The Jurassic/Cretaceous boundary and high resolution biostratigraphy of the pelagic sequences of the kurovice section (Outer Western Carpathians, the northern Tethyan margin)

GEOLOGICA CARPATHICA, APRIL 2019, 70, 2, 153–182 doi: 10.2478/geoca-2019-0009 www.geologicacarpathica.com The Jurassic/Cretaceous boundary and high resolution biostratigraphy of the pelagic sequences of the Kurovice section (Outer Western Carpathians, the northern Tethyan margin) ANDREA SVOBODOVÁ1, , LILIAN ŠVÁBENICKÁ2, DANIELA REHÁKOVÁ3, MARCELA SVOBODOVÁ1, PETR SKUPIEN4, TIIU ELBRA1 and PETR SCHNABL1 1The Czech Academy of Sciences, Institute of Geology, Rozvojová 269, 165 00 Prague, Czech Republic;  [email protected], [email protected], [email protected], [email protected] 2Czech Geological Survey, Klárov 131/3, 118 21 Prague, Czech Republic; [email protected] 3Comenius University, Faculty of Natural Sciences, Department of Geology and Paleontology, Mlynská dolina G. Ilkovičova 6, 842 15 Bratislava, Slovakia; [email protected] 4Institute of Geological Engineering, VŠB — Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; petr[email protected] (Manuscript received September 27, 2018; accepted in revised form March 12, 2019) Abstract: Microfacies and high resolution studies at the Kurovice quarry (Czech Republic, Outer Western Carpathians) on calpionellids, calcareous and non-calcareous dinoflagellate cysts, sporomorphs and calcareous nannofossils, aligned with paleomagnetism, allow construction of a detailed stratigraphy and paleoenvironmental interpretation across the Jurassic/Cretaceous (J/K) boundary. The Kurovice section consists of allodapic and micrite limestones and marlstones. Identified standard microfacies types SMF 2, SMF 3 and SMF 4 indicate that sediments were deposited on a deep shelf margin (FZ 3), with a change, later, into distal basin conditions and sediments (FZ 1). The sequence spans a stratigraphic range from the Early Tithonian calcareous dinoflagellate Malmica Zone, nannoplankton zone NJT 15 and magnetozone M 21r to the late Early Berriasian calpionellid Elliptica Subzone of the Calpionella Zone, nannoplankton NK-1 Zone and M 17r magnetozone. The J/K boundary is marked by a quantitative increase of small forms of Calpionella alpina, the base of the Alpina Subzone (that corresponds to NJT 17b and M 19n.2n) and by the rare occurrence of Nannoconus wintereri. Palynomorphs include Early Berriasian terrestrial elements — non-calcareous dinoflagellate cysts Achomo sphaera neptunii, Prolixosphaeridium sp. A and Tehamadinium evittii. The depositional area for Kurovice was situated at the margin of the NW Tethys. The influence of cold waters from northern latitudes and potential upwellings is highlighted by: 1) the high proportion of radiolarians and sponge spicules, 2) rare calpionellids represented mostly by hyaline forms, 3) the absence of microgranular calpionellids — chitinoidellids, 4) the small percentage of the genera Nannoconus, Polycostella and Conusphaera in nannofossil assemblages, as compared to other sites in Tethys, 5) scarce Nannoconus compressus, which has otherwise been mentioned from the Atlantic area. Keywords: Tithonian, Berriasian, calcareous and non-calcareous microfossils, calcareous nannofossils, palynomorphs, magnetostratigraphy. Introduction Determining the Global Boundary Stratotype Section and Point (GSSP) for the Berriasian Stage in the Tethys has been the objective of elaborate research and discussions of the Berriasian Working Group during the past several years. Tethys was the largest depositional area during Tithonian and Berriasian times that is available for study by diverse stratigraphic methods, namely lithostratigraphy, biostratigraphy (based on calpionellids, nannofossils, dinoflagellates, radiolarians, foraminifers, ammonites and belemnites), as well as by magnetostratigraphy, geochemistry and sequence stratigraphy (Andreini et al. 2007; Houša et al. 2007; Michalík et al. 2009, 2016; Casellato 2010; Lukeneder et al. 2010; Pruner et al. 2010; Grabowski et al. 2010a, b; Grabowski 2011; Michalík & Reháková 2011; Wimbledon et al. 2011, 2013; Petrova et al. 2012; Guzhikov et al. 2012; Lakova & Petrova 2013; López-Martínez et al. 2013, 2015; Schnabl et al. 2015; Svobodová & Košťák 2016; Hoedemaeker et al. 2016; Grabowski et al. 2017; Kietzmann 2017; Lakova et al. 2017; Wimbledon 2017; Elbra et al. 2018a, b, Kowal-Kasprzyk & Reháková 2019). Much research has been focused on the Jurassic/Cretaceous (J/K) boundary of the Western Carpathians (Grabowski & Pszczółkowski 2006; Grabowski et al. 2010b, 2013; Michalík et al. 2016; Skupien et al. 2016); and the Brodno section in Slovakia was chosen as a regional stratotype (Michalík et al. 1990, 2009; Houša et al. 1996, 1999). Marine strata at the locality of Kurovice were suggested as another possible J/K profile for multidisciplinary research. Reháková (in Eliáš et al. 1996) noted calpionellid zones ranging from the Late Tithonian Crassicollaria Zone to the Late Berriasian 154 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Calpionellopsis Zone. However, the J/K boundary could not then be strictly determined. Recent bed-by-bed study confirmed a similar calpionellid distribution, with a biozonation, and the J/K boundary to be precisely located (Svobodová et al. 2017; Švábenická et al. 2017; Elbra et al. 2018a). This work follows the Elbra et al. (2018a) paper, which presented the magnetostratigraphy of the Kurovice sequence, beds 1–148, compared to concise biostratigraphic data. The aim of this study is to provide detailed documentation of the biota in an extended succession (beds −29 to 148) and to compare the distribution of calpionellids, calcareous dinoflagellates, palynomorphs and calcareous nannofossils, with a focus on the biostratigraphic and paleoenvironmental interpretations. In addition, the work also includes the magnetostratigraphy of the lower part of the sequence (beds −1 to −29), which was not mentioned by Elbra et al. (2018a). Geological setting The Kurovice Quarry (49°16’25.0” N, 17°31’19.0” E; 260– 269 m a.s.l.) is located in the