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Investigation of litho-biostratigraphic characteristics and geographical distribution of Coniacian-Santonian formations: a case study in the Aures Mountains, eastern Saharan Atlas, Algeria

Bentahar Fahima, Defaflia Nabil, Benmansour Sana, Fehdi Chemseddine

Geomatics, Landmanagement and Landscape

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2023

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no. 3

73--94

EN

The Coniacian-Santonian series in the Aures Mountains of northeastern Algeria is characterized by marly-dominated sedimentation processes. This study aims to comprehensively investigate this series by combining lithostratigraphic and biostratigraphic data. The unique paleogeographic position of the Aures basin supports the co-occurrence of diverse paleontological contents in the Upper Cretaceous sediments. The methodology employed in this study includes a detailed bio-lithostratigraphic analysis to subdivide the Coniacian-Santonian series into two distinct sets. The first set comprises alternating marl-limestone units that exhibit a high fossil concentration from the Coniacian age, while the second set mainly consists of marly sediments corresponding to the Santonian age. The results obtained from this study highlight the geographical distribution of litho-biostratigraphic characteristics and reveal the presence of two formations. The lower formation is characterized by carbonated marls intercalated with limestone banks, containing fossils of Peroniceras (Tissotia tissoto) from the Coniacian age. Meanwhile, the upper formation is predominantly marly and indicates the Santonian age by displaying fossils of Palcenticeras polypsis. Furthermore, a biostratigraphic analysis focused on foraminifers allows for the subdivision of the Coniacian-Santonian series in the Aures Mountains into three distinct biozones. The first biozone corresponds to the lower Coniacian age and is identified by the presence of Dicarinella primitiva. The second biozone represents the middle to upper coniacian age and contains Dicarinella concavata fossils. Finally, the third biozone, belonging to the Santonian age, is marked by the occurrence of Dicarinella asymetrica. The boundary between the Coniacian and Santonian series in the Aures Mountains is characterized by the first appearance of Dicarinella asymetrica and Palcenticeras polypsis species. This multidisciplinary study provides valuable insights into the litho-biostratigraphic characteristics and geographical distribution of the Coniacian-Santonian series in the Aures Mountains. The findings make a significant contribution to a better understanding of sedimentary processes and the paleontological content within this region during the Upper Cretaceous period.

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Palaeobiogeography, palaeoecology, and sequence stratigraphy of the Upper Jurassic carbonate succession of the Lar Formation, central Alborz Zone, Iran

Saleh Zahra, Reháková Daniela

Geological Quarterly

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2023

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Vol. 67, No. 2

art. no. 15

EN

Foraminifera, ammonites, and calcareous dinoflagellates were used for stratigraphy and, together with microfacies, for the assessment of the palaeoenvironmental conditions of the Upper Jurassic deposits in the central Alborz Zone of northern Iran. The Lar Formation (Lar Fm.) in the Polur section is of latest Oxfordian to early Kimmeridgian age. The ammonite Subnebrodites planula and the calcareous dinoflagellate Colomisphaera nagyi have been introduced as new biomarkers of the lower Kimmeridgian in the central Neo-Tethys. The distribution of calcareous dinoflagellates reflects possible dispersal routes along a narrow seaway between the western Neo-Tethys and the Alborz Zone in the central Neo-Tethys. The Terebella-Crescentiella associations of the Lar Fm. represent a low-energy setting under dysoxic conditions in the Central Neo-Tethys Ocean. The benthic foraminiferal assemblages in this formation show a high dominance of infaunal taxa and r-selected strategists. This assemblage is reminiscent of eutrophic conditions and low oxygen levels in the lower part of the Lar Fm. Good preservation of the hexactinellid sponges in the upper part of the Lar Fm. also indicates an oxygen-minimum zone. Three third-order depositional sequences can be distinguished in the study area based on six microfacies. Depositional sequence 1 (DS1) is composed mainly of argillaceous limestone and medium- to thick-bedded limestone, corresponding to an outer ramp-to-middle ramp environment. Depositional sequence 2 (DS2) comprises breccia limestone and thick-bedded limestone facies in its lower part and thin-bedded limestone to massive limestone in its upper part. The breccia limestone facies may be associated with subaerial exposure and reworking of previously deposited sediment during a relative sea level fall. The thin-bedded limestone to massive limestone of DS2 consists mainly of bioclastic mudstone to wackestone (outer ramp). These represent an deep-water outer homoclinal ramp facies. Depositional sequence 3 (DS3) consists mainly of massive limestone to thick-bedded limestone with a bioclastic peloidal microbial Crescentiella packstone (middle ramp). The relative stratigraphic positions of DSs1–3 and sequence boundaries in the uppermost Oxfordian to lower Kimmeridgian of the Polur area show a fair match to the upper Oxfordian to lower Kimmeridgian sequences (JOx7, JOx8, JKi1 and JKi2) on the global sea level curve.

