Potential Unconventional Gas Plays in Mature Basin of the Czech Republic

The presence of unconventional resources has been proven in deeper parts of mature oil and gas provinces and coal basins of the world. In this context, it is worth to focus also on the prospects of unconventional gas production from within hydrocarbon provinces of the Moravian part of the Vienna basin. The estimation of hydrocarbon generation potential of Jurasic marls from the Mikulov Formation of the Czech part of the Vienna Basin was performed based on the Rock Eval pyrolysis

Palaeoecology of Valletia antiqua Favre in Joukowsky & Favre, 1913 (Bivalvia, Hippuritida, Diceratidae); with comments on the taxonomy and distribution of the genus Valletia

The early rudist bivalve Valletia antiqua Favre in Joukowsky & Favre, 1913 is recorded for the first time from the Tithonian to Berriasian Štramberk Limestone (northeastern Czech Republic) and Ernstbrunn Limestone (Lower Austria). The species is re-described and its spatial distribution and stratigraphical range are outlined. Furthermore, the palaeoecology of Valletia antiqua is discussed in the light of novel data on palaeocommunities and microfacies, habitat selection and intraspecific competition for settling space among juveniles. The study is supplemented with a commented list of all nominal species that have been assigned to Valletia, including data on type localities, type strata, and distribution.Web of Science90363261

Biostratigrafie spodní křídy manínské jednotky (lom Butkov, Strážovské vrchy, Západní Karpaty)

This paper is a continuation of systematic stratigraphical research of Lower Cretaceous sequence of the Manín Unit excavated in the Butkov quarry. Calcareous deposits are significant especially by richness of ammonites. Attention is focused on the parts enabling the definition of ammonite zones. The following ammonite zones were determined: the Campylotoxus Zone (Early Valanginian), the Furcillata Zone (Late Valanginian), the Balearis Zone (Late Hauterivian) and boundary between the Pulchella Zone and the Compresissima Zone (Early Barremian). Non-calcareous and calcareous dinoflagellates, calpionellids and calcareous nannoplankton were analysed in the same places to provide a correlation of their ranges with ammonite zones.Tato práce je pokračováním systematických stratigrafických výzkumů spodnokřídových uloženin manínské jednotky těžených v lomu Butkov. Tamější karbonátové uloženiny se vyznačují bohatým výskytem amonitů. Pozornost je věnována úsekům umožňujícím definování amonitových zón. Zjištěny byly následující amonitové zóny: zóna Campylotoxus (spodní valangin), zóna Furcillata (svrchní valangin), zóna Balearis (svrchní hauteriv) a hraniční uloženiny mezi zónou Pulchella a zónou Compressissima (spodní barrem). Ve stejných úsecích byly studovány vzorky na nevápnitá a vápnitá dinoflageláta, kalpionely a vápnitý nanoplankton za účelem jejich korelace s příslušnými amonitovými zónami

The origin of native selenium microparticles during the oxidation of sideritic mudstones in the Verovice Formation (Outer Western Carpathians)

Microparticles of native selenium were detected in weathered sideritic mudstones of the Veřovice Formation (Aptian) of the Silesian Unit (Outer Western Carpatians, NE part of the Czech Republic). This mineral forms small needle-like crystals with lengths of up to 20 μm, and is confined to fissures in sideritic mudstones covered by goethite or rarely also by hydrated Mn-oxide minerals. The oxidized sideritic mudstones show zonal structure and resemble the initial stage of the formation of the so-called rattle stones. From the superposition of phase diagrams of selenium and Fe-oxyhydroxides, Fe apparently occupies a large field in which Se(0) and FeOOH and/or Fe(OH)3 can co-exist. The reduction of selenites or selenates by pyrite or by any other phase, capable of charge transfer, is likely to have been responsible for the formation of microparticles of native selenium. The crucial factor controlling the origin of these particles is the extremely low solubility of Se(0). The source of Se is not obvious. It can be released in trace concentrations during the weathering of pyrite. Sediments of the Veřovice Formation correspond to the anoxic event OAE1b and accumulation of siderophile elements in similar sediments is very probable. A probable mechanism for the origin of Se microcrystals is gradual crystallization from solution.Web of Science66431030

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

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 SMF2, SMF3 and SMF4 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 M21r to the late Early Berriasian calpionellid Elliptica Subzone of the Calpionella Zone, nannoplankton NK-1 Zone and M17r 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 M19n.2n) and by the rare occurrence of Nannoconus wintereri. Palynomorphs include Early Berriasian terrestrial elements - non-calcareous dinoflagellate cysts Achomosphaera neptunii, Prolixosphaeridium sp. A and Tehatnadinium 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.Web of Science70218215

