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Geological Quarterly

Tytuł artykułu

Secondary sulphate minerals from Bhanine Valley coals (South Lebanon) : a crystallochemical and geochemical study

Autorzy Kruszewski, Łukasz 
Treść / Zawartość
Warianty tytułu
Języki publikacji EN
EN Rich efflorescences of various Fe and Al sulphate mineral mixtures on coal seams of Bhanine, South Lebanon, were examined using (1) Powder X-Ray Diffraction (with the Rietveld method and unit cell parameters calculation), (2) Scanning Electron Microscopy with standardized Electron-Dispersive Spectroscopy system, and (3) Inductively-Coupled Plasma Mass Spectroscopy. The sulphates most likely originated from coal-contained pyrite to form Fe(II) sulphates (melanterite, rozenite, and the most common szomolnokite), followed by Fe3+-rich sulphates (coquimbite group, copiapite group) and Al sulphates (alunogen, tamarugite). The halotrichite group and minor voltaite, metavoltine, and possibly secondary rozenite and szomolnokite were the last species to be formed. Strong enrichment in Al in copiapites and coquimbites, common occurrence of aluminocoquimbite, and Al likely entering the structure of Fe(II) sulphates makefurther phenomena, during which the initial ferrous copiapites were oxidized in the presence of Al-rich solutions, not out of the question. The obtained unit cell parameters sometimes stand for threshold values in the literature-based ranges drawn, but the values are usually below the 2% discrepancy. The Bhanine sulphates bear relatively large amounts of Tl, Hg, and Co when compared to Coal Clarke and mean crustal abundancies, being also moderately enriched in Ni and As.
Słowa kluczowe
EN iron sulphates   aluminium sulphates   coquimbite   coal   unit cell parameters   standardized Energy Dispersive Spectroscopic analysis  
Wydawca Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
Czasopismo Geological Quarterly
Rocznik 2019
Tom Vol. 63, No. 1
Strony 65--87
Opis fizyczny Bibliogr. 97 poz., rys., tab., wykr.
autor Kruszewski, Łukasz
1. Ackermann, S., Lazic, B., Armbruster, T., Doyle, S., Grevel, K.-D., Majzlan, J., 2009. Thermodynamic and crystallographic properties of kornelite [Fe2(SO4)3 ~7.75H2O] and paracoquimbite [Fe2(SO4)3 9H2O]. American Mineralogist, 94: 1620-1628.
2. Anderson, J.L., Peterson, R.C., Swainson, I., 2009. The atomic structure and hydrogen bonding of deuterated melanterite, FeSO4 7D2O. The Canadian Mineralogist, 45: 457-469.
3. Anthony, J.W., Bideaux, R.A., Bladh, K.W., Nichols, M.C. eds., 2003. Handbook of Mineralogy (vol. 5),, Mineralogical Society of America, Chantilly, VA 2015l-1110, USA; http:/
4. Bandy, M.C., 1938. Mineralogy of three sulphate deposits of Northern Chile. Journal of the Mineralogical Society of America, 23: 670-760.
5. Baur, W.H., 1964. On the crystal chemistry of salt hydrates. III. The Determination of the Crystal Structure of FeSO4 7H2O (Melanterite). Acta Crystallographica, 17: 1167-1174.
6. Baur, W.H., Rolin, J.L., 1972. Salt hydrates. IX. The comparison of the crystal structure of magnesium sulphate pentahydrate with copper sulphate pentahydrate and magnesium chromate pentahydrate. Acta Crystallographica, 28: 1448-1455.
7. Bayliss, P., Atencio, D., 1985. X-ray powder-diffraction data and cell parameters for copiapite-group minerals. Zeitschrift für Kristallographie, 135: 34-55.
8. Berry, L.G., 1947. Composition and optics of copiapite. University of Toronto Studies, Geological Series, 51: 21-34.
9. Bielowicz, B., Misiak, J., 2016. Siarczki w pokładach węgla kamiennego warstw orzeskich s.s. serii mułowcowej (westfal B) we wschodniej części GZW (in Polish). Gospodarka Surowcami Mineralnymi - Mineral Resources Management, 32: 23-38.