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Middle Devonian Foraminifera from the Holy Cross Mountains

Gajewska Maria

Annales Societatis Geologorum Poloniae

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2022

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Vol. 92, No. 4

411--424

EN

The Middle Devonian was an exceptional time for foraminiferal evolution because of the emergence of the first true calcareous multilocular taxa. Despite being key forms for an understanding of the origin of foraminiferal multilocularity, which is one of the most intriguing events in the evolutionary history of the group, they are largely unstudied. These unique foraminifera, including representatives of the genera Cremsia, Moravammina, Pseudopalmula, Semitextularia, and Vasicekia, are presented herein as well as foraminifer-like microfossils of uncertain biological position. The studied material comes from the Middle Givetian strata of the Miłoszów section and the Eifelian part of the Grzegorzowice-Skały section (Holy Cross Mountains, Poland). Described isolated specimens are in an exceptionally good state of preservation on a worldwide scale, which enabled the detailed analysis of test morphologies, complementing previous papers based on less well-preserved material. The suggested systematics of the foraminifera collected attempts to revise scarce taxonomic data that is still under debate, especially the classification of Moravammina, Cremsia, and Vasicekia. The Devonian foraminifers presented were prominent endobenthic and epibenthic inhabitants of common organic coral-stromatoporoid buildups. Palaeobiogeographical records show that during the Middle Devonian, the studied forms extended their exclusive European distribution into further Laurussian shelves and shallow seas, located in the northern and southeastern parts of the Rheic basin. This assumes that such assemblages may be used as palaeoenvironmental indicators. However, at present, their correlative potential is unknown.

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Stratigraphy and palaeoenvironments in the upper Turonian to lower Coniacian of the Saxonian Cretaceous Basin (Germany) - insights from calcareous and agglutinated foraminifers

Besen Richard M., Achilles Mareike, Alivernini Mauro, Voigt Thomas, Frenzel Peter, Struck Ulrich

Acta Geologica Polonica

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2022

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Vol. 72, no. 2

159--186

EN

Upper Turonian to lower Coniacian marls of the Strehlen Formation of the Graupa 60/1 core were investigated for their foraminiferal content to add stratigraphical and palaeoenvironmental information about the transitional facies zone of the Saxonian Cretaceous Basin. Further comparison with foraminiferal faunas of the Brausnitzbach Marl (Schrammstein Formation) were carried out to clarify its relationship to the marls of the Graupa 60/1 core. Tethyan agglutinated marker species for the late Turonian to early Coniacian confirm the proposed age of the marls of the Graupa 60/1 core and the Brausnitzbach Marl. The palaeoenvironment of the marls reflects middle to outer shelf conditions. The maximum flooding zones of genetic sequences TUR6, TUR7 and CON1 could be linked to acmes of foraminiferal species and foraminiferal morphogroups. In general, a rise of the relative sea-level can be recognised from the base to the top of the marls of the Graupa 60/1 core. While agglutinated foraminiferal assemblages suggest a generally high organic matter influx and variable but high productivity in the Graupa 60/1 core, the Brausnitzbach Marl deposition was characterized by moderate productivity and a generally shallower water depth.

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The K-Pg boundary section at Nasiłów, Poland : stratigraphic reassessment based on foraminifers, dinoflagellate cysts and palaeomagnetism

Remin Zbyszek, Cyglicki Michał, Barski Marcin, Dubicka Zofia, Roszkowska-Remin Joanna