Cretaceous palynofacies and isotopes 13C in the Silesian unit

Monotonous, grey to dark grey, mostly pelitic Lower Cretaceous deposits of the Silesian Unit are usually considered to be deposits of a dysoxic to anoxic environment. During the Cenomanian the sedimentation was changed to oxic one. The stratigraphic record of organic carbon isotopic composition has been correlated to the carbonate carbon isotope record from Europe. Organic carbon isotope values display a negative shift through the Upper Albian to Cenomanian. Negative excursion in δ13Corg value suggested warmer and more humid climates in the Cenomanian than in the Late Albian.Monotonous, grey to dark grey, mostly pelitic Lower Cretaceous deposits of the Silesian Unit are usually considered to be deposits of a dysoxic to anoxic environment. During the Cenomanian the sedimentation was changed to oxic one. The stratigraphic record of organic carbon isotopic composition has been correlated to the carbonate carbon isotope record from Europe. Organic carbon isotope values display a negative shift through the Upper Albian to Cenomanian. Negative excursion in δ13Corg value suggested warmer and more humid climates in the Cenomanian than in the Late Albian

The northernmost occurrence of the Lower Berriasian ammonite Pseudosubplanites grandis (Stramberk Limestone, Outer Western Carpathians, Czech Republic)

The first finding of the index ammonite Pseudosubplanites grandis (Mazenot, 1939) in the Lower Berriasian Štramberk Limestone (Outer Western Carpathians, northeastern Czech Republic) is important from the point of view of both the paleogeographical distribution of this species and of more precisely defining the upper boundary of the Štramberk Limestone (Early Berriasian Berriasella jacobi Zone) formerly regarded as Late Tithonian in age. From the taxonomical point of view, new data on a non-deformed cross-section of the adult whorl and above all on the shape of the adult suture line of this species have been obtained.Web of Science64646646

Biostratigraphy and paleoecology of the Lower Cretaceous sediments in the Outer Western Carpathians (Silesian Unit, Czech Republic)

Almost black shale filling fissures in the Štramberk Limestone belonging to the Silesian Unit, Outer Western Carpathians contain prolific and poorly to moderately well preserved spores, pollen, organic-walled dinoflagellate cysts, foraminifers, and calcareous nannofossils. A detailed micropaleontological analysis of the proved stratigraphical interval from the Valanginian to the Albian indicated sedimentary conditions of brackish, restricted marine, shallow-marine and neritic sedimentation. Moreover, it drew attention to occasional influence from the Boreal province in the depositional area of the NW part of Tethys, especially during the Early Valanginian and Hauterivian, as supported by the presence of highlatitude nannofossils and organic-walled dinoflagellate cysts. Terrestrial miospores form a significant component of palynoassemblages and give evidence of continent proximity in the Valanginian-Barremian interval. Samples were acquired from isolated fissure fills in the Štramberk Limestone and, therefore, they do not represent a continuous section.Web of Science62433230

IZOTOPY UHLÍKU V ORGANICKÉ HMOTĚ SVRCHNOKŘÍDOVÝCH SEDIMENTŮ SLEZSKÉ JEDNOTKY

Organic carbon content and stable organic carbon isotopes were studied in the complete section across the change anoxic to oxic sedimentation in the Bystrý potok stream by Trojanovice (in the vicinity of Frenštát p. R., Czech Republic). Pelitic deposits of the higher Lower Cretaceous and the lower Upper Cretaceous of basinal sedimentation in the Godula development of the Silesian Unit of the Western Carpathians outcrop here. TOC values in the black shales of the Late Albian and Eatly Cenomanian Lhoty Formation is higher (3.59 %). Th e δ13C isotopic values of claystones show positive excursion in the lower part of the Mazák Formation (Upper Cenomanian, ?OAE2) and lower part of the Godula Formation (Upper Santonian)

A contribution to the knowledge of stratigraphic position of magmatic rocks of teschenite association in the Silesian Unit

New results of stratigraphic investigations of the Early Cretaceous sediments of the Hradiště Formation accompanying magmatic rocks of the teschenite association of the Silesian Unit (flysch belt, the Western Carpathians) were made based on noncalcareous dinoflagellate cysts. In view of the dinoflagellate cysts found, the stratigraphic range of the magmatic rocks under study is from the Late Hauterivian to the Late Barremian. It is also possible to assume that the main area of the magmatic activity around Nový Jičín and Příbor is associated with the Late Barremian.New results of stratigraphic investigations of the Early Cretaceous sediments of the Hradiště Formation accompanying magmatic rocks of the teschenite association of the Silesian Unit (flysch belt, the Western Carpathians) were made based on noncalcareous dinoflagellate cysts. In view of the dinoflagellate cysts found, the stratigraphic range of the magmatic rocks under study is from the Late Hauterivian to the Late Barremian. It is also possible to assume that the main area of the magmatic activity around Nový Jičín and Příbor is associated with the Late Barremian