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Illite ‘crystallinity’, maturation of organic matter and microstructural development associated with lowest-grade metamorphism of Neoproterozoic sediments in the Teplá-Barrandian unit, Czech Republic

Published online by Cambridge University Press:  09 July 2018

V. Suchý
Affiliation:
Jiránkova 1136/4, 163 00 Prague 6 - Řepy, Czech Republic
I. Sýkorová*
Affiliation:
Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V Holešovičkách 1820 9 Prague 8, Czech Republic
K. Melka
Affiliation:
Institute ofGeology, Academy of Sciences of the Czech Republic, Rozvojová 135, 165 00 Prague 6 – Suchdol, Czech Republic
J. Filip
Affiliation:
Institute ofGeology, Academy of Sciences of the Czech Republic, Rozvojová 135, 165 00 Prague 6 – Suchdol, Czech Republic
V. Machovič
Affiliation:
Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V Holešovičkách 1820 9 Prague 8, Czech Republic Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic
*

Abstract

Metamorphic grade, palaeothermal history and the influence of tectonic strain on clay minerals and organic matter transformation were studied in the eastern part of the Teplá-Barrandian unit in the Czech Republic. The metamorphic grade of pelitic sediments ranges from the lower anchizone (IC ~0.30–0.36Δº2θ) to the lowermost epizone (IC ~0.24–0.26Δº2θ). Increase in metamorphic grade is paralleled by the development of anastomosing cleavage and lenticular quartz grains in the anchizone which give way to slaty cleavage and dynamically recrystallized ribbon quartz grains in the lower epizone. White mica in highly strained rocks generally has greater IC values whereas chlorite displays reduced values in deformed and cleaved samples. The organic matter dispersed in the sediments represents a complex assemblage of highly matured particles of uncertain origin, pyrobitumen and ‘transitional matter’. The reflectance of organic fragments generally varies from 3.1% to 7.7% of Rmax which suggests anthracite to meta-anthracite rank progrades to semigraphite in higher-grade samples, although the overall link between Rmax and IC values is weak, if present at all. Newly formed shear-induced graphite appears abruptly near the anchizone-epizone boundary and correlates with the onset of plastic deformation and dynamic recrystallization of quartz grains in the host sediments.

Maximum metamorphic temperatures within the Neoproterozoic sequence in the range of 250–350ºC were attained during the Cadomian (Pan-African) orogeny at 540–550 Ma. Apatite fission-track analysis reveals a subsequent decrease in rock temperature over the period 340–350 Ma that persisted throughout the late Palaeozoic. The most recent episode of accelerated cooling occurred between 20 and 40 Ma, corresponding with the regional uplift of the Bohemian Massif due to the Alpine orogeny.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2007

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References

Abad, I., Nieto, F. & Alonso-Gutiérrez, G. (2003) Textural and chemical changes in slate-forming phyllosilicates across the external-internal zones transition in the low-grade metamorphic belt of the NW Iberian Variscan Chain. Schweizerische Mineralogische un . Petrographische Mitteilungen, 83, 6380.Google Scholar
Árkai, P. (1991) Chlorite crystallinity: an empirical approach and correlation with illite crystallinity, coal rank and mineral facies as exemplified by Paleozoic and Mesozoic rocks of northeast Hungary. Journal of Metamorphic Geology, 9, 723734.Google Scholar
