High-Resolution Biostratigraphy of the Tournaisian-Visean (Carboniferous

Geobios 43 (2010) 317–331

Original article High-resolution biostratigraphy of the Tournaisian-Visean (Carboniferous) boundary interval, Mokrá quarry, Czech Republic§ Biostratigraphie haute-résolution de la limite Tournaisien-Viséen (Carbonifère), carrière de Mokrá, République Tchèque Jirí Kalvoda a,*, François-Xavier Devuyst a,b, Ondrej Bábek a, Ladislav Dvorák a, Stepán Rak c, Jirí Rez a a Institute of Geological Sciences, Masaryk University, 2 Kotlarska, 61137 Brno, Czech Republic b Carmeuse Lime and Stone, Technology Center, 3600 Neville Road, Pittsburgh PA 15225, USA c Institute of Geology and Palaeontology, Faculty of Sciences, Charles University, 6 Albertov, Praha 2, Czech Republic Received 9 June 2009; accepted 19 October 2009 Available online 8 April 2010

Abstract This paper summarizes the results of investigations carried out in the Mokrá quarry since 2006 on the biostratigraphy of the Tournaisian-Visean (T-V) boundary interval. It also integrates previous results obtained by J. Kalvoda and collaborators. The main focus is on the boundary itself, but stratigraphically lower and higher levels have been investigated as well to provide a biostratigraphical context spanning the late Tournaisian to early Visean. This stratigraphical level has been the focus of intense international research in the recent years under the auspices of the Subcommission on Carboniferous Stratigraphy (SCCS) in order to find a new criterion and reference section (Global Stratotype Section and Point, GSSP) for the base of the Visean Stage. The appearance of Eoparastaffella simplex from its ancestor E. ‘‘ovalis’’ and the Pengchong section (Guangxi, southern China) have recently been proposed by the Task Group on the Tournaisian-Visean Boundary and ratified by the SCCS as the new biostratigraphic criterion and GSSP for the base of the Visean, respectively. The sequence exposed in Mokrá is not suitable as a GSSP, notably because it is an active quarry, but it contains most of the foraminifer and conodont guides allowing a high-resolution biostratigraphy of the boundary interval. In addition, it contains abundant trilobites. For these reasons, it constitutes one of the best sections across the T-V boundary in Europe and can serve as a useful additional reference. # 2010 Elsevier Masson SAS. All rights reserved.

Keywords: Biostratigraphy; Foraminifers; Conodonts; Tournaisian; Visean; Carboniferous Résumé Cet article fait la synthèse des études biostratigraphiques menées depuis 2006 sur la limite Tournaisien-Viséen (T-V) dans la carrière de Mokrá. Les résultats obtenus précédemment par J. Kalvoda et ses collaborateurs ont été inclus. L’objet principal de l’article est la limite elle-même, mais l’intervalle stratigraphique étudié couvre le Tournaisien supérieur et le Viséen inférieur afin que la limite puisse être comprise dans son contexte. Ces dernières années, cet intervalle stratigraphique a été l’objet d’intenses recherches internationales sous les auspices de la Sous-commission de Stratigraphie du Carbonifère (SCCS) dans le but de trouver le meilleur critère biostratigraphique possible pour la base de l’étage Viséen ainsi qu’un stratotype global (Global Stratotype Section and Point, GSSP). L’apparition d’Eoparastaffella simplex dans la lignée évolutive E. « ovalis »àE. simplex et la coupe de Pengchong (Guangxi, Chine du sud) ont récemment été proposés par le Groupe de Travail sur la Limite Tournaisien-Viséen et ratifiés par la SCCS comme nouveau critère biostratigraphique et GSSP pour la base du Viséen, respectivement. La séquence stratigraphique visible à Mokrá ne remplit pas les critères d’un GSSP, notamment car il s’agit d’une carrière active, mais elle contient la plupart des espèces de foraminifères et conodontes qui permettent de définir une biostratigraphie haute-résolution de la limite Tournaisien-Viséen. La coupe de Mokrá

§ Corresponding editor: Frédéric Quillévéré. * Corresponding author. E-mail address: [email protected] (J. Kalvoda).

0016-6995/$ – see front matter # 2010 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.geobios.2009.10.008 318 J. Kalvoda et al. / Geobios 43 (2010) 317–331 contient par ailleurs une riche faune de trilobites. Ces qualités en font une des meilleures coupes de la limite T-V en Europe et une coupe de référence complémentaire au stratotype. # 2010 Elsevier Masson SAS. Tous droits réservés.