south-eastern part of the Czech Republic, 9 km NW from Zlín (Fig. 1). It is situated in the front of the Magura Group of nappes (Fig. 2) that represent a sig nificant regional unit of the Outer Western Carpathians (Švábenická et al. 1997; Pícha et al. 2006). In Tithonian and Berriasian times, this depositional area was situated on the nor thern margin of Tethys and was confined to the south by the Czorsztyn Ridge and the Silesian Cordillera (Golonka et al. 2006). Limestone quarrying started in Kurovice during the first half of the 18th century, and continued until 1997. In 1999, the area of the abandoned quarry was declared as a nature reserve due to its geological and paleontological significance, and for the protection of rare biota. The geological age of the quarry’s rocks described as the Kurovice Limestone (Glöckner 1841) has always been a subject of discussion. On the basis of finds of aptychi, a Jurassic age was assigned. Andrusov (1933, 1945) documented both a Jurassic and a Lower Cretaceous age for the deposits. The Kurovice Limestone is a sequence consisting of centimetreto decimetre-scale micrite limestones alternating with whitish-grey allodapic limestones, silty limestones and marlstones, deposited on a deep shelf margin passing into deposition in distal basinal conditions (Vašíček & Reháková 1994). The formation’s thickness is estimated to be approximately 120–150 m. Material and methods Samples from the Kurovice section were taken in 2016 and 2017. An almost 77 m thick sequence was recorded, numbered from −29 to 148 and sampled for paleomagnetic and geochemical research (Fig. 3). The paleomagnetic methods employed here have already been described in Elbra et al. (2018a). Calcareous nannofossils Calcareous nannofossils have been analyzed in 114 smear slides. These came from the size fraction of 1–30 µm, separated by a pro cess of decantation using 7 % solution of H2O2 (e.g., Švábenická 2012). In order to obtain the relative nannofossil abundances and semiquantitative data, 500 specimens were counted on each slide. Some samples did not provide many specimens, so the number of all nannofossils found on such slides was used as the basis for interpretation. Slides were observed under an Olympus BX51 and Nikon Microphot-FXA transmitting light microscopes with immersion objectives of ×100 magnifications. The identifications of species follow Bralower et al. (1989), Bown & Cooper (1989, 1998), Bown et al. (1998), Casellato (2010), and Nannotax website (Young et al. 2013); and biostratigraphic data were interpreted with reference to the nannofossil zonation of Casellato (2010). The smear slides are stored at the Institute of Geology of the Czech Academy of Sciences, v.v.i. (Department of Paleobiology and Paleoecology) and at the Czech Geological Survey in Prague. Fig. 1. Simplified geological map of the Outer Western Carpathians. The Kurovice section is marked with an arrow. 1 — Bohemian Massif, 2 — Carpathian Foredeep, 3 — Vienna Basin, 4 — Žďánice-Subsilesian Unit, 5 — Silesian Unit, 6 — Fore magura Unit, 7 — Magura Group of Nappes, 8 — Outer Klippen Belt, 9 — Inner Klippen Belt. Simplified after Švábenická (2012). 155J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Microfacies, calcareous dinoflagellates and calpionellids Microfacies and calcareous microfossils — calpionellids and calcareous dinoflagellates were studied in 220 thin sections under a Leica DM 2500 transmitting light microscope and documented by the Axiocam ERc 5s camera in the Department of Geology and Paleontology, Comenius University in Bratislava. The standard calpionellid zones of Remane et al. (1986) and Reháková & Michalík (1997) and calcareous dinoflagellate succession of Nowak (1968) and Reháková (2000) were applied. Carbonate rocks were classified according to the Folk (1959) and Dunham (1962) schemes. Standard microfacies types (SMFs) and facies zones (FZs) were determined following Wilson (1975) and Flügel (2004). Palynomorphs A total of 24 samples were processed to concentrate the resistant palynological component using standard maceration techniques, including treatment with hydrochloric (HCl) and hydrofluoric (HF) acids to remove carbonates and silicates. The remaining inorganic fraction was removed by acetolysis and HNO3. Due to the rare appearance of palynomorphs, sieving was not used. The palynofacies analysis and photodocumentation were carried out using Leica DM 2500 optical microscope (software Leica IM 50) with magnifications of 200 –1000× (MS), and by Olympus BX60 optical microscope, SW NIS-Elements 3.1. The formalized non-calcareous dinoflagellate taxa are fully referenced in Fensome & Williams (2004) and Fensome et al. (2009). The palynological slides are stored in the Department of Paleobiology and Paleoecology of the Institute of Geology of the Czech Academy of Sciences, and Institute of Geological Engineering VŠB — Technical University Ostrava. Results Calcareous nannofossils In samples from Kurovice, calcareous nannofossils are usually poorly preserved. Overgrowth and etching are extensive, making identification of some specimens difficult. Generally, nannofossil assemblages are characterized by the dominance of ellipsagelosphae rids, making up more than 90 % of spe cimens. The genera Conusphaera, Nannoconus and Polycostella are found in small numbers (Fig. 4). Other nannoliths and placoiths are rare, fragmented and often cannot be identified. Fig. 2. Probable paleogeographic position of the depositional area (Kurovice section marked by the red dot). After Michalík 2011, modified. Legend: white — dry land; light gray — epicontinental sea; gray — marine basins; bricks — carbonate platforms and basins; dark gray — oceanic bottom). Fig. 3. The profile in the Kurovice quarry. A — location of the J–K boundary marked with black line. B — a detailed view of the middle part of the section. 156 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 4. Percentage share of selected nannofossil genera in the assemblages across the Kurovice section. Lithology after M. Bubík in Košťák et al. (2018), nannofossil zones (CNZ) by Casellato (2010). 