Árkai, P., Sassi, F.P. & Sassi, R. (1995) Simultaneous measurements of chlorite and illite crystallinity: a more reliable tool for monitoring low- to very low grade metamorphism in metapelites. A case study from the Southern Alps (NE Italy). European Journal of Mineralogy, 7, 11151128.Google Scholar
Árkai, P., Mählmann, R.F., Suchý, V., Balogh, K., Sykorová, I. & Frey, M. (2002) Possible effects of tectonic shear strain on phyllosilicates: a case study from the Kandersteg area, Helvetic domain, Central Alps. Switzerland. Schweizerische Mineralogische und Petrographische Mitteilungen, 82, 273290.Google Scholar
Barker, C.E. & Pawlewicz, M.J. (1986) The correlation of vitrinite reflectance with maximum temperature in humic organic matter. Pp. 7993 in. Paleogeothermics, Lecture Notes in Earth Sciences, 5 (Buntebarth, G. & Stegena, L., editors). Springer-Verlag, Berlin.Google Scholar
Beyssac, O., Goffé, B., Chopin, C. & Rouzaud, J.N. (2002a) Raman spectra of carbonaceous material in metasediments: a new geothermometer. Journal of Metamorphic Geology, 20, 859871.Google Scholar
Beyssac, O., Rouzaud, J.N., Goffé, B., Brunet, F. & Chopin, C. (2002b) Graphitization in a high-pressure, low-temperature metamorphic gradient: a Raman microspectroscopy and HRTM study. Contributions to Mineralogy and Petrology, 143, 1931.Google Scholar
Bouchez, J.L. (1982) Microstructures in low temperature porphyroclastic quartzites. Pp. 357358 in: Atlas of Deformational and Metamorphic Rock Fabrics (Borradaile, G.J., Bayly, M.B. & Powell, Ch.M.A., editors). Springer-Verlag, Berlin.Google Scholar
Brandon, M.T. (1992) Decomposition of fission-track grain-age distribution. American Journal of Science, 292, 535564.CrossRefGoogle Scholar
Burkhard, M. & Goy-Eggenberger, D. (2001) Near vertical iso-illite-crystallinity surface cross-cut the recumbent fold structure of the Morcles nappe, Swiss Alps. Clay Minerals, 36, 157168.CrossRefGoogle Scholar
Bustin, R.M. (1983) Heating during thrust faulting in the Rocky Mountains: Friction or fiction. Tectonophysics, 95, 309328.CrossRefGoogle Scholar
Bustin, R.M., Ross, J.V. & Rouzaud, J.N. (1995) Mechanism of graphite formation from kerogen: experimental evidence. International Journal of Coal Geology, 28, 136.CrossRefGoogle Scholar
Carlson, W.D., Donelick, R.A. & Ketcham, R.A. (1999) Variability of apatite fission track annealing kinetics: I. Experimental results. American Mineralogist, 84, 12131223.Google Scholar
Carosi, R., Leoni, L., Montomoli Ch. & Sartori, F. (2003) Very low-grade metamorphism in the Tuscan Nappe, Northern Apennines, Italy: relationship between deformation and metamorphic indicators in the La Spezia mega-fold. Schweizerische Mineralogische und Petrographische Mitteilungen, 83, 1532.Google Scholar
Cháb, J. & Bernardová, E. (1974) Prehnite and pumpellyite in the Upper Proterozoic basalts of the NW part of the Barrandian. Krystalinikum, 10, 5365.Google Scholar
Cháb, J. & Pelc, Z. (1973) Proterozoic greywackes of the NW part of the Barrandian area. Sborník geologických vïd, geologie, 25, 784 (in Czech with German summary).Google Scholar
Cháb, J. & Suk, M. (1977) Regionalní metamorfóza na území Cech a Moravy (Regional metamorphism on the territory of Bohemia and Moravia). Knihovnicka Ústředního ústavu geologického, 50, 1156 (in Czech).Google Scholar
Cháb, J., Suchý, V. & Vejnar, Z. (1995) Metamorphic evolution of the Teplá—Barrandian Zone (Bohemicum). Pp. 403410 in: Pre-Permian Geology of Central and Eastern Europe (Dallmeyer, R.D., Franke, W. & Weber, K., editors). Springer-Verlag, Berlin.CrossRefGoogle Scholar
Chlupáč, I. (1992) Geology of the Barrandian. A Field Trip Guide. Waldemar Kramer, Frankfurt am Main, Germany, 1-192.Google Scholar
Dallmeyer, R.D., Franke, W. & Weber, K. (1995) Pre-Permian Geology of Central and Eastern Europe. Springer-Verlag, Berlin, 1-604.CrossRefGoogle Scholar
