Paleocene Flysch Research Articles

Деформації зони насуву між скибами Зелем’янка і Парашка Скибового покриву Українських Карпат (Гребенівський кар’єр)

In the article, based on own field observations, the deformation structures into the thrust zone of the Zelemianka Skyba (=thrust-sheet) onto the Parashka Skyba (the Ukrainian Carpathian Skyba Nappe) are described. They are exposed in the Hrebeniv quarry located in the Opir River basin (Lviv Region, Skole district). The tectonically disintegrated Stryi Formation (Upper-Cretaceous–Paleocene flysch) characterized by the rigid sandstone blocks (formed mainly as a result of boudinage) placed in a ductile clay matrix is represented in the Hrebeniv quarry. This formation is proposed to be classified as a “broken formation”, which is strongly tectonized, but retain their lithological and stratigraphic identity. It is a transitional element between the weakly deformed strata and tectonic mélange. Their characteristic features are: linearity of the distribution zone; significant monomictic composition and absence of exotic formations; the presence of an intensively tectonized matrix with clastolites (blocks) of less tectonized rocks of the same lithostratum (formation, series); the presence of newly formed hydrothermal minerals in clastolite cracks; the upper and lower contacts limiting the broken formation have a tectonic nature. An intensely tectonized matrix and a weakly tectonized rigid blocks belong to the same stratigraphic unit in a broken formation. The structural features suggest a brittle deformations in the studied rocks. Tectonic processes occurred in the completely lithified deposits. Thrust processes were accompanied by the formation of the duplexes, including antiformal stack duplexes, which are well expressed in the quarry. Duplexes are observed in different parts of the quarry, and the most representative ones are developed in its central section. Horses in the duplexes are characterized by a size of 1 to 3 meters here. They are generally subparallel, which is consistent with monoclinal bedding, however, they sometimes acquire an antiform appearance as a result of tectonic thrusting.

Paleocene deposits of the Ukrainian Carpathians: geological and petrographic characteristics, reservoir properties

The Paleocene Yamna Formation represents one of the main oil-bearing sequences in the Ukrainian part of the Carpathian petroleum province. Major oil accumulations occur in the Boryslav-Pokuttya and Skyba Units of the Ukrainian Carpathians. In the great part of the study area, the Yamna Formation is made up of thick turbiditic sandstone layers functioning as reservoir rocks for oil and gas. The reconstructions of depositional environments of the Paleocene flysch deposits performed based on well log data, lithological and petrographic investigations showed that the terrigenous material was supplied into the sedimentary basin from two sources. One of them was located in the northwest of the study area and was characterized by the predominance of coarse-grained sandy sediments. Debris coming from the source located in its central part showed the predominance of clay muds and fine-grained psammitic material. The peculiarities of the terrigenous material distribution in the Paleocene sequence allowed singling out four areas with the maximum development (> 50% of the total section) of sandstones, siltstones and mudstones. The performed petrographic investigations and the estimation of reservoir properties of the Yamna Formation rocks in these four areas allowed establishing priority directions of further exploration works for hydrocarbons in the study territory.

Calcareous nannofossil assemblages from Paleocene sediments of the Ukrainian Carpathians

