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Mineralogy and Petrology

, Volume 109, Issue 5, pp 531–553 | Cite as

Orogenic-type copper-gold-arsenic-(bismuth) mineralization at Flatschach (Eastern Alps), Austria

  • Johann G. RaithEmail author
  • Thomas Leitner
  • Werner H. Paar
Original Paper

Abstract

Structurally controlled Cu-Au mineralization in the historic Flatschach mining district (Styria, Austria) occurs in a NE–SW to NNE–WSW oriented vein system as multiple steep-dipping calcite-(dolomite)-quartz veins in amphibolite facies metamorphic rocks (banded gneisses/amphibolites, orthogneisses, metagranitoids) of the poly-metamorphosed Austroalpine Silvretta-Seckau nappe. Vein formation postdated ductile deformation events and Eoalpine (Late Cretaceous) peak metamorphism but predated Early to Middle Miocene sediment deposition in the Fohnsdorf pull-apart basin; coal-bearing sediments cover the metamorphic basement plus the mineralized veins at the northern edge of the basin. Three gold-bearing ore stages consist of a stage 1 primary hydrothermal (mesothermal?) ore assemblage dominated by chalcopyrite, pyrite and arsenopyrite. Associated minor minerals include alloclasite, enargite, bornite, sphalerite, galena, bismuth and matildite. Gold in this stage is spatially associated with chalcopyrite occurring as inclusions, along re-healed micro-fractures or along grain boundaries of chalcopyrite with pyrite or arsenopyrite. Sericite-carbonate alteration is developed around the veins. Stage 2 ore minerals formed by the replacement of stage 1 sulfides and include digenite, anilite, “blue-remaining covellite” (spionkopite, yarrowite), bismuth, and the rare copper arsenides domeykite and koutekite. Gold in stage 2 is angular to rounded in shape and occurs primarily in the carbonate (calcite, Fe-dolomite) gangue and less commonly together with digenite, domeykite/koutekite and bismuth. Stage 3 is a strongly oxidized assemblage that includes hematite, cuprite, and various secondary Cu- and Fe-hydroxides and -carbonates. It formed during supergene weathering. Stage 1 and 2 gold consists mostly of electrum (gold fineness 640–860; mean = 725; n = 46), and rare near pure gold (fineness 930–940; n = 6). Gold in stage 3 is Ag-rich electrum (fineness 350–490, n = 12), and has a high Hg content (up to 11 mass %). The Cu-Au deposits in the Flatschach area show similarities with meso- to epizonal orogenic lode gold deposits regarding the geological setting, the structural control of mineralization, the type of alteration, the early (stage 1) sulfide assemblage and composition of gold. Unique about the Flatschach district is the lower-temperature overprint of copper arsenides (domeykite and koutekite) and copper sulfides (djurleite, yarrowite/spionkopite) on earlier formed sulfide mineralization. Based on mineralogical considerations temperature of stage 2 mineralization was between about 70 °C and 160 °C. Gold was locally mobilized during this low-temperature hydrothermal overprint as well as during stage 3 supergene oxidation and cementation processes.

Keywords

Pyrite Chalcopyrite Gold Deposit Arsenopyrite Bornite 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

The authors are grateful to Universalmuseum Joanneum, namely Bernd Moser and Hans-Peter Bojar, for providing historic polished sections and ore samples from the so-called “Friedrich Archiv” at Universalmuseum. Helmut Mühlhans and Federica Zaccarini are thanked for assistance with electron microprobe analyses, Ronald Bakker for assistance with Laser Raman spectroscopy. Ralf Schuster, Alexander Schmiderer and Heinz Mali are thanked for introducing us to the field area. We thank Albert Schedl for providing unpublished maps and documents from archives of Geologische Bundesanstalt in Vienna. Gerd Rantisch is thanked for redrawing Fig. 2. Noricum Gold Ltd., namely Greg Künzel, is thanked for financing of this project and permission to publish results of an exploration project. We acknowledge the constructive reviews by L. Diamond and P. Spry.

