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Micro structural and mineralogical evidence for limited involvement of magma mixing in the petrogenesis of a Hercynian high-K calc-alkaline intrusion: the Kozárovice granodiorite, Central Bohemian Pluton, Czech Republic

Published online by Cambridge University Press:  03 November 2011

Vojtěch Janoušek
Affiliation:
Czech Geological Survey, Klárov 3, 118 21 Prague 1, Czech Republic.e-mail:[email protected]
D. R. Bowes
Affiliation:
Division of Earth Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
Colin J. R. Braithwaite
Affiliation:
Isotope Geosciences Unit, Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, Scotland, UK.
Graeme Rogers
Affiliation:
Isotope Geosciences Unit, Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, Scotland, UK.

Abstract

Textural and mineralogical features in the high-K calc-alkaline Kozárovice granodiorite (Hercynian Central Bohemian Pluton, Bohemian Massif) and associated small quartz monzonite masses imply that mixing between acid (granodioritic) and basic (monzonitic/monzogabbroic) magmas was locally petrogenetically significant.

Net veining, with acicular apatite and numerous lath-shaped plagioclase crystals present in the quartz monzonite, and abundant mafic microgranular enclaves (MME) in the granodiorite, indicate that as the monzonitic magma was injected into the granodioritic magma chamber, it rapidly cooled and was partly disintegrated by the melt already present. Evidence from cathodoluminescence suggests that the two magmas exchanged early-formed plagioclase crystals. In the quartz monzonite, granodiorite-derived crystals were overgrown by narrow calcic zones, followed by broad, normally zoned sodic rims. In the granodiorite, plagioclase crystals with calcic cores overgrown by normally zoned sodic rims are interpreted as xenocrysts from the monzonite. After thermal adjustment, crystallisation of the monzonitic magma ceased relatively slowly, forming quartz and K-feldspar oikocrysts.

Although the whole-rock geochemistry of the quartz monzonite and the MME support magma mixing, major- and trace-element based modelling of the host granodiorite has previously indicated an origin dominated by assimilation and fractional crystallisation. Magma mixing therefore seems to represent a local modifying influence rather than the primary petrogenetic process.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 2000

