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TECTONICS, VOL. 22, NO. 6, 1066, doi:10.1029/2002TC001472, 2003Cretaceous collision and indentation in the West Carpathians:View based on structural analysis and numerical modelingOndrej Lexa and Karel SchulmannInstitute of Petrology and Structural Geology, Charles University, Prague, Czech RepublicJosef JežekInstitute of Applied Mathematics and Computer Science, Charles University, Prague, Czech RepublicReceived 29 October 2002; revised 13 March 2003; accepted 30 July 2003; published 21 November 2003.[1] A model of indentation of a rigid promontory intoweak metasedimentary rocks during Cretaceousconvergence is suggested for tectonic evolution ofsouthern part of West Carpathians. An early arcuatecleavage fan has developed in front of northwardmoving southern rigid basement block. The interactionof the moving indenter with western stationarybasement promontory is responsible for developmentof the boundary-parallel shear zone along which themain southern indenter is shifted to the east. This resultsin development of a new steep transpressional cleavageoverprinting the early fabric. Eastward displacement ofthe southern indenter causes the development of a thrustzone parallel to the margin of the eastern stationarypromontory. A proposed numerical model of thedeformation of a thin viscous sheet in front of ovalrigid indenter reliably simulates the development of theobserved deformation pattern. Modeled discretepartitioning between the western promontory and theindenting block fully agrees with the observedsecondary cleavage associated with the transpressionalshear zone. Our numerical model interconnects thiscomplex kinematic frame with finite strain pattern,which was to date possible only for simple boundaryconditions. In addition, the model explains thepolyphase cleavage patterns in terms of complexshapes of promontories and changes in movements ofindenting blocks. INDEX TERMS: 5475 Planetology: SolidSurface Planets: Tectonics (8149); 8005 Structural Geology: Foldsand folding; 8020 Structural Geology: Mechanics; 8110Tectonophysics: Continental tectonics—general (0905);KEYWORDS: Cretaceous collision, indentation, west Carpathians,numerical model. Citation: Lexa, O., K. Schulmann, and J. Ježek,Cretaceous collision and indentation in the West Carpathians: Viewbased on structural analysis and numerical modeling, Tectonics,22(6), 1066, doi:10.1029/2002TC001472, 2003.1. Introduction[2] Existing interpretations of Mesozoic tectonic evolutionof Alpine and Carpathian chains are based on broadCopyright 2003 by the American Geophysical Union.0278-7407/03/2002TC001472$12.005 - 1knowledge of metamorphic and structural data obtainedfrom studies of internal parts of these orogenic belts[Genser et al., 1996; Schmid et al., 1996; Trumpy, 1973].These data underline subduction-related tectonics associatedwith lithospheric-scale subduction of oceanic and Europeanlithosphere below the African indenter [Allemand andLardeaux, 1997]. The Mesozoic evolution of the WestCarpathian belt is an integral part of the closing of theTethyan ocean, being characterized by Jurassic subductionand Late Jurassic exhumation of high pressure rocks[Faryad, 1995; Faryad and Henjes-Kunst, 1997; Maluskiet al., 1993; Mock and Reichwalder, 1992].[3] The West Carpathian structure is traditionally interpretedas a result of Cretaceous crustal shortening ofVariscan basement crustal segments associated withdécollement of Mesozoic sedimentary sequences. TheMesozoic strata originally formed basins separating individualcrustal segments, which were inverted and passivelytransported toward the north in the form of twolarge-scale nappes (the lower Krížna and upper Chočnappes) [Andrusov, 1936, 1958; Biely et al., 1968;Plašienka, 1991; Plašienka et al., 1997]. The Cretaceoustectonic evolution in West Carpathians was mostly studiedin Mesozoic rocks with well-known stratigraphy[Biely and Bystrický, 1967; Bystrický, 1967; Vozár,1978]. Consequently, the Cretaceous stacking of Mesozoicsequences, the kinematics and displacement ofMesozoic nappes and the degree of their metamorphicreequilibration are well defined and understood [cf.Plašienka, 1995]. However, the Alpine structural andmetamorphic evolution of pre-Mesozoic crystalline rocksis poorly described due to difficulties in distinguishingVariscan and Alpine fabrics.[4] This paper presents new information on structural andmechanical behavior of the southern part of West Carpathianpre-Mesozoic crystalline segments during Cretaceousconvergence. We have investigated the polyphase cleavagepatterns developed in low-grade metasedimentary EarlyPaleozoic sequences. It is generally accepted that suchcleavage patterns reflect the geometry and directionof movement of adjacent rigid blocks [Sintubin, 1999;Woodcock et al., 1988]. The detailed knowledge of shapesof rigid Variscan promontories and the geometry andsuperposition of cleavage patterns allow modeling of thecollisional process in time. We use the finite elementnumerical method introduced by England et al. [1985] to85
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“It strikes me that all our knowl
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Contentsviii4.7 Schulmann, Konopás
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Dedicated to my wife Markéta, daug
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Foreword 2First topic “Quantitati
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Foreword 4source and freely availab
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1. Quantitative analysis of deforma
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Chapter 2Mechanisms of lower crusta
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2. Mechanisms of lower crustal flow
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Chapter 3Quantitative analyses ofme
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3. Quantitative analyses of metamor
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274 K. SCHULMANN ET AL.orogenic roo
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276 K. SCHULMANN ET AL.Moldanubian-
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278 K. SCHULMANN ET AL.Fig. 4. P-T
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280 K. SCHULMANN ET AL.gneisses, mi
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282 K. SCHULMANN ET AL.characterize
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284 K. SCHULMANN ET AL.(a)(b)OrMeOm
