Home Microtexture investigation of amblygonite–montebrasite series with lacroixite: Characteristics and formation process in pegmatites
Article
Licensed
Unlicensed Requires Authentication

Microtexture investigation of amblygonite–montebrasite series with lacroixite: Characteristics and formation process in pegmatites

  • Yohei Shirose EMAIL logo and Seiichiro Uehara
Published/Copyright: January 2, 2018
Become an author with De Gruyter Brill
Author Information
American Mineralogist
From the journal American Mineralogist Volume 103 Issue 1

Abstract

Amblygonite–montebrasite series and lacroixite from Nagatare Li–Cs–Ta (LCT) pegmatite, Fukuoka Prefecture, Japan, were investigated by powder X-ray diffraction (XRD), electron microprobe analyses, and transmission electron microscope (TEM)/scanning transmission electron microscope (STEM) analyses. Scattered patchy or lamellar lacroixite was contained in montebrasite and amblygonite in all observed specimens. TEM/STEM observations revealed that the patchy and lamellar texture comprised lacroixite and low-fluorine montebrasite having same crystal orientations as that of host montebrasite and the boundaries corresponded to well-developed {110} planes. The observed microtexture was newly discovered, and it is an important evidence of the exsolution process. In XRD experiments conducted at high temperature, the unit-cell parameters of amblygonite were closer to that of monoclinic structures such as lacroixite with increasing temperature. Results suggested that scattered patches or lamellae of lacroixite were exsolution textures from a high-temperature phase.

Montebrasite and amblygonite specimens from other localities involved varying textures corresponding to their occurrence. The amblygonite–montebrasite series from petalite-bearing pegmatite included low to high lacroixite contents and that from lower-temperature pegmatite with spodumene either did not possess or involved low lacroixite contents. Gem-quality montebrasite from drusy vugs formed at low temperature did not include any exsolution texture or lacroixite. The variety of texture of the amblygonite–montebrasite series indicated in this study generated new possibilities as the indicator of pegmatite-forming process.

Keywords: Amblygonite–montebrasite series; lacroixite; exsolution; Nagatare pegmatite; TEM

* Present address: The Kyoto University Museum, Kyoto University, Kyoto 606-8501, Japan

Acknowledgments

The authors thank S. Kikuchi of Hitachiota City the Board of Education for giving permission to collect samples in Myokenzan. We appreciate K. Watanabe for supplying specimens (MY13, 14). We are grateful to D. London for handling the manuscript and many constructive comments. We sincerely thank P Vignola and an anonymous reviewer for their constructive and critical comments on this manuscript. This work was supported by JSPS KAKENHI Grant No. 14J03404. The authors thank the Professor Matsumoto Scholarship Fund.

References Cited

Baldwin, J.R., Hill, P.G., von Knorring, O., and Oliver, G.J.H. (2000) Exotic aluminum phosphates, natromontebrasite, brazilianite, goyazite, gorceixite and crandallite from rare-element pegmatites in Namibia. Mineralogical Magazine, 64, 1147–1164.10.1180/002646100549940Search in Google Scholar

Černý, P, and Ercit, T.S. (2005) The classification of granitic pegmatites revisited. Canadian Mineralogist, 43, 2005–2026.10.2113/gscanmin.43.6.2005Search in Google Scholar

Černá, I., Černý, P, and Ferguson, R.B. (1973) The fluorine content and some physical properties of the amblygonite–montebrasite minerals. American Mineralogist, 58, 291–301.Search in Google Scholar

Fransolet, A.M. (1989) The problem of Na–Li substitution in primary Li–Al phosphates: new data on lacroixite, a relatively widespread mineral. Canadian Mineralogist, 27, 211–217.Search in Google Scholar

Fransolet, A.M., Fontan, F., and de Parseval, P. (2007) Natromontebrasite, a discredited mineral species. Canadian Mineralogist, 45, 391–396.10.2113/gscanmin.45.2.391Search in Google Scholar

Galliski, M.Á., Černý, P, Márquez-Zavalía, M.F., and Chapman, R. (2012) An association of secondary Al–Li–Be–Ca–Sr phosphates in the San Elías pegmatite, San Luis, Argentina. Canadian Mineralogist, 50, 933–942.10.3749/canmin.50.4.933Search in Google Scholar

Greiner, D.J., and Bloss, F.D. (1987) Amblygonite–montebrasite optics: Response to (OH−) orientation and rapid estimation of F from 2V. American Mineralogist, 72, 617–624.Search in Google Scholar

Groat, L.A., Raudsepp, M., Hawthorne, F.C., Ercit, T.S., Sherriff, B.L., and Hartman, J.S. (1990) The amblygonite–montebrasite series: Characterization by single-crystal structure refinement, infrared spectroscopy, and multinuclear MAS–NMR spectroscopy. American Mineralogist, 75, 992–1008.Search in Google Scholar

