Geology, 92(3), 368–376.Google Scholar

  • Namur, O., Charlier, B., and Holness, M.B. (2012) Dual origin of Fe-Ti-P gabbros by immiscibility and fractional crystallization of evolved tholeiitic basalts in the Sept Iles layered intrusion. Lithos, 154, 100–114.Google Scholar

  • Nielsen, R.L., Gallahan, W.E., and Newberger, F. (1992) Experimentally determined mineral-melt partition coefficients for Sc, Y and REE for olivine, orthopyroxene, pigeonite, magnetite and ilmenite. Contributions to Mineralogy and Petrology, 110(4), 488–499.Google Scholar

  • Otten, M.T. (1984) The origin of brown hornblende in the Artfjället gabbro and dolerites. Contributions to Mineralogy and Petrology, 86(2), 189–199.Google Scholar

  • Pan, Y., Fleet, M.E., and Macrae, N.D. (1993) Oriented monazite inclusions in apatite porphyroblasts from the Hemlo gold deposit, Ontario, Canada. Mineralogical Magazine, 57, 697–707.Google Scholar

  • Prowatke, S., and Klemme, S. (2006) Trace element partitioning between apatite and silicate melts. Geochimica et Cosmochimica Acta, 70(17), 4513–4527.Google Scholar

  • Reynolds, I.M. (1985) The nature and origin of titaniferous magnetite-rich layers in the upper zone of the Bushveld Complex; a review and synthesis. Economic Geology, 80(4), 1089–1108.Google Scholar

  • Ridolfi, F., and Renzulli, A. (2012) Calcic amphiboles in calc-alkaline and alkaline magmas: thermobarometric and chemometric empirical equations valid up to 1,130 °C and 2.2 GPa. Contributions to Mineralogy and Petrology, 163(5), 877–895.Google Scholar

  • Roeder, P.L., MacArthur, D., Ma, X.-P., Palmer, G.R., and Mariano, A.N. (1987) Cathodoluminescence and microprobe study of rare-earth elements in apatite. American Mineralogist, 72(7-8), 801–811.Google Scholar

  • She, Y.-W., Song, X.-Y., Yu, S.-Y., Chen, L.-M., and Zheng, W.-Q. (2016) Apatite geochemistry of the Taihe layered intrusion, SW China: Implications for the magmatic differentiation and the origin of apatite-rich Fe-Ti oxide ores. Ore Geology Reviews, 78, 151–165.Google Scholar

  • Tegner, C., Cawthorn, R.G., and Kruger, F.J. (2006) Cyclicity in the Main and Upper Zones of the Bushveld Complex, South Africa: crystallization from a zoned magma sheet. Journal of Petrology, 47(11), 2257–2279.Google Scholar

  • Tollari, N., Barnes, S.-J., Cox, R., and Nabil, H. (2008) Trace element concentrations in apatites from the Sept-Îles Intrusive Suite, Canada-implications for the genesis of nelsonites. Chemical Geology, 252(3), 180–190.Google Scholar

  • Van Tongeren, J., and Mathez, E. (2012) Large-scale liquid immiscibility at the top of the Bushveld Complex, South Africa. Geology, 40(6), 491–494.Google Scholar

  • Von Gruenewaldt, G. (1993) Ilmenite-apatite enrichments in the upper zone of the Bushveld Complex: A major titanium-rock phosphate resource. International Geology Review, 35(11), 987–1000.Google Scholar

  • Wang, C.Y., and Zhou, M.-F. (2013) New textural and mineralogical constraints on the origin of the Hongge Fe-Ti-V oxide deposit, SW China. Mineralium Deposita, 48, 787–798.Google Scholar

  • Webster, J.D., and Piccoli, P.M. (2015) Magmatic apatite: a powerful, yet deceptive, mineral. Elements, 11(3), 177–182.Google Scholar

About the article

Received: 2016-11-26

Accepted: 2017-03-14

Published Online: 2017-07-19

Published in Print: 2017-07-26


Citation Information: American Mineralogist, Volume 102, Issue 7, Pages 1390–1401, ISSN (Online) 1945-3027, ISSN (Print) 0003-004X, DOI: https://doi.org/10.2138/am-2017-6028.

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© 2017 by Walter de Gruyter Berlin/Boston.

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