Wyniki wyszukiwania - Biblioteka Nauki

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Geology and Petrography of a Large Porphyritic Andesite Dyke at Paradise Harbour, Danco Coast, West Antarctica

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Birkenmajer K. , Lorenc M.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2003

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tom Vol. 51, nr 2

161-171

EN

A large porphyritic dyke exposed at Porphyry Ridge, Paradise Harbour, Danco Coast (northern Antarctic Peninsula, West Antarctica), consists of albitized andesite. Together with other hypabyssal intrusions (dyke swarm) and plutonic intrusions (granite-granodiorite-gabbro - mainly sills), it belongs to the Late Cretaceous Andean Intrusive Suite (AIS) which post-dates a monotonous, some 2000 m thick, Early Cretaceous basaltic-andesitic volcanic pile (Antarctic Peninsula Volcanic Group - APVG). The volcanic effusions (APVG) and the successive plutonic and hypabyssal intrusions (AIS) had formed in response to subduction of the SE Pacific oceanic crust under continental crust of Antarctic Peninsula.

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Late Cretaceous nautilids from northern Cantabria, Spain

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Wilmsen M.

Acta Geologica Polonica

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2000

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tom Vol. 50, no. 1

29-43

EN

Nautilids do not occur throughout the Upper Cretaceous succesion in northern Cantabria. Alrhough relatively rare, they preferentially occur in condensed transgressive horizons. Nine species belonging to the genera Angulithes MONTFORT 1808, Eutrephoceras HYATT 1894, and Pseudocenoceras SPATH 1927 are recorded. A. westphalicus (SCHLUTER 1872) and E. cf. justum (BLANFORD 1861) are reported for the first time from the Iberian Peninsula. The diagnosis of A. vascogoticus WIEDEMANN 1960 is emended. The Cenomanian was characterized by a relative abundance of nautilids of the genus Angulithes which display a major radiative event, evolving relatively short-lived species. This development was probably related to the "Cenomanian transgression". Compared to co-occuring ammonite faunas, Angulithes inhabited deeper and more distal environments. A possible transitional form, connecting the two genera Angulithes and Deltocymatoceras KUMMEL 1956 (?Turonian, Coniacian - Santonian), is recorded from the Mid-/Late Cenomanian. The Turonian to Campanian succession is dominated by long-ranging nautilids of the genus Eutrephoceras.

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On the systematics of rugoglobigerinids (planktonic Foraminifera, Late Cretaceous)

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Georgescu M. D.

Studia Geologica Polonica

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2005

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tom Vol. 124

87-98

EN

A subdivision of the Late Cretaceous planktonic foraminiferal family Rugoglobigerinidae is now proposed according to the nature and patterns in ornamentation as well as the development of peripheral structures. Typical rugoglobigerinids, namely those presenting meridionally arranged pustules, rugosities and costellae are retained within the subfamily Rugoglobigerininae. The sub- family Archaeoglobigerininae is now erected to accommodate taxa presenting chamber ornamen- tation consisting of not fused pustules, papillae, rugosities, and spines which are not arranged following a meridional pattern. In what concerns the peripheral structures, whose development is regarded as indicative for adaptation to deeper water environments. It is demonstrated that the two subfamilies, Rugoglobigerininae and Archaeoglobigerininae respectively, present quasi-parallel evolutionary strategies. The status of the genus Rugotruncana is revised. Transitional specimens between Archaeoglobigerina blowi and Rugotruncana subcircumnodifer from the Upper Campanian of the New Jersey coastal plain demonstrate that Rugotruncana is the only known double-keeled rugoglobigerinid, and is included in the subfamily Archaeoglobigerininae, rather than among the Globotruncanidae.

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Plectoeratidus subarcticus, n.gen., n.sp., a new agglutinated foraminifer from the Upper Cretaceous of the western Barents Sea

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Kaminski M. A. , Setoyama E. , Tyszka J.