Groat, L.A., Chakoumakos, B.C., Brouwer, D.H., Hoffman, C.M., Fyfe, C.A., Morell, H., and Schultz, A.J. (2003) The amblygonite (LiAlPO4F)–montebrasite (LiAlPO4OH) solid solution: A combined powder and single-crystal neutron diffraction and solid-state 6Li MAS, CP MAS, and REDOR NMR study. American Mineralogist, 88, 195–210.10.2138/am-2003-0123Search in Google Scholar

Kallio, P. (1978) A new X-ray method for the estimation of fluorine content in montebrasites. American Mineralogist, 63, 1249–1251.Search in Google Scholar

Karakida, Y., Tomita, S., Shimoyama, S., and Chijiwa, K. (1994) Geology of the Fukuoka district, Geological Sheet Map 1:50,000, Fukuoka (14), no. 51, 192 p. Geological Survey of Japan, Tokyo (in Japanese with English abstract).Search in Google Scholar

Kataoka, Y, and Uehara, S. (2000) Lepidolite in a lithium pegmatite from Nagatare, Fukuoka Prefecture, Japan. Proceedings of 2000 Annual Meeting of the Mineralogical Society of Japan, 101. Mineralogical Society of Japan (in Japanese).Search in Google Scholar

Kuwano, N., and Hikita, T. (1967) Montebrasite from Nagatare, Fukuoka, Japan. Chigaku Kenkyuu (Present “Journal of Geoscience”), 18, 243–245 (in Japanese).Search in Google Scholar

London, D. (1984) Experimental phase equilibria in the system LiAlSiO4–SiO2– H2O: A petrogenetic grid for lithium-rich pegmatites. American Mineralogist, 69, 995–1004.Search in Google Scholar

London, D. (2008) Pegmatites. Canadian Mineralogist Special Publication, 10, 368.10.1016/B978-0-12-409548-9.12489-3Search in Google Scholar

London, D. (2014) A petrologic assessment of internal zonation in granitic pegmatites. Lithos, 184-187, 74–104.10.1016/j.lithos.2013.10.025Search in Google Scholar

London, D. (2017) Reading pegmatites: What lithium minerals say. Rocks & Minerals, 92, 144–157.10.1080/00357529.2017.1252636Search in Google Scholar

London, D., and Burt, D.M. (1982) Alteration of spodumene, montebrasite and lithiophilite in pegmatites of the White Picacho District, Arizona. American Mineralogist, 67, 97–113.Search in Google Scholar

London, D., Morgan, G.B. VI, and Icenhower, J. (1998) Stability and solubility of pollucite in the granite system at 200 MPa H2O. Canadian Mineralogist, 36, 497–510.10.3749/canmin.ER00001Search in Google Scholar

London, D., Wolf, M.B., Morgan, G.B. VI, and Gallego Garrido, M. (1999) Experimental silicate-phosphate equilibria in peraluminous granitic magmas, with a case study of the Alburquerque batholith at Tres Arroyos, Badajoz, Spain. Journal of Petrology, 40, 215–240.10.1093/petroj/40.1.215Search in Google Scholar

London, D., Morgan, G.B. VI, and Wolf, M.B. (2001) Amblygonite–montebrasite solid solution as monitors of fluorine in evolved granitic and pegmatite melts. American Mineralogist, 86, 225–233.10.2138/am-2001-2-303Search in Google Scholar

Nabelek, P.I., Whittington, A.G., and Sirbescu, M.C. (2010) The role of H2O in rapid emplacement and crystallization of granite pegmatites: Resolving the paradox of large crystals in highly undercooled melts. Contributions to Mineralogy and Petrology, 160, 313–325.10.1007/s00410-009-0479-1Search in Google Scholar

Pajunen, A., and Lathi, S.I. (1985) New data on lacroixite, NaAlFPO4. Part II. Crystal structure. American Mineralogist, 70, 849–855.Search in Google Scholar

Rondeau, B., Fritsch, E., Lefevre, P., Guiraud, M., Fransolet, A.M., and Lulzac, Y. (2006) A Raman investigation of the amblygonite-montebrasite series. Canadian Mineralogist, 44, 1109–1117.10.2113/gscanmin.44.5.1109Search in Google Scholar

Shibata, H. (1934) A lithium pegmatite from Nagatare, Imajyuku, Itoshima, Fukuoka Prefecture, Japan. Journal of the Geological Society Japan, 41, 582–603 (in Japanese).10.5575/geosoc.41.582Search in Google Scholar

Shirose, Y., and Uehara, S. (2013) Li tourmaline from Nagatare, Fukuoka Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 108, 238–243.10.2465/jmps.121022eSearch in Google Scholar

Shirose (2014) Secondary phosphates in montebrasite and amblygonite from Nagatare, Fukuoka Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 109, 103–108.10.2465/jmps.131022dSearch in Google Scholar

Uehara, S., and Shirose, Y. (2013) Namibite and hechtsbergite from the Nagatare mine, Fukuoka Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 108, 105–110.10.2465/jmps.121022dSearch in Google Scholar

Received: 2016-12-7
Accepted: 2017-8-30
Published Online: 2018-1-2
Published in Print: 2018-1-26

