Summary
The type-locality granulites from the Granulitgebirge of Saxony, Germany, are rocks of broadly granitic composition containing minor garnet and kyanite within a commonly mylonitised matrix of feldspars and quartz. Petrographic evidence indicates a primary assemblage of ternary feldspar + quartz + garnet + kyanite + rutile, most likely resulting from partial melting of a granitic protolith, for which equilibrium temperature and pressure conditions of >1000 °C and >1.5 GPa have been deduced. These extreme (for crustal rocks) conditions, and the inferred peak assemblage, are supported by the newly-developed Zr-in-rutile geothermometer and experimental studies on the same bulk composition, respectively. As these conditions lie above those required for plagioclase stability in quartz tholeiites, they are thus in the eclogite facies. Widespread modification of the peak assemblage, for example mesoperthite formation after ternary feldspar, deformation-induced recrystallisation of perthites to two-feldspar + quartz aggregates, biotite replacing garnet, Ca-loss at garnet rims, sillimanite replacing kyanite or secondary garnet growth, makes reliable interpretation of equilibrium assemblages and compositions very difficult and explains the spread of published pressure-temperature values and consequent confusion about formation depths and the validity of tectonometamorphic models. Such extreme metamorphic conditions in rock compositions typical for the upper continental crust, reflecting a hot subduction environment, has important consequences for understanding some collisional orogens.
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References
H-J Behr (1961) ArticleTitleBeiträge zur petrographischen und tektonischen Analyse des Sächsischen Granulitgebirges. Freiberger Forschungsh C 119 5–118
A Baldwin SA Bowring ML Williams (2003) ArticleTitlePetrological and geochronological constraints on high pressure, high temperature metamorphism in the Snowbird tectonic zone, Canada. J Metamorph Geol 21 81–98 Occurrence Handle10.1046/j.1525-1314.2003.00413.x
DA Carswell PJ O’Brien (1993) ArticleTitleThermobarometry and geotectonic significances of high-pressure granulites: examples from the Moldanubian Zone of the Bohemian Massif in Lower Austria. J Petrol 34 427–459
RA Cooke (2000) ArticleTitleHigh-pressure/temperature metamorphism in the St. Leonhard Granulite Massif, Austria: evidence from intermediate pyroxene-bearing granulites. Geol Rundsch 89 631–651
RA Cooke PJ O’Brien (2001) ArticleTitleResolving the relationship between high P–T rocks and gneisses in collisional terranes: an example from the Gföhl gneiss-granulite association in the Moldanubian Zone, Austria. Lithos 58 33–54 Occurrence Handle10.1016/S0024-4937(01)00049-4
RA Cooke PJ O’Brien DA Carswell (2000) ArticleTitleGarnet zoning and the identification of equilibrium mineral compositions in high-pressure–temperature granulites from the Moldanubian Zone, Austria. J Metamorph Geol 18 551–569 Occurrence Handle10.1046/j.1525-1314.2000.00273.x
D De Waard (1965) ArticleTitleA proposed subdivision of the granulite facies. Am J Sci 263 455–461
R Eigenfeld (1962) ArticleTitleÜber die mineralfazielle Stellung der Pyroxengranulite (auf Grund von Untersuchungen des Prototyps von Hartmanndorf/Sa. als polymetamorphen eklogitogenen Metabasit in Hornfelsfazies). Geol Rundsch 52 65–94 Occurrence Handle10.1007/BF01840065
Fiala J, Mat\(\breve{e}\)jovská O, Vaňková VB (1987a) Moldanubian granulites: source material and petrogenetic considerations. N Jahrb Mineral Abh 157: 133–165
Fiala J, Mat\(\breve{e}\)jovská O, Vaňková VB (1987b) Moldanubian granulites and related rocks: petrology, geochemistry and radioactivity. Rozpravy Československé akademie v\(\breve{e}\)d, řada matematických a přírodních v\(\breve{e}\)d 97: 1–102
ML Fuhrman DH Lindsley (1988) ArticleTitleTernary-feldspar modelling and thermometry. Am Mineral 73 201–215