157J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Calcarenites contain extremely poor nannofossil associations (Fig. 5A). Scarce nannofossil fragments (1–3 specimens per 10 fields of view of the microscope, FOM) are represented almost exclusively by ellipsagelosphaerids. Watznaueria div. spec. may total up to 80 % and Cyclagelosphaera margerelii up to 11 % of nannofossil assemblage. Micrite limestones contain poorly preserved nannofossils with abundance ±1 up to 10 specimens per 1 FOM (Fig. 5B). The associations comprise numerous specimens of the genera Watznaueria (Fig. 6S–AB) and Cyclagelosphaera (Fig. 6AC–AH) accompanied by rare specimens of Conusphaera (C. mexicana mexicana, C. mexicana minor, Conusphaera sp. 1), Polycostella beckmannii, Nannoconus spp., Zeugrhabdotus (Z. embergeri, Z. cooperi), and fragments of outer rims of the genera Retecapsa and Helenea. Specimens of W. barnesiae may comprise 70 % and C. margerelii up to 13 %. Marlstone interbeds contain highly abundant (10–20 up to ±50 specimens per FOM and more) diversified nannofossil assemblages (Fig. 5C). Although ellipsagelosphaerids still predominate quantitatively, abundances of Watznaueria species (W. manivitiae, W. fossacincta, W. britannica, W. communis, W. cynthae, W. ovata) and Cyclagelosphaera (C. deflandrei, C. argoensis) increase. Specimens of genera Conusphaera (Fig. 7I–P), Nannoconus (Fig. 7S–AJ), Polycostella (Fig. 7Q, R), Retecapsa (Fig. 6O, P), Helenea (Fig. 6A–D), Diazomatolithus (Fig. 7B), Zeugrhabdotus (Fig. 6I–L), Hexalithus (Fig. 7E, F) are present in higher quantities than in calcarenites and micrite limestones. Generally, the composition of calcareous nannofossil assemblage in the studied material corresponds to the Tithonian and Early Berriasian age, compared with the previous studies (e.g., Michalík et al. 2009; Casellato 2010; Lukeneder et al. 2010; Svobodová & Košťák 2016). Selected calcareous nannofossil taxa are presented in Figs. 6 and 7. The distribution of all nannofossil species is shown in Table 1, and a list of calca reous nannofossil taxa is given in Appendix. Microfacies, calcareous dinoflagellates and calpionellids The deposits contain selected bioclasts and allochems, such as calpionellids, radiolarians, globochaetes, saccocomids, filaments, fragments of benthic organisms, quartz and lithoclasts. Calpionellids are generally rare and hyaline forms dominate. Calpionellids are not well preserved. Gradually in the overlying beds, they exhibit loricae with thinned walls, which are often damaged or have poorly preserved collars. Through the section, calcified radiolarians and sponge spicules determine the prevailing type of spiculite-radiolarian and radiolarian–spiculite microfacies. In the lowermost part of the section, cysts of dinoflagellates and crinoid fragments are locally a significant part of fossil assemblages. Microgranular chitinoidellid loricae were not found. On the basis of microfacies, calcareous dinoflagellate and calpionellid development, the Kuro vice succession is divided into several intervals (from the bottom to the top): Beds −29 to −7 (~0 –7.7 m): Marly and slightly laminated, locally bioturbated limestones (mudstones), in some places with thin layers and laminae rich in a silt admixture and silt-sized fragments of lithoand bioclasts, locally also siltstones. Further, biomicritic slightly bioturbated limestone of Fig. 5. Kurovice section, abundance of nannofossils in the particular types of rock. Fields of views in the microscope. A — calcarenite; B — micrite limestone; C — marlstone. 158 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 6. Kurovice section, calcareous nannofossils, Heterococcoliths. Photographs in cross polarized light, figures E, G, AE and AG in plane polarized light. A, B — Helenea staurolithina: A — sample 1t, B — sample 5b; C, D — Helenea chiastia, C — sample 142s, D — sample 107; E, F — Rhagodiscus nebulosus, sample 145; G, H — Umbria granulosa minor (fragment), sample 100 marlstone; I, J – Zeugrhabdotus fluxus, sample −6; K — Zeugrhabdotus cooperi, sample 1t; L — Zeugrhabdotus embergerii, sample 142s; M — Pickelhaube furtiva, sample 8/9; N — Biscutum ellipticum, sample 133/134; O — Retacapsa surirella, sample 132; P — Retacapsa cf. octofenestrata, sample 133/134; Q, R — Speetonia colligata (specimen in 0o and 30o), sample 133/134; S — Watznaueria barnesiae, sample 1t; T — Watznaueria communis, sample 94; U — Watznaueria fossacincta, sample 105b; V, W — Watznaueria britannica: V — sample 1t, W — sample 144s; X — Watznaueria ovata, sample 111/112; Y — Watznaueria biporta, sample 30; Z, AA — Watznaueria cynthae: Z — sample 46, AA — sample 142s; AB — Watznaueria manivitiae, sample 132; AC, AD — Cyclagelosphaera margerelii: AC — sample 9, AD — sample 1t, small specimen; AE, AF — Cyclagelosphaera deflandrei, sample 9; AG, AH — Cyclagelosphaera argoensis, sample 1t; AI — Parhabdolithus cf. robustus, sample 5b, reworked specimen from the older Jurassic strata; AJ — Parhabdolithus marthae, sample 89, reworked specimen from the older Jurassic strata. 159J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 7. Kurovice section, calcareous nannofossils, Nannoliths including Eoconusphaeraceae, Nannoconaceae and uncertain “polycycloliths”. Photographs in cross polarized light, D, E, G, I, J, Q, S, U, W, X, Z, AA, AC, AF and AG in plane polarized light. A — Lithraphidites carniolensis, sample 142 s; B — Diazomatolithus lehmanii, sample 1t; C — Rotelapillus crenulatus, sample 133/134; D — pentalith, sample 8/9; E, F — Hexalithus noeliae, sample 100 limestone; G, H — Assipetra infracretacea, sample 138; I–L — Conusphaera sp.: I–K — sample 103 (specimen in 0o and 30o), L — sample 1a; M, N — Conusphaera mexicana mexicana, sample 69 (specimen in 0o and 30o); O — Conusphaera mexicana minor, sample 1t (specimen in 0o); P — Conusphaera mexicana minor, sample 1t (specimen exceeding the size of 4 µ), cf.; Q, R — Polycostella beckmanii, sample 5b; S, T — Nannoconus sp., sample 1t; U, V — Nannoconus puer, sample 5b; W — Nannoconus compressus, sample 133/134, reworked specimen; X — Nannoconus globulus minor, sample 75; Y, Z — Nannoconus globulus globulus, sample 132; AA, AB — Nannoconus wintereri, sample 100 limestone; AC, AD — Nannoconus wintereri, sample 100 limestone (probably early form of N. wintereri), cf.; AE, AF — Nannoconus steinmannii minor, sample 145; AG, AH — Nannoconus kamptneri minor, sample 133/134; AI, AJ — Nannoconus kamptneri kamptneri, sample 124. 