Abstract The Weglowka field is one of the biggest oil fields in the Outer Polish Carpathians, situated north of Krosno between Frysztak and Brzozow in the Subsilesian tectonic unit. The field was discovered in 1888 and has produced 998,220 t of oil and 214.52 million m 3 (7.575 bcf) of gas since exploitation began. More than 350 wells have been drilled in the Weglowka oil field; it was completed in the reservoir intervals that range in depth from 100 to 1200 m (330 to 3900 ft). The Weglowka oil field is now in the final phase of exploitation. Oil is accumulated in several Lower Cretaceous sandstone bodies. The trap is an anticline that is cut by two second-order longitudinal, small thrust faults that subdivide the field between two thrust sheets. Stratigraphic traps probably exist in the Lgota sandstone (the main reservoir), associated with lowstand systems tract sandstones deposited in basin-floor fans. The main seals in the field are the Verovice shales, Lgota Shales, and the younger Godula Shales and Weglowka marls.

Abstract Study of the Upper Cretaceous oceanic red beds (CORBs) in the Outer Western Carpathians, Czech Republic, was based on integrated biostratigraphy (foraminifera, dinoflagellata, calcareous nannofossils). Agglutinated foraminifers are the only abundant microfossil group in red shale. Reconstruction of the sedimentary paleoenvironment was supported by mineralogical and paleoichno-logical analysis. Bioturbation and lack of organic matter indicate highl oxic sedimentary conditions. The CORBs range from the Albian to the Lower Paleocene. Both their bases and their tops are heterochronous through individual facies zones of the Outer Carpathians. Generally, the time span of the CORBs decreases from abyssal to slope facies and from inner to outer zones. The CORBs reached their maximum extent during the Turonian. The CORBs were terminated by increased influx of terrigenous organic matter. Key words: Outer Carpathians, red beds, Cretaceous, dinoflagellates, agglutinated foraminifera, calcareous nannofosils, ichnofossils

Abstract This chapter presents a stratigraphic review of reservoirs and their parameters, trap types, and important fields in all of the tectonic units (nappes) in the Polish Outer Carpathians, where hydrocarbon deposits have been discovered and exploited for more than 150 yr. The first part of this chapter is an introduction to the information about the occurrence of reservoir rocks in the Carpathians; however, the variability of these parameters is commonly surprising. Well-known examples are present where reservoir parameters vary greatly even in the same field, but this is a separate problem, and this is only mentioned here. Despite the very large number of wells drilled in the Polish Carpathians, the quantity of detailed petrophysical data is not so large. Good-quality data have been obtained only during the last 30 yr. The most recent and best quality data originate from wells drilled by Polish Petroleum Industry in areas of known fields during research of deeper prospects and from recognized wells. Copyright © 2006. The American Association of Petroleum Geologists. DOI:10.1306/985611M843071 The best reservoir data are from the Skole and Silesian nappes, and these are presented in this chapter in great detail. Within the region of the Outer Polish Carpathians, reservoir rocks are found to have good potential as in shallow as well as deep structures in deposits of Lower Cretaceous to lower Oligocene in age. The majority of hydrocarbon accumulations in the thrusted and folded Carpathians are within structural style traps. Exploration for them throughout the past 150 yr has enabled geologists to recognize their many different types, such as those related to thrust anticlines and folds, but which before were only interpreted as related to folds. Most of the oldest exploited oil accumulations in the Carpathians are of the contractional anticline type, commonly associated with thrusting. Most of these fields can only be illustrated by line-drawn sections based on drilling information because no seismic data are available. Some of the more spectacular traps in the Outer Carpathians are connected to disharmonic thrusted folds, tilted thrust faults, overturned frontal parts of thrust sheets, imbricate fan types, sandstone pinch-out, and traps sealed by asphalt. In this chapter, selected and more important oil and gas fields that can be examples of characteristic hydrocarbon accumulations are also described. The most southern nappe is the Dukla unit, which lies beneath the Magura nappe, where six hydrocarbon accumulations have been discovered in the Oligocene Cergowa sandstone to date. A good example of the hydrocarbon accumulations and tectonic styles of the fields in the Dukla unit is the Slopnice– Limanowa oil and gas field. Here, the hydrocarbons have accumulated in recumbent thrust folds. The Silesian nappe is represented by two important fields: the Bobrka oil field, which is located in the Bobrka anticline, and the Potok oil and gas field in the Potok anticline. Both of these fields have hydrocarbon accumulations in the Ciezkowice and Istebna reservoirs, which are trapped by thrust-related anticlines. The minor tectonic elements, such as thrust-related anticlines and synclines that separate the two fields, however, do not yield hydrocarbons. The Bobrka oil field lies in the world’s oldest area of petroleum exploration and production. This field is taken as the symbol of the Polish and international oil industry and is presented here from a historical point of view. The Potok oil and gas field is located approximately 10 km (6 mi) to the north of the Bobrka oil field. It is one of the six most productive oil fields in the region and produces from an anticlinal structure more than 40 km (25 mi) long. The Skole nappe is a similarly important unit for hydrocarbon exploration. Four oil fields have produced 1.7 million t of oil and more than 180 million m 3 (3.8 bcf) of gas from accumulations in the Menilite sandstone. One example of such an accumulation is seen in the Lodyna oil field. Here, the hydrocarbons are accumulated in a series of almost vertical beds of menilites within pinching out of Kliwa Sandstone.

