Abstract Micritic sediments containing dark, discrete, organic-rich burrows, situated in a light grey background carbonate mud, were deposited over a broad geographical area in deep-shelf, bathyal and basinal environments in the western margin of the Tethys Ocean during the Early and Middle Jurassic. These hemipelagic deposits represent a distinct depositional regime marked by low-energy, soft-bottom and only locally dysoxic environments. Still, it is unclear whether the trace-fossil assemblages occurring in these deposits pertain to a network of several community types – the ichnotaxa differing from basin to basin – or to a single community of environmentally broad-ranging, burrow-producing species. Lower Jurassic trace-fossil assemblages are found in the Western Carpathians and in the Subbetic, Betic Cordillera: that is, in basins separated by more than 2000 km in their original palaeogeographical areas. The stereotypical Chondrites and Zoophycos trace-fossil assemblages that occur in the analysed deposits share two ichnogenera of distinctive morphology (Lamellaeichnus and Teichichnus). Agglutinated foraminifera Bathysiphon occurs together with the described trace-fossil assemblage and determines the epibenthic palaeoenvironmental conditions. In the Western Carpathians, a Lamellaeichnus -dominated assemblage alternates with a Zoophycos -dominated assemblage in small, metre-scale cycles in the upper Pliensbachian, and the proportion of the Zoophycos assemblage increases stratigraphically upwards, probably owing to reduced basin ventilation during the early Toarcian. Within the southern Iberian palaeomargin, represented by the Betic Cordillera, Zoophycos is scarce in the facies.

Abstract The Western Carpathians in the territory of Moravia (the eastern part of the Czech Republic) and northeastern (Lower) Austria represent the westernmost segment of the entire Carpathian orogenic system linked to the Eastern Alps. Based on differences in their depositional and structural history, the Carpathians are divided into two primary domains: the Inner Carpathians deformed and thrusted in the Late Jurassic to Early Cretaceous, and the Outer Carpathians deformed and thrusted over the European foreland during the Paleogene and Neogene. These two domains are separated by the Pieniny Klippen Belt, which bears signatures of both these domains and stands out as a primary suture in the Western Carpathians. Only the Outer Carpathians, including the thin-skinned thrust belt partly overlain by the Vienna basin and the undeformed Neogene foredeep, are present in the territory of Moravia and, as such, are subjects of our deliberation. The foreland of the Carpathians in Moravia is represented by the Bohemian Massif, which is a part of the West European plate. It consists of the Hercynian orogenic belt and the late Precambrian (Cadomian) foreland terrane of the Brunovistulicum. The unmetamorphosed sedimentary cover of the cratonic basement of the Bohemian Massif in Moravia extends through two plate-tectonic cycles, the Paleozoic Hercynian and the Mesozoic to Cenozoic Tethyan-Alpine. The Bohemian Massif continues far below the Carpathian foredeep and the thin-skinned Outer Carpathian thrust belt. Various deep antiformal structures have been identified in the subthrust plate by seismic methods and drilling. Some of these structures apparently formed during the Hercynian orogeny, whereas others are related either to the Jurassic rifting or to the compressional Alpine tectonics extending from the Late Cretaceous to Miocene. During the Laramide uplifting of the European foreland, in the Late Cretaceous to early Paleogene, two large paleovalleys and submarine canyons were cut into the foreland plate and filled with deep-water Paleogene strata. The Carpathian orogenic system, as we know it today, evolved during the late Paleozoic, Mesozoic, and Cenozoic through the divergent and convergent processes of the plate-tectonic cycle. In the Outer Western Carpathians of Moravia, the divergent stage began in the Middle to Late Jurassic by rifting, opening of Tethyan basins, and development of the passive margins dominated by the carbonate platforms and basins. Further rifting and extension occurred in the Early Cretaceous. The convergent orogenic process in the Outer Carpathians began in the Late Cretaceous by the subduction of the Penninic-Pieninic oceanic basin and collision of the Inner Carpathians with the fragmented margins of the European plate. Since the Late Cretaceous, a major foreland basin dominated by the siliciclastic shelf and deep-water flysch sedimentation has formed in the Outer Carpathian domain. The Carpathian foreland basin, especially during the Late Cretaceous to the early Eocene, displayed a complex topography marked by an existence of intrabasinal ridges (cordilleras) such as the Silesian cordillera. We interpret them as preexisting rift-related crustal blocks activated during the Late Cretaceous-early Paleocene uplifting as foreland-type compressional structures. During the Paleogene and early Miocene, the Upper Jurassic to lower Miocene sequences of the Outer Carpathian depositional system were gradually deformed and thrusted over the European foreland. The tectonic shortening occurred not only in the decoupled thin-skinned thrust belt but also at the deeper crustal level, where various blocks of the previously rifted margins were apparently at least partly accreted back to the foreland plate instead of being subducted. Since the early Miocene, the synorogenic, predominantly deep-water flysch sedimentation was replaced by the shallow-marine and continental molasse-type sedimentation of the Neogene foredeep, which remained mostly undeformed. Also during the Miocene, the Vienna basin formed in the Carpathian belt of southern Moravia and northeastern Austria as a result of subsidence, back-arc extension, and the orogen-parallel pull-apart strike-slip faulting. During its entire history, the evolution of Outer Western Carpathians in Moravia was significantly affected by the existence of two main structural elements, the Western Carpathian transfer zone and the Dyje-Thaya depression. The southwest-northeast-trending Western Carpathian transfer zone actually separated the Alps from the Carpathians. During the divergent stage, in the Early Cretaceous, the dextral motion in this zone accommodated a significant extension in the Outer Carpathian domain. Conversely, during the convergent stage in the Paleogene and Neo-gene, the sinistral transpressional motion in this zone facilitated the northeastern translation (escape) of the Carpathian belt and the opening of the pull-apart depocenter in the Vienna basin. The northwest-southeast-trending Dyje-Thaya depression, in southern Moravia and northeastern Austria, formed, or at least was activated, during the Jurassic rifting. Within the fault-bounded limits of this depression, thick, organic-rich marls were deposited in the Late Jurassic, shallow-marine clastic strata were laid down and preserved in the Late Cretaceous, two paleovalleys were excavated in the Late Cretaceous-early Paleogene, and finally, the Vienna basin formed in the Miocene. The complex structural and depositional history of the depression and its surroundings created one of the most prolific petroleum systems in the entire Carpathian region, from which more than 850 million bbl of oil has been produced to date. Historically, the Vienna basin has been the dominant producer in Austria and Moravia. More recently, however, the subthrust European platform with multiple hydrocarbon plays has become the main producing province in Moravia. Some of the identified deep subthrust structures represent significant exploration prospects, which yet have to be tested.