Problem statement. Detail study of both vertical and spatial distribution of calcareous nannofossils from the Paleocene sediments of the Ukrainian Carpathians enabled to determine the evolutional development of Haptophyta algae during the Paleocene, and became the basis for correlation of boundary markers and correlative biohorizons. Here we summarize data obtained from previous research, and also our own, and propose an updad biozonation of Paleocene sediments of the Northern and Southern slopes of the Ukrainian Carpathians. Prerious work. Calcareous nannofossil research of the area goes back to the 1960’s. These studies had a fragmentary character with only few sections examined for their nannofossil content. Materials and research methods. The paper includes the results of nannofossil research from numerous sections of Paleocene Flysch developed in the Outer and Inner Carpathian nappes. Discussion of the research data. The paper discusses the biozonation and correlation of local lithostratigraphic units of the Ukrainian Carpathians based on the detail study of nannofossils. For the first time, the complete successions of nannozones of the latest Geological Time Scale have been identified in the Ukrainian Carpathians. In the Outer (Flysch) Carpathians several nannozones were determined within the Skyba and Boryslav-Pokuttya nappes. There include – Markalius inversus / Biantholithus sparsus (NP1), Cruciplacolithus tenuis (NP2), Chiasmolithus danicus (NP3) and Ellipsolithus macellus (lower NP4) in the Upper Striy subsuite; top Ellipsolithus macellus (NP4), Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6) in Yaremcha Formation, Discoaster mohleri (NP7) in Bytkiv layers, Heliolithus riedelii (NP8), Discoaster multiradiatus (bottom NP9) from the Yamna suite; Chiasmolithus danicus (NP3) from Upper Bereznyan subsuite of Dukla nappe; Fasciculithus tympaniformis (NP5) in Gnylets suite of Chornohora nappe and Markalius inversus (NP1) in Urdyn suite of Svydovets nappe. Within the Inner Carpathians nannozones were defined in the Lower Metova subsuite of the Vezhany nappe – Biantholithus sparsus (NP1), Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6), Heliolithus riedelii (NP8); Sushmanets suite of Monastyrets nappe contained Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6) and Tribrachiatus contortus (NP10) of the Early Ypresian. The stratigraphic positioning of nannofossil assemblages was rectified and their correlation with foraminifera and dinocyst zones was demonstrated. These nannozone assemblages from the Ukrainian Carpathians are correlated with the Danian, Selandian and Thanetian stages of the Geological Time Scale (GTS, 2012 and 2016). This integrated research enables to rectify and modify the stratigraphic scheme of the Paleogene from the Carpathian region. Conclusions. A modern calcareous nannofossil biozonation of the latest International schemes has been recognized from the studied Paleocene sections of the Ukrainian Carpathians. Nine (9) nannozones ranging from NP1 (Early Danian) to NP9 (Late Thanetian – Early Ypresian) and also the lowest NP10 nannozone of Early Ypresian have been identified in strata from different structural-tectonic units. The nannofossil biozonation is correlated with those foraminifera and dinocyst biochronology. The age and correlation for the Paleocene stratigraphic subdivisions has been justified based on the nannofossil biostratigraphy. This resulted in the upgrading of the existing stratigraphic scheme of the Paleogene of the Ukrainian Carpathians.

Impact of geodynamics on fluid circulation and diagenesis of carbonate reservoirs in a foreland basin: Example of the Upper Lacq reservoir (Aquitaine basin, SW France)

Abstract Orogeny-driven fluids that circulate in foreland basins can have strong impacts on petroleum systems and reservoir properties. This applies to the Upper Cretaceous Lacq reservoir of the Aquitaine Basin in southwestern France located north of the Pyrenean Mountains. We study a drillcore from a 650 m deep oil reservoir to document how the evolution of a foreland basin, which formed after a hyperextension phase, affected fluid circulation and eventually reservoir diagenesis. Using drillcore samples, petrographic observations, fluid inclusion studies coupled with thermodynamic modeling, isotopic and rare earth element geochemistry, as well as basin modeling were performed to investigate and describe the fluid types and sources, the pressure-temperature evolution and the timing of diagenetic fluid flow. Early diagenesis involves some bacterial activity represented by micrite rims and framboidal pyrites, as well as early dolomitization involving a mixture of meteoric and formation fluids. During burial, dolomite overgrowth, saddle dolomites, coarse blocky calcites and anhydrites precipitate. The last products consist of iron oxide precipitation and meteoric recharge of the reservoir with groundwater. Our results indicate that after the deposition of the Paleocene flysch formation, Mg-rich, low salinity, hot, and relatively deep clay-released fluids migrated along thrust faults from deeper parts of the basin during the climax of the compressional Pyrenean phase (Eocene). They acted as dolomitizing hydrothermal fluids with a thermal disequilibrium in the order of 30–40 °C hotter than the ambient host rocks. Another orogeny-driven, hydrothermal and Mg-poor fluid mixed with oil generated by Jurassic-Barremian source rocks and precipitated calcites and anhydrites. Finally, during uplift, oxidizing fluids were laterally introduced as the present-day groundwater. Hence, by combining different petrographic, geochemical and modeling proxies, we document how the Eocene orogenic phase played a crucial role in basin-scale fluid flow and carbonate diagenesis.