160 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Chronostratigraphy Zonation (Casellato 2010) Sample No. Nannofossil abundance Nannofossil preservation Assipetra infracretacea Biscutum ellipticum Conusphaera mexicana mexicana Conusphaera mexicana minor Conusphaera sp. 1 Cretarhabdus sp. Cruciellipcis cuvillieri Cyclagelosphaera argoensis Cyclagelosphaera deflandrei Cyclagelosphaera margereli Cyclagelosphaera reinhardtii Diazomatolithus lehmanii Discorhabdus cf. ignotus Ethmorhabdus gallicus Ethmorhabdus hauterivianus Favioconus multicolumnatus Helenea chiastia Helenea staurolithina Hexalithus noeliae Hexalithus strictus Lithraphidites carniolensis Lotharingius hauffii Lotharingius sigillatus Manivitella pemmatoidea Micrantholithus sp. Miravestina favula Nannoconus colomi Nannoconus compressus Nannoconus erbae Nannoconus globulus globulus Nannoconus globulus minor Nannoconus infans Nannoconus kamptneri kamptneri Nannoconus kamptneri minor Nannoconus puer Nannoconus steinmannii minor Nannoconus st. steinmannii B e r r i a s i a n NK-1 148 VL EP VR R F ER ER ER 147 b VL EP ? ER VR VR VR ? VR ER ER 145 L VP ? VR ER ER VR R R-F VR ER ER ER ER ER 144 s VL VP ER VR R ER ER ER ? ER 143 b VL EP VR ER ER R R-F VR 142 s L-M P R VR ER VR VR R ? f ? VR 140 EL VP VR VR R VR ?ER ?r ?r ?f ER ER 138 L-M VP ER R VR ER ER R R ER ER 136 EL EP ER ?f fER ER VR ?f ?F 135 L VP R VR VR VR R-F VR 133/134 VL VP ER VR ER ER ?f ER VR VR ? VR ER ER ER ER ER ER ER 132 M P ER ER VR R R ER ER ?f ER 131 VL EP R ER ER R R-F ?ER ER 130 t L-M VP VR ER fVR VR R ER ER ?f ER ER 129 VL EP R VR VR ER R R ER ?ER ER ER 128 EL EP ?ER VR VR VR R R-F ER ER ?ER ER ?ER 127 VL VP VR ER ER VR R ?r ER 126 L P R ER ER ER VR R ? 124 VL VP ?ER VR VR ER ?f VR R ER ER ER ER ER NKT ZONE 122 VL EP VR ER ER ER R F ER ?ER 120 M P R VR ER R F ER ER ?ER 118 M P ?ER R VR VR R F ER ER ER ?ER ER 116 VL VP VR ER ER R F ER ER 114 L-M VP R ER ?ER R F ?ER ER 112 L VP R VR ER R R-F ER ER 111/112 M P R ? R R-F ER f? 110 VL EP R VR VR ER R F ER r ER 109 L VP VR ER ER R R ER ER 107 VL VP ER ER ER 106 t VL VP R VR ER ER R F ER ER 106 b L VP VR VR R F VR ER ER 105 s EL VP VR ER ER R R ER ER 105 b L VP ER R R ER ER ER f 103 L VP VR VR VR R ER ER 102 VL VP R VR ER ER R R ER ER ER ER 101 t L VP R VR R R-F ER VR ER ER 101 y VL VP R VR R R ER ER ?ER ER 101 x L VP R VR ER VR R R-F ER ER ?ER 101 b L VP R VR ER VR R C VR ER ER 100 lime EL EP ER ER VR ER ER f 100 marl L P ER ER VR R-F f? ER 99 t EL EP ER R VR R F ER ER ER 99 b EL EP ER R VR ER R R ER VR ER 98 EL EP ER ER R F-C ER ER 97 VL EP ER R VR R F ER ER r VR ER ?ER 96 VL EP R VR ER R F ER ER ER 95 t EL EP VR ER R C ER ER 95 L VP ER ER R ER f ER 95 b VL VP R VR ER R F ER VR ER ER 94 L VP R R R F-C ER ?ER 93 VL VP R VR R F ER ER ER 92 t VL EP ER R VR R F ER ER ER ER ER Table 1a: Distribution of calcareous nannofossils in the Kurovice section. Semi-quantitative data as follows. Nannofossil abundance: EL (extremely low = 1–10 specimens per 20 FOM); VL (very low = 1–10 specimens per 10 FOM); L (low = 1–10 specimens per FOM); M (moderately = 10–40 specimens per FOM). Nannofossil total abundance: A (abundant = >5 specimens per FOM); C (common = 1–5 specimens per FOM); F (few = >1 specimen per FOM); R (rare = 0–1 specimen per FOM); VR (very rare = <5 specimens per sample); ER (extremely rare = 1–2 specimens per sample). Nannofossil preservation: EP (extremely poor = strong etching and overgrowth); VP (very poor = strong dissolution); P (poor = moderate etching). Nannofossil zones follow Casellato (2010); r = reworked; ? = uncertain specimen; f = fragment. Stratigraphically significant taxa marked with grey colour. 161J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Chronostratigraphy Zonation (Casellato 2010) Sample No. Nannofossil abundance Nannofossil preservation Assipetra infracretacea Biscutum ellipticum Conusphaera mexicana mexicana Conusphaera mexicana minor Conusphaera sp. 1 Cretarhabdus sp. Cruciellipcis cuvillieri Cyclagelosphaera argoensis Cyclagelosphaera deflandrei Cyclagelosphaera margereli Cyclagelosphaera reinhardtii Diazomatolithus lehmanii Discorhabdus cf. ignotus Ethmorhabdus gallicus Ethmorhabdus hauterivianus Favioconus multicolumnatus Helenea chiastia Helenea staurolithina Hexalithus noeliae Hexalithus strictus Lithraphidites carniolensis Lotharingius hauffii Lotharingius sigillatus Manivitella pemmatoidea Micrantholithus sp. Miravestina favula Nannoconus colomi Nannoconus compressus Nannoconus erbae Nannoconus globulus globulus Nannoconus globulus minor Nannoconus infans Nannoconus kamptneri kamptneri Nannoconus kamptneri minor Nannoconus puer Nannoconus steinmannii minor Nannoconus st. steinmannii Berriasian NJT 17 Zone NJT 17b Subzone 92 b VL VP RER ER ER ER R R ER ?ER rER ER 91 VL EP R VR ER ?ER RR-F ER 90 L P R VR ?ER ER RR-F ER ER ?r ER 89 VL VP ?ER RVR ER R R ER ER r 88 L VP ?ER RER ?ER R F ER ?ER ER 87 EL EP ?ER RVR ?ER R R ?ER ?r 86/87 EL EP ER RVR ER VR R R ER VR 86 VL EP R R ER RR-F ER ?r ER T i t h o n i a n 85/86 VL EP R VR ER RR-F VR ?ER ER 85 VL EP ER RVR VR ER FER ER ER 84 VL EP R VR ER RR-F ER ER 82 VL EP ER VR VR ER R C ER ER ?r 81 VL P ER RVR ER R F ER ER ER ?ER 79/80 VL VP ?ER?ER RER ER R F ER NJT 17a Subzone 79 VL VP R ER R F ER ER 78 VL EP ER fER ER RER 75 EL EP R VR ER RR-F ER ER 71/72 EL EP R VR ER R F VR 70 t VL VP ER VR RER f?r ?ER ER 69 EL EP R VR R F ER ?ER ER ?r 66/67 EL VP R VR ?ER R F VR ER ER ?ER 66 t L VP R ER Rf? 66 VL EP ER R 60 L VP ?ER VR VR R R ER ?ER ER ER 55 VL EP VR ER R F ER NJT 16 Zone 52/52 M VP ?ER VR VR ER R R ER ER ?ER 50/51 VL EP ? VR R 46 L EP ? ER fER ER R R ?ER ER ? 44 t VL EP ER ?ER ER RER ER ER 43 L EP ?ER VR R R ER ? 42/43 L EP ER RER f 40 b VL EP ER VR R ? 