Mots clés : Biostratigraphie ; Foraminifères ; Conodontes ; Tournaisien ; Viséen ; Carbonifère

1. Introduction region were revised and potential new reference sections were investigated worldwide (see summary and references in Devuyst, Active research on the Tournaisian-Visean (T-V) boundary 2006). Results showed that: interval has been carried out in the past 10 years as a result of the decision of the International Commission on Stratigraphy (ICS)  Eoparastaffella, used in conjunction with other foraminifer to revise and standardize the Phanerozoic chronostratigraphic and conodont taxa, allows a high-resolution biostratigraphy scale. ATask Group on the T-V boundary was set up in 1995 by in the latest Tournaisian and early Visean at the scale of the Subcommission on Carboniferous stratigraphy in order to Eurasia (Devuyst, 2006; Devuyst and Kalvoda, 2007; find a better section to replace the historical stratotype for the Devuyst and Hance in Poty et al., 2007); base of the Visean (Bastion section, Namur-Dinant Basin,  The historical criterion for the base of the Visean can be southern Belgium) and to evaluate critically the applicability of retained as E. simplex is part of an evolutionary lineage the existing criterion (appearance of the foraminifer Eopar- starting in the latest Tournaisian (Hance and Muchez, 1995; astaffella simplex Vdovenko; Devuyst et al., 2003 and references Hance, 1997; Devuyst, 2006); therein). The sequence stratigraphy context (Hance et al., 2001)  The Pengchong section of Guangxi, southern China, and biostratigraphy (Poty et al., 2006) of the Namur-Dinant constitutes the best-known section to replace Bastion as a

Fig. 1. Satellite photograph (A) and sketch (B) showing the location of the profiles studied in Mokrá quarry (based on http://earth.google.com/). Dotted lines indicate the floors in each sub-quarry; the floors of the main quarry are numbered from B1 to B4 for reference; profiles studied are numbered from 1 to 6. J. Kalvoda et al. / Geobios 43 (2010) 317–331 319

new stratotype for the base of the Visean (Hance, 1997; Devuyst et al., 2003).

Both the criterion for the base of the Visean and the new stratotype section have now been ratified by the SCCS and the International Union of Geological Sciences (IUGS; Work, 2002, 2008). Although Mokrá quarry cannot serve as a stratotype because of its sedimentary context (relatively discontinuous sedimentation), tectonic setting (see below and Dvorák et al., 1987) and because it is an active quarry, it exposes one of the best successions known for the biostrati- graphy of the T-V boundary interval with abundant and diverse foraminifers, conodonts and trilobites. Such sections are especially rare in Europe. The goal of the present work is therefore to describe the distribution of the main foraminifer and conodont guides together with trilobite occurrences in the latest Tournaisian and early Visean of Mokrá and to provide a reference T-V boundary succession in Europe.

2. Material and methods

Different profiles were studied and sampled over the years, following the advance of the quarry faces. A first series of thin sections was typically made and examined to identify the richest levels. Additional numerous thin sections (over 700) were cut in the best beds. Foraminifers were studied with a high-magnification binocular microscope Nikon 80i. About 40 samples, 3 to 4 kg each, were collected, processed (standard technique with acetic acid and bromoform) and examined for conodonts in profiles 1, 2 and 3; not all were productive. Between 1500 and 2000 specimens of trilobites were collected in the late Tournaisian to early Visean part of the Brezina Fm. Two main levels were especially productive, one in the latest Tournaisian and one in the early Visean. Trilobite specimens are currently being studied by S. Rak for a Ph.D. thesis. Fig. 2. General lithostratigraphical column for the late Devonian and early Carboniferous of southern Moravia. Lithological symbols are of standard use. 3. Mokrá quarry See text for detail.

3.1. Location, general stratigraphy and sections studied located at the entrance of the eastern quarry (Fig. 1). The stratigraphically oldest profile studied (Fig. 5) exposes the Mokrá quarry is a vast active quarry composed of three sub- upper part of the Hády-Rícka Mbr (Fig. 2), characterized here quarries (Fig. 1) located 15 km east-northeast of Brno in the by medium to dark, fine-grained, sandy and cherty limestones southernmost Moravian Karst. It exposes rocks of Frasnian to overlain by dark, very sandy, medium-grained limestones and late Visean age. The Frasnian is represented by reefoid massive sandy limestone sedimentary breccias passing to the limestones (Macocha Fm) whereas the Famennian to Visean lowermost part of the Brezina Fm. The lower part of the section interval is composed of mass flow deposits, basinal shales (Hády-Rícka Lm) is not folded but becomes strongly folded in (Hády-Rícka Mbr of the Lísen, and Brezina Fms) and rarer the Brezina Fm (alternating medium- to thin-bedded bioclastic- hemipelagites (Krtiny Mbr of the Lísen Fm). The Tournaisian- lithoclastic calcarenites, bioclastic calcilutites and greenish to Visean boundary occurs in the lower part of the Brezina Fm reddish calcareous shales, locally with abundant trilobites). (Fig. 2). The middle to upper Visean is represented by typical Profile 4 (quarried out; Fig. 4) used to expose the upper part of flysch facies of the Rozstání and Myslejovice Fms (Dvorák the same massive sandy limestone breccias and the lowermost et al., 1987). part of the overlying Brezina Fm directly N-Westwards of The late Tournaisian to early Visean succession was studied Profile 3. Profile 1 (quarried out; Fig. 6) used to expose a in six main subsections referred to as ‘‘profiles’’ (Figs. 1, 3 and moderately folded (small scale) sequence in the lowermost part 4). The numbering of the profiles was made as research of the Brezina Fm with alternating thin- to medium-bedded progressed. Profiles 1 and 3 to 6 are/were located in the bioclastic and often sandy calcarenites and calcilutites and northeastern corner of the middle quarry whereas Profile 2 is brownish calcareous shales (1/1 ratio). The limestone beds 320 J. Kalvoda et al. / Geobios 43 (2010) 317–331