LOFTUSIA CF. ANATOLICA HORIZON IN UPPER MAASTRICHTIAN LIMESTONES OF THE EASTERN GREECE PLATFORM (MOUNT PTOON, BOEOTIA, GREECE): PALAEOBIOGEOGRAPHICAL REMARKS

Researches on upper Cretaceous limestones from the Eastern Greece platform in the area between Kokkinon and Akrefnion (Boeotia, Greece) revealed the presence of a horizon rich in Loftusia cf. anatolica (foraminifer). In this horizon, of late Maastrichtian age, L. cf. anatolica is associated with debris of Rudists, Orbitoides media, O. apiculata, O. gensacicus, Siderolites calcitrapoides, Omphalocyclus macroporus, Hellenocyclina beotica, Miliolidae, Dasycladaceae and echinoderms. It is found in an undisturbed sequence of limestones, where both the underlying and the overlying horizons are of the same facies and contain debris of Rudists, Hellenocyclina beotica, Orbitoides media, Siderolites calcitrapoides, Sulcoperculina sp., Rotaliidae, Mélobesiées,Nummofallotia sp., echinoderms. L. cf. anatolica is confined in the above mentioned horizon and it is found neither in the underlying nor in the overlying beds. This fades reflects an outer shelf environment in front of the rudist reefs. It is the first time that this species is reported in situ in Greece in an undisturbed stratigraphie sequence of upper Cretaceous limestones up to Paleocene flysch.

Olistostromes of the Pieniny Klippen Belt, Northern Carpathians

AbstractThe olistostromes form two belts within the Pieniny Klippen Belt (PKB) in the Northern Carpathians. They mark an early stage of the development of the accretionary prism. The first belt was formed during Late Cretaceous time as a result of subduction of the southern part of the Alpine Tethys. The fore-arc basin originated along this subduction zone, with synorogenic flysch deposits. Huge olistoliths deposited within the Cretaceous–Palaeogene flysch of the Złatne Basin, presently located in the vicinity of the Haligovce village (eastern Slovakia), provide a good example of the fore-arc olistostrome setting. The second belt is related to the movement of the accretionary prism, which overrode the Czorsztyn Ridge during Late Cretaceous–Paleocene time. The destruction of this ridge led to the formation of submarine slumps and olistoliths along the southern margin of the Magura Basin. The Upper Cretaceous – Paleocene flysch sequences of the Magura Basin constitute the matrix of olistostromes. The large Homole block in the Jaworki village represents the best example of the Magura Basin olistolith. Numerous examples of olistoliths were documented in western Slovakia, Poland, eastern Slovakia and Ukraine. The olistostromes formed within the Złatne and Magura basins orginated during the tectonic process, forming the olistostrome belts along the strike of the PKB structure.

Origin and resedimentation of rhodoliths in the Late Paleocene flysch of the Polish Outer Carpathians

This study analyses the rhodolith-bearing deposits in the largest and most rhodolith-rich outcrop of the Polish Outer Carpathian flysch, located in the Silesian Nappe, at the village of Melsztyn. The rhodoliths and sparse associated biota occur as resedimented components in a deep-marine succession of siliciclastic conglomerates and coarse-grained sandstones, deposited by high-density turbidity currents and debris flows. The sediment was derived from a fan-delta system located at the southern margin of the Silesian flysch basin. Stratigraphic data indicate that the succession represents the Upper Istebna Sandstone deposited during the Late Paleocene. The rhodoliths are composed mostly of coralline red algae with seven genera and eight species representing the family Sporolithaceae and the subfamilies Mastophoroideae and Melobesioideae. Rhodoliths show sub-spheroidal and sub-ellipsoidal shapes with encrusting, warty and lumpy growth forms. Lumpy growth forms show massive inner arrangements, whereas the encrusting growth forms are usually made of thin thalli and show more loosely packed inner arrangements. The rhodoliths grew on a moderately mobile siliciclastic substrate in a shallow-marine environment with a low net sedimentation rate. It is inferred that the growth of rhodoliths was favored during a relative sea-level rise. During the subsequent sea-level fall, the rhodoliths and associated siliciclastic deposits were resedimented by gravity flows into the deep-sea setting. The analyzed deposits, like other Paleocene–Eocene deposits of the Polish Outer Carpathians, provide no evidence of coeval widespread shallow-marine carbonate sedimentation along the margins of the Outer Carpathian flysch 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.

Geologie der Iberger Klippen und ihrer Flysch-Unterlage

Geologie der Iberger Klippen und ihrer Flysch-Unterlage

Detrital blue amphiboles from the western Othrys Mountain and their relationship to the blueschist terrains of the Hellenides (Greece)

In contrast to blue amphiboles of the Ossa and Olympos tectonic windows in Thessaly, detrital blue amphiboles in Paleocene flysch deposits in the western Othrys Mountain (Pelagonian Zone s.l.) are chemically comparable with blue amphiboles from the Cyclades. For the detrital material, therefore, a source with "Cycladic" chemical affinities is assumed. The occurrence of these detrital minerals is in line with a Cretaceous onset of blueschist facies metamorphism in parts of the Hellenides, especially in the Cycladic belt. This was in response to Cretaceous subduction of the Pindos oceanic plate along the external margin of the Pelagonian micro-continent. Blueschist complexes were exhumed latest in the Paleocene when the terrigenous flysch sedimentation started in the Pelagonian and Pindos zones.

