Mineralogy and Petrology

, 97:173 | Cite as

Compositional zoning of garnet porphyroblasts from the polymetamorphic Wölz Complex, Eastern Alps

  • Martina BestelEmail author
  • Timo Gawronski
  • Rainer Abart
  • Dieter Rhede
Original Paper


We employ garnet isopleth thermobarometry to derive the P–T conditions of Permian and Cretaceous metamorphism in the Wölz crystalline Complex of the Eastern Alps. The successive growth increments of two distinct growth zones of the garnet porphyroblasts from the Wölz Complex indicate garnet growth in the temperature interval of 540°C to 560°C at pressures of 400 to 500 MPa during the Permian and temperatures ranging from 550°C to 570°C at pressures in the range of 700 to 800 MPa during the Cretaceous Eo-Alpine event. Based on diffusion modelling of secondary compositional zoning within the outermost portion of the first garnet growth zone constraints on the timing of the Permian and the Eo-Alpine metamorphic events are derived. We infer that the rocks remained in a temperature interval between 570°C and 610°C over about 10 to 20 Ma during the Permian, whereas the high temperature stage of the Eo-Alpine event only lasted for about 0.2 Ma. Although peak metamorphic temperatures never exceeded 620°C, the prolonged thermal annealing during the Permian produced several 100 µm wide alteration halos in the garnet porphyroblasts and partially erased their thermobarometric memory. Short diffusion profiles which evolved around late stage cracks within the first garnet growth zone constrain the crack formation to have occurred during cooling below about 450°C after the Eo-Alpine event.


Compositional Zoning Garnet Growth Bulk Rock Composition Garnet Porphyroblasts Secondary Zoning 
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.



This work was funded by DFG research grant AB 314/2-1 in the framework of the FOR 741 research group. We thank Ralf Milke for his help on the electron microprobe, Ralf Schuster for his lead in the field and Georg Hoinkes, Lukas Keller, and Sha-Wali Faryad for stimulating discussion.