Fig. 3. Photo-panoramas of the N-NE wall of the main quarry showing the location of all profiles studied. Profile 2 is in the east quarry. B is an enlargement of A and C is an enlargement of B. The locations of outcrops of the massive breccias are shown in C. Note large quarry truck in A, drill on second bench in B and car in C forscale. were finer-grained and more micritic up-section. Outcrop is complicated (see below) and some of the profiles studied conditions were not suitable to produce a detailed log of Profile undoubtedly belong to separate thrust sheets with distinct 1 and the thickness shown in Fig. 7 is probably significantly lateral variations of facies in a N-S direction (Fig. 2). Such increased by folding. Profile 3b (quarried out) used to display a variations are observed, for instance, in the thickness of the part of the lower Brezina Fm laterally equivalent to the top of massive limestone breccias and in the grain size of the profile 3a and beds slightly higher stratigraphically (Figs. 4, 8 calcarenite beds of the Brezina Fm at equivalent stratigraphical and 9). It was characterized by alternating medium- to thin- levels. The correlation between profiles shown in Figs. 4 and 6 bedded bioclastic calcarenites and calcilutites and brownish is interpretative and based both on biostratigraphic (forami- calcareous shales (limestones were dominant, maybe because nifers, conodonts) and lithostratigraphic (massive breccias) of tectonic reduction of shales). The succession was highly evidences. folded and beds were slightly displaced by creep. An approximate doubling of the thickness is inferred. Profile 3c 3.2. Paleogeographical, geological and sedimentary (bench 3; Fig. 3) outcrops at present on the quarry wall located setting directly S-Eastwards of former Profile 3b. It exposes a highly folded part of the Brezina Fm overlying the succession of In southern Moravia upper Devonian and lower Carbonifer- Profile 3b. Profile 6 (Fig. 6) exposes a highly folded sequence of ous rocks represent the sedimentary cover of the Brunovistulian alternating reddish-grey, fine- to coarse, bioclastic calcarenites terrane, which is generally regarded as an eastern continuation and reddish-green, calcareous shales (the shales largely of the Rhenohercynian Zone (e.g., Franke, 1989; Kalvoda, dominate). There is again probably an approximate doubling 1998; Chadima and Melichar, 1999; Hartley and Otava, 2001; of thicknesses due to folding. Profile 2 (eastern quarry; Fig. 6) Kalvoda et al., 2002, 2003, 2008). Fig. 10 shows the general displays an overturned and highly condensed sequence of the geological context of the eastern Czech Republic. During the lower Brezina Fm resting tectonically on lower Tournaisian Variscan orogeny the Brunovistulian terrane was located on the nodular calcilutites (Krtiny Mbr of the Lísen Fm). Here, the southern tip of Laurussia and was involved in the collision with lower Brezina Fm is composed of alternating medium- to the Lugodanubian terranes (Armorican Terrane Assemblage of coarse-grained bioclastic calcarenites (some very rich in Tait et al., 1997; Kalvoda et al., 2003). foraminifers) and calcareous shales. In the upper part of the In the early Famennian, extension and block tilting profile, limestone beds become finer-grained and more micritic. transformed the carbonate platform, which occupied the Mokrá Outcrop conditions do not allow detailed logging but there is no area into a graben basin. The structure of this basin was apparent major folding. The structural context of Mokrá quarry maintained up to the start of flysch sedimentation in the middle J. Kalvoda et al. / Geobios 43 (2010) 317–331 321

Fig. 4. Stratigraphical logs of selected profiles studied. Profile 3b (after Rak, 2004) is not as detailed as other profiles; profiles 3c and 5 were not logged. For interpretation of colours, see the web version of this article.

Visean. Famennian limestones were deposited in the graben of feldspar grains in some beds at that stratigraphic level either as upper slope hemipelagic carbonate oozes (Krtiny Mbr) suggests a more arid climate. Higher in the late Tournaisian and or as lower slope skeletal calciturbidites (lower Hády-Rícka in the early Visean, thicker-bedded and coarser-grained Mbr; Kalvoda et al., 1996a,b). The source area for the calciturbidites and other mass-flow deposits were deposited calciturbidites was situated on another carbonate platform in the upper slope to the north whereas thinner-bedded and located north of Mokrá. This platform is now covered by nappes finer-grained calciturbidites and reddish to greenish shales of flysch sediments. At the Devonian-Carboniferous boundary (Brezina Fm) were deposited in the deeper part of the basin to an important sea-level fall occurred and resulted in the the south. A general fining upwards trend is observed in the emergence of the platform. The lower Tournaisian was Brezina Fm. The calciturbidites contain, among other grain characterized by deposition of hemipelagites, mud calciturbi- types (dominated by crinoids and moravamminids), abundant dites and rare skeletal calciturbidites. A transgression at the foraminifers, locally rugose corals, trilobites and variable base of the crenulata Zone (Kalvoda, 1989, 1992) is evidenced amount of conodonts whereas the shales contain trilobites and by the change from nodular limestones (Krtiny Mbr) to planar- brachiopods, but also some bivalves and rare unidentified bedded, fine-grained limestones with frequent chert nodules ammonoids. and rare thin radiolarite layers (upper Hády-Rícka Mbr). The onset of Variscan compression is recorded at the base of 3.3. Tectonic setting the late Tournaisian by the deposition of sandy lithoclastic calciturbidites, sandstones and massive sandy limestone The sedimentary sequence exposed in the Mokrá area breccias (top of the Hády-Rícka Mbr; Fig. 2). The presence underwent polyphased deformation in a tectonically convergent 322 J. Kalvoda et al. / Geobios 43 (2010) 317–331