Geological Quarterly

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2021

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Vol. 65, No. 3

art. no. 45

EN

The Nasiłów section represents the uppermost part of the Middle Vistula River section, a classical Polish extra-Carpathian Cretaceous section, and gives access to the Cretaceous-Paleogene (K-Pg) boundary interval. Despite many papers that have been published so far, our newly collected data shed new light on the completeness of biostratigraphic and sedimentary records of the K-Pg at that site. The Nasiłów section encompasses the upper Maastrichtian regional XII and XIII foraminiferal assemblage zones and the lower Danian P0?-Pα standard planktonic foraminiferal zones. The K-Pg boundary is placed at the top of a phosphatic layer. The grey marly chalk unit, never before subjected to examination of biostratigraphically important taxa, displays blooms of guembelitrids pointing to the uppermost Maastrichtian (XIII foraminiferal assemblage Zone) as well as of planktonic and benthic foraminifers of a reduced test size. Such foraminiferal dwarfism is commonly observed near the end of the Cretaceous and interpreted as a response to the Deccan volcanism (possible 2nd phase) that caused climate changes and ocean acidification. The terminal Maastrichtian age of the marly chalk unit is additionally supported by an acme of the dinoflagellate cyst Palinodinium grallator, together with Tallasiphora pelagica and Disphaerogena carposphaeropsis. The “Greensand”, a distinct glauconite-quartz sand unit, contains exclusively terminal Maastrichtian planktonic foraminifers and dinoflagellate cyst assemblages. Individual specimens of Danian age are interpreted to be either an effect of contamination or were translocated down by burrowers into the Greensand. The lowermost portion of the Siwak (informal lithostratigraphic unit) demonstrates an early Danian age based on the co-occurrence of the common planktonic foraminifers Globoconusa daubjergensis, Guembelitria cretacea, Muricohedbergella monmouthensis, M. planispira, Planoheterohelix globulosa, Parvularuglobigerina extensa and P. alabamensis. The last occurrence of Palynodinium grallator and the first occurrences of Carptella cornuta and Senoniasphaera inornata, recorded directly above the phosphatic layer, support the same age assignment. The new palaeomagnetic data cannot prove remagnetization at the boundary interval, in contrast to previous research which gave support to a hiatus in the critical interval.

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Foraminiferal and calcareous nannoplankton biostratigraphy of the upper Badenian-lower Sarmatian strata in the SE Polish Carpathian Foredeep

Peryt Danuta, Garecka Małgorzata, Peryt Tadeusz Marek

Geological Quarterly

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2021

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Vol. 65, No. 1

art. no. 18

EN

The Badenian/Sarmatian boundary in the Central Paratethys has been traditionally identified by the faunal turnover recording an important environmental change possibly controlled by the change from marine to brackish conditions. The strata below the Badenian/Sarmatian boundary in the northern Carpathian Foredeep are included into the Pecten beds, and those above it into the Syndesmya beds. Foraminiferal study of the Babczyn 2 borehole which is one of the crucial sections in the northern Carpathian Foredeep, well-known for the depositional age of rhyolite tuff within the Pecten beds dated by Śliwiński et al. (2012) at 13.06 ±0.11 Ma, indicated that in fact the boundary occurs within the Syndesmya beds. This conclusion is based upon the rapid change from a stenohaline foraminiferal fauna to a euryhaline one, and the appearance of the species Anomalinoides dividens, the taxon regarded as the marker for the Sarmatian. In the Babczyn 2 and Cieszanów 1 (located ~2.5 km basinward of Babczyn 2) boreholes, Anomalinoides dividens appears 3.1-3.8 m above the replacement of stenohaline by euryhaline foraminifers. The calcareous nannoplankton study shows that the upper Badenian and the lower Sarmatian strata in the studied sections represent the NN6, undivided NN6-NN7, and NN7 zones.

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Biostratigraphy and sequence stratigraphy of the Lower Cretaceous in the NW part of the Mid-Polish Trough

Dziadzio Piotr, Ploch Izabela, Smoleń Jolanta

Geological Quarterly

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2021

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Vol. 65, No. 4

s. 237--257

EN

By comparison with the Lower Cretaceous of central and SE Poland, that of NW Poland (the Pomeranian, Szczecin, and Mogilno-Łódź troughs) has scarce biostratigraphic data. But, despite the lack of Lower Cretaceous exposure in the NW Polish Lowlands, borehole data, including borehole-cores and geophysical logs, allow analysis of complete successions. We refine the stratigraphic units using parallel studies of ammonites, microfauna and calcareous nannoplankton collected from the same intervals, and by correlating age-defined intervals with geophysical logs. Ostracod zones F to A are documented by the presence of ostracod assemblages representing the interval between the Upper Tithonian (ostracod zone F) and the lower part of the Upper Berriasian (ostracod zones E to A). The fragmentary and poorly preserved ammonites allowed only for distinguishing the uppermost Middle and Upper Berriasian (Ryazanian), while the informal subdivisions from the central part of the basin could not be identified unequivocally. Nannoplankton recognized in the succession analysed was very rare due to shallow marine facies of the strata. Only one nannoplankton zone was recognized in the lower part of the succession studied: the CC2 Stradneria crenulata Zone (uppermost Middle and Upper Berriasian and lowermost Valanginian). An additional study only on nannoplankton enabled recognition of certain boreal taxa typical of the BC2 zone of the Uppermost Riazanian. Valaginian ammonites occur in core material located closer to the central part of the trough. Some planktonic foraminiferal species indicate the Lower Aptian. Some Upper Cretaceous nannoplankton zones were also recognized: the CC9 Eiffellithus turriseiffeli (Uppermost Albian to Lower Cenomanian) and UC0, UC1-2 and UC3 zones which correspond to the Upper Albian and Lower as well as Middle Cenomanian. The sequence stratigraphic interpretation was based on geophysical logs with the application of gamma-ray, neutron-gamma, spontaneous potential and resistivity logging, as well as caliper logging. These studies allowed recognition and correlation of sedimentary sequences within the part of the sedimentary basin analysed, characterized by a similar cyclic pattern of geological phenomena described using depositional sequences as in the central and SE part of the Polish Basin. Third-order depositional sequences with maximum flooding surfaces were distinguished. Effective correlation of depositional cycles with biostratigraphy and with the global sea level curve was demonstrated for several boundaries, confirming the applicability of this method for the Polish part of the the Central-European Basin. Other boundaries recognized that are not correlatable and shifted relative to Haq’s curve may reflect autogenous factors (e.g., local tectonics) overlapping with the global changes controlled by allogenic processes.

