Nestor Oszczypko

Carpathian Foredeep Basin (Poland and Ukraine): Its Sedimentary, Structural, and Geodynamic Evolution

The Polish and Ukrainian Carpathian Foredeep, about 600 km (376 mi) long and as much as 100 km (62 mi) wide, is part of the large sedimentary basin that stretches for more than 1300 km (816 mi) from the Danube in Vienna (Austria) to the Iron Gate on the Danube (Romania). To the west, the Carpathian Foredeep is linked with the Alpine Molasse Basin, and to the east, it passes into the Balkan foreland basin. Like other foreland basins, the Carpathian Foredeep is asymmetric and filled with predominantly clastic sediments of the Miocene age as much as 3 and 6 km (1.8 and 3.6 mi) thick at the Carpathian front in Poland and Ukraine, respectively. The molasse deposits of the Carpathian Foredeep are underlain by the basement of the European Platform, covered mainly by Permian–Mesozoic terrestrial and shelf sediments and locally by the Paleogene deposits. According to seismic, magnetotelluric, and well data, the platform basement with Miocene molasse cover dips southward underneath the Outer Carpathian nappes to a distance of at least 50 km (31 mi). The early to middle Miocene Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The Paleozoic–Mesozoic and Tertiary strata of the Carpathian Foredeep are oil and gas productive.

Plate-tectonic Evolution and Paleogeography of the Circum-Carpathian Region

Sixteen time interval maps were constructed that depict the latest Precambrian to Neogene plate-tectonic configuration, paleogeography, and lithofacies of the circum-Carpathian area. The plate-tectonic model used was based on PLATES and PALEOMAP software. The supercontinent Pannotia was assembled during the latest Precambrian as a result of the Pan-African and Cadomian orogenies. All Precambrian terranes in the circum-Carpathian realm belonged to the supercontinent Pannotia, which, during the latest Precambrian–earliest Cambrian, was divided into Gondwana, Laurentia, and Baltica. The split of Gondwana during the Paleozoic caused the origin of the Avalonian and then Gothic terranes. The subsequent collision of these terranes with Baltica was expressed in the Caledonian and Hercynian orogenies. The terrane collision was followed by the collision between Gondwana and the amalgamation of Baltica and Laurentia known as Laurussia. The basement of most of the plates, which was an important factor in the Mesozoic–Cenozoic evolution of the circum-Carpathian area, was formed during the late Paleozoic collisional events. The older Cadomian and Caledonian basement elements experienced Hercynian tectonothermal overprint. The Mesozoic rifting events resulted in the origin of oceanic-type basins like Meliata and Pieniny along the northern margin of the Tethys. The separation of Eurasia from Gondwana resulted in the formation of the Ligurian–Penninic–Pieniny Ocean as a continuation of the Central Atlantic Ocean and as part of the Pangean breakup tectonic system. During the Late Jurassic–Early Cretaceous, the Outer Carpathian rift developed. The latest Cretaceous–earliest Paleocene was the time of the closure of the Pieniny Ocean. The Adria–Alcapa terranes continued their northward movement during the Eocene–early Miocene. Their oblique collision with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and foreland basin. The northward movement of the Alpine segment of the Carpathian–Alpine orogen has been stopped because of the collision with the Bohemian Massif. At the same time, the extruded Carpatho-Pannonian units were pushed to the open space toward the bay of weak crust filled up by the Outer Carpathian flysch sediments. The separation of the Carpatho-Pannonian segment from the Alpine one and its propagation to the north were related to the development of the north–south dextral strike-slip faults. The formation of the Western Carpathian thrusts was completed by the Miocene. The thrust front was still progressing eastward in the Eastern Carpathians. The Carpathian loop, including the Pieniny Klippen structure, was formed. The Neogene evolution of the Carpathians resulted also in the formation of the genetically different sedimentary basins. The various basins were formed because of the lithospheric extension, flexure, and strike-slip-related processes.