36 L EP VR ER VR VR R 30 H VP ?ER RER fER R F ER 29 EL EP ER ER VR 24/25 L-M P ER VR R-F ER ?ER 20/21 L EP VR ER VR R-F 20 L EP fER fER R 14 t M P R ER ER R F VR ER ?ER 13 L EP ER ER R 9 L-M VP VR ER ER VR F ? 8/9 L P ?ER ER R F VR ER ER 5 b M P VR VR VR FER VR VR ER 3 L EP ER ER ER RER f? 1 t VH P VR RfER VR R F ER ER fER f? ?ER ER fER ?VR NJT 15 Zone NJT 15b Sbz -1 L-M P ER ER ER R R -2 L-M P ER R F ER -3 L-M P ER VR ER VR FER ER -6 L P ER VR RER -7 L VP VR ER ER ER R -8 L-M VP ER ER ER VR F -11 L-M P VR ER ER VR F -13 L P R VR ER VR FER -16 L P R ER ER ER VR R-F ER ER ? ? -17 L-M P VR ER ER VR R-F -19 L VP ER RER ER ERE VR RER ER -20 VL VP VR ER ER ER RER -21 L P R ER ER ER RER -26 EL EP VR ER ER RER -28 VL EP VR RER ER -29 t VL EP VR VR ER -29 L VP VR VR RER ER ER Table 1b (continued): 168 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 S. orbifera and S. silybum, the acritarch Micrhystridium sp., a prasinophyte alga Pterospermella helios, spores of the fern Cyathidites minor, and gymnosperm Classopollis torosus pollen. The palynospectrum corresponds to the Tithonian age. Sample 30a: frequent phytoclasts of brown and black colour with broken non-calcareous dinoflagellate cysts, namely: Gonyaulacysta sp., Gochteodinia cf. virgula, Ctenidodinium ornatum, Pareodinia sp., the acritarch Micrhystridium stellatum, Veryhachium irregulare, and pollen of Classopollis torosus — often present in tetrads. Sample 49: frequent phytoclasts of brown and black colour with a rich assemblage of non-calcareous dinoflagellate cysts similar to associations in the underlying strata and, additionally, Cribroperidinium globatum, C. sarjeantii, Pareodinia robusta, Gonyaulacysta helicoidea, Hystrichodinium pulchrum, Neuffenia willei, Oligosphaeridium pulcherrimum, Sentu - sidinium sp., Stiphrosphaeridium dictyophorum, Systematophora areolata, and Tanyosphaeridium isocalamum. Sporadic Micrhys tridium sp. and gymnosperm pollen, Classopollis torosus, also occur. Sample 50: common phytoclasts of brown and black colour, tracheids of Pinaceae, non-calcareous dinoflagellate cysts, namely: Dingodinium tuberosum, Oligosphaeridium aff. patulum, Chytroeisphaeridia chytroeides, Jansonia sp., isolated opercula of Cribroperidinium sp. and Wallodinium sp., linings of planispiral agglutinated foraminifers, the acritarch Micrhystridium sp., Leiosphaeridia sp., Pterospermella australiensis, pteridophyte spores Gleicheniidites senonicus, Neoraistrickia truncata, Lycopodiumsporites sp., Poly cingulatisporites and Classopollis torosus, Spheripollenites subgra nulatus. The palynospectrum corresponds to the Tithonian age. Sample 85: abundant black phytoclasts with Micrhystridium sp., and the prasinophyte alga Pterospermella. Dinocyst association is similar to underlying strata. Sample 105: brown and black phytoclasts and radiolarian remains. Non-calcareous dinocysts are represented both by species derived from underlying strata and by in situ taxa Dissiliodinium giganteum, Prolixosphaeridium deirense, Prolixosphaeridium sp. A sensu Monteil (1993), and Tehamadinium evittii. Sample 111/112: abundant black phytoclasts, amorphous organic matter, broken radiolarian tests, linings of agglutinated foraminifers, rich dinoflagellate cyst association with species known from the underlying strata as well as Achomosphaera neptuni, Circulodinium vermiculatum, Dapsilidinium multispinosum, Endoscrinium campanula, E. cf. pharo, Gonyaulacysta sp., Kiokansium polypes, P. anasillum, and Classopollis torosus. The palynospectrum corresponds to the Berriasian age with the redeposition of Jurassic species. Sample 132: brown and black phytoclasts, radiolarian remnants, non-calcareous dinocysts similar to the assemblages of the underlying strata with new taxa Cyclonephelium hystrix, Spiniferites sp. and Sirmidiniopsis sp. An admixture of continental pteridophyte spores (Echinatisporites sp.) and gymnosperm pollen (Classopollis torosus and Cerebropollenites macroverrucosus) is subsidiary. It corresponds to the Berria sian age with the redeposition of Jurassic species. Sample 132/133: abundant black phytoclasts, non-calcareous dinoflagellate cysts Circulodinium sp., Dichadogonyaulax bensonii, Endoscrinium campanula, Gonyaulacysta sp., Leptodinium sp., Oligosphaeridium asterigerum and Prolixosphaeridium granulosum. Pteridophyte spores Densoisporites velatus, Gleicheniidites sp. and conifers of Classopollis torosus is subsidiary. It corresponds to the Berriasian age with the redeposition of Jurassic species. Selected palynomorphs are shown in Figures 14 and 15. Biostratigraphy Despite the poor preservation, microorganisms provide important data that help us to detect the Jurassic/Cretaceous boundary at Kurovice. According to the calcareous dinoflagellate cyst and calpionellid zonations (sensu Reháková 2000; Reháková & Michalík 1997) the section spans the interval from the Early Tithonian cyst Malmica Zone up to the Early Berriasian Calpionella Zone, Elliptica Subzone (Figs. 11, 12, 16). Nannofossils confirm this stratigraphic interpretation, with a zonal range from NJT 15b up to NK-1 (zones of Casellato 2010; Bralower et al. 1989). The following calcareous dinocyst and calpionellid zones compared to nannofossil events were identified: The calcareous dinocyst Malmica Zone (Nowak 1968), early Early Tithonian was established in the lowermost part of the sequence (samples −29 to −7; ~0–7.7 m) by the presence of Parastomiosphaera malmica. Nannofossil assemblages contain Polycostella beckmanii and are assigned to the NJT 15b Nannofossil Subzone. The first, questionable, small nannoconids were found in sample −16 (Table 1b). The following calcareous dinoflagellate and calpionellid zones were previously mentioned by Elbra et al. (2018a): The Semiradiata Zone (Reháková 2000), Early Tithonian (samples −6 to 35; ~7.7–35.5 m; Elbra et al. 2018a) was recognized based on the abundance of the cysts Cadosina semiradiata semiradiata and C. semiradiata fusca. The first occurrence (FO) of Helenea chiastia (NJT 16 Nannofossil Zone) was recorded immediately above the base of the Semiradiata Zone in sample 3. The Tenuis-Fortis Zone, early Late Tithonian (samples 36–42, ~35.5–37.65 m). It was not possible to strictly separate the Tenuis from the Fortis zones (Řehánek 1992) because of the absence of Colomisphaera tenuis. Only one specimen of Colomisphaera sp. was found in sample 20. Reháková (2000) assumed that the Fortis Zone coincided with the disappearance of chitinoidellids and their substitution by the first transitional hyaline–microgranular calpionellids of the Praetintinnopsella Zone. A single lorica of Praetintinnopsella andrusovi was found in the sample 42/43, but in the overlying Crassicollaria Zone. This phenomenon confirms the opinion of Reháková (2000). 