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286 K. SCHULMANN ET AL.Fig. 8. Fiel
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288 K. SCHULMANN ET AL.(d)(c)PrRe(b
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290 K. SCHULMANN ET AL.top-to-the-N
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292 K. SCHULMANN ET AL.example in t
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294 K. SCHULMANN ET AL.at 330-325 M
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296 K. SCHULMANN ET AL.thermal and
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Author's personal copyC. R. Geoscie
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Author's personal copy268K. Schulma
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80 O. LEXA ET AL.rocks (greenstone
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82 O. LEXA ET AL.(a)(a´)(b)(b´)(a
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84 O. LEXA ET AL.mechanism lead to
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86 O. LEXA ET AL.(a)(b)(c)and high-
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88 O. LEXA ET AL.Fig. 7. Results of
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90 O. LEXA ET AL.Fig. 8. Results of
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92 O. LEXA ET AL.Fig. 10. P-T evolu
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94 O. LEXA ET AL.(a)(b)(c)(d)Fig. 1
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96 O. LEXA ET AL.subsolidus conditi
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98 O. LEXA ET AL.of momentum (Eqn A
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100 O. LEXA ET AL.Hasalova´, P., S
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102 O. LEXA ET AL.(Bohemian Massif)
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54 J. FRANĚK ET AL.represented mos
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56 J. FRANĚK ET AL.Fig. 2. Summary
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58 J. FRANĚK ET AL.to c. 346 Ma (J
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60 J. FRANĚK ET AL.(a)(b)(c)(d)Fig
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62 J. FRANĚK ET AL.Fig. 7. Equal a
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64 J. FRANĚK ET AL.Fig. 9. The 9HR
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66 J. FRANĚK ET AL.At the top, the
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68 J. FRANĚK ET AL.Fig. 12. Interp
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70 J. FRANĚK ET AL.and underlying
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72 J. FRANĚK ET AL.Bohemian Pluton
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74 J. FRANĚK ET AL.weak lower and
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76 J. FRANĚK ET AL.Janousˇek, V.,
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78 J. FRANĚK ET AL.Weber, K., 1984
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650 O. LEXA ET AL.followed by moder
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652 O. LEXA ET AL.(a)(b)Fig. 3. Geo
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654 O. LEXA ET AL.(a)(b)(c)(d)Fig.
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656 O. LEXA ET AL.Table 2. Summariz
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658 O. LEXA ET AL.Table 5. Represen
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660 O. LEXA ET AL.Fig. 7. Chemical
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662 O. LEXA ET AL.Fig. 9. (a) Plot
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664 O. LEXA ET AL.onset of dynamic
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666 O. LEXA ET AL.clase thermometry
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98 L. BARATOUX ETAL.bearing rocks a
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100 L. BARATOUX ETAL.regime but und
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102 L. BARATOUX ETAL.is observed wi
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104 L. BARATOUX ETAL.only 10-20% of
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106 L. BARATOUX ET AL.Fig. 7. Drawi
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108 L. BARATOUX ET AL.Fig. 9. BSE i
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110 L. BARATOUX ETAL.r~t'-,IMdMdddd
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112 L. BARATOUX ET AL.Quantitative
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114 L. BARATOUX ETAL.o ._,
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116 L. BARATOUX ETAL.Plagioclase -
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118 L. BARATOUX ETAL.Plagioclase -
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120 L. BARATOUX ET AL.are contempor
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122 L. BARATOUX ET AL.recrystallize
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124 L. BARATOUX ETAL.KNIPE, R. J. 1
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ClickHereforFullArticleJOURNAL OF G
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B10210ZÁVADA ET AL.: EXTREME DUCTI
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B10406SCHULMANN ET AL.: RHEOLOGY OF
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30 P. HASALOVÁ ET AL.These authors
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32 P. HASALOVÁ ET AL.The onset of
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34 P. HASALOVÁ ET AL.Table 1. Repr
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36 P. HASALOVÁ ET AL.Evidence of m
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38 P. HASALOVÁ ET AL.PlQtz70% 30%B
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40 P. HASALOVÁ ET AL.(a)(b)(c)Fig.
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42 P. HASALOVÁ ET AL.Fig. 9. Grain
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44 P. HASALOVÁ ET AL.(a)(b)Fig. 11
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46 P. HASALOVÁ ET AL.steep D 1 fab
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48 P. HASALOVÁ ET AL.refractory. I
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50 P. HASALOVÁ ET AL.creep and gra
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52 P. HASALOVÁ ET AL.Lafeber, D.,
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J. metamorphic Geol., 2011, 29, 103
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PRECURSOR AND RHEOLOGY OF VARISCAN
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