10. Blass, G., Strehler, H., 1993. Mineralbildungen in einer durch Selbstentzündung brennenden Bergehalde des Aachener Steinkohlen reviers. Mineralien-Welt, 4: 35-42.
11. Bobos, I., Durăes, N., Noronha, F., 2006. Mineralogy and geochemistry of mill tailings impoundments from Algares (Aljustrel), Portugal: implications for acid sulfate mine waters formation. Journal of Geochemical Exploration, 88: 1-5.
12. Buckby, T., Black, S., Coleman, M.L., Hodson, M.E., 2003. Fe-sulphate-rich evaporative mineral precipitates from the Rio Tinto, southwest Spain. Mineralogical Magazine, 67: 263-278.
13. Chipera, S.J., Vaniman, D.T., 2007. Experimental stability of magnesium sulfate hydrates that may be present on Mars. Geochimica et Cosmochimica Acta, 71: 241-250.
14. Cooper, J.F., Jr., Dunning, G.E., Hadley, T.A., Moller, W.P., Reynolds, R.E., 2005. The sulfur hole, Calico Disctrict, San Bernardino County, California. Axis, 1: 1-18.
15. Čech, F., 1979. Rostite, a new name for orthorhombic Al(SO4)(OH) 5H2O. Neues Jahrbuch für Mineralogie - Monatshefte: 193-194.
16. Dai, S., Liu, J., Ward, C.R., Hower, J.C., Xie, P., Jiang, Y., Hood, M.M., O'Keefe, J.M.K., Song, H., 2015. Petrological, geochemical, and mineralogical compositions of the low-Ge coals from the Shengli Coalfield, China: a comparative study with Ge-rich coals and a formation model forcoal-hosted Ge ore deposit. Ore Geology Reviews, 71: 318-349.
17. Dai, S., Wang, X., Zhao, L., 2017. Mineral Matter and Trace Elements in Coal, Special Issue, 1st ed. MDPI Books, Basel, Switzerland.
18. Demartin F., Castellaro, C., Gramaccioli, C.M., Campostrini, I., 2010. Aluminium-for-iron substitution, hydrogen bonding, and a novel structure-type in coquimbite-like minerals. The Canadian Mineralogist, 48: 323-333.
19. Dill, H.G., Pöllmann, H., Bosecker, K., Hahn, L., Mwiya, S., 2002. Supergene mineralization in mining residues of the Matchless cupreous pyrite deposit (Namibia) - a clue to origin of modern and fossil duricrusts in semiarid climates. Journal of Geochemical Exploration, 75: 43-70.
20. Dokoupilová, P., Sracek, O., Losos, Z., 2007. Geochemical behaviour of and mineralogical transformations during spontaneous combustion of a coal waste pile in Oslavany, Czech Republic. Mineralogical Magazine, 71: 443-460.
21. ELARD, 2017. Updated master plan for the closure and rehabilitation of uncontrolled dumpsites thorough the country of Lebanon. Earth Link and Advanced Resources Development, Vol. A, United Nations Development Programme (UNDP) and the Ministry of Environment, non/en/home/library/environment_energy/MASTER-PLAN-FOR-THE-CLOSURE-AND-REHABILITATION.html
22. Fanfari, L., Nunzi, A., Zanzari, P.F., Zanzari, A.R., 1973. The copiapite problem: the crystal structure of a ferrian copiapite. American Mineralogist, 58: 314-322.
23. Fang, J.H., Robinson, P.D., 1970. Crystal structures and mineral chemistry of hydrated ferric sulfates. I. The crystal structure of coquimbite. American Mineralogist, 55: 1534-1540.
24. Fang, J.H., Robinson, P.D., 1976. Alunogen, Al2(H2O)i 2(SO4)3 5H2O: its atomic arrangement and water content. American Mineralogist, 61: 311-317.
25. Fernández-Remolar, D.C., Morris, R.V., Gruener, J.E., Amils, R., Knoll, A.H., 2005. The Rio Tinto Basin, Spain: mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars. Earth and Planetary Science Letters, 240: 149-167.
26. Filippidis, A., Georgakopoulos, A., Kassoli-Fournaraki, A., 1996. Mineralogical components of some thermally decomposed lignite and lignite ash from the Ptolemais basin, Greece. International Journal of Coal Geology, 30: 303-314.