Annales Societatis Geologorum Poloniae

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2009

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tom Vol. 79, No 2

141-146

EN

We describe the new foraminiferal genus and species Plectoeratidus subarcticus n.gen. n.sp., from the Upper Cretaceous deep-water deposits of the Kviting and Kveite formations in the western Barents Sea. The genus is characterised by its planispiral-biserial-uniserial chamber arrangement, terminal aperture and lateral compre- ssion. The biometric analysis of test ontogenesis has been applied to document its dimorphism attributed to megalospheric and microspheric generations. This taxon may represent an evolutionary transition between the Cretaceous genera Spiroplectammina or Bolivinopsis and the Cenozoic genus Eratidus. The taxon appears to be endemic to the flysch-type agglutinated foraminiferal assemblages in the Norwegian Sea area.

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The stratigraphically earliest record of Diplomoceras cylindraceum (heteromorph ammonite) : implications for Campanian/Maastrichtian boundary definition

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Remin Z. , Machalski M. , Jagt J. W. M.

Geological Quarterly

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2015

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tom Vol. 59, No. 4

843--848

EN

A fragmentary specimen of the diplomoceratid heteromorph Diplomoceras cylindraceum, one of three ammonite markers used for the definition of the base of the Maastrichtian Stage, is recorded from the middle Campanian of the Roztocze Hills, southeast Poland. The new find, well constrained by associated ammonites and inoceramid bivalves, represents the earliest well-dated occurrence of this species worldwide to date. Therefore, the first occurrence (FO) of D. cylindraceum is conspicuously below the traditional base of the Maastrichtian as defined by the FO of the belemnite Belemnella lanceolata. Indeed, this is also far below the boundary designated in the Global Stratotype Section at Tercis les Bains (Landes, France). A comparison of the FOs of D. cylindraceum in sections acrossEurope clearly shows a significant diachroneity, which diminishes its value for definition of the Campanian/Maastrichtian boundary.

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Foraminiferal biostratigraphy and palaeobathymetry of Senonian marls (Upper Cretaceous) in the vicinity of Kraków (Januszowice-Korzkiew area, Bonarka quarry) - preliminary study

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Machaniec E. , Zapałowicz-Bilan B.

Studia Geologica Polonica

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2005

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tom Vol. 124

285-296

EN

In the vicinity of Kraków, Upper Cretaceous sediments rest upon the Upper Jurassic (Oxfordian) massive limestones and are developed as sands, conglomerates and marls. Foraminiferal assemblages from Upper Cretaceous sediments are dominated by calcareous benthic forms whereas planktonic foraminifers are rare and represented by Hedbergella and Whiteinella (sporadically also Marginotruncana and Globotruncana). Taxa identified in foraminiferal assemblages enable to distinguish several zones: Lower Santonian Gavelinella thalmanni partial range zone, the Bolivinoi- des strigillatus partial range zone (Upper Santonian and lowermost Turonian) and the Lower Campanian Bolivinoides decoratus partial range zone. Analysis of foraminiferal assemblages allows us to draw preliminary conclusions concerning the palaeobathymetry of the Late Cretaceous basin in the study area. Palaeobathymetric evaluations give a maximum basin depth of about 200 meters.

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Biostratigraphy and Palaeoenvironmental Analysis of the Żegocina Marls in the Żegocina Tectonic Window (Subsilesian Unit, Polish Outer Carpathians)

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Gasiński M. , Leśniak T. , Wróbel A.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2003

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tom Vol. 51, nr 1

1-9

EN

The Żegocina siliceous marls contain well preserved and diversified foraminiferal assemblages dated as late Early Campanian - Early Maastrichtian (from G. ventricosa to G.gansseri standard zones). Based on qualitative and quantitative analyses of foraminiferal assemblages, external shelf - upper slope have been suggested as the deposition palaeodepths of the studied marls.