DH Green IB Lambert (1965) ArticleTitleExperimental crystallisation of anhydrous granite at high pressures and temperatures. J Geophys Res 70 5259–5268
DH Green AE Ringwood (1967) ArticleTitleAn experimental investigation of the gabbro to eclogite transformation and its petrological applications. Geochim Cosmochim Acta 31 767–833
B Hagen S Hoernes J Rötzler (1995) ArticleTitleConsistent ultra-high temperatures in the Saxonian granulite massif as deduced from cation exchange and O-isotope thermometry. Terra Abstr 7 340
B Hansen (1981) ArticleTitleThe transition from pyroxene granulite facies to garnet clinopyroxene granulite facies: experiments in the system CaO–MgO–Al2O3–SiO2. Contrib Mineral Petrol 76 234–242 Occurrence Handle10.1007/BF00371963
SL Harley (1989) ArticleTitleThe origins of granulites: a metamorphic prospective. Geol Mag 126 215–247
Harley SL (1998) On the occurrence and characterization of ultrahigh-temperature crustal metamorphism. In: Treloar PJ, O’Brien PJ (eds) What drives metamorphism and metamorphic reactions? Geol Soc Lond Spec Publ 138: 81–107
Ito K, Kennedy GC (1971) An experimental study of the basalt-garnet granulite-eclogite transition. In: Heacock JG (ed) The structure and physical properties of the Earth’s crust. Am Geophys Union Monogr 14: 303–314
V Janoušek F Finger M Roberts J Frýda C Pin D Dolejš (2004) ArticleTitleDeciphering the petrogenesis of deeply buried granites: whole-rock geochemical constraints on the origin of largely undepleted felsic granulites from the Moldanubian Zone of the Bohemian Massif. Trans Roy Soc Edinb Earth Sci 95 141–159
W Johannes F Holtz (1996) Petrogenesis and experimental petrology of granitic rocks. Springer, Berlin Heidelberg New York Tokyo 335
Justi JHG von (1754) Nachricht von einer neuen Art eines neues Halbedelgesteines so kürzlich in Mähren entdeckt worden. Neue Wahrheiten zum Vorteil der Naturkunde und des gesellschaftlichen Lebens der Menschen 1
R Klemd M Bröcker (1999) ArticleTitleFluid influence on mineral reactions in ultrahigh-pressure granulites: a case study in the Snieznik Mts. (West Sudetes, Poland). Contrib Mineral Petrol 136 358–373 Occurrence Handle10.1007/s004100050544
J Kotková A Gerdes RR Parrish M Novak (2001) ArticleTitlePressure–temperature-time evolution of granulite clasts from Lower Carboniferous conglomerates – evidence for rapid exhumation at the eastern margin of the Variscan Bohemian Massif. J Conf Abstr 6 434
J Kotková SL Harley (1999) ArticleTitleFormation and evolution of high-pressure leucogranulites: experimental constraints and unresolved issues. Phys Chem Earth (A) 24 299–304
J Kotková A Kröner W Todt J Fiala (1996) ArticleTitleZircon dating of North Bohemian granulites, Czech Republic: further evidence for the Lower Carboniferous high-pressure event in the Bohemian Massif. Geol Rundsch 85 154–161
A Kröner P Jaeckel T Reischmann U Kroner (1998) ArticleTitleFurther evidence for an early Carboniferous (similar to 340 Ma) age of high-grade metamorphism in the Saxonian granulite complex. Geol Rundsch 86 751–766 Occurrence Handle10.1007/s005310050174
A Kröner PJ O’Brien AA Nemchin RT Pidgeon (2000) ArticleTitleZircon ages for high pressure granulites from South Bohemia, Czech Republic, and their connection to Carboniferous high temperature processes. Contrib Mineral Petrol 138 127–142
A Kröner AP Willner (1998) ArticleTitleTime of formation and peak of Variscan HP–HT metamorphism of quartz-feldspar rocks in the central Erzgebirge, Saxony, Germany. Contrib Mineral Petrol 132 1–20
U Kroner (1995) ArticleTitlePost-collisional extension at the northern margin of the Bohemian Massif: the exhumation of the Saxonian Granulite Massif (in German). Freiberger Forschungshefte C457 1–114
R Kryza C Pin D Vielzeuf (1996) ArticleTitleHigh-pressure granulites from the Sudetes (south-west Poland): evidence of crustal subduction and collisional thickening in the Variscan Belt. J Metamorph Geol 14 531–546 Occurrence Handle10.1046/j.1525-1314.1996.03710.x
