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Al-free di-trioctahedral substitution in chlorite and a ferri-sudoite end-member

Published online by Cambridge University Press:  02 January 2018

Vincent Trincal*
Laboratoire Chrono-Environnement, UMR CNRS 6249, University of Bourgogne Franche-Comté, 16 Route de Gray, F-25000 Besançon, France
Pierre Lanari
Institute of Geological Sciences, University of Bern, Baltzestrasse 1+3, CH-3012 Bern, Switzerland


A compilation of Fe3+-bearing chlorite analyses is used: (1) to investigate the Alfree di-trioctahedral (AFDT) substitution 2Fe3+ +□= 3(Mg,Fe2+) in chlorite; and (2) to estimate the composition of a ferri-sudoite end-member (Si3Al)[(Fe2+,Mg)2□Al]O10(OH)8 within the chlorite solid-solution domain. According to our observations, up to two Fe3+ cations might be allocated in the M2-M3 chlorite sites by the substitution AFDT, which does not involve Al. These unexpected observations were made possible by the development of μXANES techniques allowing in situ measurements of XFe3+ (Fe3+/(Fe2+ + Fe3+)) in heterogeneous chlorite. Although further studies are required to confirm the crystallographic position of Fe3+ and refine its ionic/ magnetic behaviour in chlorite, this development creates opportunities for developing new geothermometers.

Research Article
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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This work was originally presented during the session ‘The many faces of chlorite’, part of the Euroclay 2015 conference held in July 2015 in Edinburgh, UK.


Ahn, J.H. & Buseck, P.R. (1988) Al-chlorite as ahydration reaction product of andalusite. Mineralogical Magazine, 52, 396399.Google Scholar
Aja, S.U. & Dyar, D.M. (2002) The stability of Fe-Mg chlorites in hydrothermal solutions—I. Results of experimental investigations. Applied Geochemistry, 17, 12191239.CrossRefGoogle Scholar
Aleksandrova, V.A., Drits, V.A. & Sokolova, G.V. (1972) Structural features of dioctahedral one-packet chlorite. Soviet Physics-Crystallography, 17, 456461.Google Scholar
Alysheva, E.I., Rusinova, O.V. & Chekvaidze, V.B. (1977) On sudoites from the polymetal deposits of Rydnyy Altai. Doklady Academii Nauk SSSR, 236, 722724.Google Scholar
Anceau, A. (1992) Sudoite in some Visean (lower Carboniferous) K-bentonites from Belgium. Clay Minerals, 27, 283292.Google Scholar
Bailey, S.W., editor (1988) Hydrous Phyllosilicates (exclusive of Micas). Reviews in Mineralogy, 19, Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Ballet, O., Coey, J.M.D. & Burke, K.J. (1985) Magnetic properties of sheet silicates; 2: 1: 1 layer minerals. Physics and Chemistry of Minerals, 12, 370378.Google Scholar
Bannister, F.A. & Whittard, W.F. (1945) A magnesian chamosite from the Wenlock Limestone of Wickwar, Gloucestershire. Mineralogical Magazine, 27, 99111.Google Scholar
Banno, S. (1964) Petrologic studies on Sanbagawa crystalline schists in the Bessi-Ino district, central Sikoku, Japan. Journal of Faculty Science, University of Tokyo, Section II, 15, 203319.Google Scholar
Battey, M.H. (1956) The petrogenesis of a spilitic rock series from New Zealand. Geological Magazine, 93, 89110.CrossRefGoogle Scholar
Bertoldi, C., Benisek, A., Cemic, L. & Dachs, E. (2001) The heat capacity of two natural chlorite group minerals derived from differential scanning calorimetry. Physics and Chemistry of Minerals, 28, 332336.Google Scholar
Bilgrami, S.A. & Howie, R.A. (1960) The mineralogy and petrology of a rodingite dike, Hindubagh, Pakistan. American Mineralogist, 45, 791801.Google Scholar
Billault, V., Beaufort, D., Patrier, P. & Petit, S. (2002) Crystal chemistry of Fe-sudoites from uranium deposits in the Athabasca basin (Saskatchewan, Canada). Clays and Clay Minerals, 50, 7081.Google Scholar