169J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 10. Kurovice section, calpionellids. A — Crassicollaria massutinianna, sample 100; B — Calpionella grandalpina, sample 101b; C — Calpionella elliptalpina, sample 88; D — Calpionella sp., sample 125; E — Lorenziella hungarica, sample 124; F — Remaniella duranddelgai, sample 132; G — Remaniella borzai, sample 120; H — Remaniella colomi, sample 125; I — Remaniella ferasini, sample 127; J — Calpionella elliptica, sample 133; K — Calpionella elliptica, sample 134; L — Tintinopsella carpathica, sample 139. 170 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 11. Kurovice section, lithology and vertical distribution of calpionellids and calcareous dinoflagellate cysts. TFZ — Tenuis–Fortis Zone; R Sbz — Remanei Subzone; CrZ — Crassicollaria Zone. Open circles indicate reworked specimens. Lithology after M. Bubík in Košťák et al. (2018). Calpionellid zones after Reháková & Michalík (1997), cyst zones sensu Reháková (2000). 171J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 12. Kurovice section, lithology and vertical distribution of calpionellids and calcareous dinoflagellate cysts. Open circles indicate reworked specimens. Lithology after M. Bubík in Košťák et al. (2018). Calpionellid zones after Reháková & Michalík (1997), cyst zones sensu Reháková (2000). 172 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 The Crassicollaria Zone (Remane et al. 1986), early to late Late Tithonian (samples 42/43–84, ~37.65–51.9 m) is subdivided into three subzones: The Remanei Subzone (Remane et al. 1986) (samples 42/43 –51/52; ~37.65–42.9 m) is identified by very rare calpionellids Tintinnopsella remanei and Crassicollaria intermedia, followed by rare C. massutiniana, C. parvula and Calpionella alpina. The Intermedia Subzone (Remane et al. 1986) (samples 52–70; ~42.9–48.25 m) is clearly recognizable by a frequent and more diversified association with Calpionella alpina, C. grandalpina, C. elliptalpina, Crassicollaria intermedia, C. massutiniana, C. parvula, C. brevis, and Tintinnopsella carpathica. In the lower part of this interval (sample 55) is the FO of Nannoconus globulus minor, so that the base of the NJT 17a Nannofossil Subzone is recorded (Fig. 16). Just above this bioevent, the last occurrence of Polycostella beckmannii was identified. The Colomi Subzone (Pop 1994) (samples 70/71–84; ~48.25–51.9 m) is characterized by the dominance of Crassicollaria parvula, associated with scarce C. colomi and other deformed crassicollarians. Larger forms of Calpionella grandalpina and C. elliptalpina show rapid quantitative decline. The FO of Nannoconus wintereri was found in the upper part of this interval in sample 79/80. This bioevent defines the base of the NJT 17b Subzone which has a short stratigraphic interval spanning the uppermost Tithonian (Casellato 2010). The overlying bed, unit 81, yielded the first Nannoconus globulus globulus. The Calpionella Zone, Early Berriasian in age, is here subdivided again into three subzones. The Alpina Subzone (sensu Pop 1974; Remane et al. 1986) was first detected in the sample 85/86 and its top was recorded in sample 118; spanning the interval from ~51.9 m to 68.5 m with disappearance of large Calpionella species and domination of small spherical specimens of Calpionella alpina (Calpionella alpina event sensu Kowal-Kasprzyk & Reháková 2019). The species Crassicollaria parvula and Tintinnopsella carpathica are very rare. The base of the calcareous nannofossil NKT Zone is marked by the FO of Nannoconus steinmannii minor in sample 92. The Ferasini Subzone (Remane et al. 1986), Early Berriasian in age (samples 119–131; ~68.5–71.8 m) is distinguished by a decrease in the number of calpionellids. The Rema niella ferasini was not recorded in sample 119, so, the base of the bio zone is fixed on the FO of R. duranddelgai (sample 119) and the appearance of other remaniellids. The FO of Nanno conus kamptneri kamptneri (NK-1 Zone) occurs in sample 124. The Elliptica Subzone (Pop 1974), late Early Berriasian (samples 132–148; ~71.8–76.7 m) was established on the presence of Calpionella elliptica accompanied by rare specimens of the genera Calpionella, Remaniella, Tintinnopsella and Lorenziella. The FO of Speetonia colligata was registered in sample 133/134. The species Nannoconus infans, N. kamptneri minor and N. steinmannii steinmannii appear sporadically in the limestone sediments at Kurovice, and for this reason their first occurrences are not used in our stratigraphic interpretations (Table 1). The above-mentioned stratigraphic data are reinforced by that provided by palynomorphs. The non-calcareous dinoflagellate cysts Amphorula metaelliptica, Dingodinium tuberosum, Systematophora areolata, and S. silybum support a Tithonian age for sample 30a, the uppermost part of the Semiradiata Zone, and for sample 50 — an assignment to the Remanei Subzone. Dinoflagellate cysts of Berriasian age — Achomosphaera neptunii, Prolixosphaeridium sp. A and Tehamamadinium evittii — were recorded in samples 105 and 111/112 in the Alpina Subzone and in the samples 132 and 132/133 in the Elliptica Subzone. Prolixosphaeridium sp. A (sample 105) is mentioned by Monteil (in Stover et al. 1996) within the ammonite Jacobi Subzone (within the calpionellid Alpina Subzone) of the Early Berriasian. According to Leereveld (1995), the FO of Achomosphaera neptunii (sample 111/112) is connected to the late Early Berriasian (uppermost part of the Jacobi ammonite