Abstract For the identification of the North European platform below the Western Carpathian Flysch belt and for the definition of the lithospheric and crustal relationships in the collisional zone between the Western Carpathian block and the North European platform, two migrated re flection seismic profiles with deep registration were chosen in the eastern sector of the West ern Carpathians. Both of them were newly reprocessed (1999-2000), deep and composite seis mic profiles, which define some new features in the geological structure in the eastern part of the Western Carpathians. From a general point of view, both seismic profiles are dominated by a fanwise (flower like) structure. However, we define this structure as fanwise, because in many features, it looks like a classic flower structure. The described fanwise structure has a great impact on the final form of the collisional zone. The impact of the fanwise structure is also clearly visible on both seismic sections in the area of the Inner Carpathian Paleogene basin. The Inner Car pathian Paleogene basin base dips moderately toward the Pieniny Klippen Belt in the north east, and according to our interpretation of seismic lines, the Inner Carpathian Paleogene basin sedimentary package is divided into three or four structural levels (the oldest level is built up by basal Paleogene sediments, and the overlying folded Sambron Member beds consist of two structural levels and three structural levels [our opinion] of sediments; see mainly seismic section AB below). What is very interesting is that the uppermost level of the Sambron Member beds displays clear extensional features. The Pieniny Klippen Belt is a major tectonic unit at the surface, where it separates the Outer and Inner Western Carpathians. However, both seismic lines reveal that the Pieniny Klippen Belt has no continuous depth prolongation as a tectonostratigraphic unit. The seismic image allows an interpretation of an older subhorizontal structure of laterally wedging-out and interfingering rock units that originated by collisional processes in a wider zone asso ciated with the Pieniny Klippen Belt. Younger and steep brittle structures that accompany the Pieniny Klippen Belt and its surroundings may be traced to great depths where they merge into a subvertical fault zone. This fanwise fault zone closely resembles a transpressional flower structure. From the point of view of hydrocarbon prospection, the most important feature of both seismic lines is the anticline structure of the North European platform below the thrust stack of the Flysch belt. This strong reflection package probably indicates the presence of carbonates in the North European platform cover (see seismic profile AB below). In our opinion, this structure is the most attractive for hydrocarbon exploration in the eastern part of the Slovakian Flysch Belt.

Abstract The Western Carpathians are a part of the extensive Alpine-Carpathian mountain system composed of the Western and Eastern Alps passing eastward into the Carpathians and Dina-rides. The Western Carpathians represent the northernmost part of the Alpine orogen adjacent at its foredeep to the North European and Russian platforms. They are divided into two belts: the Outer Western Carpathians, consisting mostly of Neoalpine nappes, and the Inner Western Carpathians, with essentially a Paleoalpine structure overlain by Tertiary postnappe deposits. The Hercynian basement of the Inner Western Carpathians is covered by late Paleozoic and Mesozoic rock sequences that either are autochthonous or form allochthonous nappes. The tectogenesis of the Tertiary postnappe basins is mainly related to the convergence of the Carpathian-Pannonian block and North European lithospheric plate, the tectonic escape of lithosphere fragments from the Alpine realm, as well as the rise of the Pannonian asthenolite. The Paleozoic units of the Inner Western Carpathians have their hydrocarbon potential practically exhausted. The oldest Paleozoic units of the Tatricum, Veporicum, and Gemericum are altered by different grades of metamorphism. The Mesozoic units are the most prospective in the western part of the region, where total possible resources of natural gas are estimated to be about 50 x 10 9 m 3 (1.76 x 10 12 ft 3). The highest potential for hydrocarbon exploration has Tertiary basins represented by Inner Carpathian Paleogene basins and Neogene basins, particularly Vienna, Danube, and the East Slovakian basins. Although knowledge on the Neogene basins is relatively good (existence of three-dimensional seismic data and many boreholes), the area of the Inner Paleogene basin is still at the early stage of prospection.