Fig. 5. Photograph of Profile 5 showing the uppermost part of the Lísen Fm (Hády-Rícka Mbr) and the lower part of the Brezina Fm with the location of samples.

context characterized by complex overthrusting (Rez, 2004a,b). 3.4. Fauna The most obvious deformation features are folds. Two main phases of folding can be distinguished. Older folds are mostly 3.4.1. Conodonts asymmetric and recumbent with axes dipping to the SE. Conodonts are abundant in the late Tournaisian and early Stretching lineations indicate a NNE-SSW compression, and Visean of the Mokrá sequence; their study is still in progress (L. the asymmetry suggests a NNE movement. Younger folds are Dvorák). They will be the subject of a forthcoming publication almost perpendicular to the previous ones, gently refolding but stratigraphically important taxa are mentioned here to them. Stretching lineations indicate NW-SE shortening. These complement the foraminiferal biostratigraphy. Scaliognathus structures are further complicated by brittle tectonics. In anchoralis Branson and Mehl (mainly S. anchoralis europensis addition to minor faults, there are two main faulting systems, Lane and Ziegler but also S. anchoralis fairchildi Lane and which cross-cut the folds. The first system is represented by Ziegler and probably S. anchoralis anchoralis) and Gnathodus NNE-SSW normal faults and the second by WNW-ESE strike- pseudosemiglaber Thompson and Fellows are particularly slip faults (Figs. 10 and 11). The orientation of these faults and abundant, but Pseudopolygnathus pinnatus Voges, Proto- their relationship to other structures suggest an alpine origin. gnathodus cordiformis Lane, Sandberg and Ziegler, Poly- The most important tectonic features of the Mokrá area, gnathus bischoffi Rhodes, Austin, and Druce and however, are thrust faults separating sedimentary sequences of Spathognathodus sp. are common as well. The Visean guide different facies (and paleo-positions in the sedimentary basin) Gnathodus homopunctatus Ziegler was found only in profile 2. in normal and reversed position (Fig. 11). These faults appear in The distribution of the main guides is discussed in the the field as decimetric to metric-thick black mylonitic zones Biostratigraphy section. with graphitic organic material. Stretching lineations and the asymmetry of duplexes developed during thrusting indicate 3.4.2. Foraminifers NNE directed movement. Equal area plots of fault planes and Foraminifers of the late Tournaisian and early Visean are bedding planes show the same pattern. Moreover, some remarkably abundant and diverse in Mokrá. In particular the duplexes present in the thrust sheets have anticlinal or synclinal fauna comprises the following guides: Eotextularia diversa geometries. This suggests that the thrusting took place during (Chernysheva), Tetrataxis sp., Brunsia sp., Endospiroplecta- the older phase of folding, when the shortening could not be minna sp. (E. conili Lipina and E. venusta (Vdovenko)), accommodated by folding only. During the same compression Laxoendothyra ex. gr. laxa (Conil and Lys) (various forms), phase the newly formed thrusts were progressively folded (NW- Pseudolituotubella sp., Dainella sp., Florenella sp., Bessiella SE folds) and the resulting complex thrust/fold structure was sp., Darjella monilis Malakhova, Elevenella parvula Bozorg- subsequently refolded by younger folds. The general structure nia, Biseriella bristolensis (Reichel), Lysella gadukensis in the Mokrá area can therefore be interpreted as a part of fold Bozorgnia and Eoparastaffella sp. The last genus is represented thrust belt, refolded during the Variscan Orogeny and affected by an exceptional number of species for Europe with: E. ex. gr. by later faulting resulting from thrusting in the western rotunda Vdovenko, E. vdovenkoae Devuyst and Kalvoda, E. Carpathians. interiecta Vdovenko, E. macdermoti Devuyst and Kalvoda, E. J. Kalvoda et al. / Geobios 43 (2010) 317–331 323

Fig. 6. Stratigraphical logs of selected profiles studied. Profiles 1 and 2 are after Ondrácková (2001) and are not as detailed as other profiles. For interpretation of colours, see the web version of this article. tumida subsp. 1 (Devuyst and Kalvoda, 2007), E. ex. gr. makes Mokrá a unique locality in Europe and allows a very florigena (Pronina), E. ex. gr. asymmetrica Vdovenko, E. finely resolved biostratigraphy of the late Tournaisian and early ‘‘ovalis’’ M2, E. ‘‘ovalis’’ M3, E. simplex and E. simplex Visean. The only section known to date, which rivals Mokrá in simplex. The common presence of these taxa in a single section abundance and diversity of foraminifers of that age is 324 J. Kalvoda et al. / Geobios 43 (2010) 317–331

Fig. 7. Correlation of the profiles based on ranges of important foraminiferal and conodont taxons.