  1. Abart R, Martinelli W (1989) Alpidische und variszische Entwicklungsgeschichte des Wölzer Kristallins. Mitt Ges Geol Bergbaustud Österr 37:1–14Google Scholar
  2. Carlson WD (1991) Competitive diffusion-controlled growth of porphyroblasts. Mineral Mag 55:317–330CrossRefGoogle Scholar
  3. Carlson WD (2002) Scales of disequilibrium and rates of equilibration during metamorphism. Am Mineral 87:185–204Google Scholar
  4. Chakraborty S, Ganguly J (1992) Cation diffusion in aluminosilicate garnets: experimental determination in spessartine–almandine diffusion couples, evaluation of effective binary, diffusion coefficients, and applications. Contrib Mineral Petrol 111:74–78CrossRefGoogle Scholar
  5. Connolly JAD (1990) Multivariable phase diagrams: an algorithm based on generalized thermodynamics. Am J Sci 290:666–718Google Scholar
  6. Connolly JAD, Petrini K (2002) An automated strategy for calculation of phase diagram sections and retrieval of rock properties as a function of physical conditions. J Metamorph Geol 20:697–708CrossRefGoogle Scholar
  7. Faryad SW, Chakraborty S (2005) Duration of Eo-Alpine metamorphic events obtained from multicomponent diffusion modeling of garnet: a case study from the Eastern Alps. Contrib Mineral Petrol 150:306–318CrossRefGoogle Scholar
  8. Faryad SW, Hoinkes G (2003) P–T gradient of Eo-Alpine metamorphism within the Austroalpine basement units east of the Tauern Window (Austria). Mineral Petrol 77:129–159CrossRefGoogle Scholar
  9. Gaidies F, Abart R, de Capitani C, Schuster R, Connolly JAD, Reusser E (2006) Characterisation of polymetamorphism in the Austroalpine basement east of the Tauern Window using garnet isopleth thermobarometry. J Metamorph Geol 24:451–475CrossRefGoogle Scholar
  10. Gaidies F, de Capitani C, Abart R (2008a) THERIA_G: a software program to numerically model prograde garnet growth. Contrib Mineral Petrol 155:657–671CrossRefGoogle Scholar
  11. Gaidies F, de Capitani C, Abart R, Schuster R (2008b) Prograde garnet growth along complex P–T-t paths: results from numerical experiments on polyphase garnet from the Wölz Complex (Austroalpine basement). Contrib Mineral Petrol 155:673–688CrossRefGoogle Scholar
  12. Gaidies F, Krenn E, de Capitani C, Abart R (2008c) Coupling forward modelling of garnet growth with monazite geochronology: an application to the Rappold Complex (Austroalpine crystalline basement). J Metamorph Geol 26:775–793CrossRefGoogle Scholar
  13. Ganguly J, Cheng WJ, Chakraborty S (1998) Cation diffusion in aluminosilicate garnets: experimental determination in pyrope–almandine diffusion couples. Contrib Mineral Petrol 131:171–180CrossRefGoogle Scholar
  14. Hoinkes G, Koller F, Rantisch G et al (1999) Alpine metamorphism of the Eastern Alps. Schweiz Mineral Petrogr Mitt 79:155–181Google Scholar
  15. Holland TJB, Powell R (1998) An internally consistent thermodynamic data set for phases of petrological interest. J Metamorph Geol 16:309–343CrossRefGoogle Scholar
  16. Keller L, Abart R, Wirth R, Schmid D, Kunze K (2006) Enhanced mass transfer through short circuit diffusion: growth of garnet reaction rims at eclogite facies conditions. Am Mineral 91:1024–1038CrossRefGoogle Scholar
  17. Keller L, Hauzenberger CA, Abart R (2007) Diffusion along interphase boundaries and its effect on retrograde zoning patterns of metamorphic minerals. Contrib Mineral Petrol 154:205–216CrossRefGoogle Scholar
  18. Lasaga AC (1979) Multicomponent exchange and diffusion in 861 silicates. Geochim Cosmochim Acta 43:455–469CrossRefGoogle Scholar
  19. Prenzel J, Abart R (2009) Prograde breakdown of staurolite in polymetamorphic micaschists from the Rappold complex, Austroalpine basement, Eastern Alps. Mineral Petrol (this volume)Google Scholar
  20. Prenzel J, Abart R, Keller L (2009) Complex chemical zoning in eclogite facies garnet reaction rims: the role of grain boundary diffusion. Mineral Petrol 95:303–313CrossRefGoogle Scholar
  21. Schmid SM, Fügenschuh B, Kissling E, Schuster R (2004) Tectonic map and overall architecture of the Alpine orogen. Eclogae Geol Helv 97:61–77CrossRefGoogle Scholar
  22. Schuster R, Frank W (1999) Metamorphic evolution of the Austroalpine units east of the Tauern Window: indications for Jurassic strike slip tectonics. Mitt Ges Geol Bergbaustud Österr 42:37–58Google Scholar
  23. Schuster R, Thöni M (1996) Permian garnets: indication for a regional Permian metamorphism in the southern part of the Austroalpine basement units. Mitt Ges Geol Bergbaustud Österr 141:219–221Google Scholar
  24. Schuster R, Schabert S, Abart R, Frank W (2001) Permo-Triassic extension and related HT/LP metamorphism in the Austroalpine–Southalpine realm. Mitt Ges Geol Bergbaustud Österr 45:111–141Google Scholar
  25. Schuster R, Koller F, Hoeck V, Hoinkes G, Bousquet R (2004) Explanatory notes to the map: metamorphic structure of the Alps—Metamorphic evolution of the Eastern Alps. Mitt Österr Mineral Ges 149:179–199Google Scholar
  26. Spear FS, Selverstone J (1983) Quantitative P–T paths from zoned minerals: theory and tectonic applications. Contrib Mineral Petrol 83:348–357CrossRefGoogle Scholar
  27. Symmes GH, Ferry JM (1991) Evidence from mineral assemblages for infiltration of pelitic schists by aqueous fluids durino metamorphism. Contrib Mineral Petrol 108:419–438CrossRefGoogle Scholar
  28. Thöni M (2002) Sm-Nd isotope systematics in garnet from different lithologies (Eastern Alps): age results, and an evaluation of potential problems for garnet Sm-Nd chronometry. Chem Geol 185:255–281CrossRefGoogle Scholar
  29. Thöni M (2006) Dating eclogite-facies metamorphism in the Eastern Alps approaches, results, interpretations: a review. Mineral Petrol 88:123–148CrossRefGoogle Scholar
  30. Vance D, Holland TJB (1993) A detailed isotopic and petrological study of a single garnet from the Gassetts Schist, Vermont. Contrib Mineral Petrol 114:101–118CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Martina Bestel
    • 1
    Email author
  • Timo Gawronski
    • 2
  • Rainer Abart
    • 3
  • Dieter Rhede
    • 4
  1. 1.Labor für NeutronenstreuungETH Zürich & Paul Scherrer InsitutVilligenSwitzerland
  2. 2.Institute of Geological SciencesFree University BerlinBerlinGermany
  3. 3.Department für LithosphärenforschungUniversität WienWienAustria
  4. 4.Helmholtzzentrum Potsdam, Deutsches GeoForschungsZentrumPotsdamGermany

Personalised recommendations