© 2018 Walter de Gruyter GmbH, Berlin/Boston

Articles in the same Issue

  2. The third isotope of the third element on the third planet
  4. Visible, near-infrared, and mid-infrared spectral characterization of Hawaiian fumarolic alteration near Kilauea’s December 1974 flow: Implications for spectral discrimination of alteration environments on Mars
  6. Magnetite-apatite deposit from Sri Lanka: Implications on Kiruna-type mineralization associated with ultramafic intrusion and mantle metasomatism
  8. The ore-forming magmatic-hydrothermal system of the Piaotang W-Sn deposit (Jiangxi, China) as seen from Li-mica geochemistry
  10. Chlorine incorporation into amphibole and biotite in high-grade iron-formations: Interplay between crystallography and metamorphic fluids
  12. Depth of formation of super-deep diamonds: Raman barometry of CaSiO3-walstromite inclusions
  14. Microtexture investigation of amblygonite–montebrasite series with lacroixite: Characteristics and formation process in pegmatites
  16. Sound velocity measurements of hcp Fe-Si alloy at high pressure and high temperature by inelastic X-ray scattering
  18. New insights into the metallogeny of MVT Zn-Pb deposits: A case study from the Nayongzhi in South China, using field data, fluid compositions, and in situ S-Pb isotopes
  20. Slow weathering of a sandstone-derived Podzol (Falkland Islands) resulting in high content of a non-crystalline silicate
  22. Mineralogy, paragenesis, and mineral chemistry of REEs in the Olserum-Djupedal REE-phosphate mineralization, SE Sweden
  24. Leesite, K(H2O)2[(UO2)4O2(OH)5]·3H2O, a new K-bearing schoepite-family mineral from the Jomac mine, San Juan County, Utah, U.S.A
  26. Chromium-bearing phases in the Earth’s mantle: Evidence from experiments in the Mg2SiO4–MgCr2O4 system at 10–24 GPa and 1600 °C
  27. Crossroads in Earth and Planetary Materials
  28. High-pressure phase transitions in MgCr2O4·Mg2SiO4 composition: Reactions between olivine and chromite with implications for ultrahigh-pressure chromitites
  29. Letter
  30. A novel carbon bonding environment in deep mantle high-pressure dolomite
  31. Letter
  32. Structuration under pressure: Spatial separation of inserted water during pressure-induced hydration in mesolite
  33. Book Review
  34. Book Review: The International Atlas of Mars Exploration: From Spirit to Curiosity
https://doi.org/10.2138/am-2018-6049
Keywords for this article
Amblygonite–montebrasite series; lacroixite; exsolution; Nagatare pegmatite; TEM

Articles in the same Issue

  2. The third isotope of the third element on the third planet
  4. Visible, near-infrared, and mid-infrared spectral characterization of Hawaiian fumarolic alteration near Kilauea’s December 1974 flow: Implications for spectral discrimination of alteration environments on Mars
  6. Magnetite-apatite deposit from Sri Lanka: Implications on Kiruna-type mineralization associated with ultramafic intrusion and mantle metasomatism
  8. The ore-forming magmatic-hydrothermal system of the Piaotang W-Sn deposit (Jiangxi, China) as seen from Li-mica geochemistry
  10. Chlorine incorporation into amphibole and biotite in high-grade iron-formations: Interplay between crystallography and metamorphic fluids
  12. Depth of formation of super-deep diamonds: Raman barometry of CaSiO3-walstromite inclusions
  14. Microtexture investigation of amblygonite–montebrasite series with lacroixite: Characteristics and formation process in pegmatites
  16. Sound velocity measurements of hcp Fe-Si alloy at high pressure and high temperature by inelastic X-ray scattering
  18. New insights into the metallogeny of MVT Zn-Pb deposits: A case study from the Nayongzhi in South China, using field data, fluid compositions, and in situ S-Pb isotopes
  20. Slow weathering of a sandstone-derived Podzol (Falkland Islands) resulting in high content of a non-crystalline silicate
  22. Mineralogy, paragenesis, and mineral chemistry of REEs in the Olserum-Djupedal REE-phosphate mineralization, SE Sweden
  24. Leesite, K(H2O)2[(UO2)4O2(OH)5]·3H2O, a new K-bearing schoepite-family mineral from the Jomac mine, San Juan County, Utah, U.S.A
  26. Chromium-bearing phases in the Earth’s mantle: Evidence from experiments in the Mg2SiO4–MgCr2O4 system at 10–24 GPa and 1600 °C
  27. Crossroads in Earth and Planetary Materials
  28. High-pressure phase transitions in MgCr2O4·Mg2SiO4 composition: Reactions between olivine and chromite with implications for ultrahigh-pressure chromitites
  29. Letter
  30. A novel carbon bonding environment in deep mantle high-pressure dolomite
  31. Letter
  32. Structuration under pressure: Spatial separation of inserted water during pressure-induced hydration in mesolite
  33. Book Review
  34. Book Review: The International Atlas of Mars Exploration: From Spirit to Curiosity
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 6.9.2025 from https://www.degruyterbrill.com/document/doi/10.2138/am-2018-6049/html
Scroll to top button