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Campanian-Paleocene Jaworzynka Formation in its type area (Magura Nappe, Outer Carpathians)

Waśkowska Anna, Golonka Jan, Starzec Krzysztof, Cieszkowski Marek

Acta Geologica Polonica

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2021

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Vol. 71, no. 3

345--370

EN

The Campanian-Paleocene Jaworzynka Formation, a part of the Magura Nappe succession in the Polish Outer Carpathians, is described in terms of its detailed litho- and biostratigraphy. The formation stretches along the marginal part of the Siary Unit, from the Jaworzynka stratotype area in the Silesian Beskid Mts up to the Mszana Dolna area in the Beskid Wyspowy Mts. Its equivalent in the Moravskoslezské Beskydy Mts of the Czech Republic is the Soláň Formation. In the stratotype area, the formation displays complex structure. We distinguish four lithological units, i.e., Biotite Sandstone and Shale (I), Shale (II), Mutne Sandstone Member (III) and Thin-bedded Turbidite (IV) and provide the first detailed biostratigraphy of particular units. The first unit forms the most prominent part of the formation. It was deposited in the Middle Campanian-earliest Maastrichtian within the upper part of Caudammina gigantea Zone up to the lower part of the Rzehakina inclusa Zone. The second unit occurs only locally and its age is limited to the Maastrichtian, to the Rzehakina inclusa Zone. The third unit is composed of thick-bedded sandstones that in some parts may form more than the half of the total thickness of the formation. It is Late Maastrichtian-Danian in age and is placed in the upper part of the Rzehakina inclusa Zone and the lower part of the Rzehakina fissistomata Zone. It is usually covered by a thin package of thin-bedded turbiditic sandstone and shales of Danian-Thanetian age with foraminifera of the Rzehakina fissistomata Zone.

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The evolution of the Carpathian Foredeep Basin during the latest Badenian and Sarmatian (Middle Miocene) : inferences from micropalaeontological data

Dumitriu Simina Dumitriţa, Dubicka Zofia, Loghin Sergiu, Melinte-Dobrinescu Mihaela Carmen, Paruch-Kulczycka Jolanta

Geological Quarterly

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2020

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Vol. 64, No. 4

1004--1022

EN

Seven Middle Miocene (Upper Badenian to Lower Sarmatian) sedimentary sections of the Central Paratethys, two from the Polish Carpathian Foredeep Basin (PCFB) and five from the Eastern Carpathian Foreland Basin (ECFB) of Romania and the Republic of Moldova have been analysed micropalaeontologically to better constrain the Badenian-Sarmatian Extinction Event, characterized by significant taxonomic impoverishment of both foraminifers and ostracods. Our studies show significant palaeoenvironmental changes in the basin including depth, salinity, oxygenation, and organic matter flux. The occurrence of moderately diverse planktonic foraminifera (Globigerina, Globigerinita, Globorotalia, Trilobatus, Orbulina, Velapertina) in the Upper Badenian deposits of the PCFB as well as in the ECFB and their rarity in the lowermost Sarmatian indicate an almost fully marine environment during the latest Badenian, followed by a significant regression and possible appearance of much more restricted marine conditions across the boundary. The taxonomic composition of the Sarmatian foraminifera, ostracoda and calcareous nannofossils indicate that during this interval the salinity fluctuated strongly, with the water regime varying from brackish to normal marine. In addition, the identified micropalaeontological assemblages identified show palaeoenvironmental similarity across different basins of the Central Paratethys. This supports a hypothesis of possible connections during the latest Badenian between different areas of the Central Paratethys, as well as of the existence of a gateway between the Central Paratethys and the Mediterranean realm.