Supplementary material

710_2015_391_MOESM1_ESM.docx (92 kb)
Electronic supplementary material appendix 1 (DOCX 91 kb)
710_2015_391_MOESM2_ESM.xlsx (15 kb)
Electronic supplementary material appendix 2 (XLSX 15 kb)
710_2015_391_MOESM3_ESM.xlsx (44 kb)
Electronic supplementary material appendix 3 (XLSX 43 kb)

References

  1. Amann G, Daxner G, Neubauer F, Paar WH, Steyrer HP, Genser J, Handler R, Kurz W (1997) Structural evolution of the Schellgaden gold district, eastern Tauern Window, Austria; a preliminary report. Zentralbl Geol Palaeont Teil I 1996:215–228Google Scholar
  2. Amann G, Paar WH, Neubauer F, Daxner G (2002) Auriferous arsenopyrite-pyrite and stibnite mineralization from the Siflitz-Guginock area (Austria); indications for hydrothermal activity during Tertiary oblique terrane accretion in the Eastern Alps. In: Blundell DJ, Neubauer F, von Quadt A (eds) The timing and location of major ore deposits in an evolving orogen. Geol Soc London Spec Publ 204:103–117Google Scholar
  3. Barton PB (1973) Solid solutions in the system Cu-Fe-S, Part I; The Cu-S and Cu-Fe-S joins. Econ Geol 68:455–465CrossRefGoogle Scholar
  4. Bestel M, Gawronski T, Abart R, Rhede D (2009) Compositional zoning of garnet porphyroblasts from the polymetamorphic Wölz Complex, Eastern Alps. Miner Petrol 97:173–188CrossRefGoogle Scholar
  5. Craw D, Teagle DAH, Belocky R (1993) Fluid immiscibility in late-Alpine gold-bearing veins, eastern and northwestern European Alps. Mineral Deposita 28:28–36CrossRefGoogle Scholar
  6. Ebner F, Cerny I, Eichhorn R, Götzinger M, Paar W, Prochaska W, Weber L (2000) Mineral resources in the Eastern Alps and adjoining areas. Mitt Österr Geol Ges 92(1999):157–184Google Scholar
  7. Faryad SW, Hoinkes G (2003) P-T gradient of Eo-Alpine metamorphism within the Austroalpine basement units east of the Tauern Window (Austria). Miner Petrol 77:129–159CrossRefGoogle Scholar
  8. Faryad SW, Melcher F, Hoinkes G, Puhl J, Meisel T, Frank W (2002) Relics of eclogite facies metamorphism in the Austroalpine basement, Hochgrössen (Speik complex), Austria. Miner Petrol 74:49–73CrossRefGoogle Scholar
  9. Feitzinger G, Paar WH, Tarkian M, Holzer H, Weinzierl G (1995) Vein type Ag-(Au)-Pb, Zn, Cu-(W, Sn) mineralization in the Southern Kreuzeck Mountains, Carinthia Province, Austria. Miner Petrol 53:307–332CrossRefGoogle Scholar
  10. Frank W, Esterlus M, Frey I, Jung G, Krohe A, Weber J (1983) Die Entwicklungsgeschichte von Stub- und Koralpenkristallin und die Beziehung zum Grazer Paläozoikum. In: Flügel H (ed) Die frühalpine Geschichte der Ostalpen, Hochschulschwerpunkt S15, Heft 4, Jahresbericht 1982, vol 4. Universität Graz, Graz, pp 263–293Google Scholar
  11. Friedrich OM (1964) Die Kupfererzänge von Flatschach bei Knittelfeld. Dissertation vorgelegt 1951 von Wassil Jarlowsky. Arch Lagerst Forsch 2:32–75Google Scholar
  12. Gaidies F, Abart R, De Capitani C, Schuster R, Connolly JAD, Reusser E (2006) Characterization of polymetamorphism in the Austroalpine basement east of the Tauern Window using garnet isopleth thermobarometry. J Metamorph Geol 24:451–475CrossRefGoogle Scholar