Y Liu D Zhong (1997) ArticleTitlePetrology of high-pressure granulites from the eastern Himalayan syntaxis. J Metamorph Geol 15 451–466 Occurrence Handle10.1111/j.1525-1314.1997.00033.x
LG Medaris SuffixJr HF Wang Z Mísař E Jelínek (1990) ArticleTitleThermobarometry, diffusion modelling and cooling rates of crustal garnet peridotites: two examples from the Moldanubian Zone of the Bohemian Massif. Lithos 25 189–202 Occurrence Handle10.1016/0024-4937(90)90014-R
LG Medaris SuffixJr E Jelínek SuffixJr Z Mísař (1995a) ArticleTitleCzech eclogites: Terrane settings and implications for Variscan tectonic evolution of the Bohemian Massif. Eur J Mineral 7 7–28
LG Medaris SuffixJr BL Beard CM Johnson JW Valley MJ Spicuzza E Jelínek Z Mísař (1995b) ArticleTitleGarnet pyroxenite and eclogite in the Bohemian Massif: geochemical evidence for Variscan recycling of subducted lithosphere. Geol Rundsch 84 489–505 Occurrence Handle10.1007/BF00284516
KR Mehnert (1972) ArticleTitleGranulites – results of a discussion II. N Jahrb Mineral Monatsh 1972 139–150
L Nasdala H-J Massonne (2000) ArticleTitleMicrodiamonds from the Saxonian Erzgebirge, Germany: in situ micro-Raman characterisation. Eur J Mineral 12 495–498
PJ O’Brien (1999) ArticleTitleAsymmetric zoning profiles in garnet from HP–HT granulite and implications for volume and grain boundary diffusion. Mineral Mag 63 227–238
O’Brien PJ (2000) The fundamental Variscan problem: high-temperature metamorphism at different depths and high-pressure metamorphism at different temperatures. In: Franke W, Haak V, Onken O, Tanner D (eds) Orogenic processes: quantification and modelling in the Variscan Belt. Geol Soc Lond Spec Publ 179: 369–386
PJ O’Brien J Rötzler (2003) ArticleTitleHigh-pressure granulites: formation, recovery of peak conditions, and implications for tectonics. J Metamorph Geol 21 3–20
PJ O’Brien A Kröner P Jaeckel E Hegner A Żelaźniewicz R Kryza (1997) ArticleTitlePetrological and isotopic studies on Palaeozoic high-pressure granulites, Góry Sowie Mts, Polish Sudetes. J Petrol 38 433–456
JV Owen J Dostal (1996) ArticleTitleContrasting corona structures in mafic granulite from the Blansky les complex, Bohemian Massif, Czech Republic. Can Mineral 34 959–966
K Petrakakis (1997) ArticleTitleEvolution of Moldanubian rocks in Austria: review and synthesis. J Metamorph Geol 15 203–222 Occurrence Handle10.1111/j.1525-1314.1997.00015.x
K Petrakakis C Jawecki (1995) ArticleTitleHigh-grade metamorphism and retrogression of Moldanubian granulites, Austria. Eur J Mineral 7 1183–1203
C Pin D Vielzeuf (1983) ArticleTitleGranulites and related rocks in Variscan median Europe: a dualistic interpretation. Tectonophys 93 47–74 Occurrence Handle10.1016/0040-1951(83)90233-0
Z Pouba K Paděra J Fiala (1985) ArticleTitleOmphacite granulite from the NE marginal area of the Bohemian Massif, (Rychleby Mts). N Jahrb Mineral Abh 151 29–52
A von Quadt (1993) ArticleTitleThe Saxonian Granulite Massif: new aspects from geochronological studies. Geol Rundsch 82 516–530 Occurrence Handle10.1007/BF00212414
J Reinhardt U Kleemann (1994) ArticleTitleExtensional unroofing of granulitic lower crust and related low-pressure, high-temperature metamorphism in the Saxonian Granulite Massif, Germany. Tectonophys 238 71–94 Occurrence Handle10.1016/0040-1951(94)90050-7
R Romer J Rötzler (2001) ArticleTitleP–T-t evolution of ultrahigh-temperature granulites from the Saxon Granulite Massif, Germany, part II. U–Pb dating of trace and major phases. J Petrol 42 2015–2032 Occurrence Handle10.1093/petrology/42.11.2015
J Rötzler (1992) ArticleTitleZur Petrogenese im Sächsischen Granulitgebirge: die pyroxenfreien Granulite und die Metapelite. Geotekt Forsch 77 1–100
J Rötzler RL Romer (2001) ArticleTitleP–T-t evolution of ultrahigh-temperature granulites from the Saxon Granulite Massif, Germany, part I. Petrology. J Petrol 42 1995–2013