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Foraminiferal and calcareous nannoplankton bioevents and changes at the Late Cretaceous : earliest Paleogene transition in the northern margin of Tethys (Hyżne section, Polish Carpathians)

Machaniec Elżbieta Katarzyna, Kowalczewska Oliwia, Jugowiec Małgorzata, Gasiński M. Adam, Uchman Alfred

Geological Quarterly

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2020

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Vol. 64, No. 3

567--588

EN

Foraminifera and calcareous nannoplankton from the Cretaceous-Paleogene (K-Pg) transition in the Hyżne section (Outer Carpathians, south-eastern Poland) show a relatively complete biostratigraphic record. Despite the absence of the Pα Zone in turbiditic deposits of the Polish Carpathians, the planktonic foraminiferal zones of the Late Cretaceous-Early Paleogene interval are well defined, including (1) the late Maastrichtian Abathomphalus mayaroensis Zone and its equivalents, (2) the earliest Danian Guembelitria cretacea second bloom Zone (P0 Zone), and (3) the top of the early Danian Parasubbotina cf. pseudobulloides (P1a) Zone. The foraminiferal events recorded in the studied section at the K-Pg transition are stratigraphically important. They include: (1) the interval with A. mayaroensis occurrence, (2) the interval with gradual disappearance of planktonic foraminifera from the most complex K-strategy forms, through the less specialized species to the large Heterohelicidae turnovers, and (3) the G. cretacea first and second blooms. Furthermore, the bloom of the opportunistic, benthic Bolivinita sp., the size reduction event, and the dissolution of the tests of the planktonic foraminifera are recorded. The K-Pg interval bioevents can be useful for better stratigraphic resolution of the flysch deposits of the Outer Carpathians. The nannoplankton event is represented by the appearance of Cruciplacolithus primus, which marks the onset of the return to more stable environmental conditions after the perturbations at the K-Pg boundary. The K-Pg boundary occurs within dark grey marly mudstones, above the upper boundary of the G. cretacea first bloom, and above the highest occurrence of the agglutinated foraminifera Goesella rugosa, at the top of the nannofossil CC 26 Zone, and below the deep-water agglutinated foraminifera (DWAF) dominance. The foraminiferal assemblages derive from different bathymetric zones corresponding to (1) the upper bathyal zone in the late Campanian (nannoplankton CC 22 Zone) and early late Maastrichtian (A. mayaroensis Zone), (2) the shelf margin in the latest late Maastrichtian (CC 26 nannoplankton Zone, G. cretacea first bloom), (3) the shelf margin in the earliest Danian (G. cretacea second bloom, Np1/2 Zone), and (4) the middle-lower bathyal depth, below a local foraminiferal lysocline and above CCD, in the latest early Danian (P. pseudobulloides Zone). As the foraminifera could have been redeposited by turbiditic currents, they do not necessarily show real bathymetric changes in the area of deposition. Such changes have not been observed in sedimentary features of the studied deposits. Foraminiferal and nannoplankton assemblages are typical of the “transitional zone” between the Tethyan and Boreal domains.

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Turonian-Coniacian (Upper Cretaceous) of the Babadag Basin (North Dobrogea, Romania) : integrated biostratigraphy and microfacies succession

Lodowski Damian Gerard, Walaszczyk Ireneusz Piotr, Grădinaru Eugen

Geological Quarterly

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2019

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Vol. 63, No. 1

39--64

EN

The Upper Turonian to Middle Coniacian (Upper Cretaceous) succession of the Babadag Basin (North Dobrogea, Romania) constitutes an apparently continuous fossiliferous carbonate succession. The presence of moderately rich inoceramid, ammonite and foraminiferal assemblages allows for the application of a precise biostratigraphic subdivision. The palaeoenvironmental conditions and evolution of the Babadag Basin during the Late Turonian-Middle Coniacian are inferred using microfacies analysis and foraminiferal spectra. Together, these suggest the Turonian-Coniacian Badabag Basin reflects relatively shallow-water conditions in a near-shore environment, punctuated by two regression events in the Late Turonian and in the Middle Coniacian.