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References

Albarède, F. 1995. Introduction to Geochemical Modelling. Cambridge University Press.Google Scholar
Barbarin, B. 1990. Plagioclase xenocrysts and mafic magmatic enclaves in some granitoids of the Sierra Nevada Batholith, California. Journal of Geophysical Research 95, 17747–56.Google Scholar
Barbarin, B.& Didier, J. 1991. Macroscopic features of mafic microgranular enclaves. In Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 253–62. Amsterdam: Elsevier.Google Scholar
Bateman, R. 1993. Mineral disequilibria under the microscope. In Bateman, R.& Castro, A. (eds) Heterogeneities in felsic igneous rocks at scales from crystals to plutons. Workshop notes, 47. Sevilla: Universidad de Sevilla.Google Scholar
Bateman, , 1995. The interplay between crystallization, replenishment and hybridization in large felsic magma chambers. Earth Science Reviews 39, 91106.Google Scholar
Blundy, J. D.& Shimizu, N. 1991. Trace element evidence for plagioclase recycling in calc-alkaline magmas. Earth and Planetary Science Letters 102, 178–97.Google Scholar
Bowes, D. R.& Košler, J. 1993. Geochemical comparison of the subvolcanic appinitc suite of the British Caledonidcs and the durbachite suite of the Central European Hercynides: evidence for associated shoshonitic and granitic magmatism. Mineralogy and Petrology 48, 4763.Google Scholar
Castro, A. 1993. Biotite-hornblende relationships in calc-alkaline granitoids and enclaves. In Bateman, R.& Castro, A. (eds) Heterogeneities in felsic igneous rocks at scales from crystals to plutons. Workshop notes, 3. Sevilla: Universidad de Sevilla.Google Scholar
Castro, A., De la Rosa, J. D.& Stephens, W. E. 1990. Magma mixing in the subvolcanic environment: petrology of the Gerena interaction zone near Seville, Spain. Contributions to Mineralogy and Petrology 105, 926.Google Scholar
Castro, A., Moreno-Ventas, I.& De la Rosa, J. D. 1991. Multistage crystallisation of tonalitic enclaves in granitoid rocks (Hercynian belt, Spain): implications for magma mixing. Geologische Rundschau 80, 109–20.Google Scholar
Castro, A.& De la Rosa, J. D. 1994. Nomarski study of zoned plagioclases from granitoids of the Seville Range batholith, SW Spain. Petrogenetic implications. European Journal of Mineralogy 6, 647–56.Google Scholar
Castro, A.& Stephens, W. E. 1992. Amphibole-rich polycrystallinc clots in calc-alkaline granitic rocks and their enclaves. Canadian Mineralogist 30, 1093–112.Google Scholar
Chaloupský, J., Chlupáč, I., Mašek, J., Waldhausrová, J.& Cháb, J. 1995. VII.B.I. Teplá–Barrandian Zone (Bohemieum)—Stratigraphy. In Dallmeyer, R. D., Franke, W.& Weber, K. (eds) Pre-Permian Geology of Central and Eastern Europe. 379–91. Berlin: Springer.Google Scholar
Debon, F.& Le Fort, P. 1988. A cationic classification of common plutonic rocks and their magmatic associations: principles, method, applications. Bulletin de Minéralogie 111, 493510.Google Scholar
DcPaolo, D. J. 1981. Trace element and isotopic effects of combined wallrock assimilation and fractional crystallisation. Earth and Planetary Science Letters 53, 189202.Google Scholar
Didier, J.& Barbarin, B. (eds) 1991a. Enclaves and Granite Petrology. Amsterdam: Elsevier.Google Scholar
Didier, J.& Barbarin, B. 1991b. The different types of enclaves in granites – nomenclature. In Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 1924. Amsterdam: Elsevier.Google Scholar
Dörr, W., Fiala, J., Franke, W., Haack, U., Philippe, S., Schastok, J., Scheuvens, D., Vejnar, Z.& Zulauf, G. 1998. Cambrian vs Variscan tectonothermal evolution within the Teplá-Barrandian: evidence from U-Pb zircon ages of syn-tectonic plutons (Bohemian Massif, Czech Republic). Acta Universitatis Carolinae, Geologica 42, 229–30.Google Scholar
Finch, A. A.& Klein, J. 1999. The causes and petrological significance of cathodoluminescence emissions from alkali feldspars. Contributions to Mineralogy and Petrology 135, 234–43.Google Scholar
Fourcade, S.& Allègre, C. J. 1981. Trace elements behavior in granite genesis: a case study. The calc-alkaline plutonic association from the Quérigut Complex (Pyrénées, France). Contributions to Mineralogy and Petrology 76, 177–95.Google Scholar
Götze, J., Habermann, D., Neuser, R. D.& Richter, D. K. 1999. Highresolution spectrometric analysis of rare earth elements-activated cathodoluminescence in feldspar minerals. Chemical Geology 153, 8191.Google Scholar
Hejtman, B. 1948. Les carrières du district de Kozárovice et de Zalužany. Geoteehnica 6, 150 [in Czech with French summary].Google Scholar
Hejtman, B. 1949. Enclaves of granodiorite at Kozárovice in the Mirovice area. Rozpravy České Akademie Věd 59, 125 [in Czech].Google Scholar
Hibbard, M. J. 1981. The magma mixing origin of mantled feldspars. Contributions to Mineralogy and Petrology 76, 158–70.Google Scholar
Hibbard, M. J. 1991. Textural anatomy of twelve magma-mixed granitoid systems. In Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 431–44. Amsterdam: Elsevier.Google Scholar
Holub, F. V. 1997. Ultrapotassic plutonic rocks of the durbachite series in the Bohemian Massif: petrology, geochemistry and petrogenetic interpretation. Sborník geologických věd, Ložisková geologicmineralogie 31, 525.Google Scholar
Holub, F. V. 1999. Contrasting types of mafic and silicic magma interactions in the Central Bohemian Plutonic Complex: mixing, mingling, and composite layered intrusions. In Barbarin, B. (ed.) The origin of granites and related rocks—Abstracts of the 4th Hutton Symposium, Documents du BRGM 290, 24. Clermont-Ferrand: BRGM.Google Scholar