Geodynamic evolution and palaeogeography of the Polish Carpathians and adjacent areas during Neo-Cimmerian and preceding events (latest Triassic-earliest cretaceous)

Abstract The aim of this paper is to place the geodynamic and palaeogeographical evolution and position of the major crustal elements of the Polish Carpathians within a global framework. Neo-Cimmerian movements and their synsedimentary consequences are the main objects of our elaboration in relation to sedimentary record. Five time-interval maps are presented, which depict the plate-tectonic configuration, palaeogeography and lithofacies for the circum-Carpathian region and adjacent areas from the Late Triassic through to the Early Cretaceous. Almost simultaneous tectonic events proceeding within different types of Carpathian sedimentary basins (Pieniny Klippen Belt and Outer Carpathian Silesian Basins) indicate the very important role of the Neo-Cimmerian movements (mainly of the Osterwald Phase) in the geodynamic history of the northernmost margin of the Tethyan Ocean. The global plate reorganization is related to this Tethyan Neo-Cimmerian tectonic activity.

Geology and Hydrocarbon Resources of the Outer Carpathians, Poland, Slovakia, and Ukraine: General Geology

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). 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.

The Northern Carpathians plate tectonic evolutionary stages and origin of olistoliths and olistostromes

The olistostromes formed in Northern Carpathians during the different stages of the development of flysch basins, from rift trough post-rift, orogenic to postorogenic stage. They are known from the Cretaceous, Paleocene, Eocene, Oligocene and Early Miocene flysch deposits of main tectonic units. Those units are the Skole, Subsilesian, Silesian, Dukla and Magura nappes as well as the Pieniny Klippen Belt suture zone. The oldest olistoliths in the Northern Carpathians represent the Late Jurassic-Early Cretaceous rifting and post-rifting stage of the Northern Carpathians and origin of the proto-Silesian basin. They are known from the Upper Jurassic as well as Upper Jurassic-Lower Cretaceous formations. In the southern part of the Polish Northern Carpathians as well as in the adjacent part of Slovakia, the olistoliths are known in the Cretaceous- Paleocene flysch deposits of the Pieniny Klippen Belt Zlatne Unit and in Magura Nappe marking the second stage of the plate tectonic evolution - an early stage of the development of the accretionary prism. The most spectacular olistostromes have been found in the vicinity of Haligovce village in the Pieniny Klippen Belt and in Jaworki village in the border zone between the Magura Nappe and the Pieniny Klippen Belt. Olistoliths that originated during the second stage of the plate tectonic evolution occur also in the northern part of the Polish Carpathians, in the various Upper Cretaceous-Early Miocene flysch deposits within the Magura, Fore-Magura, Dukla, Silesian and Subsilesian nappes. The Fore-Magura and Silesian ridges were destroyed totally and are only interpreted from olistoliths and exotic pebbles in the Outer Carpathian flysch. Their destruction is related to the advance of the accretionary prism. This prism has obliquely overridden the ridges leading to the origin of the Menilite-Krosno basin. In the final, postcollisional stage of the Northern Carpathian plate tectonic development, some olistoliths were deposited within the late Early Miocene molasse. These are known mainly from the subsurface sequences reached by numerous bore-holes in the western part of the Polish Carpathians as well as from outcrops in Poland and the Czech Republic. The largest olistoliths (kilometers in size bodies of shallow-water rocks of Late Jurassic-Early Cretaceous age) are known from the Moravia region. The largest olistoliths in Poland were found in the vicinity of Andrychów and are known as Andrychów Klippen. The olistostromes bear witness to the processes of the destruction of the Northern Carpathian ridges. The ridge basement rocks, their Mesozoic platform cover, Paleogene deposits of the slope as well as older Cretaceous flysch deposits partly folded and thrust within the prism slid northward toward the basin, forming the olistostromes.