27. Fitzpatrick, R., Shand, P., Raven, M., McClure, S., 2010. Occurrence and environmental significance of sideronatrite and other mineral precipitates in Acid Sulfate Soils. 19th World Congress of Soil Science, Soil Solutions for a Changing World, 1-6 August 2010, Brisbane, Australia: 80-83.
28. Gluskoter, H.J., 1977. Inorganic sulfur in coal. Energy Sources, 3: 125-131.
29. Goldschmidt, V.M., 1937. The principles of distribution of chemical elements in minerals and rocks. 7th Hugo Müller Lecture; Journal of the Chemical Society (Resumed): 655-673.
30. Gornitz, V., 2004. Minerals as keys to ancient climates. Mineral News, 20: 9-13.
31. Gornitz, V., 2005. Mapping the minerals on Mars. Mineral News, 21: 1-11.
32. Hammarstrom, J.M., Seal II, R.R., Meier, A.L., Kornfeld, J.M., 2005. Secondary sulphate minerals associated with acid mine drainage in the eastern US: recycling of metals and acidity in surficial environments. Chemical Geology, 215: 407-431.
33. Hudson-Edwards, K.A., Schell, C., Macklin, M.G., 1999. Mineralogy and geochemistry of alluvium contaminated by metal mining in the Rio Tinto, southwest Spain. Applied Geochemistry, 14: 1015-1030.
34. Jamie son, H.E., Robinson, C., Alpers, C.N., McCleskey, R.B., Nordstrom, D.K., Peterson, R.C., 2005. Major and trace element composition of copiapite-group minerals and coexisting water from the Richmond mine, Iron Mountain, California. Chemical Geology, 215: 387-405.
35. Joeckel, R.M., Ang Clement, B.J.A., Van Fleet Bates, L.R., 2005. Sulfate-mineral crusts from pyrite weathering and acid rock drainage in the Dakota Formation and Graneros Shale, Jefferson County, Nebraska. Chemical Geology, 541: 69.
36. Kampf, A.R., Mills, S.J., Housley, R.M., Williams, P.A., Dini, M., 2012. Alcaparrosaite, K3Ti4+Fe3+(SO4)4O(OH)2, a new hydrophobic Ti4+ sulfate from Alcaparrosa, Chile. Mineralogical Magazine, 76: 851-861.
37. Keith, D.C., Runnels, D.D., Esposito, K.L., Chermak, L.A., Levy, D.B., Hannula, S.R., Watts, M., Hall, L., 2001. Geochemical models of the impact of acid groundwater and evaporative sulfate salts on Boulder Creek at Iron Mountain, California. Applied Geochemistry, 16: 947-961.
38. Ketris, M.P., Yudovich, Ya.E., 2009. Estimations of clarkes forcarbonaceous biolithes: World averages for trace element contents in black shales and coals. International Journal of Coal Geology, 78: 135-148.
39. Kostova, I., Marinov, S., Stefanova, M., Markova, K., Stamenova, V., 2005. The distribution of sulphur forms in high-S coals of the Maritza West Basin, Bulgaria. Bulletin of Geosciences, 80: 23-32.
40. Kruszewski, Ł., 2006. Oldhamite-periclase-portlandite-fluorite assemblage and coexisting minerals from burnt dump in Siemianowice Śląskie - Dąbrówka Wielka area (Upper Silesia, Poland) - preliminary report. Mineralogia Polonica - Special Papers, 28: 118-120.
41. Kruszewski, Ł., 2013. Supergene sulphate minerals from the burning coal mining dumps in the Upper Silesian Coal Basin, South Poland. International Journal of Coal Geology, 105: 91-109.
42. Kruszewski, Ł., Fabiańska, M.J., Ciesielczuk, J., Segit, T., Orłowski, R., Motyliński, R., Moszumańska, I., Kusy, D., 2018a. First multi-tool exploration of a gas-condensate-pyrolysate system from the environment of burning coal mine heaps: an in situ FTIR and laboratory GC and PXRD study based on Upper Silesian materials. Science of the Total Environment, 640-641: 1044-1071.
43. Kruszewski, Ł., Gatel, P., Thiéry, V., Moszumańska, I., Kusy, D., 2018b. Crystallochemical behavior of slag minerals and the occurrence of potentially new mineral species from Lapanouse-de-Sévérac, France. Coal and Peat Fires, 5: 241-300.