Zone; calpionellid Elliptica Subzone; Reboulet et al. 2014, Wimbledon 2017) along with the FO of Dichadogonyaulax bensonii (sample 132/133). Monteil (1992, 1993) correlates the FOs of both species in the Berriasian type section with the late Early Berriasian, the uppermost part of the Alpina Subzone, respectively. Monteil (1993) and Hunt (2004) combine the first occurrences of the D. bensonii, Endoscrinium campanula (sample 111/112) and Tehamadinium evittii (sample 105) as key range bases for correlation with the ammonite Grandis Subzone (upper Jacobi Zone) and Subalpina subzone (that is lowest Occitanica Zone). The similar relative age is indicated by calpionellids and nannofossils. Paleoecology According to Elbra et al. (2018a), the sediments at Kurovice were deposited on the continental slope during the Late Tithonian–Early Berriasian. The section is characterized by distal limestone sediments with sporadic turbidites. Košťák et al. (2018) supposed tsunami deposition/influence which might explain the presence of debris in the abyssal environment. Pelagic sediments are characterized by the large proportion of calcareous and siliceous marine microplankton which predominates over the turbidity material. These statements are in line with microfacies analyses (see above). The interpretation of the deposits as the standard microfacies types SMF 2, SMF 3 and SMF 4 indicates deposition on a deep shelf margin within facies zone FZ 3, changing into a basinal environment in its later/upper part, facies zone FZ 1 (Wilson 1975). Sedimentation occurred under the influence of enhanced water dynamics, which affected nutrient supply and caused the periodical erosion and redeposition of older rocks. The nutrient supply is here demonstrated by the quantitative predominance of radiolarians and sponge spicules. Calpionellids are generally rare and they are represented almost exclusively by 173J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 hyaline species, which first appear in the Late Tithonian. The absence of typical microgranular chitinoidellids from the late Early Tithonian and the early Late Tithonian can be explained by the dominant presence of radiolarians. These microorganisms with silica tests preferred conditions rich in nutrients, something not suitable for calpionellids, and their development was probably inhibited. The location of the depositional area on the northern margin of Tethys (Golonka et al. 2006) and the possible influence of incoming northern waters can also not be ignored. The nannoconids Conusphaera and Polycostella beckmannii are referred to as predominantly Tethyan taxa (Bown & Cooper 1998; Bown et al. 1998). Other nannofossils that confirm the Tethyan province are randomly found — Watznaueria manivitiae, Zeugrhabdotus embergeri, Cruciellipsis cuvillieri, and Speetonia colligata (Bown & Cooper 1998; Bown et al. 1998). The small percentage of these taxa found in our study may be explained by the paleogeographic location on the margin of Tethys (Golonka et al. 2006; Svobodová et al. 2018). This region could have been affected by cold waters from Fig. 13. Kurovice section, lithology and vertical distribution of palynomorfs and non-calcareous cysts. Reworked specimens marked with dashed line. Lithology after M. Bubík in Košťák et al. (2018). 174 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 14. Kurovice section, palynomorphs. Scale bar 10 µm. A–F, L–N, P sample 50 middle, G–K, O sample 132. A — Dingodinium tuberosum; B — aff. Oligosphaeridium patulum; C — Ctenidodinium ornatum; D — Chytroeisphaeridia chytroeides; E — Jansonia sp.; F — Pterospermella australiensis; G — Tanyosphaeridium isocalamum; H — radiolarian remnant; I — Circulodinium distinctum; J — Gonyaulacysta cf. helicoidea; K — Cribroperidinium sp., fragment; L — Gleicheniidites senonicus; M — Neoraistrickia sp.; N — Classopollis torosus; O — Densoisporites velatus; P — Corollina sp. 175J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Subboreal regions, such as the Russian Platform. The influence from higher latitudes might also be shown by the scarce presence of Nannoconus compressus (Fig. 7Y) mentioned in the Atlantic Ocean (Bralower et al. 1989; Casellato 2010). Stoykova et al. (2018) mentioned N. compressus from the SW Bulgaria, and Halásová in Bakhmutov et al. (2018) from the Crimea (southern Ukraine). The question remains whether these areas were also under marine influence from the north. Significantly higher percentages of nannoconids (up to 20 % in the Berriasian), conusphers (up to 50 % in the Late Tithonian and 20–40 % in the Early Berriasian) and P. beckmannii (up to 20–30 % in Late Tithonian) are mentioned in Fig. 15. Kurovice section, non-calcareous dinoflagellate cysts. Scale bar 10 μm. A–F sample 49 middle, G–J sample 105, K–M sample 111/112, N–P sample 132/133. A — Systematophora daveyi; B — Cometodinium habibii; C — Stiphrosphaeridium dictyophorum, archeopyle; D — Systematophora orbifera; E — Pareodinia robusta; F — Gonyaulacysta helicoidea; H — Lithodinia sp.; K — Prolixosphaeridium anasillum; L — Prolixosphaeridium sp. A sensu Monteil (1993); M — Endoscrinium campanula; N — Systematophora areolata; O — Prolixosphaeridium granulosum; P — Dichadogonyaulax bensonii. 