Borggaard, O.K., Lindgreen, H.B. & Morup, S. (1982) Oxidation and reduction of structural iron in chlorite at 480°C. Clays and Clay Minerals, 30, 353364.CrossRefGoogle Scholar
Bourdelle, F., Benzerara, K., Beyssac, O., Cosmidis, J., Neuville, D.R., Brown, G.E. Jr. & Paineau, E. (2013) Quantification of the ferric/ferrous iron ratio in silicates by scanning transmission X-ray microscopy at the Fe L2,3 edges. Contributions to Mineralogy and Petrology, 166, 423434.Google Scholar
Brandt, F., Bosbach, D., Krawczyk-Bärsch, E., Arnold, T. & Bernhard, G. (2003) Chlorite dissolution in the acid pH range: a combined microscopic and macroscopic approach. Geochimica et Cosmochimica Acta, 67, 14511461.Google Scholar
Brindley, G.W. (1951) The crystal structure of some chamosite minerals. Mineralogical Magazine, 29, 502522.Google Scholar
Brindley, G.W. & Youell, R.F. (1953) Ferrous chamosite and ferric chamosite. Mineralogical Magazine, 30, 5770.Google Scholar
Brydon, J.E., Clark, J.S. & Osborne, V. (1961) Dioctahedral chlorite. The Canadian Mineralogist, 6, 595609.Google Scholar
Caillere, S., Hénin, S. & Pobeguin, T. (1962) Présence d'un nouveau type de chlorite dans les ‘bauxites’ de Saint-Paul-de-Fenouillet (Pyrénées orientales). Compte Rendu de l’Adadémie des Sciences, 254, 16571658.Google Scholar
Chamberlain, S.C., Robinson, G.W. & Richards, R.P. (1989) Mineralogy of the Alpine veins near Sherbrooke, Quebec. Mineralogical Record, 20, 20920.Google Scholar
Chernykh, Y.Y. (1926) Physicochemische Untersuchung der Serpentine und Chlorite. Mémoire de la Société Russe de Minéralogie Série 2, 55, 183194.Google Scholar
Dana, E.S. (1915) Descriptive Mineralogy. John Wiley & Sons, New York, 659 pp.Google Scholar
De Andrade, V., Vidal, O., Lewin, E., O'Brien, P. & Agard, P. (2006) Quantification of electron microprobe compositional maps of rock thin sections: an optimized method and examples RID C-2856-2009. Journal of Metamorphic Geology, 24, 655668.Google Scholar
Debret, B., Bolfan-Casanova, N., Padrón-Navarta, J.A., Martin-Hernandez, F., Andreani, M., Garrido, C.J., Sánchez-Vizcaíno, V.L., Gómez-Pugnaire, M.T., Muñoz, M. & Trcera, N. (2015) Redox state of iron during high-pressure serpentinite dehydration. Contributions to Mineralogy and Petrology, 169, 118.Google Scholar
De Grave, E., Vandenbruwaene, J. & Bockstael, M.V. (1987) 57Fe Mössbauer spectroscopic analysis of chlorite. Physics and Chemistry of Minerals, 15, 173180.Google Scholar
De Waal, S.A. (1970) Nickel minerals from Barberton, South Africa: III. Willemseite, a nickel-rich talc. American Mineralogist, 55, 3142.Google Scholar
Drits, V.A. & Lazarenko, E.K. (1967) Structural and mineralogical characteristics of donbassites. Mineral Sb Lvov, 21, 408.Google Scholar
Dschang, G. (1931) Die Beziehungen Zwischen Chemischer Zusammensetzung und den Physikalisch-Optischen Eigenschaften in der Chloritgruppe. Doctoral Dissertation Thesis, Fischer.Google Scholar
Engelhardt, W.V. (1942) Die Strukturen von Thuringit, Bavalit und Chamosit und ihre Stellung in der Chloritgruppe. Zeitschrift für Kristallographie-Crystalline Materials, 104, 142159.Google Scholar
Ericsson, M.T., Wäppling, D.R. & Punakivi, M.K. (1977) Mössbauer spectroscopy applied to clay and related minerals. Geologiska Föreningen i Stockholm Förhandlingar, 99, 229244.Google Scholar
Fransolet, A.M. & Bourguignon, A. (1978) Di/trioctahe-dral chlorite in quartz veins from the Ardennes, Belgium. The Canadian Mineralogist, 16, 365373.Google Scholar
Frenzel, G. & Schembra, F.W. (1965) Ein dioktaedrischer chlorit vom Kaiserbachtal (Südpfalz). Neues Jahrbuch für Mineralogie Monatshefte, 1965, 108114.Google Scholar