44. Lafuente, B., Downs, R.T., Yang, H., Stone, N., 2015. The power of databases - the RRUFF project, In: Highlights in Mineralogical Crystallography (eds. T. Armbruster and D.M. Danisi): 1-30. W. De Gruyter.
45. Lebanon Ministry of Tourism, 2011.
46. Lipiarski, I., Muszyński, M., Wyszomirski, P., 2004. Alunites in the Red Beds of the „Marcel” coal mine, Upper Silesian Coal Basin, Poland. Mineralogia Polonica, 35: 3-18.
47. Liu, J., Ward, C.R., Graham, I.T., French, D., Dai, S., Song, X., 2018. Modes of occurrence of non-mineral inorganic elements in lignites from the Mile Basin, Yunnan Province, China. Fuel, 222: 146-155.
48. Lovas, G.A., 1986. Structural strudy of halotrichite from Recsk (Mátra Mts., N-Hungary) (in Hungarian with English summary). Acta Geologica Hungarica, 29: 389-398.
49. Lutz Ehrlich, H., Newman, D.K., 2009. Geomicrobiology. 5th Ed., CRC Press, Tay! or Francis Group, Boca Raton, FL, USA.
50. Majzlan, J., Michalik, R., 2007. The crystal structures, solid solutions and infrared spectra of copiapite-group minerals. Mineralogical Magazine, 71: 553-559.
51. Majzlan, J., Alpers, C.N., Koch, Bender Koch, C., McCleskey, R.B., Myneni, S.C.B., Neil, J.M., 2011. Vibrational, X-ray absorption, and Mössbauer spectra of sulfate minerals from the weathered massive sulfide deposit at Iron Mountain, California. Chemical Geology, 284: 296-305.
52. Martin, R., Rodgers, K.A., Browne, P.R.L., 1999. The nature and significance of sulphate-rich, aluminous efflorescences from the Te Kopia geothermal field, Taupo volcanic zone, New Zealand. Mineralogical Magazine, 63: 413-419.
53. Masalehdani, M.N.-N., Mees, F., Dubois, M., Coquinot, Y., Potdevin, J.-L., Fialin, M., Blanc-Valleron, M.-M., 2009. Condensate minerals from a burning coal-waste heap in Avion, northern France. The Canadian Mineralogist, 47: 573-591.
54. Menchetti, S., Sabelli, C., 1974. Alunogen. Its structure and twinning. Tschermaks Mineralogische und Petrographische Mitteilungen, 21: 164-178.
55. Mereiter, K., 2013. Redetermination of tamarugite, NaAl(SO4)2 6H2O. Acta Crystallographica, E69: i63-i64.
56. Montano, P.A., 1981. Characterization of iron-bearing minerals in coal. Advances in Chemistry, Ch. 22, 192: 337-361.
57. Miura, H., Niida, K., Hirama, T., 1994. Mikasaite, (Fe3+,Al)2(SO4)3, a new ferric sulphate mineral from Mikasa County, Hokkaido, Japan. Mineralogical Magazine, 58: 649-653.
58. Murray, J., Kirschbaum, A., Dold, B., Mendes Guimaraes, E., Pannunzio Miner, E., 2014. Jarosite versus soluble iron-sulfate formation and their role in acid mine drainage formation at the Pan de Azúcar Mine Tailings (Zn-Pb-Ag), NW Argentina. Minerals, 4: 477-502.
59. Nanhas, C., 2012. Jezzine fifth highest waterfall in the world. National News Agency (NNA) News;
60. O'Connor, V.A., 2005. Comparative crystal chemistry of hydrous iron sulfates from different terrestrial environments. B.A. thesis, Department of Geology of Smith College.
61. Palache, C., Berman, H., Frondel, C., 1951. Dana's system of mineralogy, 7th ed., 2, 495-496.
62. Parker, R.L., 1967. Composition of the Earth's crust. Data of Geochemistry (ed. M. Fleischer). Geological Survey Professional Paper 440-D, United States Government Printing Office, Washington, D1-D19.
