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Sulphide mylonites from the Renström VMS deposit, Northern Sweden

Published online by Cambridge University Press:  05 July 2018

Rowena C. Duckworth  and
David Rickard
Rowena C. Duckworth
Affiliation:
Department of Geology, University of Wales, Cardiff CF1 3YE
David Rickard
Affiliation:
Department of Geology, University of Wales, Cardiff CF1 3YE
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Abstract

Sulphide mylonites are fine-grained massive sulphides which have deformed in a plastic manner. In the Renström Zn-Pb-Cu-Ag-Au VMS deposit, one of several operating mines in the Early Proterozoic Skellefte District in Northern Sweden, shear-zone metamorphism has resulted in the development of mylonitic fabrics within the sulphides. The massive sulphide ore is hosted in a shallow submarine to subaerial volcano-sedimentary sequence which has been variably metamorphosed and deformed. Initially, the sequence underwent burial metamorphism which was followed by an amphibolite grade regional metamorphic event at pressures of around 7.5 kbar and temperatures of 540-600°C This has been overprinted by a retrogressive metamorphic event at greenschist facies (at ca. 400°C with concomitant ductile deformation. Finally the area was uplifted to shallower crustal levels with associated cataclastic deformation.

Both the regional and dynamic metamorphic events have resulted in the development of specific textures in the sulphide ores. Textural evidence indicates that pressure solution has been mainly responsible for the plastic deformation in pyrite, while the weaker sulphide minerals such as pyrrhotite, chalcopyrite and galena have generally recrystallised in response to the high strains.

Sulphide mylonites are probably common rocks in many polydeformed massive sulphide deposits like Renström. They may have previously been misinterpreted as primary depositional textures.

Keywords

volcanogenic massive sulphide depositSwedensulphidemylonitepressure solution
Type
Research Article
Information
Mineralogical Magazine , Volume 57 , Issue 386 , March 1993 , pp. 83 - 91
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1993

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References

Clark, B. R. and Kelly, W. C. (1976) Experimental deformation of common sulphide minerals. In Physics and chemistry of minerals and rocks (R. G. G. Strcns, ed.). Wiley, New York, 51–69.Google Scholar
Cox, S. F. (1987) Flow mechanisms in sulphide min-erals. Ore Geology Reviews, 2, 133–71.Google Scholar
Cox, S. F. Etheridge, M. A., and Hobbs, B. E. (1981) The experimental ductile deformation of polycrystalline and single crystal pyrite. Econ. Geol., 76, 105–17.Google Scholar
Duckworth, R. C. (1991) The geology and depositional environment of the Early Proterozoic massive sulphide-bearing sequence, Renström, Northern Sweden. Unpublished PhD thesis, University of Wales, College of Cardiff.Google Scholar
Gaál, G. (1990) Tectonic styles of Early Proterozoic ore deposition in the Fennoscandian Shield. Precamb. Res., 46, 83–114.Google Scholar
Higgs, D. V. and Handin, J. W. (1959) Experimental deformation of dolomite single crystals. Geol. Soc. Am. Bull., 70, 245–78.Google Scholar
Knipe, R. J. (1989) Deformation mechanisms—recognition from natural tectonites. J. Struct. Geol., 11, 127–46.Google Scholar
Marshall, B. and Gilligan, L. B. (1987) An introduction to remobilisation: Information from ore-body geometry and experimental considerations. Ore Geology Reviews, 2, 87–131.Google Scholar
Marshall, B. and Gilligan, L. B. (1989) Durchbewegung structure, piercement cusps and piercement veins in massive sulphide deposits: Formation and interpretation. Econ. Geol., 84, 2311–9.Google Scholar
McClay, K. R. and Ellis, P. G. (1983) Deformation and recrystallisation of pyrite. Mineral Mag., 74, 527-38.Google Scholar
McClay, K. R. and Ellis, P. G. (1984) Deformation of pyrite. Econ. Geol., 79, 400-3.Google Scholar
Nicolas, A. and Poirier, J.-P. (1976) Crystalline plasticity and solid state flow in metamorphic rocks. Wiley-Interscience, London. pp. 444.Google Scholar
Ohmoto, H. and Rye, R. O. (1979) Isotopes of sulphur and carbon. In Geochemistry of hydrothermal ore deposits (H. L. Barnes ed.). Wiley & Sons, 509-67.Google Scholar
Rickard, D. T., ed. (1986) The Skellefte Field. SGU ser. Ca, Nr. 62.Google Scholar
Scott, S. D. (1973) Experimental calibration of the sphalerite geobarometer. Econ. Geol., 68, 466–74.Google Scholar
Skiöld, T. (1988) Implications of new U-Pb zircon chronology to Early Proterozoic crustal accretion in Northern Sweden. Precamb. Res., 38, 147–64.Google Scholar
Stanton, R. L. (1972) Ore Petrology. McGraw-Hill, New York, 713 pp.Google Scholar
Vokes, F. M. (1973) ‘Ball texture’ in sulphide ores. Geol. Fören. Förh, 195, 403–6.Google Scholar