Frondel, C. (1955) Two chlorites: gonyerite and melano-lite. American Mineralogist, 40, 10901094.Google Scholar
Ginzburg, A.I. (1953) On lithium chlorite-cookeite. Doklady Akademii Nauk SSSR, 90, 871.Google Scholar
Gomes, C.S.F. (1967) Alteration of spodumene and lepidolite with formation of dioctahedral chlorite plus dioctahedral chlorite-dioctahedral montmorillon-ite interstratifications. Publ Museu e Laboratorio Mineralogico e Geologico, Universidade de Coimbra, (Portugal), Memorias Noticias, 64, 3257.Google Scholar
Goodman, B.A. & Bain, D.C. (1979) Mössbauer spectra of chlorites and their decomposition products, Pp. 6574 in. Developments in Sedimentology, Vol. 27 (M.M. Mortland and YC Farmer, editor). Elsevier, Amsterdam.Google Scholar
Gregori, D.A. & Mercader, R.C. (1994) Mössbauer study of some Argentinian chlorites. Hyperfine Interactions, 83, 49598.Google Scholar
Hallimond, A.F., Harvey, C.O. & Bannister, F.A. (1939) On the relation of chamosite and daphnite to the chlorite group. MineralogicalMagazine, 25, 441465.Google Scholar
Hawes, G.W. (1875) On diabantite, a chlorite occurring in the trap of the Connecticut valley. American Journal of Science, 454-457.Google Scholar
Hayashi, H. & Oinuma, K. (1965) Relationship between infrared absorption spectra in the region of 450—900 CM-1 and chemical composition of chlorite. American Mineralogist, 50, 476.Google Scholar
Hödl, A. (1942) Über Chlorite der Ostalpen. Ein Beitrag zur Systematik der Chlorite. Neues Jahrbuch für Mineralogie, Beil. Bd, 77, 1-77. Google Scholar
Holland, T., Baker, J. & Powell, R. (1998) Mixing properties and activity-composition and relationships of chlorites in the system MgO-FeO-Al2O3-SiO2-H2O. European Journal of Mineralogy, 10, 395406.Google Scholar
Holzner, J. (1937) Beiträge zur kentnnis der varistischen gesteins-und mineralprovinz im Lahn-Dillgebiet. Zeitschrift für Kristallographie, Mineralogie und Petrographie, 49, 168215.Google Scholar
Honda, S. (1975) Dioctahedral chlorite, closely associated with kaolinite from the Kamikita mine (Kuroko deposit). Report of the Research Institute of Underground Resesarch Mining College Akita University, 43, 18.Google Scholar
Horikoshi, E. (1965) Kuroko-type exhalative sedimentary mineral deposits. Journal of the Mining Institution of Kyusyu, 33, 300210.Google Scholar
Hutton, C.O. (1938) The Stilpnomelane Group of Minerals. Oxford University Press, Oxford, UK.Google Scholar
Hutton, C.O. (1940) Metamorphism in the Lake Wakatipu Region (E.V. Paul, editor). Government Printer, Western Otago, New Zealand, 90 pp.Google Scholar
Hutton, C.O. & Seelye, F.T. (1945) Contributions to the mineralogy of New Zealand - Part I. Pp. 160168 in. Transactions of the Royal Society of New Zealand, vol. 75. (J. Hughes, editor).Google Scholar
Inoue, A. & Kogure, T. (2016) High-angle annular dark field scanning transmission electron microscopic (HAADF-STEM) study of Fe-rich 7 Å-14 Å inter-stratified minerals from a hydrothermal deposit. Clay Minerals, 51, 603613.Google Scholar
Inoue, A., Meunier, A., Patrier-Mas, P., Rigault, C., Beaufort, D. & Vieillard, P. (2009) Application of chemical geothermometry to low-temperature trioctahedral chlorites. Clays and Clay Minerals, 57, 371382.Google Scholar
Inoue, A., Kurokawa, K. & Hatta, T. (2010) Application of chlorite geothermometry to hydrothermal alteration in Toyoha geothermal system, southwestern Hokkaido, Japan. Resource Geology, 60, 5270.Google Scholar
Joswig, W. & Fuess, H. (1990) Refinement of a one-layer triclinic chlorite. Clays and Clay Minerals, 38, 216218.Google Scholar
Jung, H. (1931) Untersuchungen über den Chamosit von Schmiedefeld I. Thüringen. Cheme der Erde, 6, 275306.Google Scholar
Jung, H. & Köhler, E. (1930) Untersuchungen über den Thuringit von Schmiedefeld in Thüringen. Chemie der Erde, 5, 182.Google Scholar