Diessel, C.F.K. & Öffler, R. (1975) Change in physical properties of coalified and graphitised phytoclasts with grade of metamorphism. Neues Jahrbuch für Mineralogie Monatshefte, 11, 1126.Google Scholar
Diessel, C.F.K., Brothers, R.N. & Black, P.M. (1978) Coalification and graphitization in high-pressure schists in New Caledonia. Contributions to Mineralogy and Petrology, 68, 6378.Google Scholar
Dörr, W., Zulauf, G., Fiala, J., Franke, W. & Vejnar, Z. (2002) Neoproterozoic to early Cambrian history of an active plate margin in the Tepla—Barrandian unit: a correlation of U-Pb isotopic-dilution-TIMS ages (Bohemia, Czech Republic). Tectonophysics, 352, 6585.Google Scholar
Dudek, A. & Fediuk, F. (1955) Zur Altersfrage der Metamorphose im barrandienischen Proterozoikum. Geologie, 4, 397403.Google Scholar
Durand, B. & Nicaise, G. (1980) Procedures for kerogen isolation. Pp. 3554 in: Kerogen. Insoluble Organic Matter from Sedimentary Rocks (Durand, B., editor). Technip, Paris.Google Scholar
Eberl, D.D. & Velde, B. (1989) Beyond the Kübler Index. Clay Minerals, 24, 571577.Google Scholar
Essene, E.J. & Peacor, D.R. (1995) Clay mineral thermometry: a critical perspective. Clays and Clay Minerals, 43, 540553.CrossRefGoogle Scholar
Ferrill, D.A. (1991) Calcite twin widths and intensities as metamorphic indicators in natural low—temperature deformation of limestone. Journal of Structural Geology, 13, 667675.Google Scholar
Filip, J. & Suchý, V. (2004) Thermal and tectonic history of the Barrandian Lower Paleozoic, Czech Republic: is there a fission track evidence for Carboniferous-Permian overburden and pre-Westphalian alpinotype thrusting. Bulletin of Geosciences, 79, 107112.Google Scholar
Franke, W. (1989) Tectonostratigraphic units in the Variscan belt of central Europe. Pp. 6790 in: Terranes in the Circum-Atlantic Paleozoic Orogens (Dallmeyer, R.D., editor). Geological Society of America Special Paper, 230.Google Scholar
Franke, W., Dallmeyer, D. & Weber, K. (1995) Geodynamic evolution. Pp. 579593 in: Pre-Permian Geology of Central and Eastern Europe (Dallmeyer, R.D., Franke, W. & Weber, K., editors). Springer-Verlag, Berlin.CrossRefGoogle Scholar
Frey, M. (1970) The step from diagenesis to metamorphism in pelitic rocks during Alpine orogenesis. Sedimentology, 15, 261279.Google Scholar
Frey, M. (1987) Very low-grade metamorphism of clastic sedimentary rocks. Pp. 958 in: Low Temperature Metamorphism (Frey, M., editor). Blackie, Glasgow.Google Scholar
Frey, M. & Robinson, D. (editors) (1999) Low-Grade Metamorphism. Blackwell Science, Oxford.Google Scholar
Frey, M., Teichmüller, M., Teichmüller, R., Mullis, J., Künzi, B., Breitschmid, A., Gruner, U. & Schwizer, B. (1980) Very low-grade metamorphism in external parts of the Central Alps: Illite crystallinity, coal rank and fluid inclusion data. Eclogae Geologicae Helvetiae, 73, 173203.Google Scholar
Giorgetti, G., Memmi, I. & Peacor, D.R. (2000) Retarded illite crystallinity caused by stress-induced sub-grain boundaries in illite. Clay Minerals, 35, 693708.CrossRefGoogle Scholar
Guggenheim, S., Bain, D.C., Bergaya, F., Brigatti, F., Drits, V.A., Eberl, D.D., Milton, L.L., Galán, E., Merriman, R.J., Peacor, D.R., Stanjek, H. & Watanabe, T. (2002) Report of the Association Internationale pour l’Etude des Argiles (AIPEA) Nomenclature Committee for 2001: order, disorder, and crystallinity in phyllosilicates and the use of the ‘Crystallinity Index’. AIPEA Newsletter, 38, 1015.Google Scholar
Hirth, G. & Tullis, J. (1992) Dislocation creep regimes in quartz aggregates. Journal of Structural Geology, 14, 145159.Google Scholar