  13. Garofalo PS, Fricker MB, Guenther D, Bersani D, Lottici PP (2014) Physical-chemical properties and metal budget of Au-transporting hydrothermal fluids in orogenic deposits. In: Garofalo PS, Ridley JR (eds) Gold-transporting hydrothermal fluids in the Earth’s crust, vol 402, Geol Soc London Spec Pub., pp 71–102Google Scholar
  14. Goble RJ (1980) Copper sulfides from Alberta; yarrowite Cu9S8 and spionkopite Cu39S28. Can Mineral 18:511–518Google Scholar
  15. Göd R (1987) Projekt Gold-Tremmelberg. Unpublished report, ViennaGoogle Scholar
  16. Goldfarb RJ, Baker T, Dube B, Groves DI, Hart CJR, Gosselin P (2005) Distribution, character, and genesis of gold deposits in metamorphic terranes. 100th Anniversary Volume Society of Economic Geologists, Littleton, pp 407–450Google Scholar
  17. Groves DI (1993) The crustal continuum model for late-Archaean lode-gold deposits of the Yilgarn Block, Western Australia. Miner Deposita 28:366–374CrossRefGoogle Scholar
  18. Groves DI, Goldfarb RJ, Gebre-Mariam M, Hagemann SG, Robert F (1998) Orogenic gold deposits: A proposed classification in the context of their crustal distribution and relationship to other gold deposit types. Ore Geol Rev 13:7–27CrossRefGoogle Scholar
  19. Groves DI, Goldfarb RJ, Fo R, Hart CJR (2003) Gold deposits in metamorphic belts: Overview of current understanding, outstanding problems, future research, and exploration significance. Econ Geol 98:1–29Google Scholar
  20. Hart C, Goldfarb RJ (2005) Distinguishing intrusion-related from orogenic gold systems. New Zealand Minerals Conference: Realising New Zealand’s Mineral Potential. Australasian Institute of Mining and Metallurgy, pp 125–133Google Scholar
  21. Horner J, Neubauer F, Paar WH, Hansmann W, Koeppel V, Robl K (1997) Structure, mineralogy, and Pb isotopic composition of the As-Au-Ag deposit Rotgülden, Eastern Alps (Austria): significance for formation of epigenetic ore deposits within metamorphic domes. Miner Deposita 32:555–568CrossRefGoogle Scholar
  22. Hough RM, Butt CRM, Fischer-Bühner J (2009) The crystallography, metallography and composition of gold. Elements 5:297–302CrossRefGoogle Scholar
  23. Inger S, Cliff RA (1994) Timing of metamorphism in the Tauern Window, Eastern Alps; Rb-Sr ages and fabric formation. J Metamorph Geol 12:695–707CrossRefGoogle Scholar
  24. Jarlowsky W (1951) Die Kupfererzgänge von Flatschach bei Knittelfeld. PhD thesis Montanuiversität LeobenGoogle Scholar
  25. Kerrich R, Goldfarb R, Groves D, Garwin S, Jia Y (2000) The characteristics, origins, and geodynamic settings of supergiant gold metallogenic provinces. Sci China Sers D 43:1–68CrossRefGoogle Scholar
  26. Kretschmar U, Scott SD (1976) Phase relations involving arsenopyrite in the system Fe-As-S and their application. Can Mineral 14:364–386Google Scholar
  27. Kurz W, Neubauer F, Genser J, Horner H (1994) Sequence of Tertiary brittle deformations in the Eastern Tauern Window (Eastern Alps). Mitt Österr Geol Ges 86(1993):153–164Google Scholar
  28. Leitner T (2013) Gold in the historic copper deposits at Flatschach, Styria. Master thesis, Montanuniversitaet LeobenGoogle Scholar
  29. Melcher F, Meisel T (2004) A metamorphosed early Cambrian crust–mantle transition in the Eastern Alps, Austria. J Petrol 45:1689–1723CrossRefGoogle Scholar