Abstract A genetic analysis of oils and potential source rocks and their mutual correlation from three areas of hydrocarbon occurrence in three tectonic units (thrust nappes), Subsilesian, Silesian, and Dukla nappes of the Outer Carpathians in Poland, between Gorlice in the west and Krosno to the east, revises existing opinions on the genesis, migration, and accumulation of hydrocarbons in this part of the Carpathians. One of the important hydrocarbon accumulations occurs in the Subsilesian unit (Weglowka oil field). Detailed geochemical studies show that the oil that accumulated in the Weglowka oil field is the same type as the oil that accumulated in the Potok anticline located about 10 km (6 mi) to the south in the Silesian nappe and derived from the same Oligocene Menilite shales source rock. The oldest known source-prone interval in the Subsilesian nappe is the Verovice shales (Lower Cretaceous), which are likely to have produced the hydrocarbons found in the nearby Wola Jasienicka field located 8 km (5 mi) to the east from the Weglowka oil field. The lower Istebna Shales (Upper Cretaceous) that occurred in the Silesian nappe in the area of Potok anticline could be good source rocks for oil. It is also possible that hydrocarbon generation occurred during several stages, and that mixing of oils derived from Menilite beds and Istebna Shales could have occurred in this area. Similar studies have been made in the southern part of the study area around the oil-rich Gorlice region in the Silesian nappe. This study indicates that the oils accumulated in fields of this region were generated from the Menilite shales of the Dukla nappe, which occurred in tectonic windows in the Magura nappe. Copyright ©2006. The American Association of Petroleum Geologists. DOI:10.1306/985618M843076 The tectonic relationship of the producing fields in the Weglowka–Potok clearly shows the occurrence of several major syncline around the fields. The deepest are to the south of the Wola Jasienicka and Potok fields, which could represent the generative kitchen for these fields during the different stages of Carpathian thrusting. In addition, computer-generated simulations of oil generation in the vicinity of Gorlice and Potok areas suggest hydrocarbon generation and expulsion during the middle Miocene to Pliocene (Holocene).

