Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

New Results on Mineralography and Crystal Chemistry of Magnetite and Pyrite at Baba-Ali & Galali Iron Deposits, West of Hamedan, Iran

Document Type : Original Research Paper

Authors
Ghodratollah Rostami Paydar 1
M. Lotfi 2
M. Ghaderi 3
A. Amiri 4
M. Vossoughi-Abedini 5
1 Department of Geology, Faculty of Sciences, Ahvaz branch, Islamic Azad University, Ahvaz, IRAN
2 Department of Geology, Islamic Azad University, North Tehran Branch, Tehran, Iran
3 Department of Economic Geology, Faculty of Basic Science, Tarbiat Modares University, Tehran, Iran
4 Department of Geography, Islamic Azad University, Ahvaz Branch, Ahvaz, Iran
5 Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
10.22071/gsj.2010.55356
Abstract
Baba-Ali and Galali iron deposits in west of Hamedan are emplaced within the Songhor volcano-sedimentary sequence of Sanandaj-Sirjan geological-structural zone. Mineralography and SEM-EDAX analyses on magnetite iron ores at both deposits for better understanding of mineralogy and crystal-chemistry of the ores have shown some interesting results. Studies on concentrations of some trace elements such as V, Co, Ni, Cu, Cr, Ti, Au, PGE as well as S and P impurities in the ore indicate that only some of the primary pyrites have considerable concentrations of Pt. It seems that other generations of pyrite and magnetite are depleted in these trace elements. Late stage hydrothermal fluids that lead to mineralization of pyrite in calcite-quartz gangue veins, have also been impotant for gold mineralization and pyrite has actually acted as a favorable carrier for Au. Detection of abundant phlogopite and trace element concentration patterns at Galali iron ore have strengthened volcanogenic magnesian skarn hypothesis.
Keywords
Mineralography
Crystal-Chemistry
Scanning electron microscopy
Iron ore
Baba-Ali
Galali
References
Barud, J., 1975- Geological map of the Kermanshah Quadrangle, 1:250000, Published by Geological Survey of Iran, Tehran, Iran.
Champness, P. E., Cliff, G. and Lorimer, G. W., 1982- Quantitative analytical electron microscopy of metals and minerals. J. Microsc., 108, 231-49.
Frietsch, R. and Perdahl, J. A., 1995- Rare earth elements in apatite and magnetite in Kiruna-type iron ores and some other iron ore types, Ore Geology Reviews, v. 9, p. 489-510.
Goldstein, J. and Newbury, D. E., 2003- Scanning Electron Microscopy and X-Ray Microanalysis, Third Edition, Plenum Press, 358p.
Hall, M.G., Lloyd, G.E., 1981- The SEM examination of geological samples with a semiconductor back-scattered electron detector, Am. Mineral, v. 66, p. 362-368.
Hobart, H. and Willard, H., 1998- Instrumental methods of analysis. Wadsworth Inc., Seventh edition.
Lloyd, G. E. and Hall, M. G., 1981- Application of scanning electron microscopy to the study of deformed rocks. Tectonophysics, v. 78, p. 687-698.
Meinert, L. D., 1993- Skarns and skarn deposits, in Ore deposit models, Volume II: Geoscience Canada, reprint series 6, p. 117-134.
Passchier, C. W. and Trouw, R.A.J., 2005- Microtectonics, special techniques, Scanning Electron Microscope, Springer, 288p.
Pirajno, F., 1992- Hydrothermal mineral deposits, Springer-Verlag, 709p.
Reed, S. J. B., 1996- Electron microprobe analysis and scanning electron microscopy in geology, Cambridge Univ Press., 201p.
Torab, F. M.  and Lehmann, B., 2007- Magnetite-apatite deposits of the Bafq district, Central Iran: apatite geochemistry and monazite geochronology, Mineralogical Magazine, v. 71, no. 3, p. 347-363.
Zamanian, H., Yousefi, B. and Alavi, S. A., 2007- Mineralogical and geochemical skarn zoning across the Baba-Ali deposit, western Iran, Geoscience Scientific Quarterly Journal, vol. 16, No. 62, p. 194-203.
Zheng, J. G., 2006- Electron microscopy: TEM and SEM, in Materials Science & Engineering Congress, EPIC/NUANCE Center, USA.
Scientific Quarterly Journal of Geosciences
Volume 20, Issue 77
Winter 2010
Pages 121-130