Kawano, M. & Tomita, K. (1991) Mineralogy and genesis of clays in postmagmatic alteration zones, Makurazaki volcanic area, Kagoshima prefecture, Japan. Clays and Clay Minerals, 39, 597608.Google Scholar
Kimbara, K. & Nagata, H. (1974) Clay minerals in the core samples of the mineralized zone of Niida, southern part of Odate Akita Prefecture, Japan. Japanese Association of Mineralogists, Petrologists and Economic Geologists Journal, 69, 239254.Google Scholar
Kimbara, K. & Sudo, T. (1973) Chloritic clay minerals in tuffaceous sandstone of the Miocene Green Tuff formation, Yamanaka district, Ishikawa Prefecture, Japan. Japanese Association of Mineralogists, Petrologists and Economic Geologists Journal, 68, 246258.Google Scholar
Kimbara, K., Shimoda, S. & Sudo, T. (1973) An unusual chlorite as revealed by the high temperature X-ray diffractometer. Clay Minerals, 10, 7178.Google Scholar
Kittrick, J.A. (1982) Solubility of two high-Mg and two high-Fe chlorites using multiple equilibria. Clays and Clay Minerals, 30, 167179.Google Scholar
Kodama, H., Longworth, G. & Townsend, M.G. (1982) A Mössbauer investigation of some chlorites and their oxidation products. The Canadian Mineralogist, 20, 585592.Google Scholar
Kramm, U. (1980) Sudoite in low-grade metamorphic manganese rich assemblages. Neues Jahrbuch für Mineralogie Abhandlungen, 138, 113.Google Scholar
Lanari, P., Wagner, T. & Vidal, O. (2014a) A thermo-dynamic model for di-trioctahedral chlorite from experimental and natural data in the system MgO-FeO-Al2O3-SiO2-H2O: applications to P-T sections and geothermometry. Contributions to Mineralogy and Petrology, 167, 119.Google Scholar
Lanari, P., Vidal, O., De Andrade, V., Dubacq, B., Lewin, E., Grosch, E.G. & Schwartz, S. (2014b) XMapTools: A MATLAB©-based program for electron microprobe X-ray image processing and geothermobarometry. Computers and Geosciences, 62, 227240.Google Scholar
Lapham, D.M. (1958) Structural and chemical variation in chromium chlorite. American Mineralogist, 43, 921956.Google Scholar
Laird, J. (1988) Chlorites; metamorphic petrology. Pp. 405453 in: Hydrous Phyllosilicates (exclusive of Micas) (S.W. Bailey, editor). Reviews in Mineralogy, 19, Mineralogical Society of America, Washington, D.C. Google Scholar
Lazarenko, E.K. (1940) Donbassites, a new group of minerals from the Donetz Basin. CR Academy Science URSS, 28, 519521.Google Scholar
Lin, C.Y. & Bailey, S.W. (1985) Structural data for sudoite. Clays and Clay Minerals, 33, 410414.Google Scholar
Lougear, A., Grodzicki, M., Bertoldi, C., Trautwein, A.X., Steiner, K. & Amthauer, G. (2000) Mössbauer and molecular orbital study of chlorites. Physics and Chemistry of Minerals, 27, 258269.Google Scholar
MacKenzie, K.J.D. & Bowden, M.E. (1983) Thermal and Mössbauer studies of iron-containing hydrous silicates. IV. Amesite. Thermochimica Acta, 64, 83106.Google Scholar
Malmström, M., Banwart, S., Lewenhagen, J., Duro, L. & Bruno, J. (1996) The dissolution of biotite and chlorite at 25°C in the near-neutral pH region. Journal of Contaminant Hydrology, 21, 201213.Google Scholar
Malysheva, T.V., Satarova, L.M. & Polyakova, N.P. (1977) Thermal transformations of layered silicates and the nature of the iron-bearing phase in the CII type Murray carbonaceous chondrite. Geokhimiya, 8, 11361148.Google Scholar
Mathias, M. (1952) A note on two actinolites and a chlorite from the Prieska district, Cape Province. Transactions and Proceedings of the Geological Society of South Africa, 55, 1318.Google Scholar
May, H.M., Acker, J.G., Smyth, J.R., Bricker, O.P. & Dyar, M.D. (1995) Aqueous dissolution of low-iron chlorite in dilute acid solutions at 25 C. Clay Minerals Society Proceedings, Abstract, 32, p. 88.Google Scholar