Holubec, J. (1995) VII.B.2. Structure. Pp. 392397 in: Pre-Permian Geology of Central and Eastern Europe (Dallmeyer, R.D., Franke, W. & Weber, K., editors). Springer-Verlag, Berlin.Google Scholar
Houseknecht, D.W., Bensley, D.F., Hathon, L.A. & Kastens, P.H. (1993) Rotational reflectance properties of Arkoma Basin dispersed vitrinite: insights for understanding reflectance populations in high thermal maturity regions. Organic Geochemistry, 20, 187196.Google Scholar
Ishii, K. (1988) Grain growth and re-orientation of phyllosilicate minerals during the development of slaty cleavage in the South Kitakami Mountains, northeast Japan. Journal of Structural Geology, 10, 145154.Google Scholar
Jacob, H. (1989) Classification, structure, genesis and practical importance of natural solid oil bitumen (‘migrabitumen’). International Journal of Coal Geology, 11, 6579.CrossRefGoogle Scholar
Jakeš, P., Zoubek, J., Zoubková, J. & Franke, W. (1979) Greywackes and metagreywackes of the Teplá- Barrandian Proterozoic area. Sborník geologicky vïd, Geologie, 33, 83122.Google Scholar
Jehlička, J. & Bény, C. (1992) Application of Raman microspectroscopy in the study of structural changes in Precambrian kerogens during regional metamorphism. Organic Geochemistry, 2, 211213.Google Scholar
Jehlička, J. & Rouzaud, J.N. (1990) Organic geochemistry of Precambrian shales and schists (Bohemian Massif, Central Europe). Organic Geochemistry, 16, 865872.Google Scholar
Ketcham, R.A., Donelick, R.A. & Donelick, M.B. (2000) AFTSolve: a program for multi kinetic modelling of apatite fission track data. Geological Materials Research, 2, 132.Google Scholar
Kisch, H.J. (1983) Mineralogy and petrology of burial diagenesis (burial metamorphism) and incipient metamorphism in clastic rocks. Pp. 289493 in: Diagenesis in Sediments and Sedimentary Rocks 2 (Larsen, G. & Chilingar, G.V., editors). Elsevier, Amsterdam.Google Scholar
Kisch, H.J. (1987) Correlation between indicators of very low-grade metamorphism. Pp. 227300 in: Low Temperature Metamorphism (Frey, M., editor). Blackie, Glasgow.Google Scholar
Kisch, H.J. (1991) Development of slaty cleavage and degree of very low-grade metamorphism. Journal of Metamorphic Geology, 6, 735750.Google Scholar
Kossovskaya, A.G. & Shutov, V.D. (1970) Main aspects of the epigenesis problem. Sedimentology, 15, 1140.Google Scholar
Kretz, R. (1983) Symbols for rock-forming minerals. American Mineralogist, 68, 277279.Google Scholar
Kříbek, B., Hrabal, J., Landais, P. & Hladíková, J. (1994) The association of poorly ordered graphite, coke and bitumen in greenschist facies rocks of the Poniklá Group, Lugicum, Czech Republic: the result of graphitisation of various types of carbonaceous matter. Journal of Metamorphic Geology, 12, 493503.CrossRefGoogle Scholar
Kříbek, B., Pouba, Z., Skocek, V. & Waldhausrová, J. (2000) Neoproterozoic of the Teplá-Barrandian Unit as a part of the Cadomian orogenic belt: a review and correlation aspects. Vïstník Ceského geologického ústavu, 75, 175196.Google Scholar
Kübler, B. (1964) Les argiles, indicateurs de métamorphisme. Revue Institute Française du Pétrole, 1, 10931112.Google Scholar
Kübler, B. (1967) La cristallinité de l’illite et les zones tout à supérieures du métamorphisme. Pp. 105121 in: Etage tectoniques. Colloque de Neuchâtel 1966. À la Baconière, Neuchâtel, France.Google Scholar
Kübler, B. & Goy-Eggenberger, D. (2001) La cristallinité de l’illite revisitée: un bilan des connaissances acquises ces trente dernières années (Illite crystallinity revisited: review of studies over the past 30 years). Clay Minerals, 36, 143157.Google Scholar
Kwiecińska, B. & Petersen, H.I. (2004) Graphite, semi-graphite, natural coke, and natural char classification —ICCP system. International Journal of Coal Geology, 57, 99116.Google Scholar