Abstract The purpose of this chapter is to provide the general overview of the stratigraphy and tectonics of the Polish, Ukrainian, and adjacent parts of the Slovakian Outer Carpathians. The Polish and Ukrainian Outer Carpathians form the north and northeastern part of the Carpathians that expand from the Olza River on the Polish–Czech border to the Ukrainian–Romanian border. Traditionally, the Northern Carpathians are subdivided into an older range, known as the Inner Carpathians, and the younger ones, known as the Outer Carpathians. These ranges are separated by a narrow, strongly tectonized belt, the Pieniny Klippen Belt. The Outer Carpathians are made up of a stack of nappes and thrust sheets showing a different lithostratigraphy and tectonic structures. Generally, each Outer Carpathian nappe represented separate or partly separate sedimentary subbasin. In these subbasins, enormous continuous sequence of flysch-type sediments was deposited; their thickness locally exceeds 6 km (3.7 mi). The sedimentation spanned between the Late Jurassic and early Miocene. During the folding and overthrusting, sedimentary sequences were uprooted, and generally, only sediments from the central parts of basins are preserved. The Outer Carpathian nappes are overthrust on each other and on the North European platform and its Miocene–Paleocene cover. In the western part, overthrust plane is relatively flat and becomes more and more steep eastward. Boreholes and seismic data indicate a minimal distance of the overthrust of 60–80 km (37–50 mi). Copyright ©2006. The American Association of Petroleum Geologists. DOI:10.1306/985610M843070 The evolution of the Northern Outer Carpathian Flysch basins shows several tectonostratigraphic stages. The first period (Early Jurassic–Kimmeridgian) began from the incipient stage of rifting and formation of local basins. The next stage (Tithonian–Early Cretaceous) is characterized by rapid subsidence of local basins where calcareous flysch sedimentation started. The third period (Late Cretaceous–early Miocene) is characterized by compression movements, appearance of intensive turbiditic sedimentation, and increased rate of subsidence in the basins.

Abstract Twelve time-interval maps have been presented that depict the plate-tectonic configuration, paleogeography, and lithofacies for the circum-Carpathian area from the Late Carboniferous through Neogene and for the circum-Ouachita region from the Late Cambrian through Early Permian. The following geodynamic evolution stages can be distinguished in these two orogens:-stage I: rifting of terranes off the major continent, forming oceanic basins, Triassic–Early Cretaceous in the Carpathian region, Cambrian–Devonian in the Ouachita basin; stage II: formation of subduction zones along the active margin, partial closing of the oceanic basin, development of flysch basin associated with this rifting on the platform (passive margin) with the attenuated crust, Late Cretaceous–Paleocene in the Carpathian region, Early Carboniferous in the Ouachitas; stage III: collision, perhaps terrane-continent, with the accompanying convergence of two large continents, development of accretionary prisms, the Eocene–early Miocene in the Carpathian region, Late Carboniferous in the Ouachitas; stage IV: postcollisional, Miocene–present–future(?) in the Carpathians, Permian–Triassic in the Ouachitas. Both Carpathians and Ouachitas are an accretionary prism formed in response to terrane-continent and continent-continent collision. The paleogeographic approach we have taken shows how these mountain belts were constructed through the orogenic cycle, which reflects complex plate-tectonic processes. The Carpathians and Ouachitas record complete and homologous Wilson cycles. Copyright ©2006. The American Association of Petroleum Geologists. DOI:10.1306/985629M841463

Abstract The interrelationship between slope deformation and fault-induced weathering as a predisposing factor for the development of sliding is analysed through several case studies from the Western Carpathians in the Czech Republic. The study area comprises flysch nappes with alternating sandstone and shale of different permeability. These lithological structures are affected by systems of faults. Recurring slope instability is found associated with zones of deep weathering in tectonically weakened areas. Climatic variability of landslide activity can be identified during the Holocene by means of radiocarbon dating and pollen analysis. Areas affected by recurring landsliding suggest gradual and cyclic landslide frequency.