Stages of development in the Polish Carpathian Foredeep Basin

In southern Poland, Miocene deposits have been recognised both in the Outer Carpathians and the Carpathian Foredeep (PCF). In the Outer Carpathians, the Early Miocene deposits represent the youngest part of the flysch sequence, while in the Polish Carpathian Foredeep they are developed on the basement platform. The inner foredeep (beneath the Carpathians) is composed of Early to Middle Miocene deposits, while the outer foredeep is filled up with the Middle Miocene (Badenian and Sarmatian) strata, up to 3,000mthick. The Early Miocene strata are mainly terrestrial in origin, whereas the Badenian and Sarmatian strata are marine. The Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The main episodes of intensive subsidence in the PCF correspond to the period of progressive emplacement of the Western Carpathians onto the foreland plate. The important driving force of tectonic subsidence was the emplacement of the nappe load related to subduction roll-back. During that time the loading effect of the thickening of the Carpathian accretionary wedge on the foreland plate increased and was followed by progressive acceleration of total subsidence. The mean rate of the Carpathian overthrusting, and north to north-east migration of the axes of depocentres reached 12 mm/yr at that time. During the Late Badenian-Sarmatian, the rate of advance of the Carpathian accretionary wedge was lower than that of pinch-out migration and, as a result, the basin widened. The Miocene convergence of the Carpathian wedge resulted in the migration of depocentres and onlap of successively younger deposits onto the foreland plate.

Stages in the Magura Basin: a case study of the Polish sector (Western Carpathians)

The Magura Basin domain developed in its initial stage as a Jurassic-Early Cretaceous rifted passive margin that faced the eastern parts of the oceanic Alpine Tethys. In the pre- and syn-orogenic evolution of the Magura Basin the following prominent periods can be distinguished: Middle Jurassic-Early Cretaceous syn-rift opening of basins (1) followed by Early Cretaceous post-rift thermal subsidence (2), latest Cretaceous–Paleocene syn-collisional inversion (3), Late Paleocene to Middle Eocene flexural subsidence (4) and Late Eocene - Early Miocene synorogenic closing of the basin (5). The driving forces of tectonic subsidence of the basin were syn-rift and thermal post-rift processes, as well as tectonic loads related to the emplacement of accretionary wedge. This process was initiated at the end of the Paleocene at the Pieniny Klippen Belt (PKB)/Magura Basin boundary and was completed during Late Oligocene in the northern part of the Magura Basin. During Early Miocene the Magura Basin was finally folded, thrusted and uplifted as the Magura Nappe.

Sarmatian paleoecological environment of the Machów Formation based on the quantitative nannofossil analysis — a case study from the Sokołów area (Polish Carpathian Foredeep)

Sarmatian paleoecological environment of the Machów Formation based on the quantitative nannofossil analysis — a case study from the Sokołów area (Polish Carpathian Foredeep) The Machów Formation belongs to a supra-evaporitic succession of the Polish Carpathian Foredeep Basin (PCFB). Our studies were concentrated in the eastern part of the PCFB, north of Rzeszów. 33 samples were collected from five boreholes, at depth intervals as follows: Stobierna 2 — 1016-1338 m; Stobierna 3 — 715-1669 m; Stobierna 4 — 1016-1238 m; Stadnicka Brzóza 1 — 350-356 m and 1043-1667 m; Pogwizdów 2 — 1161-1390 m. The obtained biostratigraphical data gave evidence for the upper part of the NN6 (the Early Sarmatian) and for the NN7 (the lowermost part of the Late Sarmatian) Zones. All the nannofossil assemblages from Stobierna 2, Stobierna 4 and Pogwizdów 2 were assigned to the NN6 Zone. In the Stobierna 3 borehole the interval 1669-1113 m was assigned to NN6, whereas assemblages from depth interval 843-715 m belong to NN7 Zone. In Stadnicka Brzóza 1 interval 1667-1043 m belongs to NN6 Zone and interval 350-356 m to NN7 Zone. The Discoaster exilis Zone (NN6) was defined by the presence of Reticulofenestra pseudoumbilica, Sphenolithus abies, Helicosphaera walbersdorfensis and absence of Discoaster kugleri. The Discoaster kugleri Zone (NN7) assignment was based on the abundance of Coccolithus miopelagicus (> 10 μm), used as an alternative species essentially confined to that interval, and absence of Catinaster coalithus. The observed nannoplankton assemblages are predominantly composed of a high number of redeposited material, abundant long-ranging taxa and taxa resistant to carbonate dissolution. General assemblage compositions, obtained from quantitative data, indicate shallow near-shore environment and could confirm basin isolation.