J Rötzler R Romer H Budzinski R Oberhänsli (2004) ArticleTitleUltrahigh-temperature high-pressure granulites from Tirschheim, Saxon Granulite Massif, Germany: P–T-t path and geotectonic implications. Eur J Mineral 16 917–937 Occurrence Handle10.1127/0935-1221/2004/0016-0917
H-G Scharbert (1963) ArticleTitleDie Granulite des südlichen niederösterreichischen Moldanubikums I. N Jahrb Mineral Abh 100 59–86
KH Scheumann (1961) ArticleTitle‘Granulit’, eine petrographische Definition. N Jahrb Mineral Monatsh 1961 75–80
Schulmann K, Kröner A, Hegner E, Wendt I, Konapasek J, Lexa O, Stipska P (2005) Geodynamics of the eastern margin of the Variscan thickened root: a model based on petrological, structural and new geochronological data. Am J Sci (in press)
Spear FS (1993) Metamorphic phase equilibria and pressure–temperature-time paths. Mineralogical Society of America, Washington, DC
P Stipska K Schulmann A Kröner (2004) ArticleTitleVertical extrusion and middle crustal spreading of omphacite granulite: a model of syn-convergent exhumation (Bohemian Massif, Czech Republic). J Metamorph Geol 22 179–198 Occurrence Handle10.1111/j.1525-1314.2004.00508.x
Tajčmanová L, Konopásek J, Schulmann K (2004) Structural and metamorphic record of exhumation of the thickened lower crust in the hot orogenic root (NE Moldanubian Domain, Bohemian Massif). In: Janousek V (ed) International workshop on petrogenesis of granulites and related rocks, excursion guide and abstract volume, 62–63. Moravian Museum, Brno
Tropper P, Konzett J, Finger F (2005) Experimental constraints on the formation of high-P/high-T granulites in the Southern Bohemian Massif. Eur J Mineral (in press)
DR Snoeyenbos ML Williams S Hanmer (1995) ArticleTitleArchean high-pressure metamorphism in the western Canadian Shield. Eur J Mineral 7 1251–1272
O van Breemen M Aftalion DR Bowes A Dudek Z Mísař P Povondra S Vrána (1982) ArticleTitleGeochronological studies of the Bohemian Massif, Czechoslovakia, and their significance in the evolution of Central Europe. Trans Roy Soc Edinb Earth Sci 73 89–108
Vellmer C (1992) Stoffbestand und Petrogenese von Granuliten und granitischen Gesteinen der südlichen Böhmischen Masse in Niederösterreich. Thesis, University of Göttingen
Vielzeuf D, Clemens JD, Pin C, Moinet E (1990) Granites, granulites, and crustal differentiation. In: Vielzeuf D, Vidal Ph (eds) Granulites and crustal evolution. Kluwer Academic Publishers, Dordrecht, pp 59–85
S Vrána (1989) ArticleTitlePerpotassic granulites from southern Bohemia. A new rock-type derived from partial melting of crustal rocks under upper mantle conditions. Contrib Mineral Petrol 103 510–522 Occurrence Handle10.1007/BF01041756
DJ Waters CJ Whales (1984) ArticleTitleDehydration melting and the granulite transition in metapelites from southern Namaqualand, S. Africa. Contrib Mineral Petrol 88 269–275 Occurrence Handle10.1007/BF00380171
CS Weiss (1803) ArticleTitleÜber die Gebirgsart des sächsichen Erzgebirges, welche unter dem Namen Weiss-Stein neuerlich bekannt gemacht worden ist. Neue Schriften Gesellschaft naturforschender Freunde 4 342–366
AP Willner K Rotzler WV Maresch (1997) ArticleTitlePressure–temperature and fluid evolution of quartzo-feldspathic metamorphic rocks with a relic high-pressure, granulite-facies history from the Central Erzgebirge (Saxony, Germany). J Petrol 38 307–336 Occurrence Handle10.1093/petrology/38.3.307
HGF Winkler (1979) Petrogenesis of metamorphic rocks, fifth edn. Springer New York 348
T Zack A Moraes A Kronz (2004) ArticleTitleTemperature dependence of Zr in rutile: empirical calibration of a rutile thermometer. Contrib Mineral Petrol 148 471–488
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O’Brien, P. Type-locality granulites: high-pressure rocks formed at eclogite-facies conditions. Mineralogy and Petrology 86, 161–175 (2006). https://doi.org/10.1007/s00710-005-0108-2
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DOI: https://doi.org/10.1007/s00710-005-0108-2