63. Parzentny, H.R., Lewińska-Preis, R., 2006. The role of sulphide and carbonate minerals in the concentration of chalcophile elements in the bituminous coal seams of a paralic series (Upper Carboniferous) in the Upper Silesian Coal Basin (USCB), Poland. Chemie der Erde, 66: 227-247.
64. Pecharsky, V.K., Zavalij, P.Y., 2003. Fundamentals of powder diffraction and structural characterization of materials. Springer Science+Business Media, Inc., New York, USA.
65. Pekov, I.V., Siidra, O.I., Chukanov, N.V., Yapaskurt, V.O., Belakovskiy, D.I., Turchkova, a.G., Möhn, G., 2016. Calamaite, IMA 2016-036. CNMNC Newsletter, 33, October 2016: 1136; Mineralogical Magazine, 80: 1135-1144.
66. Peterson, R.C., 2003. The relationship between Cu content and distortion in the atomic structure of melanterite from the Richmond mine, Iron Mountain, California. The Canadian Mineralogist, 41: 937-949.
67. Quartieri, S., Triscari, M., Viani, A., 2000. Crystal structure of the hydrated sulphate pickeringite (MgAl2(SO4)4 22H2O: X-ray powder diffraction study. European Journal of Mineralogy, 12: 1131-1138.
68. Ramusino, C.C., Giuseppetti, G., 1973. Ritrovamento di un materiale naturale riferible al composto sintético: 6Fe2(SO4)3 Fe2O3.xH2O nelle miniere d'oro di Challant - St. Anselme (Valle d'Ayas) (in Italian). Natura Rivisita di Scienze Naturali, 64: 45-460 .
69. Rice, M.S., Bell III, J.F., Cloutis, E.A., Wang, A., Ruff, S.W., Craig, M.A., Bailey, D.T., Johnson, J.R., de Souza, P.A., Farrand, W.H., 2010. Silica-rich deposits and hydrated minerals at Gutsev Crater, Mars: Vis-NIR spectral characterization and regional mapping. Icarus, 205: 375-395.
70. Robinson, P.D., Fang, J.H., 1969. Crystal structure and mineral chemistry of double-salt hydrates: I. Direct determination of crystal structure of tamarugite. American Mineralogist, 54: 19-30.
71. Robinson, P.D., Fang, J.H., 1971. Crystal structures and mineral chemistry of hydrated ferric sulfates. II. The crystal structure of paracoquimbite. American Mineralogist, 56: 1567-572.
72. Rodgers, K.A., Hamlin, K.A., Borwne, P.R.L., Campbell, K.A., Martin, R., 2000. The steam condensate alteration mineralogy of Ruatapu cave, Orakei Korako geothermal field, Taupo Vocanic Zone, New Zealand. Mineralogical Magazine, 64: 125-142.
73. Romero, A., González, I., Galán, E., 2016. The role of efflorescent sulfates in the storage of trace elements in stream waters polluted by acid mine-drainage: the case of Pena del Hierro, Southwestern Spain. The Canadian Mineralogist, 44: 1431-1446.
74. Rosse, H., 1883. Ueber einige in Südamerika vorkommende Eisenoxydsalze. Annalen der Physik und Chemie, 72, J.C. Poggendorf, Berlin: 309-319.
75. Segnit, E.R., 1976. Tamarugite from Anglesea, Victoria, Australia. Mineralogical Magazine, 40: 642-644.
76. Sgavetti, M., Pompillo, L., Roveri, M., Manzi, V., Valentino, G.M., Lugli, S., Carli, C., Amici, S., Marchese, F., Lacava, T., 2009. Two geologic systems providing terrestrial analogues for the exploration of sulfate deposits on Mars: initial spectral characterization. Planetary and Space Science, 57: 614-627.
77. Skarpelis, N., Argyraki, A., 2009. The geology and origin of supergene ores in Lavrion (Attica, Greece). Resource Geology, 59: 1-14.
78. Smith, G.I., Almond, H., Sawyer, D.L., Jr., 1958. Sassolite from the Kramer borate district, California. American Mineralogist, 43: 1074.
79. Smuda, J., Dold, B., Friese, K., Morgenstern, P., Glaesser, W., 2007. Mineralogical and geochemical study of element mobility at the sulfide-rich excelsior waste rock dump from the polymetallic Zn-Pb-(Ag-Bi-Cu) deposits, Cerro de Pasco, Peru. Journal of Geochemical Exploration, 92: 97-110.