Mélon, J. (1938) Description des Chlorites et Clintonites Belges. Palais des Académies, France.Google Scholar
Meunier, A. (2005) Clays. Springer Science & Business Media, Berlin, 490 pp.Google Scholar
Mitra, S. & Bidyananda, M. (2001) Crystallo-chemical characteristics of chlorites from the greenstone belt of south India, and their geothermometric significance. Clay Science, 11, 479501.Google Scholar
Muñoz, M., De Andrade, V., Vidal, O., Lewin, E., Pascarelli, S. & Susini, J. (2006) Redox and speciation micromapping using dispersive X-ray absorption spectroscopy: Application to iron chlorite mineral of a metamorphic rock thin section. Geochemistry Geophysics Geosystems, 7, Doi: 10.1029/2006GC001381.CrossRefGoogle Scholar
Nakamura, T. (1960) On chlorite from the Ashio copper mine, Japan. Minerals Journal, 4, 383397.Google Scholar
Nockholds, S.R. & Richey, J.E. (1939) Replacement veins in the Mourne Mountains granites, N. Ireland. American Journal of Science, 237, 277.Google Scholar
Orcel, J. (1927) Recherches sur la Composition Chimique des Chlorites. Société Générale d'Imprimerie et d'édition, France.CrossRefGoogle Scholar
Pal, T., Maity, P.K., Das, D. & Mitra, S. (1993) Oxidation character of chlorite from Byrapur chromite deposit, India — An 57Fe Mössbauer evaluation. Bulletin of Materials Science, 16, 229237.Google Scholar
Phillips, T.L., Loveless, J.K. & Bailey, S.W. (1980) Cr3+ coordination in chlorites: a structural study of ten chromian chlorites. American Mineralogist, 65, 112122.Google Scholar
Poitevin, E. & Graham, R.P.D. (1918) Contributions to the Mineralogy of Black Lake Area, Quebec. Government Printing Bureau, France.Google Scholar
Post, J.L. & Plummer, C.C. (1972) The chlorite series of Flagstaff Hill area, California: A preliminary investi-gation. Clays and Clay Minerals, 20, 27183.Google Scholar
Rigault, C. (2010) Cristallochimie dufer dans les chlorites de basse température: implications pour la géothermométrie et la détermination des paléoconditions redox dans les gisements d'uranium. These de doctorat, Université de Poitiers, France.Google Scholar
Ross, C.S. (1935) Origin of the Copper Deposits of the Ducktown Type in the southern Appalachian Region. US Government Printing Office, USA.Google Scholar
Rule, A.C. & Bailey, S.W. (1987) Refinement of the crystal structure of a monoclinic ferroan clinochlore. Clays and Clay Minerals, 35, 129138.Google Scholar
Shannon, E.V. & Wherry, E.T. (1922) Notes on white chlorites. Journal of the Washington Academy of Science, 12, 239.Google Scholar
Shimane, H. & Sudo, T. (1958) A chloritic mineral found associated with vermiculite. Clay Minerals Bulletin, 3, 297301.Google Scholar
Shimoda, S. (1970) An expandable chlorite-like mineral from the Hanaoka Mine, Akita Prefecture, Japan. Clay Minerals Bulletin, 8, 352359.Google Scholar
Shirozu, H. (1958) X-ray powder patterns and cell dimensions of some chlorites in Japan, with a note on their interference colors. MineralogicalJournal, 2, 209223.Google Scholar
Simpson, E.S. (1936) Contributions to the mineralogy of Western Australia. Royal Society of Western Australia Journal, 22, 118.Google Scholar
Simpson, E.S. (1937) Contributions to the mineralogy of Western Australia. Royal Society of Western Australia Journal, 23, 1735.Google Scholar
Singer, D.M., Maher, K. & Brown, G.E. Jr (2009) Uranyl-chlorite sorption/desorption: Evaluation of different U(VI) sequestration processes. Geochimica et Cosmochimica Acta, 73, 59896007.Google Scholar
Smyth, J.R., Dyar, M.D., May, H.M., Bricker, O.P. & Acker, J.G. (1997) Crystal structure refinement and Mössbauer spectroscopy of an ordered, triclinic clinochlore. Clays and Clay Minerals, 45, 544550.Google Scholar