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Biostratigraphy and Palaeoecology of the Late Cretaceous Foraminiferids at Krzyworzeka Stream Section (Subsilesian Unit, Polish Outer Carpathians)

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Machaniec E. , Gasiński M. , Leśniak T.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2001

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tom Vol. 49, nr 2

99-107

EN

Assemblages of foraminiferids from the Upper Cretaceous section of the Subsilesian unit (Polish Outer Carpathians) have been analyzed. The age of the studied samples bas been estimated as Turonian-Campanian, based on agglutinated as well as planktonic foraminiferids. Morphogroup analysis of the studied foraminiferids showed an increase of the organic flux on the basin floor.

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Environmental changes during the Cenomanian-Turonian Boundary Event in the Outer Carpathian basins: a synthesis of data from various tectonic-facies units

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Bąk K.

Annales Societatis Geologorum Poloniae

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2007

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tom Vol. 77, No 2

171-191

EN

The paper summarizes the results of author’s studies on the environmental changes around the Cenomanian-Turonian Boundary Event (CTBE) in the Outer Carpathian basins located close to the northern margin of the Western Tethys, whose sea floor was situated below the calcite compensation depth. The sedimen- tary, biotic and chemical records allowed to recognize the successions related to the oceanic anoxic event (OAE-2) and trace changes around this event sediments within the frame of the stable carbon isotope excursion and biostratigraphic datum events. The changes so traced included changes in: type of deep-water sedimentation, accumulation rate, productivity, oxygenation of bottom water and benthic foraminiferal assemblages. Correlation of the palaeoenvironmental changes with the carbon isotope curve and biostratigraphic datum events allowed the comparisons between the various sedimentary areas in the Outer Carpathians, and with other areas of the Western Tethys. Most of the interpreted events around the CTBE were synchronous in the northern branch of the Western Tethys that extended to the Umbria-Marche and Sicily carbonate platforms. These events included: (1) an increase in productivity before the interval with the highest shift in d13C values, (2) the main interval of organic-rich sedimentation (Bonarelli level), (3) a rapid change to oxygenated sediments near the Cenomanian-Turonian (C-T) boundary and continued during the Early Turonian, (4) fluctuations in oxygen content in bottom waters with short intervals of anoxia during the earliest Turonian, (5) deposition of a thick bentonite layer, near the start of the d13C excursion, roughly synchronous with the phase of a positive shift in Pb isotopic compositions in the silicate sediment fraction in one of the Umbria-Marche sections, (6) an interval of extremely low hemipelagic sedimentation with hiatuses near the base of the C-T boundary and during the earliest Turonian, correlated with the maximum rise of the sea level. The presented data from the Outer Carpathians suggest that the OAE-2 could be triggered by enhanced productivity; however, subaerial volcanic eruptions, accompanied by hydrothermal activity and formation of large igneous provinces could also be a factor which enriched the ocean-atmosphere system in CO2. Sluggish deep- water circulation, probably deteriorating through the Late Cenomanian, favoured preservation of organic matter during the latest Cenomanian. The mechanism of rapid oxygenation of bottom waters near the C-T boundary was related to recurrent inflows of (?)saline warm and oxygenated waters.

10

Provenance of Upper Cretaceous quartz-rich sandstones from the North Sudetic Synclinorium, SW Poland: constraints from detrital tourmaline

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Biernacka J.