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The Late Cretaceous Fucoid Marl of the Ropianka Formation in the Kąkolówka Structure (Skole Nappe, Outer Carpathians, Poland) : lithology and foraminiferal biostratigraphy

Waśkowska Anna, Joniec Andrzej, Kotlarczyk Janusz, Siwek Piotr

Annales Societatis Geologorum Poloniae

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2019

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Vol. 89, No. 3

259--284

EN

A 250-m-thick sedimentary succession dominated by siliciclastic deposits occurs in the Kąkolówka Structure of the Skole Nappe. The succession was deposited in the inner part of the Skole Basin during the Late Cretaceous. In position and age, it corresponds to the Kropivnik Fucoid Marl of the Wiar Member (a subdivision of the Ropianka Formation), which was comprehensively described in the external part of the Skole Nappe. In this study, the authors provide the first complete data set on the lithological development and biostratigraphy of the Kropivnik Fucoid Marl from the inner part of the Skole Nappe. The results are compared to previous data from the outer part of the Skole Nappe. In the Kropivnik Fucoid Marl of the Kąkolówka Structure, three main heterolithic facies associations are distinguished: shale-sandstone, marl-sandstone and sandstone-shale. The occurrences of hard, platy and soft marls within siliciclastic rocks are typical of the sections studied. The features observed indicate a turbiditic origin of the deposits studied, including the hard, platy marls. The allogenic material of the strata described includes the small, fragile tests of planktonic foraminifera, which were redeposited from the outer parts of the Skole Basin. Particularly large concentrations of planktonic foraminifera were observed in the hard, platy marls. They are less common in the soft marls and shales. In the Zimny Dział section, a diverse assemblage of benthic and planktonic foraminifera was found. The Kropivnik Fucoid Marl was dated as uppermost Campanian to lowermost Maastrichtian on the basis of planktonic foraminifera, which represent the Gansserina gansseri Zone. The agglutinated foraminiferal assemblages are representative for the lower part of the Rzehakina inclusa Zone and the co-occurrence of the Caudammina gigantea (Geroch) acme with Rzehakina inclusa (Grzybowski) was observed.

13

Potential source rocks in the Ropianka Formation of the Magura Nappe (Outer Carpathians, Poland) – geochemical and foraminiferal case study

Waśkowska A., Golonka J., Machowski G., Pstrucha E.

Geology, Geophysics and Environment

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2018

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Vol. 44, no. 1

49--68

EN

To optimize exploration for new hydrocarbon accumulations in the Polish Outer Carpathians, it is necessary to concentrate attention on identification of hydrocarbon accumulations of the “shale-gas” type. Results of recently completed analysis suggested new such possible targets in the Magura Basin, preserved in the Outer Carpathian Magura Nappe. Analysis of the preliminary results of paleoenvironmental and geochemical studies of these shales is the subject of this paper. Micropaleontological and geochemical study was conducted on the 300 m thick Świątkowa Member, the uppermost part of the Ropianka Formation located in the external, northernmost Siary Zone. This member is composed of thin- and medium-bedded sandstones interbedded by green, brown, black and dark-gray shales. Poor and changeable oxygenation is reflected in the composition of foraminiferal assemblages. A negative correlation between the TOC content and numbers and diversity of foraminifera is observed. The paleogeographic position and paleoenvironment assessment indicates that the Siary Zone fulfills certain conditions for organic productivity and preservation during the deposition of the Ropianka Formation.

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Timing of Langhian bioevents in the Carpathian Foredeep and northern Pannonian Basin in relation to oceanographic, tectonic and climatic processes

Holcová K., Doláková N., Nehyba S., Vacek F.

Geological Quarterly

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2018

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Vol. 62, No. 1

3--17

EN

The succession of bioevents in planktonic foraminifer and calcareous nannoplankton communities is reviewed and summarized for the Carpathian Foredeep and northern Pannonian Basin in the time interval between ~16 and 13.5 Ma. This succession can be subdivided into three principal intervals: (1) an interval with rare Praeorbulina sicana and P. glomerosa. It was characterized by a limited immigration of index taxa linked to the lack of a warm surface water layer in the Central Paratethys. This interval can be correlated with the first Badenian transgression near the Burdigalian/Langhian boundary. The rare occurrence of biostratigraphical markers does not allow its precise dating and interregional correlation; (2) a brief interval of the first occurrences of Praeorbulina circularis, Orbulina suturalis and Helicosphaera waltrans. This can be related to the formation of a warm surface water layer suitable for the survival of orbulinas and praeorbulinas and a change from estuarine to anti-estuarine circulation. This interval can be correlated with the second Badenian transgression, which, however, was not isochronous over the area as inferred from different successions of these first occurrences; (3) a limited appearance of new index taxa in the Central Paratethys prior to the Wielician Salinity Crisis. This time interval was characterized by increased seasonality and salinity oscillations followed by climate cooling. A “reverse” migration of the stress-tolerant species Helicosphaera walbersdorfensis from the Central Paratethys to the Mediterranean is suggested. Several local bioevents with limited stratigraphic correlation potential have been recognized in this interval.