Pengchong (Guangxi, southern China), which has been ratified a challenge to refine the taxonomy of the genus. The revision of as a the new stratotype for the base of the Visean (Devuyst et al., the genus Eoparastaffella is in progress (Devuyst and Kalvoda, 2003; Work, 2008). 2007) but a great deal of work remains to be done and this Remark on the taxonomy of Eoparastaffella: Recent work explains the number of provisional informal taxon names used on the genus Eoparastaffella in the late Tournaisian and early in recent publications, including this one. The reader is referred Visean has revealed a much larger diversity of forms than to Devuyst (2006) and Devuyst and Kalvoda (2007) for a previously known (e.g., Hance, 1997; Ondrácková, 2001; discussion of the various new species, subspecies and Kalvoda, 2003; Devuyst, 2006; Devuyst and Kalvoda, 2007 and morphotypes recognized to date. references herein). This is not surprising given the low number of publications dealing with the taxonomy of that genus 3.4.3. Trilobites between the pioneering work of Russian and Ukrainian Trilobites are common in beds 2R to 10R of section 3a micropalaeontologists in the late 1950s to early 1970s and (Fig. 4) but they are commonly deformed, which renders their the recent renewal of interest (late 1990s) triggered by the identification difficult in some cases. Their study is in progress research on the T-V boundary (see reviews in Devuyst, 2006; (S. Rak) but the following taxa have already been identified: Devuyst and Kalvoda, 2007). That large diversity presents an Archegonus (Archegonus) aequalis philliboloides R. Hahn, opportunity for much higher resolution biostratigraphy but also Bollandia megaira (Hahn and Hahn) and three currently J. Kalvoda et al. / Geobios 43 (2010) 317–331 325

Fig. 9. Photo-montage of Profile 3b.

accordance with the data of the Namur-Dinant Basin, identified a fauna with ‘‘Visean elements’’ as V1a (earliest Visean of the 1977 zonation) in the upper part of the Hády-Rícka Mbr and in the Brezina Fm. Based on the study of conodonts and foraminifers, Kalvoda (1982) showed that some of the taxa considered as ‘‘typical Visean’’ in the Belgian zonation actually occur at least one or two conodont zones (i.e. 1 to 2 millions years) earlier in Avalonian (including Moravia) and eastern European terranes. Kalvoda (1982) argued that this resulted from the deeper sedimentary facies that characterized most of the Dinant area in the late Tournaisian. These conclusions were Fig. 8. Photographs of Profile 3a. Note the intense folding of the shale-rich confirmed by subsequent researches (Hance, 1988; Conil et al., lower part of the Brezina Fm and the massive breccias at the top of the Hády- 1989; Lees, 1997; Hance et al., 2001; Devuyst, 2006) and Ricka Mbr (Lísen Fm). A few sample horizons are indicated. The top of the included in a regional foraminiferal zonation for Moravia profile corresponds with the hinge of a syncline (a). Rectangles in a correspond proposed by Kalvoda (1983, 1990). Other studies by Kalvoda to b and c. T = Tournaisian; V = Visean. and Ondrácková (1999), Kalvoda and Ondrácková (2001), Kalvoda (2003) and Kalvoda et al. (2005) have shown the unnamed species of Bollandia (sp. 1 to 3), ?Carbonocoryphe richness of the foraminifer (and in particular of Eoparastaf- (Winterbergia) sp., C.(Carbonocoryphe) bindemanni Richter fella), conodont and trilobite associations in the T-V boundary and Richter, Liobole (Panibole) sp., L.(Panibole) jugovensis interval of the Mokrá sequence. (Osmólska), L.(Sulcubole) glabroides (Richter and Richter), In this work the recently revised zonation of the lower Linguaphillipsia sp., Proliobole vigilax and Waribole (Lati- Carboniferous of the Franco-Belgian Basin by Devuyst and bole) granifera Chlupácˇ. The association is similar to the fauna Hance in Poty et al. (2006) is used (Fig. 12). This new zonation described from the Erdbach limestone (latest Tournaisian to brings improvements to the previous zonation of Conil et al. early Visean) in Germany (Richter and Richter, 1949; Hahn, (1991), notably in the T-V boundary interval. Eight zones (MFZ 1967; Hahn et al., 1998). 1 to 8) are distinguished in the Tournaisian and seven in the Visean (MFZ 9 to 15). Devuyst (2006) and Devuyst and 4. Biostratigraphy Kalvoda (2007) have recently shown that evolutionary lineages in the genus Eoparastaffella can be used to refine the 4.1. Previous work biostratigraphic resolution of MFZ 7 to 9 at the scale of Eurasia.