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 The northern segments of the Carpathians, stretching between Limanowa (Poland) and Kosów (Ukraine), belonged to the most prolific hydrocarbon province in the world in the late nineteenth and early twentieth centuries. The earliest written accounts of natural occurrences of hydrocarbons in the Carpathians date back to the sixteenth century. In the eighteenth and early nineteenth centuries, Rzączyński, Kluk, Hacquest and Staszic provided accounts on methods of practical use related to oil. Staszic’s geological map shows numerous oil seeps and different rock types containing hydrocarbons. The development of the oil industry was triggered by Łukasiewicz’s discovery of an oil-distillation process and the construction of a kerosene lamp. Following this, the oil industry flourished in the Northern Carpathians. Oil production peaked at 2 Mt (million tons) of crude oil in 1910. In subsequent years, the level of oil production steadily decreased due to a turbulent economy. Exploration for oil, gas and ozokerite resulted in the development of modern micropalaeontology and geological mapping, with a prime example being the regional coverage of almost the entire Northern Carpathians provided by the Atlas Geologiczny Galicyi ( Geological Atlas of Galicia ), which consisted of 99 high-quality geological maps at a scale of 1:75 000. Geophysical surveying techniques were applied to subsurface mapping, and higher educational institutions were established in order to support exploration efforts.

Abstract During the Cretaceous (145.5-65.5 Ma; Gradstein et al. 2004 ). Central Europe was part of the European continental plate, which was bordered by the North Atlantic ocean and the Arctic Sea to the NW and north, the Bay of Biscay to the SW, the northern branch of the Tethys Ocean to the south, and by the East European Platform to the east ( Fig. 15.1 ). The evolution of sedimentary basins was influenced by the interplay of two main global processes: plate tectonics and eustatic sea-level change. Plate tectonic reconfigurations resulted in the widening of the Central Atlantic, and the opening of the Bay of Biscay. The South Atlantic opening caused a counter-clockwise rotation of Africa, which was coeval with the closure of the Tethys Ocean. Both motions terminated the Permian-Early Cretaceous North Sea rifting and placed Europe in a transtensional stress field. The long-term eustatic sea-level rise resulted in the highest sea level during Phanerozoic times ( haq et al. 1988;Hardenbol et al. 1998 ). Large epicontinental shelf areas were flooded as a consequence of elevated spreading rates of mid-ocean ridges and intra-oceanic plateau volcanism, causing the development of extended epicontinental shelf seas and shelf-sea basins ( Hays & pitman 1973 ; Larson 1991 ). A new and unique lithofacies type, the pelagic chalk, was deposited in distal parts of the individual basins. Chalk deposition commenced during middle Cenomanian-early Turanian times. Chalk consists almost exclusively of the remains of planktonic coccolithophorid algae and other pelagic organisms, and its great thickness reflects a high rate of production of the algal tests. The bulk of the grains are composed of lowmagnesium calcite, representing coccolith debris with a subordinate amount of foraminifers, calcispheres, small invertebrates and shell fragments of larger invertebrates ( Håkansson et al. 1974 ; Surlyk & Birkelund 1977 ; Nygaard et al. 1983 ; Hancock 1975 , 1993 ).

Abstract The Alps and Western Carpathians constitute that part of the Alpine-Mediterranean orogenic belt which advances furthest to the north into Central Europe. They were formed by a series of Jurassic to Tertiary subduction and collision events affecting several Mesozoic ocean basins, continental margins, and continental fragments. The Western Alps form a pronounced, westward-convex arc around which the strike of the tectonic units changes by almost 180° ( Fig. 18.1 ). The Western Carpathians are a northward-convex arc of similar size but with minor curvature. The two arcs are connected by an almost straight, WSW-ENE striking portion including the Eastern Alps Stresses produced by tectonic processes in the Alps also influenced the tectonics of large parts of central and northern Europe, leading, for example, to basin inversion and strike-slip faulting. In this chapter, we will discuss the present-day structure of the different tectonic units in the Alps and Western Carpathians in relation to their palaeotectonic history in order to illustrate the plate tectonic evolution using geological data. Many tectonic problems of the Alps and Western Carpathians are still unsolved, although dramatic progress has been made, especially over the last c. 20 years. Therefore, some of the interpretations presented below are still controversial and do not always express the opinion of all three authors. Given that the main theme of this book is Central Europe, the Southern and Western Alps are discussed in less detail than those parts of the Alps which belong to Central Europe: the Central Alps, the Eastern Alps and the Western Carpathians.