15

Coiling direction in Middle Miocene globorotaliids (Foraminiferida) : a case study in the Paratethys (Upper Silesia Basin, Poland)

Gonera M.

Geological Quarterly

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2018

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Vol. 62, No. 1

155--171

EN

The paper deals with sub-evaporite Badenian deposits (Middle Miocene, Paratethys) that display a sudden appearance of globorotaliid taxa showing preferences in the taxonomic set and coiling direction. An interval of sinistrally coiled Jenkinsella mayeri with proportionally coiled Globoconella bykovae is at the bottom of the studied sequence. It is followed by an interval of proportionally coiled Jenkinsella transsylvanica. Proportionally coiled Globoconella bykovae with a small number of proportionally coiled Jenkinsella transsylvanica are at the top of the Moravian (CPN 7) substage (Orbulina suturalis alias Lagenidae Zone). The sub-evaporite part of the Wielician (CPN 8) substage (Uvigerina costai alias Spiroplectammina Zone) began with a globorotaliid-barren interval (IIC biozone). It is followed by biozone IID displaying three globorotallid peaks amongst globorotallid-barren deposits. Only globoconellas are present in all these three events. Proportionally coiled Globoconella bykovae appeared first. It is followed by proportionally coiled Globoconella minoritesta and sinistrally coiled Globoconella bykovae at the end of the biozone IID. Coiling preferences of globorotaliids have been compared to changes in the hydrographic regime unfolding during the CPN 7 and CPN 8 in the studied area of the Paratethys. The study discovers that the coiling of globorotaliids responded selectively to the hydrographic changes. Globoconella bykovae is highly opportunistic and can tolerate considerable temperature changes. Specimens of this taxon persist to coil proportionally during the sub-evaporite Badenian, except for the shift to sinistral coiling just prior to the Wielician evaporites. Sinistrally coiled Jenkinsella mayeri is the most sensitive to hydrographic changes. This taxon retreated at the onset of the temperature drop during the mid-Moravian cryptic cooling. This cooling is marked by the new jenkinsellid occurrence – proportionally coiled Jenkinsella transsylvanica. Proportionally coiled Globoconella minoritesta is present in the middle of the IID globorotaliid peaks. The globorotaliid coiling data, presented in this paper, has been calibrated to the global stratigraphy. The integrated data (foraminifera, nannofossils, oxygen and carbon stable isotopes, radiometric measurements) supports the view that the CPN 7/CPN 8 boundary is coeval to the Langhian/Serravalian one. In the Polish part of the Carpathian Foredeep, the boundary runs within the Skawina Formation.

16

Impact of shelf-transformed waters (STW) on foraminiferal assemblages in the outwash and glacial fjords of Adventfjorden and Hornsund, Svalbard

Szymańska N., Pawłowska J., Kucharska M., Kujawa A., Łącka M., Zajączkowski M.

Oceanologia

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2017

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No. 59 (4)

525--540

EN

A new dataset of benthic foraminiferal assemblages from Adventfjorden (tributary fjord of Isfjorden, West Spitsbergen) was compared with the results of a study conducted by Zajączkowski et al. (2010) in Hornsund (West Spitsbergen). According to Nilsen et al. (2016), Atlantic water inflow to the Isfjorden Trough occurs more readily than to anywhere else along the shelf of Spitsbergen; thus, we compared the foraminiferal assemblages of the outwash Adventfjorden fjord, located in the Isfjorden system, with glacial Hornsund, located in southwest Spitsbergen. Despite the juxtaposition of Adventfjorden and Hornsund the data revealed varying impacts of shelf-transformed water (STW) on the benthic foraminiferal assemblages. Outer and central Adventfjorden was dominated by Adercotryma glomerata, Recurvoides turbinata and Spiroplectammina sp., reflecting the presence of STW, while abundant Melonis barleeanus in the central area of the fjord indicated a large flux of unaltered organic matter. Only the head of the fjord was dominated by the glaciomarine taxa Cassidulina reniforme and Elphidium clavatum. Foraminiferal fauna characteristic of STW-influenced environments (i.e., Nonionellina labradorica and R. turbinata) were also observed in outer Hornsund. However, the glacier-proximal taxa E. clavatum and C. reniforme were dominant throughout the fjord, demonstrating the impacts of meltwater and high sedimentation. Therefore, it is likely that in Hornsund, glacial impact is a major environmental factor, which is stronger than the influence of STW.

17

Palaeontological analysis of Middle Miocene siltstones at Wiślica (Carpathian Foredeep, Poland)

Płonka K.