The position of the T-V boundary in Moravia has been a 4.2. New data matter of discussion for decades. In two pioneering papers Dvorák and Conil (1969) and Conil (1977) applied the Belgian A test sample taken in the dark, very sandy limestone unit foraminifer zonation of Conil et al. (1977) to Moravia and, in directly underlying the massive limestone breccias in Profile 5 326 J. Kalvoda et al. / Geobios 43 (2010) 317–331

Fig. 10. Geology and general tectonic context of the eastern Czech Republic (modified after Kodym et al., 1967).

Fig. 11. Geology of the Mokrá quarries based on field and borehole data. J. Kalvoda et al. / Geobios 43 (2010) 317–331 327

Fig. 12. Foraminiferal (Devuyst and Hance) and coral (Poty) zonation of Poty et al. (2006) with chronostratigraphical divisions and correlation with conodont occurrences (after Groessens in Conil et al., 1991) and previous zonations of Mamet (1974) and Conil et al. (1991). Liv = Livian; N = Namurian; carina = Po- lygnathus communis carina; S = Scaliognathus; P = Protognathodus; homo = Gnathodus homopunctatus; T = Taphrognathus; bilineatus = Gnathodus bilineatus bilineatus; boll = Gnathodus bilineatus bollandensis. Slightly modified after Poty et al. (2006). has yielded Brunsia sp., Endothyra sp., Granuliferella sp., resolution biostratigraphy of the T-V boundary interval Tournayellina sp., cf. Palaeospiroplectamina sp. and Eotextu- itself (Fig. 7). Correlations between Profiles 1, 2 and 3 are laria diversa. This association and especially the last taxon hypothetical due to tectonic complications. Granulometric indicate MFZ 6 (late Tournaisian). The upper part of sorting certainly played an important role in the distribution of the breccias in Profile 4 has the same microfauna with foraminifers. In a general way, calciturbidites are coarser the addition of Septabrunsiina sp., cf. Globoendothyra sp. and grained in Profiles 1 and 3b than in Profile 3a. The lower part of Quasiendothyra sp. reworked in limestone clasts. In the Profile 3a, in particular, is poor in suitable levels for same profile, the limestones directly overlying the breccias foraminifers. Despite these difficulties some interesting have the first Laxoendothyra ex gr. laxa, Dainella sp., observations can be made: Pseudolituotubella sp., Tetrataxis sp., Globoendothyra sp., Endospiroplectammina sp., Urbanella sp. and common  The lowest samples of Profile 1 and 7 already contain a MFZ Darjella monilis (Fig. 13). This association, and especially 7 foraminifer assemblage with notably: Palaeospiroplecta- the guide D. monilis, characterizes MFZ 7. Darjella monilis is mina mellina (Malakhova), Pseudolituotubella sp., Laxoen- still present in the upper part of Profile 1 with the first dothyra ex gr. laxa, Globoendothyra sp., Latiendothyranopsis Eoparastaffella, which indicate MFZ 8 and the very latest sp., Dainella sp., cf. Bessiella sp. and Florennella sp.; Tournaisian.  The first Eoparastaffella (MFZ 8) are observed in the range of More detailed sampling (foraminifers and conodonts) in the Darjella monilis, in the Scaliognathus anchoralis Zone, and upper part of Profile 1 and in Profiles 2, 3a and 3b allows a high- belong to the group rotunda; 328 J. Kalvoda et al. / Geobios 43 (2010) 317–331

Fig. 13. Illustration of foraminifers from the T-V boundary interval in the Mokrá quarry. 1. Costayella costata (Lipina), Profile 7 (M7/1). 2. Darjella monilis, Profile 7 (M7/2). 3. Forschiella prisca Mikhailov, Profile 2 (98/7). 4. Bessiella legrandi, Profile 3a (R2-I). 5. Lysella gadukensis, Profile 6b (06/27). 6. Omphalotis ex gr. chariessa (Conil and Lys), Profile 6 (06/21). 7. Lysella gadukensis, Profile 3b (02/12). 8, 9. Lysella gadukensis, Profile 3b (R2E). 10. Elevenella parvula, Profile 1 (98/ 32). 11. Paraendothyra cummingsi (Conil and Lys), Profile 3a (R2-VI). Scale bar: 0.2 mm.