Malkovsky, M. (1987) The Mesozoic and Tertiary basins of the Bohemian Massif and their evolution. Tectonophysics, 137, 3142.Google Scholar
Masek, J. (2000) Stratigraphy of the Proterozoic of the Barrandian area. Vïstník Českého Geologického ústavu, 75, 197200.Google Scholar
Matte, P., Maluski, H., Rajlich, P. & Franke, W. (1990) Terrane boundaries in the Bohemian Massif: Result of large-scale Variscan shearing. Tectonophysics, 177, 151170.Google Scholar
Merriman, R.J. & Frey, M. (1999) Patterns of very lowgrade metamorphism in metapelitic rocks. Pp. 61107 in: Low-Grade Metamorphism (Frey, M. & Robinson, D., editors). Blackwell Science, London.Google Scholar
Merriman, R.J. & Peacor, D.R. (1999) Very low-grade metapelites: mineralogy, microfabrics and measuring reaction progress. Pp. 1060 in: Low-Grade Metamorphism (Frey, M. & Robinson, D., editors). Blackwell Science, London.Google Scholar
Merriman, R.J., Roberts, B. & Peacor, D.R. (1990) A transmission electron microscope study of white mica crystallite size distribution in a mudstone to slate transitional sequence, North Wales, U.K. Contributions to Mineralogy and Petrology, 106, 2740.Google Scholar
Merriman, R.J., Roberts, B., Peacor, D.R. & Hirons, S.R. (1995) Strain-related differences in the crystal growth of white mica and chlorite - a TEM and XRD study of the development of metapelitic microfrabrics in the Southern Uplands thrust terrane, Scotland. Journal of Metamorphic Geology, 13, 559576.Google Scholar
Mullis, J., Rahn, M.K., Schwer, P., de Capitani, C., Stern, W.B. & Frey, M. (2002) Correlation of fluid inclusion temperatures with illite ‘crystallinity’ data and clay mineral chemistry in sedimentary rocks from the external part of the Central Alps. Schweizerische Mineralogische und Petrographische Mitteilungen, 82, 325340.Google Scholar
Nieto, F., Liar Mata, M., Bauluz, B., Gorgetti, G., Arkai, P. & Peacor, D.R. (2005) Retrograde diagenesis, a widespread process on a regional scale. Clay Minerals, 40, 93104.Google Scholar
Pešek, J. (1996) Carboniferous of Central and Western Bohemia, Czech Geological Survey Press, Prague, 1-95.Google Scholar
Piqué, A. (1982) Relations between stages of diagenetic and metamorphic evolution and the development of a primary cleavage in the northwestern Moroccan Meseta. Journal of Structural Geology, 4, 491500.CrossRefGoogle Scholar
Powell, M.A.C. (1979) A morphological classification of rock cleavage. Tectonophysics, 58, 2134.Google Scholar
Robert, P. (1988) Organic Metamorphism and Geothermal History. Elf-Aquitane and D. Reidel, Dordrecht Boston, 1-311.Google Scholar
Roberts, B., Merriman, R.J. & Pratt, W. (1991) The influence of strain, lithology and stratigraphic depth on white mica (illite) crystallinity in mudrocks from the vicinity of the Corris Slate Belt, Wales: implications for the timing of metamorphism in the Welsh Basin. Geological Magazine, 128, 633645.Google Scholar
Robinson, D. & Merriman, R.J. (1999) Low-temperature metamorphism: an overview. Pp. 19 in: Low- Grade Metamorphism (Frey, M. & Robinson, D., editors). Blackwell, London.Google Scholar
Röhlich, P. (2000) Some stratigraphic problems of the Barrandian Neoproterozoic. Vïstník Ceského geologického ústavu, 75, 201204.Google Scholar
Sandler, A. & Suchý, V. (2004) Deep burial diagenesis of clays in the Tobolka-1 borehole, Czech Republic. Pp. 2223 in: Annual Meeting of the Israel Society for Clay Research 2004. Jerusalem.Google Scholar
Siddans, A.W.B. (1979) Deformation, metamorphism and texture development in Permian mudstones of the Glarus Alps (Eastern Switzerland). Eclogae Geologicae Helvetiae, 72, 601621.Google Scholar