  30. mindat.org the mineral and locality data base. www.mindat.org. Accessed Mar 2015
  31. Morey AA, Tomkins AG, Bierlein FP, Weinberg RF, Davidson GJ (2008) Bimodal distribution of gold in pyrite and arsenopyrite; examples from the Archean Boorara and Bardoc shear systems, Yilgarn Craton, Western Australia. Econ Geol 103:599–614CrossRefGoogle Scholar
  32. Neubauer F, Frisch W, Schmerold R, Schlöser H (1989) Metamorphosed and dismembered ophiolite suites in the basement units of the Eastern Alps. Tectonophysics 164:49–62CrossRefGoogle Scholar
  33. Neubauer F, Frisch W, Hansen BT (2002) Early Palaeozoic tectonothermal events in basement complexes of the eastern Greywacke Zone (EasternAlps): evidence from U-Pb zircon data. Int J Earth Sci 91:775–786CrossRefGoogle Scholar
  34. Noricum Gold Limited. Company homepage www.noricumgold.com. Accessed Apr 2014
  35. Paar WH (1997) Edelmetalle. In: Weber L (ed) Handbuch der Lagerstätten der Erze, Industrieminerale und Energierohstoffe Österreichs Erläuterungen zur metallogenetischen Karte von Österreich 1 : 500000 unter Einbeziehung der Industrieminerale und Energierohstoffe, Arch Lagerst Forsch Geol B-A 19:276–284Google Scholar
  36. Paar WH (2014) Unpublished report for Noricum Gold AT, 2 ppGoogle Scholar
  37. Paar WH, Meixner H (1979) Neues aus den Kupfererz-Gängen des Flatschacher Bergbau-Reviers in Knittelfeld, Steiermark. Der Karinthin 81:148–150Google Scholar
  38. Paar W, Günther W, Gruber F (2006) Das Buch vom Tauerngold.- 2. aktualisierte, mit zahlreichen Ergänzungen versehene Auflage. Verlag Anton Pustet, SalzburgGoogle Scholar
  39. Pettke T, Diamond LW, Villa IM (1999) Mesothermal gold veins and metamorphic devolatilization in the northwestern Alps; the temporal link. Geology 27:641–644CrossRefGoogle Scholar
  40. Pfingstl S, Kurz W, Schuster R, Hauzenberger C (2015) Geochronological constraints on the exhumation of the Austroalpine Seckau Nappe (Eastern Alps). Austrian J Earth Sci 108:172–185CrossRefGoogle Scholar
  41. Pohl W, Belocky R (1994) Alpidic metamorphic fluids and metallogenesis in the Eastern Alps. Mitt Österr Geol Ges 86(1993):141–152Google Scholar
  42. Posfai M, Buseck PR (1994) Djurleite, digenite, and chalcocite; intergrowths and transformations. Am Mineral 79:308–315Google Scholar
  43. Punzengruber K, Polegeg S, Scherer J (1977) Geochemische Untersuchung von Bachsedimenten im Kristallin nördlich von Knittelfeld und ihre Bedeutung für die Lagerstättensuche. Berg- und Hüttenmänn Monatsh 122:5Google Scholar
  44. Putz H, Paar WH, Topa D, Horner J, Lüders V (2003) Structurally controlled gold and sulfosalt mineralization: the Altenberg example, Salzburg Province, Austria. Miner Petrol 78:111–138CrossRefGoogle Scholar
  45. Ramdohr P (1975) Die Erzmineralien und ihre Verwachsungen, 4th edn. Akademie-Verlag, BerlinGoogle Scholar
  46. Ridley JR, Diamond LW (2000) Fluid chemistry of orogenic lode gold deposits and implications for genetic models. Rev Econ Geol 13:141–162Google Scholar
  47. Robl J, Paar WH (1994) Fluid-Inclusion Untersuchungen an Golderzen der Goldzeche, Sonnblickgruppe, (Hohe Tauern, Kärnten). Mitt Österr Mineral Ges 139:151–158Google Scholar
  48. RRUFF http://rruff.info. Accessed 2013
