Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-27T07:11:31.469Z Has data issue: false hasContentIssue false
  • English
  • Français

An SEM examination of the chalcopyrite disease texture and its genetic implications

Published online by Cambridge University Press:  05 July 2018

Toshiro Nagase  and
Shoji Kojima
Toshiro Nagase
Affiliation:
Institute of Mineralogy, Petrology and Economic Geology, Faculty of Science, Tohoku University, Aoba Sendal 980-77, Japan
Shoji Kojima
Affiliation:
Institute of Mineralogy, Petrology and Economic Geology, Faculty of Science, Tohoku University, Aoba Sendal 980-77, Japan
Get access Rights & Permissions [Opens in a new window]

Abstract

Back-scattered electron imaging with a scanning electron microscope was applied to the intimate association of fine chalcopyrite grains and sphalerite (‘chalcopyrite disease’) in synthesized products and natural specimens, in order to distinguish between diagnostic features of two formation mechanisms: replacement and coprecipitation. In the synthetic chalcopyrite disease in Fe-bearing sphalerite formed by a replacement reaction, chalcopyrite occurs as fine lamellae, which are also observed in relatively Fe-rich growth bands of the natural zoned sphalerite. Ellipsoidal to lens-like habits of chalcopyrite appear in sphalerite that has undergone extensive replacement reactions. These textures may have grown steadily from the lamellar chalcopyrite by consuming the FeS component dissolved in the sphalerite. All the sphalerite samples formed by the coprecipitation mechanism are Fe-poor, hosting triangular or irregularly bleb-like inclusions of chalcopyrite. This variety of chalcopyrite morphology could be attributed to diffusion rates and variations in fluid saturation, and their effect on the rate of crystal growth. Thus, in both replacement and coprecipitation the chalcopyrite habit depends strongly both on the FeS content of the host sphalerite and on kinetic factors, and is significant when interpreting chalcopyrite disease textures in natural samples.

Keywords

back-scattered electron imagechalcopyrite diseasesphaleritereplacement reactioncoprecipitation mechanismlamellaetriangular habit
Type
Mineralogy
Information
Mineralogical Magazine , Volume 61 , Issue 404 , February 1997 , pp. 89 - 97
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barton, P.B., Jr. (1978) Some ore textures involving sphalerite from the Furutobe mine, Akita Prefecture, Japan. Mining Geol., 28, 293–300.Google Scholar
Barton, P.B., Jr. and Bethke, P.M. (1987) Chalcopyrite disease in sphalerite: pathology and epidemiology. Amer. Mineral., 72, 451-67.Google Scholar
Eldridge, C.S., Bourcier, W.L., Ohmoto, H. and Barnes, H.L. (1988) Hydrothermal inoculation and incubation of the chalcopyrite disease in sphalerite. Econ. Geol., 83, 978-89.CrossRefGoogle Scholar
Goble, R.J., Scott, S.D. and Hancock, R.G.V. (1979) Diffusion rates of Zn and Fe in sphalerite (abst.). Geol. Assoc. Canada, Mineral. Assoc. Canada, and Canadian Soc. Petroleum Geol., Annual Meet. Program with Abstracts, 4, 53.Google Scholar
Hall, M.G. and Lloyd, G.E. (1981) The SEM examination of geological samples with a semiconductor back-scattered electron detector. Amer. Mineral., 66, 362-8.Google Scholar
Kanbara, H., Sanga, T., Ohura, T. and Kumita, K. (1989) Mineralization of Shinano vein in the Toyoha polymetallic vein-type deposits, Hokkaido, Japan. Mining Geol., 39, 107-22.(in Japanese).Google Scholar
Kojima, S. (1990) A coprecipitation experiment in intimate association of sphalerite and chalcopyrite and its bearings on the genesis of Kuroko ores. Mining Geol., 40, 147-58.Google Scholar
Kojima, S. (1992) The nature of chalcopyrite inclusions in sphalerite: exsolution, coprecipitation, or ‘diseased'? - A discussion. Econ. Geol., 87, 1191-2.CrossRefGoogle Scholar
Kojima, S. and Sugaki, A. (1985) Phase relations in the Cu-Fe-Zn-S system between 500 ° and 300° under hydrothermal conditions. Econ. Geol., 80, 158–71.CrossRefGoogle Scholar
Kojima, S. and Sugaki, A. (1987) An experimental study on chalcopyritization of sphalerite induced by hydrothermally metasomatic reactions. Mining Geol., 37, 373-80.Google Scholar
Kojima, S., Nagase, T. and Inoue, T. (1995) A coprecipitation experiment on the chalcopyrite disease texture involving Fe-bearing sphalerite. J. Mineral. Petrol. Econ. Geol., 90, 261-7.CrossRefGoogle Scholar
Mariko, T. (1988) Compositional zoning and ‘chalcopyrite disease’ in sphalerite contained in the Pb-Zn-quartz-calcite ore from the Mozumi deposit of the Kamioka mine, Gifu Prefecture, Japan. Mining Geol., 38, 393–400.(in Japanese).Google Scholar
Mizuta, T. (1988) Interdiffusion rate of zinc and iron in natural sphalerite. Econ. Geol., 83, 1205-20.CrossRefGoogle Scholar
Nelkowski, F.R.N. and Bollman, G. (1969) Diffusion von In und Cu in ZnS-einkristallen. Zeitschr. Naturforsch., 24a, 1302-6.Google Scholar
Ohta, E. (1989) Occurrence and chemistry of indiumcontaining minerals from the Toyoha mine, Hokkaido, Japan. Mining Geol., 39, 355-72.Google Scholar
Pattrick, R.A.D., Dorling, M. and Polya, D.A. (1993) TEM study of indium- and copper-bearing growthbanded sphalerite. Can. Mineral., 31, 105-17.Google Scholar
Sawai, O., Okada, T. and Itaya, T. (1989) K-Ar ages of sericite in hydrothermally altered rocks around the Toyoha deposits, Hokkaido, Japan. Mining Geol., 39, 191–204.Google Scholar
Shimazaki, H. (1988) On chalcopyrite disease texture. In: Ore Microscope and Ore Textures (Sugaki, A., ed.), Terra Scientific Publishing Company, Tokyo, 397–413 (in Japanese).Google Scholar
Sugaki, A., Kitakaze, A. and Kojima, S. (1987) Bulk compositions of intimate intergrowths of chalcopyrite and sphalerite and their genetic implications. Mineral. Deposita, 22, 26–32.CrossRefGoogle Scholar
Toulmin, P. III, Barton, P.B., Jr. and Wiggins, L.B. (1991) Commentary on the sphalerite geobarometer. Amer. Mineral., 76, 1038-51.Google Scholar