 The last occurrence of tuberculate tournayellids (Costayella/  As in northern Iran (Gaduk section; Devuyst, 2006), typical Carbonella) is in the lower part of MFZ 8; Lysella gadukensis are preceded by narrow forms, which we  Eoparastaffella vdovenkoae (juveniles) first appears higher, attribute to Bessiella legrandi (Conil and Hance), but which at the top of the range of Darjella monilis, together with have affinities with L. gadukensis; Biseriella bristolensis in Profile 1;  Eoparastaffella tumida subsp. 1 and a particular type of  Elevenella parvula first appears together with the oldest Eoparastaffella (E. sp. 1 of Devuyst, 2006), which have been Eoparastaffella and extends up to the entry of Eoparastaffella observed only in Oughterard (western Ireland; Devuyst, ‘‘ovalis’’ M2 at the very base of the Visean (this constitutes 2006) previously, are present in Mokrá at a similar the youngest LAD of E. parvula to date), but is rarer in the stratigraphic level (very latest Tournaisian to earliest uppermost part of the Scaliognathus anchoralis Zone and in Visean); the Gnathodus Interzone;  In Mokrá, Eoparastaffella ex gr. florigena have currently only  In Profile 3a, Lysella gadukensis, Eoparastaffella vdoven- been found in the Visean but they are common in the latest koae, E. interiecta and E. macdermoti appear late, at the same Tournaisian of the Pengchong GSSP (Devuyst, 2006); level as E. ‘‘ovalis’’ M2 (earliest Visean). They are, however,  Eoparastaffella simplex simplex is well represented at one remarkably abundant in the upper part of Profile 3a and in level of Profile 2 with specimens that exactly match the type Profile 3b; material; J. Kalvoda et al. / Geobios 43 (2010) 317–331 329

Fig. 14. Illustration of Eoparastaffella from the T-V boundary interval in Mokrá quarry. Most specimens come from the entirely early Visean Profile 6. 1. Eoparastaffella simplex, Profile 6 (06/21). 2. Eoparastaffella ex gr. florigena, Profile 6 (06/21). 3. Eoparastaffella simplex, Profile 6 (06/21). 4. Eoparastaffella ex gr. tumida (Pronina), Profile 6 (06/21). 5. Eoparastaffella simplex, Profile 6 (06/21). 6. Eoparastaffella ex gr. florigena, Profile 6 (06/26). 7. Eoparastaffella ovalis, M2, Profile 6 (06/27). 8. Eoparastaffella macdermoti, Profile 6 (06/21). 9. Eoparastaffella simplex, Profile 6 (06/21). 10. Eoparastaffella ex gr. florigena, Profile 6 (06/21). 11. Eoparastaffella simplex, Profile 6 (06/21). 12. Eoparastaffella simplex, Profile 6 (06/21). 13. Eoparastaffella macdermoti, Profile 6 (06/22b). 14. Eoparastaffella interiecta, Profile 3a (13R). 15. Eoparastaffella ex gr. florigena, Profile 6 (06/21). 16. Eoparastaffella simplex, Profile 2 (98/7). 17. Eoparastaffella ex gr. florigena, Profile 2 (98/7). 18. Eoparastaffella simplex, Profile 2 (98/7). 19. Eoparastaffella simplex, Profile 6 (06/21). 20. Eoparastaffella ovalis, M2, Profile 6 (06/27). Specimen 5 shows similarities with a specimen illustrated as E. simplex by Fewtrell et al. (1989: pl. 3-3, Fig. 12). Scale bar: 0.2 mm. 330 J. Kalvoda et al. / Geobios 43 (2010) 317–331