Geological Quarterly

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2012

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tom Vol. 56, No 2

333-344

EN

Upper Cretaceous quartz arenites that fill the North Sudetic Synclinorium on the northern periphery of the Variscan Bohemian Massif show high compositional but low textural maturity. They have been interpreted for years as derived largely from nearby granite plutons, i.e. as first-cycle sediments. A different provenance was revealed on the basis of a combined light and heavy mineral analysis, and particularly a detrital tourmaline study, given that tourmaline is a sensitive indicator of granitic/metamorphic/sedimentary (multi-recycling) origin. Cenomanian, Turonian, Coniacian and Santonian sandstones contain abundant angular tourmaline grains, together with zircon and rutile, and subordinately staurolite, garnet, anatase, kyanite, sillimanite and monazite. The successive – Cenomanian to Santonian – tourmaline populations are similar with regard to shape, colour and chemical composition. The latter points unambiguously to various metamorphic rocks with a predominant group of Al-rich metapelites (Al-rich, F-poor dravite). It is concluded that, in the Late Cretaceous, large Sudetic granite plutons such as the Karkonosze and Strzegom–Sobótka massifs were not exposed but were buried under a thick siliciclastic cover. These results coupled with published apatite fission-track data from the granitic Karkonosze Pluton and the gneissic/migmatitic Góry Sowie Massif reveal that Late Cretaceous quartz arenites of the North Sudetic Synclinorium reflect gradual exhumation of the surrounding massifs, but do not record the final exposure of crystalline rocks. Since the latest Turonian, this exhumation corresponded to the Late Cretaceous inversion episode in Central Europe. The textural immaturity of Upper Cretaceous sandstones is misleading in terms of their recycled origin, and it is inherited from immature clastic source rocks.

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New biostratigraphic evidence (calcareous nannofossils, ostracods, foraminifers, ammonites, inoceramids) on the Middle Coniacian in the eastern Bohemian Cretaceous Basin

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Svobodova A. , Kočí T. , Kočová-Veselská M. , Ferré B. , Košťák M. , Čech S. , Chroustová M.

Geological Quarterly

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2019

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tom Vol. 63, No. 3

586--602

EN

The classical locality of Svinary in the eastern Bohemian Cretaceous Basin is the site of new biostratigraphic investigations. Besides some scarce macrofossil evidence, bulk sediment samples were processed to retrieve micropalaeontological assemblages, and calcareous nannofossil smear slides were analysed. The studied material provided calcareous nannofossil assemblages including Micula staurophora, Lithastrinus septenarius and Broinsonia parca expansa, thus documenting the Middle Coniacian (upper part of UC10 Zone and lower part of UC11 Zone). The foraminifera assemblage is relatively rich, planktonic species show a wide stratigraphical range, while the benthic association represented by Neoflabellina suturalis suturalis and Gaudryina carinata is very similar to the Coniacian biozone of Stensioeina granulata-Eponides whitei, valid for the Bohemian Cretaceous Basin. Ostracods are represented by two common cytherellid species, and two rare ornamented species: Imhotepia marssoni? and Pterygocythereis spinosa. Inoceramid bivalves, namely Platyceramus mantelli, and a newly recorded ammonite, Tridenticeras tridens, support the late Middle Coniacian age of the Svinary outcrop. New biostratigraphic results are given along with palaeoecological interpretations of newly collected fossil material.

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Late Cretaceous palaeoenvironmental and tectonostratigraphic reconstructions on the Polish sector of Peri-Tethys

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Kwietniak A. , Łaba-Biel A. , Urbaniec A. , Filipowska-Jeziorek K.

Geotourism / Geoturystyka

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2023

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tom nr 1-2 (72-73)