  49. Sachsenhofer RF, Kogler A, Polesny H, Strauss P, Wagreich M (2000) The Neogene Fohnsdorf Basin: basin formation and basin inversion during lateral extrusion in the Eastern Alps (Austria). Int J Earth Sci 89:415–430CrossRefGoogle Scholar
  50. Scharbert S (1981) Untersuchungen zum Alter des Seckauer Kristallins. Mitt Ges Geol Bergbaustud Österr 27:173–188Google Scholar
  51. Schermaier A, Haunschmid B, Finger F (1997) Distribution of Variscan I- and S-type granites in the Eastern Alps; a possible clue to unravel pre-Alpine basement structures. In: Neubauer F, Cloetingh S, Dinu C, Mocanu V (eds) Tectonics of the Alpine-Carpathian-Pannonian region. Elsevier, Amsterdam, pp 315–333Google Scholar
  52. Schmid SM, Fügenschuh B, Kissling E, Schuster R (2004) Tectonic map and overall architecture of the Alpine orogen. Eclog Geol Helvet 97:93–117CrossRefGoogle Scholar
  53. Schuster R (2011) Ostalpin. In: Rupp C, Linner M, Mandl G (eds) Geologische Karte von Oberösterreich 1:200000. Erläuterungen, Geologische Bundesanstalt, Wien, pp 61–67Google Scholar
  54. Schuster R, Stüwe K (2008) Permian metamorphic event in the Alps. Geology 36:603–606CrossRefGoogle Scholar
  55. Sharp ZD, Essene EJ, Kelly WC (1985) A re-examination of the arsenopyrite geothermometer; pressure considerations and applications to natural assemblages. Can Mineral 23:517–534Google Scholar
  56. Skinner BJ, Luce FD (1971) Stabilities and compositions of alpha-domeykite and algodonite. Econ Geol 66:133–139CrossRefGoogle Scholar
  57. Strauss P, Wagreich M, Decker K, Sachsenhofer RF (2001) Tectonics and sedimentation in the Fohnsdorf-Seckau Basin (Miocene, Austria); from a pull-apart basin to a half-graben. Int J Earth Sci 90:549–559Google Scholar
  58. Tectonics FP software http://www.tectonicsfp.com
  59. Tenczer V, Stuewe K (2003) The metamorphic field gradient in the eclogite type locality, Koralpe region, Eastern Alps. J Metamorp Geol 21:377–393CrossRefGoogle Scholar
  60. Thöni M (1999) A review of geochronological data from the Eastern Alps. Schweiz Mineral Petrogr Mitt 79:209–230Google Scholar
  61. Weber L (2015) IRIS Interaktives Rohstoff-Informations-System. Geologische Bundesanstalt, http://geomap.geolba.ac.at/IRIS/einstieg.html
  62. Whiteside LS, Goble RJ (1986) Structural and compositional changes in copper sulfide during leaching and dissolution. Can Mineral 24:247–258Google Scholar
  63. Whitney DL, Evans BW (2010) Abbreviations for names of rock-forming minerals. Am Mineral 95:185–187CrossRefGoogle Scholar
  64. Wieser B, Raith JG, Thöni M, Cornell DH, Stein H, Paar W (2011) In-situ trace element and ID-TIMS Sm-Nd analysis of scheelite and Re-Os dating of molybdenite at Schellgaden, a Au-(W) deposit in the Estern Alps, Austria. Pangeo, 2010 Abstracts. J Alpine Geol 52:253–254Google Scholar

Copyright information

© Springer-Verlag Wien 2015

Authors and Affiliations

  • Johann G. Raith
    • 1
    Email author
  • Thomas Leitner
    • 3
  • Werner H. Paar
    • 2
  1. 1.Department of Applied Geosciences and GeophysicsMontanuniversitaet LeobenLeobenAustria
  2. 2.SalzburgAustria
  3. 3.Salinen Austria AGBad AusseeAustria

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