80. Stracher, G.B., Prakash, A., Schroeder, P., McCormack, J., Zhang, X., Van Dijk, P., Blake, D., 2005. New mineral occurrences and mineralization processes: Wuda coal-fire gas vents of Inner Mongolia. American Mineralogist, 90: 1729-1739.
81. Susilawati, R., Ward, C.R., 2006. Metamorphism of mineral matter in coal from the Bukit Asam deposit, south Sumatra, Indonesia. International Journal of Coal Geology, 68: 171-195.
82. Süsse, P., 1972. Crystal structure and hydrogen bonding of copiapite. Zeitschrift für Kristallographie, 135: 34-55.
83. Triantafyllidis, S., Skarpelis, N., 2006. Mineral formation in acid pit lake from a high-sulfidation ore deposit: Kirki, NE Greece. Journal of Geochemical Exploration, 88: 68-71.
84. Velasco, F., Alvaro, A., Suarez, S., Herrero, J.-M., Yusta, I., 2005. Mapping Fe-bearing hydrated sulphate minerals with short wave infrared (SWIR) spectral analysis at San Miguel mine environment, Iberian Pyrite Belt (SW Spain). Journal of Geochemical Exploration, 87: 45-72.
85. Walley, C.D., 1997. The lithostratigraphy of Lebanon: a review. Lebanese Science Bulletin, 10: 81-108.
86. Ward, C.R., 2002. Analysis and significance of mineral matter in coal seams. International Journal of Coal Geology, 50: 135-138.
87. Ward, C.R., 2016. Analysis, origin and significance of mineral matter incoal: an updated review. International Journal of Coal Geology, 165: 1-27.
88. Welch, S.A., Christy, A.G., Isaacson, L., Kirste, D., 2009. Mineralogical control of the rare earth elements in acid sulphate soils. Geochimica et Cosmochimica Acta, 73: 44-64.
89. Wildner, M., Giester, G., 1991. The crystal structure of kieserite-type compounds. I. Crystal structures of Me(II)SO4 H2O (Me = Mn,Fe,Co,Ni,Zn). Neues Jahrbuch für Mineralogie - Monatshefte: 296-306.
90. Wisotzky, F., Obermann, P., 2001. Acid mine groundwater in lignite overburden dumps and its prevention - the Rhineland lignite mining area (Germany). Ecological Engineering, 17: 115-123.
91. Witzke, T., 1996. Die Minerale der brennenden Halde der Steinkohlengrube “Deutschland-schacht” in Oelsnitz bei Zwickau. Aufschluss, 47: 41-48.
92. Yalovik, L., Tatarinov, A., Danilova, E., Doroshkevich, S., 2016. Bio-inert Dome and Columnar Structures of Mud Microvolcanism in Baikal Rift Zone. International Journal of Advanced Research in Science, Engineering and Technology, 3: 2589-2600.
93. Yang, Z., Giester, G., 2018. Structure refinements of coquimbite and paracoquimbite from the Hongshan Cu-Au deposit, NW China. European Journal of Mineralogy, 30: 849-858.
94. Young, B., Nancarrow, P.H.A., 1988. Rozenite and other sulphate minerals from the Cumbrian coalfield. Mineralogical Magazine, 52: 551-553.
95. Zodrow, E.L., 1980. Hydrated sulfates from Sydney Coalfield, Cape Breton Island, Nova Scotia, Canada: the copiapite group. American Mineralogist, 65: 961-967.
96. Zielinski, R.A., Otton, J.K., Johnson, C.A., 2001. Sources of salinity near a coal mine spoil pile, north-central Colorado. Journal of Environmental Quality, 30: 1237-1248.
97. Zimbelman, D.R., Rye, R.O., Breit, G.N., 2005. Origin of secondary sulfate minerals on active andesitic stratovolcanoes. Chemical Geology, 215: 37-60.
Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2019).
Kolekcja BazTech
Identyfikator YADDA bwmeta1.element.baztech-04e6726b-ee4e-42ec-9f5d-a3a104e3d13c
DOI 10.7306/gq.1450