 Gnathodus homopunctatus, the conodont guide for the base refinement of the zonation of that stratigraphical interval. The of the Visean was only found higher in Profile 2, together with data on trilobites will be of particular importance in this Eoparastaffella simplex simplex. context. Mokrá is therefore undoubtedly a critical reference section for the western part of Eurasia. A selection of representative specimens of the T-V boundary interval is illustrated in Figs. 13 and 14. Acknowledgements The basal beds of the recently investigated Profile 6 (Fig. 6) already contain relatively evolved E. simplex together with This research was supported by grant project GACR 205/08/ a diverse Visean microfauna. This association remains 0182 and 205/08/J015 and by Ceskomoravsky´ Cement a.s. Jirˇí unchanged throughout the profile (which is intensely folded). Povolny´ is thanked for preparing numerous high-quality thin Its most significant characteristic is the common presence of sections. relatively advanced E. simplex (but not E. simplex simplex, which is present in the upper part of Profile 2), wide E. simplex References in axial section and common representatives of E.exgr. florigena (Fig. 14). This association belongs to MFZ 9. Even Chadima, M., Melichar, R., 1999. Structural investigation of the Paleozoic of when structural thickening of Profile 6 (folding) is taken into the Drahany Upland, Moravia. Geolines 8, 12–13. account, there is no doubt that Profile 2 represents a very Conil, R., 1977. The use of foraminifera for the biostratigraphy of the Dinantian condensed sequence compared to other profiles. in Moravia. In: Wagner, R.H., Holub, V.M. (Eds.), Symposium on Carbon- Archaediscids (MFZ 10 and above) were not observed in the iferous Stratigraphy. IUGS Subcommission on Carboniferous Stratigraphy, Field and General Meeting. Czechoslovakia Geological Survey, (September course of this study but they are known from the uppermost part 1973), pp. 377–398. of the Brezina Fm from boreholes drilled in the late seventies in Conil, R., Groessens, E., Laloux, M., Poty, E., 1989. La limite Tournaisien/ the northwestern part of the present main quarry (Dvorák et al., Viséen dans la région-type. Annales de la Société géologique de Belgique 1984). 112, 177–189. Conil, R., Groessens, E., Laloux, M., Poty, E., Tourneur, F., 1991. Carboniferous guide foraminifera, corals and conodonts in the Franco-Belgian and Cam- 5. Conclusions pine Basins: their potential for widespread correlation. In: Brenckle, P.L., Manger, W.L. (Eds.), Intercontinental Correlation and Division of the The richness and diversity of the foraminifer and conodont Carboniferous System. Courier Forschungsinstitut Senckenberg, 130, faunas of the late Tournaisian and early Visean of the Mokrá pp. 15–30 quarry allow precise dating of the deposits. The uppermost part Conil, R., Groessens, E., Pirlet, H., 1977. Nouvelle charte stratigraphique du Dinantien type de la Belgique. Annales de la Société géologique du Nord of Hády-Rícka Mbr of the Lísen Fm, including the prominent 96, 363–371. massive breccias of its top, is of late Tournaisian (MFZ 6) age. Devuyst, F.X., 2006. The Tournaisian-Visean boundary in Eurasia. Definition, The lowermost part of the overlying Brezina Fm is still biostratigraphy, sedimentology and early evolution of the genus Eoparas- Tournaisian (MFZ 7 to 8, S. anchoralis europensis conodont taffella (foraminifer). Ph.D. thesis, Catholic University of Louvain. Zone and Gnathodus interzone) and the base of the Visean Devuyst, F.X., Hance, L., Hou, H., Wu, X., Tian, S., Coen, M., Sevastopulo, G., 2003. A proposed Global Stratotype Section and Point for the base of the occurs about 9.6 m above the base of the formation (bed 13; Visean Stage (Carboniferous): the Pengchong section, Guangxi, South Fig. 4). The remaining part of the Brezina Fm covers a China. Episodes 26, 105–115. stratigraphic interval ranging from MFZ 9 to MFZ 10 (Dvorák Devuyst, F.X., Kalvoda, J., 2007. Early evolution of the genus Eoparastaffella et al., 1984). The presence of diverse Eoparastaffella and other (Foraminifera) in Eurasia: the ‘interiecta group’ and related forms, late foraminifer guides further allows increasing the resolution in Tournaisian to early Visean (Mississippian). Journal of Foraminiferal Research 37, 69–89. MFZ 8 and MFZ 9. In particular, the near-synchronous entry of Dvorák, J., Conil, R., 1969. Foraminifères du Dinantien de Moravie. Bulletin representatives of the group E. interiecta (Devuyst and de la société Belge de géologie, de paléontologie et d’hydrologie 77, Kalvoda, 2007) above the first Eoparastaffella is useful. The 75–88. uppermost part of MFZ 8 is, however, less well defined than in Dvorák, J., Friáková, O., Hladil, J., Kalvoda, J., Kukal, Z., 1987. Geology of the the Pengchong section (Devuyst, 2006), as the first Eopar- Paleozoic rocks in the vicinity of the Mokrá Cement Factory quarries. Sborník Geologicky´ch Veˇd, Geologie 42, 41–88. astaffella ex. gr. florigena and Lysella gadukensis occur Dvorák, J., Friáková, O., Kalvoda, J., Kukal, Z., Zukalová, V., 1984. Vy´voj together with the first E. simplex (rare in the early Visean of sedimentace devonu a spodního karbonu na vrtech Mokrá S 1 a S 2 v jizní Mokrá), shortly above the first E. ‘‘ovalis’’ M2, which is also a cásti Moravského krasu a jeho srovnání s okolím Hranic na Morave. Cˇ asopis guide for the base of the Visean (MFZ 9; Devuyst, 2006). The Slezského muzea Opava 33, 205–216. successive appearances of E. tumida subsp. 1 and of E. simplex Fewtrell, M.D., Ramsbottom, W.H.C., Strank, A.R.E., 1989. Chapter 3: Car- boniferous. In: Jenkins, D.G., Murray, J.W. (Eds.), Stratigraphical Atlas of simplex allow refining the biostratigraphy of MFZ 9. It is not Fossil Foraminifera. second ed. British Micropalaeontological Society known yet if these levels can be used widely but they appear to Series, Ellis Horwood Limited, Chichester, pp. 32–86. be equally useful in western Ireland at least (Oughterard Franke, W., 1989. Tectonostratigraphic units in the Variscan belt of central section; Devuyst, 2006). The conodont guide Gnathodus Europe. Geological Society of America Special Paper 230, 67–89. homopunctatus was only found with E. simplex simplex. The Hahn, R., 1967. Neue Trilobiten aus dem Kulm von Herborn und Erdbach. Senckenbergiana lethaea 48, 99–105. distribution of foraminifers and conodonts in the late Hahn, R., Hahn, G., Müller, P., 1998. Trilobiten aus den Erdbacher Kalken Tournaisian and early Visean of Mokrá is in general agreement (Unter-Karbon) von Steeden in Hessen. Geologica et Paleontologica 32, with data from other regions of Eurasia and contributes to the 161–219. J. Kalvoda et al. / Geobios 43 (2010) 317–331 331

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