39--40

EN

The study area is located in the central part of the Carpathian Foreland in Poland (Fig. 1), and the analysed interval includes mixed carbonate-clastic sediments of the Upper Cretaceous and the uppermost part of the profile of carbonate sediments of the Upper Jurassic. The sedimentation of the studied formations during the Late Jurassic and Cretaceous took place in the shelf zone of the northern, passive margin of the Tethys Ocean. The western Tethys, unlike its eastern margins, was not a single open ocean; rather, it covered many small plates, Cretaceous island arcs and microcontinents (Palcu & Krijgsman, 2023). The spatial range of the subbasins created between these islands was significantly limited, resulting in a large diversity of palaeoenvironments and the mixed carbonate-clastic sediments of a shallow sea. The entire Upper Jurassic to Cretaceous complex can be viewed as a carbonate platform that lasted almost until the end of the Late Cretaceous with an episode of Early Cretaceous erosion. The sedimentary cover formed at that time initially reached considerable thickness (presumably about 2,000 m). Dislocation and bathymetric differentiation within the carbonate platform initiated the development of a complex depositional environment. During the Late Cretaceous, the syndepositional activity of NW-SE dislocation sequences resulted in an extensive flexural deflection within the Upper Jurassic-Lower Cretaceous sedimentary complex and lowermost part of the Upper Cretaceous complex. The resulting accommodation space was filled with a complex of Upper Cretaceous carbonate formations within which there are intervals with a significant share of siliciclastic material. At the end of the Late Cretaceous as well as in the Paleocene, movements of the Laramie phase led to the re-uplift of the analysed part of the Carpathian Foreland. During this tectonic episode, the reactivation of an older fault system occurred, mainly in the NW-SE directions. The Upper Cretaceous formations deposited in the flexural depression underwent a partial inversion and intensive erosion process, lasting until the beginning of the Neogene, which contributed to the reduction of thicknesses or the removal of some of the Upper Cretaceous formations, especially in the areas, adjacent to the major dislocations. The material for analysis consisted of 3D seismic data and geological information from the wells. In the scope of the project, we approached linking 3D seismic image and well data to reconstruct, as detailed as possible, the palaeoenvironment of the studied segment of the Late Cretaceous basin based on the chronostratigraphic method. The analysis shows various palaeomorphological elements that can bring insight into the sedimentation environments (Fig. 2). The significant influence of tectonic processes on the depositional history of the sedimentary basin was also evidenced. The tectonostratigraphic interpretation divided the Late Cretaceous sediments into two different tectonic phases (Łaba-Biel et al., 2023). Analysis of a thick Miocene interval that overlies directly on the Mesozoic formations enabled to reason about the influence of the Alpine orogenesis on the study area that was manifested by the reactivation of major regional faults in the central part of the Carpathian Foreland. This phase is directly related to the stage of progressive closure of the Tethys Ocean due to the collision of tectonic plates.

13

Injection dykes as evidence of Campanian synsedimentary tectonics on the Kraków Swell, southern Poland

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Kołodziej B. , Szulc J. , Machaniec E. , Kędzierski M. , Duda M.

Annales Societatis Geologorum Poloniae

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2010

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tom Vol. 80, No 3

285-301

EN

The topmost part of the Oxfordian limestones, building the Zakrzówek Horst in Kraków, is featured by a network of minute fissures, filled with Upper Cretaceous limestones. Fissures are dominantly subhorizontal, anastomosing and polygonal in plane. They are filled with white limestones representing mostly foraminiferal- calcisphere wackestones, with subordinate amount of quartz pebbles and fragments of stromatolite coming from the latest Turonian-?Early Coniacian conglomerate overlying Oxfordian basement. The fissures are seismically- induced injection dykes. In contrast to gravitationally-filled neptunian dykes the recognised injection dykes were filled by overpressured soft sediments. Foraminifera within some dykes are abundant, and dominated by planktonic forms, which indicate the Early/Late Campanian age (Globotruncana ventricosa and Globotruncanita calcarata zones) of the filling, and hence date also the synsedimentary tectonics. Abundant and diversified keeled globo- truncanids in the Campanian of the Kraków region are recognised for the first time. Other important findings at the studied section include karstic cavities featuring the surface of the Oxfordian bedrock filled with conglomerates of the latest Turonian-?Early Coniacian age based on foraminifera and nannoplankton, and lack of Santonian deposits, which elsewhere are common in the Upper Cretaceous sequences in the Kraków region. The discovered Campanian dykes provide new evidence for the Late Cretaceous tectonic activity on the Kraków Swell related to the Subhercynian tectonism, which resulted among others in stratigraphic hiatuses and unconformities characte- ristic of the Turonian-Santonian interval of this area.

14

Dinocysts from Upper Cretaceous deep-water marine variegated facies (Malinowa Shale Formation), Pieniny Klippen Belt, Poland: example from the Potok Trawne creek

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Gedl P.