Geologos

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2017

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Vol. 23, No. 1

29--43

EN

Middle Miocene siltstones of the Skawina Formation that crop out at Wiślica, within the axial part of the Carpathian Foredeep in Poland, were analysed. The deposits studied contain numerous benthic and planktonic foraminifera, ostracods, echinoid spines, bryozoans, bivalves and otoliths. The fossils recognised document an early ‘Badenian’ (= Langhian in the Mediterranean area), or, more precisely, ‘Moravian’ age of the deposit. Palaeoecological analysis suggests normal-marine conditions with full salinity. The studied siltstones were deposited from middle–lower shoreface to lower–offshore, warm surface water and locally suboxic to dysoxic conditions in the sediment.

18

Environmental stress in the northern Tethys during the Paleogene : a review of foraminiferal and geochemical records from the Polish Outer Carpathians

Olszewska B., Szydło A.

Geological Quarterly

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2017

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Vol. 61, No. 3

682--695

EN

During the Paleogene, the area of the northern Tethys was controlled by a turbidity system stimulated by diastrophic and geodynamic processes. These factors contributed to the dispersion and rapid oxygenation of organic debris. Its accumulation was a consequence of stagnant bottom water conditions that periodically occurred in the basin. In these periods, intense decomposition intensified by hydrothermal and diagenetic processes was associated with oxygen consumption and the release of greenhouse gases, which led to hypoxia and acidification. These phenomena intensified by thermal and density stratification had a major impact on the structure, evolution and distribution of biota. Stress associated with rapidly changing conditions induced by sedimentary process and upwelling resulted in the dominance of forms that colonized most sediments (Glomospira, Ammodiscus, Recurvoides, Rzehakina) and surface waters (Guembelitria, Chiloguembelina, Globanomalina, Globigerina, Cassigerinella, Catapsydrax). At the time, foraminifera were limited to low-diversified eutrophic assemblages or were mainly replaced by siliceous phytoplankton (radiolarians and diatoms). Geochemical data confirm that environmental crises in the Paleogene basin took place under changing thermal conditions that reflect global events (KTBE, PTME, EEOC and TTE). Thermal stress favouring the formation of certain minerals or rocks occasionally occurred during the Paleocene to Eocene (siderite, phosphates) and dominated in the Early Oligocene (silica).

19

Campanian–Maastrichtian foraminiferal stratigraphy and palaeoenvironment of the Lower Tar Member in the Wadi Tar section, Western Sirte Basin (Libya)

Tshakreen S. O., Gasiński M. A., Machaniec E., Mącznik A.

Annales Societatis Geologorum Poloniae

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2017

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Vol. 87, No. 4

349--362

EN

Upper Campanian–Maastrichtian sections on the western flank of the Hun Graben in the Western Sirte Basin (WSB) are displaying two major type facies based on the foraminiferal assemblages. The first one indicates open-marine to outer-shelf conditions, and is represented by numerous bathy-pelagic planktonic foraminiferal species referable to the Radotruncana calcarata, Globotruncana aegyptiaca and the lower part of the Gansserina gansseri Zone (all late Campanian).The second type facies indicates an inner-shelf environment and is represented in the middle-upper part of the Gansserina gansseri Zone (early Maastrichtian) and Racemiguembelina fructicosa (late Maastrichtian) dominated by epi-pelagic planktonic and large benthic foraminifers. Large benthic foraminiferal index species Siderolites calcitrapoides Lamarck and Omphalocyclus macroporus (Lamarck) occur in abundance by the middle–late Maastrichtian. Correlation between planktonic foraminiferal zonation and large benthic foraminiferal zonation is given. An open-marine to outer-shelf environment passed into shallower marine conditions during the late Campanian–early Maastrichtian to late Maastrichtian, then a slight deepening and again shallowing is noticed.

20

Within-year spatio-temporal variation in meiofaunal abundance and community structure, Sinop Bay, the Southern Black Sea

Ürkmez D., Sezgin M., Karaçuha M. E., Öksüz İ., Katağan T., Bat L., Dağlı E., Şahin F.

Oceanological and Hydrobiological Studies

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2016

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Vol. 45, No. 1

55--65

EN

The first comprehensive meiobenthos study was carried out in Turkey, the Southern Black Sea (Sinop) from August 2009 to July 2010. Sediment samples were collected monthly at eight stations at 3 m and 10 m water depths located on four transects. A metal push core sampler (surface area 12.56 cm2 and length 10 cm) was used to obtain the material. Meiofaunal abundance and composition were examined. The results revealed that the meiofaunal community consists of twenty five higher taxonomic groups. Four groups dominated the community: Nematoda, Harpacticoida, Foraminifera and Polychaeta. Spatial and temporal meiofaunal abundance fluctuated among stations and over time.