Spanu, V., Filoti, G., Ionescu, J. & Medesan, A. (1977) Mössbauer study of some chlorites. In: Proceedings of the International Conference on Mössbauer Spectroscopy, Editorial Group of the Revue Roumaine de Physique, Bucharest, pp. 323324.Google Scholar
Stone, R.L. & Weiss, E.J. (1955) Examination of four coarsely crystalline chlorites by X-ray and high-pressure DTA techniques. Clay Minerals Bulletin, 2, 214—222.Google Scholar
Sudo, T. & Shimoda, S. (1978) Clays and Clay Minerals of Japan, Vol. 26. Elsevier.Google Scholar
Tilley, C.E. (1938) The status of hornblende in low-grade metamorphic zones of green schists. Geological Magazine, 75, 497511.Google Scholar
Trincal, V., Lanari, P., Buatier, M., Lacroix, B., Charpentier, D., Labaume, P. & Muñoz, M. (2015) Temperature micro-mapping in oscillatory-zoned chlorite: Application to study of a greenschist facies fault zone in the Pyrenean Axial Zone (Spain). American Mineralogist, 100, 24682483.Google Scholar
Tschermak, G. (1891) Die Chloritgruppe. Sitzungberichte Akademie der Wissenschaften, Wien, 100, 29 pp.Google Scholar
Tsukahara, N. (1964) Dioctahedral chlorite from the Furutobe mine, Akita prefecture, Japan. Clay Science, 2, 5675.Google Scholar
Tsuzuki, Y. & Honda, S. (1977) Three examples of Mg-Al chlorite from Kuroko deposits. Journal of the Mineralogical Society of Japan, 13, 8593.Google Scholar
Vidal, O., Parra, T. & Trotet, F. (2001) A thermodynamic model for Fe-Mg aluminous chlorite using data from phase equilibrium experiments and natural pelitic assemblages in the 100 degrees to 600 degrees C, 1 to 25 kb range. American Journal of Science, 301, 557592.Google Scholar
Vidal, O., Parra, T. & Vieillard, P. (2005) Thermodynamic properties of the Tschermak solid solution in Fe-chlorite: Application to natural examples and possible role of oxidation. American Mineralogist, 90, 347358.Google Scholar
Vidal, O., De Andrade, V., Lewin, E., Muñoz, M., Parra, T. & Pascarelli, S. (2006) P-T-deformation-Fe3+/Fe2+ mapping at the thin section scale and comparison with XANES mapping: application to a garnet-bearing metapelite from the Sambagawa metamorphic belt (Japan). Journal of Metamorphic Geology, 24, 669683.Google Scholar
Vidal, O., Lanari, P., Munoz, M., Bourdelle, F. & de Andrade, V. (2016) Deciphering temperature, pressure and oxygen activity conditions of chlorite formation. Clay Minerals, 51, 615633.Google Scholar
Vrublevskaja, Z.V., Delitsin, I.S., Zvyagin, B.B. & Soboleva, S.V. (1975) Cookeite with a perfect regular structure, formed by bauxite alteration. American Mineralogist, 60, 10411046.Google Scholar
Weaver, C.E., Wampler, J.M. & Pecuil, T.E. (1967) Mössbauer analysis of iron in clay minerals. Science, 156, 504508.Google Scholar
Wiewióra, A. & Weiss, Z. (1990) Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition; II. The chlorite group. Clay Minerals, 25, 8392.Google Scholar
Wilke, M., Farges, F., Petit, P.-E., Brown, G.E. & Martin, F. (2001) Oxidation state and coordination of Fe in minerals: An Fe K-XANES spectroscopic study. American Mineralogist, 86, 714730.Google Scholar
Zazzi, Å., Hirsch, T.K., Leonova, E., Kaikkonen, A., Grins, I., Annersten, H. & Edén, M. (2006) Structural investigations of natural and synthetic chlorite minerals by X-ray diffraction, Mössbauer spectroscopy and solid-state nuclear magnetic resonance. Clays and Clay Minerals, 54, 252265.Google Scholar
Zhang, G., Burgos, W.D., Senko, J.M., Bishop, M.E., Dong, H., Boyanov, M.I. & Kemner, K.M. (2011) Microbial reduction of chlorite and uranium followed by air oxidation. Chemical Geology, 283, 242250.Google Scholar
Zheng, H. & Bailey, S.W. (1989) Structures of intergrown triclinic and monoclinic IIb chlorites from Kenya. Clays and Clay Minerals, 37, 308316.Google Scholar