Redeposited Rudists in Paleocene Flysch near Anhovo (Slovenia)

Breccias in the Lower Paleocene flysch near Anhovo contain rudists that lived at the northern edge of the Dinaric carbonate platform, from where they were transported into the flysch basin during the disintegration of the platform. We described the following redeposited rudists from the Lower and Upper Cretaceous: Vaccinites vesiculosus (Woodward), Hippuritella lapeirousei (Goldfuss), H. nov. sp. ex gr. castroi sensu Vicens, H. heritschi (Kühn), Hippurites bioculatus (Lamarck), H. conicus adriaticus Sladić-Trifunović, H. turgidus Rolland du Coquan, H. colliciatus Woodward, Bournonia cf. excavata (D’Orbigny) Douvillé, Sabinia aniensis Parona, S. sublacensis Parona, Sabinia sp., Offneria cf. italica Masse, and Offneria sp.

Pre-tertiary blueschist facies metamorphism in the Hellenides evidenced by detrital blue amphiboles in the Paleocene flysch of the Othrys mountain

Analyses of detrital blue amphiboles from Paleocene flysch deposits of the western Othrys Mountain show a narrow compositional variability and are comparable with published analyses from the Cycladic Islands. In contrast, analyses from Pelagonian blueschists (Olympos, Ossa, Ambelakia) show a wide compositional variation that is rather due to the lithological variability of their parental rocks and incomplete overprinting by blueschist facies metamorphism. Combined with published evidence, the above features exclude the Pelagonian rocks from being the potential source of the detrital blue amphiboles. The latter were derived from a source with "Cycladic" affinities that (1) presently is not exposed, but may have been covered tectonically during the Tertiary and (2) has been already exposed to erosion in response to subduction at the Pindos oceanic realm at the active external Pelagonian margin during Maastrichtian/Paleocene times. The data demonstrate that blueschist facies metamorphism in the Hellenides started at Pre-Tertiary times.

Pironaea buseri n. sp. from olistostromal breccia of Paleocene flysch by Anhovo

A new species, Pironaea buseri, found in chaotic breccia in Paleocene flysch beds in the wider region of the Soca valley, is ascribed to the genus Pironaea Meneghini. The large L-S distance and equal L-S and E-S spacings distinguish the new species from any known pironaea species. The species was found with Vaccinites giordani (Pirona) and Hippuritella cornucopiae (Defranee).

A Section Across a Tethyan Suture in Northwestern Turkey

A section across a major Tethyan suture in northwestern Turkey is described in detail. The suture of Early Tertiary age juxtaposes two continental blocks with distinct stratigraphic, structural, and metamorphic features. The Sakarya Zone in the north is represented by Permo-Triassic accretion-subduction complexes, which are unconformably overlain by Jurassic to Paleocene sedimentary rocks. The Anatolide-Tauride Block to the south of the suture consists of two tectonic zones. The Tavsanli Zone consists of a coherent blueschist sequence with Late Cretaceous isotopic ages. This blueschist sequence is tectonically overlain by Cretaceous oceanic accretionary complexes and peridotite slabs. The Bornova Flysch Zone consists of Triassic to Cretaceous limestone blocks in an uppermost Cretaceous to Paleocene flysch. The suture is represented by a N-vergent thrust fault separating lithologies from these two continental blocks. The orogenic history of the region can be considered in two stages. In the Late Cretaceous...

Note sur l'existence d'un paleodome dans la region de Burguete-Arive-Arrieta (Pyrenees basques espagnoles) et ses relations metallogeniques avec les mineralisations peripheriques

Abstract Tetrahedrite, bornite, chalcopyrite, cinnabar, galena, sphalerite, celestite, and barite occur in fractured and faulted Triassic and Cretaceous formations on the flanks of the Oroz-Betelu anticline in northern Spain. The oldest formations exposed in the anticline are Devonian karstic limestone and clastics, intensely folded by the Hercynian orogeny and truncated by an erosion surface. Lower Triassic clastics rest upon the erosion surface, and are surrounded by a peripheral zone of upper Cretaceous limestone and dolomite outcrops. Late Cretaceous and Paleocene flysch, in turn, surround the older formations of the anticline. Cinnabar was deposited with quartz and chalcedony after copper mineralization, and does not occur in the tetrahedrite.