Holub, F. V., Cocheric, A.& Rossi, P. 1997a. Radiometric dating of granitic rocks from the Central Bohemian Plutonic Complex (Czech Republic): constraints on the chronology of the thermal and tectonic events along the Moldanubian-Barrandian boundary. Comptes Rendus de l'Académie des Sciences—Series IIA—Earth and Planetary Sciences 325, 1926.Google Scholar
Holub, F. V., Machart, J.& Manová, M. 1997b. The Central Bohemian Plutonic Complex: geology, chemical composition and genetic interpretation. Sborník geologických věd, Ložisková geologicmineralogie 31, 525.Google Scholar
Janoušek, V. 1994. Geochemistry and petrogenesis of the Central Bohemian Pluton, Czech Republic. Unpublished Ph.D. thesis, University of Glasgow.Google Scholar
Janoušek, V., Rogers, G.& Bowes, D. R. 1995. Sr-Nd isotopic constraints on the petrogenesis of the Central Bohemian Pluton, Czech Republic. Geologische Rundschau 84, 520–34.Google Scholar
Janoušek, V., Bowes, D. R., Rogers, G., Farrow, C. M.& Jelínek, E. 2000. Modelling diverse processes in the petrogenesis of a composite batholith: the Central Bohemian Pluton, Central European Hercynides. Journal of Petrology 41, 511–43.Google Scholar
Košler, J., Aftalion, M.& Bowes, D. R. 1993. Mid-late Devonian plutonic activity in the Bohemian Massif: U-Pb zircon isotopic evidence from the Staré Sedlo and Mirotice gneiss complexes, Czech Republic. Neues Jahrbuch für Mineralogie, Monatshefte 1993, 417–31.Google Scholar
Ledvinková, V. 1985. Gabbroids in the Mirovice metamorphic islet. Sborník geologických věd, Geologie 40, 3561 [in Czech with English summary].Google Scholar
Leake, B. E., Wooley, A. R., Arps, C. E. S., Birch, W. D., Gilbert, M. C., Grice, J. D., Hawthorne, F. C. Kato, A., Kisch, H. J., Krivovichev, V. G., Linthout, K., Laird, J., Mandarino, J., Maresch, W. V., Nickel, E. H., Rock, N. M. S., Schumacher, J. C., Smith, J. C, Stephenson, N. C. N., Whittaker, E. J. W.& Youzhi, G. 1997. Nomenclature of amphiboles: report of the Subcommittee on Amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names. Mineralogical Magazine 61, 295321.Google Scholar
Marshall, D. J. 1988. Cathodoluminescence of Geological Materials. Boston: Unwin Hyman.Google Scholar
Maury, R. C.& Didier, J. 1991. Xenoliths and the role of assimilation. In, Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 529–44. Amsterdam: Elsevier.Google Scholar
Montel, J. M., Didier, J.& Pichavant, M. 1991. Origin of surmicaceous enclaves in intrusive granites. In Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 509–28. Amsterdam: Elsevier.Google Scholar
Pitcher, W. S. 1993. The Nature and Origin of Granite. London: Chapman & Hall.Google Scholar
Rae, D. A.& Chambers, A. D. 1988. Metasomatism in the North Qôroq centre, South Greenland: cathodoluminescence and mineral chemistry of alkali feldspars. Transactions of the Royal Society Edinburgh: Earth Sciences 79, 112.Google Scholar
Schumacher, J. C. 1991. Empirical ferric iron corrections: necessity, assumptions and effects on selected geothermometers. Mineralogical Magazine 55, 318.Google Scholar
Spear, K. S.& Kimball, K. L. 1984. Recamp: a FORTRAN IV program for estimating Fe3+ contents in amphiboles. Computers & Geosciences 10, 317–25.Google Scholar
Stirling, D., Duncan, A. M., Guest, J. E.& Finch, A. A. 1999. Petrogenesis of plagioclase phenocrysts of Mount Etna, Sicily, with particular reference to the 1983 eruption: contribution from cathodoluminescence petrography. Mineralogical Magazine 63, 189–98.Google Scholar
Tepley, F.J. III,Davidson, J. P.& Clynne, M. A. 1999. Magmatic interactions as recorded in plagioclase phenocrysts of Chaos Crags, Lassen Volcanic Center, California. Journal of Petrology 40, 787806.Google Scholar
Vavra, G.& Hansen, B. T. 1991. Cathodoluminescence studies and U/Pb dating of zircons in pre-Mesozoic gneisses of the Tauern Window—implications for the Penninic basement evolution. Geologische Rundschau 80, 703–15.Google Scholar
Vernon, R. H. 1984. Microgranitoid enclaves in granite—globules of hybrid magma quenched in a plutonic environment. Nature 309, 438–9.Google Scholar
Vernon, R. H. 1990. Crystallisation and hybridism in microgranitoid enclave magmas: microstructural evidence. Journal of Geophysical Research 95, 17, 849–59.Google Scholar
Vernon, R. H. 1991. Interpretation of microstructures of microgranitoid enclaves. In Didier, J.& Barbarin, B. (eds) Enclaves and Granite Petrology, 277–91. Amsterdam: Elsevier.Google Scholar
Wall, V. J., Clemens, J. D.& Clarke, D. B. 1987. Models for granitoid evolution and source compositions. Journal of Geology 95, 731–49.Google Scholar
Wenzel, T.& Ramseyer, K. 1992. Mineralogical and mineral-chemical changes in a fractionation-dominated diorite-monzodioritemonzonite sequence—evidence from cathodoluminescence. European Journal of Mineralogy 4, 1391–99.Google Scholar
Wiebe, R. A. 1968. Plagioclase stratigraphy: a record of magmatic conditions and events in a granite stock. American Journal of Science 266, 690703.Google Scholar
Wilcox, R. E. 1999. The idea of magma mixing: history of struggle for acceptance. Journal of Geology 107, 421–32.Google Scholar
Wyllie, P. J., Cox, K. G.& Biggar, G. M. 1962. The habit of apatite in synthetic systems and igneous rocks. Journal of Petrology 3, 238–43.Google Scholar
Zárubová, M. 1934. Les enclaves sédimentaires dans le granite des environs de Sedlčany. Věstník Ústředního ústavu geologického 10, 182–91 [in Czech with French summary].Google Scholar