Suchý, V., Frey, M. & Wolf, M. (1997) Vitrinite reflectance and shear-induced graphitization in orogenic belts: A case study from the Kandersteg area, Helvetic Alps, Switzerland. International Journal of Coal Geology, 34, 120.CrossRefGoogle Scholar
Suchý, V., Dobes, P., Filip, J., Stejskal, M. & Zeman, A. (2002) Conditions for veining in the Barrandian Basin (Lower Paleozoic), Czech Republic: evidence from fluid inclusion and apatite fission track analysis. Tectonophysics, 348, 2550.Google Scholar
Teichmüller, M. (1987) Organic material and very lowgrade metamorphism. Pp. 114161 in: Low Temperature Metamorphism (Frey, M., editor). Blackie, Glasgow.Google Scholar
Teichmüller, M., Teichmüller, R. & Weber, K. (1979) Inkohlung und Illit-Kristallinität: Vergleichende Untersuchungen im Mesozoikum und Paläozoikum von Westfalen. Fortschritte in der Geologie von Rheinland Westfalen, 27, 201276.Google Scholar
Underwood, M.B., Laughland, M.M. & Kang, S.M. (1993) A comparison among organic and inorganic indicators of diagenesis and low-temperature metamorphism, Tertiary Shimanto Belt, Shikoku, Japan. Pp. 4561 in: Thermal Evolution of the Tertiary Shimanto Belt, Southwest Japan: An Example of Ridge Trench Interaction (Underwood, M.B., editor). Geological Society of America Special Paper, 273.Google Scholar
Wagner, G. A. & Van den Haute, P. (1992) Fission Track Dating. Ferdinand Enke, Stuttgart, 1-285.Google Scholar
Wang, H., Frey, M. & Stern, W.B. (1996) Diagenesis and Metamorphism of Clay Minerals in the Helvetic Alps of Eastern Switzerland. Clays and Clay Minerals, 44, 96112.Google Scholar
Warr, L.H. & Rice, A.H.N. (1993) Crystallinity Index Standard. Unpublished report (version 1: 29.3.93), Geologisch-Paläontologisches Institut, Ruprecht- Karls Universität, Heidelberg, 1-46Google Scholar
Warr, L.H. & Rice, A.H.N. (1994) Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data. Journal of Metamorphic Geology, 12, 141152.Google Scholar
Weaver, C.E. (1960) Possible uses of clay minerals in search for oil. American Association of Petroleum Geologists Bulletin, 44, 15051518.Google Scholar
Weaver, C.E. (1989) Clays, Muds, and Shales, Elsevier, Amsterdam, 1-819.Google Scholar
Weber, J.C., Ferrill, D.A. & Roden-Tice, M.K. (2001) Calcite and quartz microstructural geothermometry of low-grade metasedimentary rocks, Northern Range, Trinidad. Journal of Structural Geology, 23, 93112.Google Scholar
Weber, K. (1981) Kinematic and metamorphic aspects of cleavage formation in very low-grade metamorphic slates. Tectonophysics, 78, 291306.Google Scholar
Yang, C. & Hesse, R. (1991) Clay minerals as indicators of diagenetic and anchimetamorphic grade in an Overthust Belt, external domain of southern Canadian Appalachians. Clay Minerals, 26, 211231.Google Scholar
Yui, T.F., Huang, E. & Xu, J. (1996) Raman spectrum of carbonaceous material: possible metamorphic indicator for low-grade metamorphic rocks. Journal of Metamorphic Geology, 14, 115124.Google Scholar
Ziegler, P.A., Cloetingh, S. & van Wees, J.D. (1999) Dynamics of intra-plate compressional deformations: the Alpine foreland and other examples. Tectonophysics, 252, 759.Google Scholar
Zulauf, G., Kleinschmidt, G. & Vejnar, Z. (1995) Polyphase Variscan extension at the western border of the Tepla—Barrandian (Bohemian Massif). Terra Nostra, 3, 110112.Google Scholar
Zulauf, G., Schnitter, F., Riegler, G., Finger, F., Fiala, J. & Vejnar, Z. (1999) Age constraints on the Cadomian evolution of the Teplá-Barrandian unit (Bohemian Massif) through electron microprobe dating of metamorphic monazite. Zeitschrift der Deutschen Geologischen Gesellschaft, 150/4, 627639.Google Scholar