176 SVOBODOVÁ, ŠVÁBENICKÁ, REHÁKOVÁ, SVOBODOVÁ, SKUPIEN, ELBRA and SCHNABL GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Michalík et al. (2016) from the Pienniny Klippen Belt. Similar nannofossil percentages were mentioned by Svobodová & Košťák (2016) from further west in Tethys, on the southern passive margin of the Iberian Plate. The occurrence of non-calcareous cavate cysts of Dingodinium, proximate cysts of Cribroperidinium, rare chorate cysts, and the frequent presence of agglutinated microforaminiferal linings indicate a shallow sea and probably reworking of terrestrial, brackish and shallow-water species into a deeper marine environment. Reworking is documented by the high diversity of Systematophora species, which characterize a littoral environment. Prasinophyte algae and acritarchs are known from the brackish to shallow marine conditions (Batten 1996). They could have been flushed into the shallow sea and continuously transported into the deeper water. Discussion Compared to most localities in Tethys, small differences in calpionellid succession are evident. Chitinoidellids, the first calpionellid representatives have not been recorded (Svobodová et al. 2018). Their absence may be explained by the blooming of siliceous microorganisms which probably suppressed chitinoidellids. This phenomenon could also have been associated with cold water influence at the margin of Tethys. The calcareous dinoflagellate Malmica Zone corresponds in the Kurovice sequence to magnetozone M 21r, as at Brodno (Central Western Carpathians; Michalík et al. 2009) and Lokút (Transdanubian range; Grabowski et al. 2010a, 2017). Even though aragonite shells did not survive sedimentation and early diagenesis of Kurovice limestones, magnetozones M 20r to M 17r in the upper part of the section may also be used to approximate the ammonite zones from Micracanthoceras microcanthum to Subthurmannia occitanica in the Vocontian Basin (Wimbledon et al. 2013; Frau et al. 2016a, b, c; Elbra et al. 2018b). Nannofossil events and their stratigraphic correlations in the J/K boundary interval are more or less comparable with the other localities in Tethys. The first occurrence (FO) of Nannoconus globulus minor is situated in magnetozone M 19r and the Intermedia Subzone, as at Puerto Escaño (Svobodová & Košťák 2016). The last occurrence (LO) of Polycostella beckmannii was recorded in the lower part of M 19n.2n, still in the Intermedia Subzone, as with the Brodno locality (Michalík et al. 2009). The FO of N. wintereri lies in the upper part of the Crassicollaria Zone, in M 19n.2n as with Puerto Escaño (Svobodová & Košťák 2016) and Le Chouet (Wimbledon et al. 2013). The FO of N. wintereri in M 19n.2n is also mentioned at Torre de’ Busi (Casellato 2010; Channell et al. 2010), before the FO of N. globulus globulus. In the Kurovice succession, the FO of N. globulus globulus occurs just above the FO of N. wintereri as with Le Chouet (Wimbledon et al. 2013). The FO of N. steinmannii minor was recorded in the lower part of the Alpina Subzone, approximately in the middle part of M 19n.2n similar to the Strapková locality (Central Western Carpathians) — Michalík et al. (2016). At Brodno (Michalík et al. 2009), this bioevent also occurs in the lower part of the Alpina Subzone, but within the M 18r. At Torre de’ Busi, Casellato (2010) and Channell et al. (2010) mentioned the FO of N. steinmannii minor in subzone M 19n.1n, and the FO of N. kamptneri kamptneri in the middle part of the Ferasini Subzone and M 18n. Generally, Wimbledon (2017) mentions the FOs of N. wintereri and N. steinmannii minor in Western Tethys within M 19n.2n, immediately below the Calpionella Zone, J/K boundary. The nannofossil record clearly depends on the lithological character of the strata and this reality may affect the final stratigraphic and paleoenvironmental interpretations. As mentioned above, calcarenites provide scarce fragmen ted specimens, whereas micrite limestones contain rare and poorly preserved nannofossils. In contrast, marlstone inter calations contain abundant and diversified assemblages. This could be the cause of the scarce and irregular occurrence of genus Nannoconus in some parts of the section, and the fact that the first occurrences of N. infans, N. kamptneri minor and N. steinmannii steinmanni could not be relied upon for stratigraphic interpretations. Strata provided N. wintereri (Fig. 7AA, AB) and also specimens that can be consider as an early forms of this species (Fig. 7AC, AD). Nannofossils were not recognized in thin sections prepared for the calpionellid and facies investigation. The quantitative predominance of the genera Watznaueria and Cyclagelosphaera furnish proof of probable secondary post-mortem modification of the original nannoflora. Other placoliths that are easily destroyed are found scarcely and mostly as fragments. Through the Kurovice sequence, the irregular occurrence of unknown specimens of Conusphaera was observed. They are forms characterized by a thinner structure than Conusphaera mexicana, and are here mentioned as Conusphaera sp. 1 (Fig. 7I–L). As the ecological affinities of Conusphaera spp. are unclear (Bornemann et al. 2003; Tremolada et al. 2006), Conusphaera sp. 1 is an object suitable for further study. Moreover, specimens that look like C. mexicana cf. minor (Fig. 7P), but which reach larger dimensions, of about 5 µm, were recorded. The height given in the original description of C. mexicana minor does not exceed 4 µm (Bown & Cooper 1989). The high content of calcium carbonate and oxic conditions were also the cause of poor preservation of palynomorphs. Sediments throughout the sequence contain reworked calcareous dinoflagellates, such as Colomisphaera fibrata, C. tenuis, C. fortis, Stomiosphaera moluccana, Commitosphaera pulla, Carpistomiosphaera tithonica, C. borzai, and Parastomiosphaera malmica, which have been mentioned from the Late Oxfordian and Early Tithonian exclusively (Lakova et al. 1999; Reháková 2000; Ivanova & Kietzman 2017). Sometimes during the Berriasian, calpionellids such as Calpionella grandalpina, C. elliptalpina, and Crassicollaria 177J/K BOUNDARY AND HIGH RESOLUTION BIOSTRATIGRAPHY OF THE KUROVICE SECTION GEOLOGICA CARPATHICA, 2019, 70, 2, 153–182 Fig. 16. Integrated biostratigraphic correlations, microfacial interpretations, important bioevents and magnetostratipgraphy of the Kurovice section. Magnetostratigraphy as well as calpionellid, calcareous dinoflagellate and nannofossil zonations of 1–148 beds interval are modified from Elbra et al. (2018a). Black — normal polarity; white — reversed polarity; gray — unclear polarity due to lack of samples or stable magnetic component. Magnetostratigraphy of sample beds −1 to −29 is preliminary. TFZ — Tenius-Fortis Zone; MPBL — microfacies prevailed in biomicrite limestone; SMF — standard microfacies types; FZ — facies zones. Calpionellid zones after Reháková & Michalík (1997); dinoflagellate cyst zones sensu Reháková (2000).