Occurrence of Upper Jurassic–Lower Cretaceous black organic-rich pelitic sediments as targets for unconventional hydrocarbon exploration in the Outer Carpathians and adjacent part of the Alps

Our work on the dark pelitic sediments of the Polish Carpathians and eastern Alps shows that these Jurassic through Lower Cretaceous sediments owe their organic content to a combination of global processes, such as climatic changes and changes to the carbonate compensation depth (CCD), and local controls, such as basin morphology, input of terrestrial organic material, and local volcanic activity. These sediments developed in basins both floored by oceanic crust as well as within the continental crust (North European platform). Our data show that these anoxic or poorly oxygenated deposits (average total organic carbon [TOC] value is around 2.5 wt. %) were laid down in the individual basins at different times, from the Late Jurassic to the Barremian and almost continuously up to the early Cenomanian, a period of 30 to 50 m.y., and their thickness reached hundreds of meters. This long time span made it impossible to distinguish precisely the known Aptian and Albian oceanic anoxic events (OAE). Our data show that sedimentation of dark organic-rich deposits was not only controlled by global events such as climatic and CCD changes, but also by local ones as a result of differences in their basin morphology and development, input of land-plant detritus, and local volcanic activity. As an example of the anoxic succession, a detailed description of the black sediments of the proto-Silesian basin is presented. Some of these anoxic shales were buried to a depth of a few thousand meters during the folding and overthrusting movements. We propose that these shales could represent a unique shale-oil and shale-gas resource in an intensely structured basin.

Tectonics of the Western Carpathians in the light of recent studies

The Western Carpathians represent a complex Alpine orogenic system developed on remnants of older orogenic cycles consolidated mainly during the Variscan orogeny. After preVariscan and Variscan deformation and metamorphism followed by extensive Carboniferous and restricted Permian granite magmatism, the Alpine evolution progressed from the Middle Triassic rifting, which was related to opening of the Meliata Ocean, and continued to the final soft collision of the frontal accretionary wedge with the North European Platform during the Miocene. Meanwhile closure of the Meliata Ocean occurred during the Jurassic, contemporaneously with rifting of the orogenic lower plate and opening of the Penninic oceanic domains. During the Cretaceous, shortening progressed northwards of the Meliata suture and a huge, foreland-propagated basement/cover thrust stack of the Austroalpine units developed in the Central Western Carpathians. The Palaeogene story is characterized by subduction-collision processes that affected the Penninic realm, with gradual frontal accretion of dominantly oceanic sediments scraped off subducted oceanic lithosphere with intervening continental ribbons (e.g. the Oravic domain of the Pieniny Klippen Belt). During the Miocene, the Western Carpathians constituted the eastern part of the ALCAPA microplate escaping from the Alpine continental collision. The escape was accompanied by a considerable CCW rotation, back-arc extension and calc-alkaline volcanism in the Pannonian basin system, and by the final shaping of the Outer Carpathian accretionary fold-and-thrust belt, which overrode the inner parts of the frontal foredeep and underlying margins of the Bohemian Massif and the North European Platform. The collection of papers included in this special issue concerns several important aspects of tectonic evolution of the Western Carpathians. During the last decades, the Meliata Ocean and its ancestors have become one of the most discussed issues in the Alpine-Carpathian geology. However, due to extremely complicated internal structure, fragmentary appearance and poor outcropping, there is still a number of unclear features linked to the Meliata and associated units. Kövér et al. bring new data about the Late Jurassic – Early Cretaceous structural and metamorphic history of some important fragments of the Meliata-related Triassic and Jurassic sedimentary complexes in northern Hungary. Their results indicate a complex imbricated structure of the area with low-grade metamorphosed rocks sandwiched between non-metamorphosed partial nappe units, thus important post-metamorphic out-of-sequence thrusting involving the Meliata accretionary complex. The Central Western Carpathians (CWC) are composed of a system of basement and cover thrust sheets located between two suture zones – Meliata in the south and Pieniny Klippen Belt in the north. Putiš et al. collected a set of new white mica 40Ar/39Ar ages from thrust-related shear zones of various CWC units, which clearly indicate a foreland-propagating, piggy-back mode of thrusting within the CWC orogenic wedge during the Cretaceous. The pre-Alpine crystalline basement complexes are widespread in the central Carpathian zones (the Tatric, Veporic and Gemeric thrust sheets from bottom to top). While the Veporic basement complexes are strongly affected by the Cretaceous