Hostname: page-component-76fb5796d-vvkck Total loading time: 0 Render date: 2024-04-27T20:16:10.626Z Has data issue: false hasContentIssue false
  • English
  • Français

Mineralization in the Bonser vein, Coniston, English Lake District: mineral assemblages, paragenesis, and formation conditions

Published online by Cambridge University Press:  05 July 2018

C. J. Stanley  and
D. J. Vaughan
C. J. Stanley
Affiliation:
Department of Mineralogy, British Museum (Natural History), Cromwell Road, South Kensington, London SW7 5BD
D. J. Vaughan
Affiliation:
Department of Geological Sciences, University of Aston in Birmingham, Birmingham B4 7ET
Get access Rights & Permissions [Opens in a new window]

Abstract

The Bonser vein, one of the most productive sources of copper in the English Lake District, contains a mineral assemblage comprising quartz, chlorite, calcite, dolomite, stilpnomelane, magnetite, pyrrhotine, pyrite, marcasite, native bismuth, bismuthinite, laitakarite, joseite, arsenopyrite, chalcopyrite, sphalerite, galena, and cosalite. The phases pyrrhotine, sphalerite, arsenopyrite, laitakarite, joseite, and cosalite were analysed by electron microprobe. The occurrence of laitakarite is the first reported in the British Isles. Textures of the ore and gangue minerals show that the vein minerals were deposited successively in open voids. The sequence of deposition was of quartz forming throughout, early chlorite and stilpnomelane with some dolomite and calcite, magnetite as the earliest opaque phase, followed by arsenopyrite, pyrrhotine, sphalerite, chalcopyrite, pyrite, and marcasite; the bismuth- and lead-bearing minerals were the last to form.

The data on the coexisting phases and their compositions have been used to estimate the temperatures of mineralization and the activities of sulphur and oxygen. Magnetite and arsenopyrite appear to have formed at 350–400% with aS2 reaching 10−12 to 10−14 atm. and aO2 around 10−24 to 10−29 atm. The assemblage of quartz, chlorite, stilpnomelane, calcite, dolomite, pyrrhoine, chalcopyrite, sphalerite, and (late) arsenopyrite was probably deposited at ∼ 240°C, with aS2 decreasing to 10−15 to 10−16 atm and aO2 to 10−38) to 10{su−44 atm. The later minerals probably formed at temperatures as low as 200°C and under similar conditions of sulphur and oxygen activity.

Type
Research Article
Information
Mineralogical Magazine , Volume 46 , Issue 340 , September 1982 , pp. 343 - 350
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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., and Skinner, B. J. (1967), 1979) Sulphide mineral stabilities. In Geochemistry of hydrothermal ore deposits (Barnes, H. L., ed.) (lst and 2nd editions) John Wiley, New York.Google Scholar
Bente, K. (1982) Mineral. Deposita, 17, 119–32CrossRefGoogle Scholar
Berry, L. G. (1963) Can. Mineral. 7, 677–9.Google Scholar
Berry, L. G. and Thompson, R. M. (1962) X-ray powder data for ore minerals. Geol. Soc. Amer. Mem. 85.Google Scholar
Bott, M. H. P. (1974) J. Geol. Soc. 130, 309–31.10.1144/gsjgs.130.4.0309CrossRefGoogle Scholar
Brown, P. E., Miller, J. A., and Soper, N. J. (1964) Proc. Yorks. Geol. Soc. 34, 331–42.10.1144/pygs.34.3.331CrossRefGoogle Scholar
Craig, J. R. (1967) Mineral. Deposita, 1, 278–306.10.1007/BF00205202CrossRefGoogle Scholar
Dagger, G. W. (1977) Geol. MOO. 144, 195–202.Google Scholar
Firman, R. J. (1957) Q. J. Geol. Soc. 113, 205–22.10.1144/GSL.JGS.1957.113.01-04.09CrossRefGoogle Scholar
Godovikov, A. A., Kochetkova, K. V., and Lavrentyev, Y. G. (1971) Zap. Vses. Mineral. Obshch. 100, 417–28.Google Scholar
Holland, H. D. (1959) Econ. Geol. 54, 184–233.CrossRefGoogle Scholar
Holland, H. D. (1965) Ibid. 60, 1101–58.Google Scholar
Ineson, P. R., and Mitchell, J. G. (1974) Geol. MOO. 111, 521–37.Google Scholar
Kato, A. (1959) Mineral. J. Japan. 2, 397–407.CrossRefGoogle Scholar
Kendall, J. D. (1884) Trans. Manchester Geol. Soc. 17, 292–341.Google Scholar
Kissin, S. A. (1974) Unpubl. Ph.D. thesis, University of Toronto.Google Scholar
Klement, W., Jayasaman, A., and Kennedy, G. C. (1963). Phys. Rev. 131, 632–7.CrossRefGoogle Scholar
Kretschmar, V., and Scott, S. D. (1976). Can. Mineral. 14, 364–86.Google Scholar
Mitchell, G. H. (1940) Q. J. Geol. Soc. 96, 301–19.10.1144/GSL.JGS.1940.096.01-04.12CrossRefGoogle Scholar
Miyashiro, A. (1973) Met amorphism and metamorphic belts. Allen and Unwin, London.Google Scholar
Morimoto, N., Gyobu, A., Mukaiyama, H., and Izawa, E. (1975) Econ. Geol. 70, 824–33.CrossRefGoogle Scholar
Peacock, M. A. (1941) Univ. Toronto Stud., Geol. Ser. 46, 83–105.Google Scholar
Rickards, R. B. (1978) In The Geology of the Lake District (Moseley, F., ed.), Yorks. GeoL Soc. Occ. Publ. No. 3.Google Scholar
Rundie, C. C. (1979) J. Geol. Soc. 136, 29–38.10.1144/gsjgs.136.1.0029CrossRefGoogle Scholar
Russell, A. (1925) Mineral. MoO. 20, 299–304.Google Scholar
Scott, S. D., and Kissin, S. A. (1973) Econ. Geol. 68, 475–9.10.2113/gsecongeo.68.4.475CrossRefGoogle Scholar
Shaw, W. T. (1970) Mining in the Lake Counties, Dalesman Publ. Co., Clapham, Lancaster.Google Scholar
Smith, F. G. (1963) Physical Geochemistry, Addison Wesley, New York.Google Scholar
Stanley, C. J., and Criddle, A. J. (1979) Mineral. MOO. 43, 103–7.Google Scholar
Vorma, A. (1960) Bull. Comm. Geol. Finl. 188, 1–10.Google Scholar
Wheatley, C. J. V. (1971). Trans. Inst. Mining Metall. 80, 211–23.Google Scholar
Wuensch, B. J. (1963). Mineral. Soc. Am. Spec. Pap. 1, 157–63.Google Scholar