Studia Geologica Polonica

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2007

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tom Vol. 127

139-152

EN

Dinocysts have been described for the first time from Upper Cretaceous deep-water marine variegated deposits of the Pieniny Klippen Belt, Poland. They have been found in the Malinowa Shale Formation (Grajcarek Succession) exposed at the Potok Trawne creek. Latest Turonian-Coniacian dinocysts occur in dark-coloured shale intercalations. Their assemblage consists mainly of well preserved small peridinioids (Palaeohystrichophora infusorioides and Alterbidinium sp.) and gonyaulacoids (Pterodinium and Spiniferites). Their motile stages inhabited offshore waters of the Magura Basin during Late Cretaceous. Dominance of peridinioids may indicate eutrophic conditions in the photic zone of the offshore waters induced by upwelling.

15

Structural inversion of the Pomeranian and Kuiavian segments of the Mid-Polish Trough-lateral variations in timing and structural style

75%

Krzywiec P.

Geological Quarterly

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2006

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tom Vol. 50, No. 1

151-168

EN

Seven high-quality reflection-seismic lines, calibrated by wells, were interpreted in an effort to assess the timing of inversion and the structural configuration of the Pomeranian and Kuiavian segments of theMid-Polish Trough. Seismostratigraphic analyses of the Upper Cretaceous successions imaged by these seismic lines in the NE and SW marginal troughs of the Mid-Polish Swell document important along-strike stratigraphic and structural changes. Thickness variations of the Upper Cretaceous series, combined with the development of erosional unconformities and associated tectonic deformations indicate that inversion movements commenced during the late Turonian and intermittently persisted into the Maastrichtian and Paleocene. Earliest inversion movements were focused on the margins of the Mid-Polish Trough where Mesozoic sequences are decoupled from the sub-Zechstein series by Zechstein salts. Whereas the NE margin of theMid-Polish Trough is devoid of compressionally reactivated salt structures, its SWmargin is characterized by strong inversion- related salt tectonics. Progressive inversion of the axial parts of the Mid-Polish Trough was accompanied by uplift of its pre-Zechstein floor to and above the level of flanking, non-inverted areas, and by deep truncation ofMesozoic series across the culmination of the evolving Mid-Polish Swell. Inversion movements ceased towards the end of the Paleocene, as evidenced by the burial of the Mid-Polish Swell beneath essentially flat lying Eocene and younger series. Turonian-Paleocene inversion of the Mid-Polish Trough is coeval with the inversion of the Bohemian Massif, the North German Basin and the Sorgenfrei-Tornquist Zone. Inversion of the Mid-Polish Trough is considered to have been controlled mainly by compressional intraplate stresses that built up in the Carpathian foreland during the collision of the Inner Carpathian orogenic wedge with the European passivemargin, attesting to their increasing mechanical coupling, commencing during the Turonian. These stresses relaxed, however, with the end-Paleocene onset of imbrication of the Outer Carpathian domain, reflecting decoupling of the Carpathian orogenic wedge from its foreland.

16

Late Cretaceous gastropod egg capsules from the Netherlands preserved by bioimmuration

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Zaton M. , Taylor P. D. , Jagt J. W. M.

Acta Palaeontologica Polonica

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2013

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tom 58

|

nr 2

EN

Clusters of gastropod egg capsules, inferred to be of neritoids and attached to the inner shell wall of the ultimate whorl of a large volutid gastropod, are here recorded from the upper Nekum Member (Maastricht Formation; late Maastrichtian) of the ENCI−Heidelberg Cement Group quarry, St Pietersberg (Maastricht, southeast Netherlands). Because the aragonitic shell of the volutid has dissolved, the outlines of the egg capsules are now revealed on the steinkern of indurated biocalcarenite, having been subsequently overgrown by cheilostome bryozoan colonies and preserved as mould bioimmurations. This represents the first example of gastropod eggs preserved through bioimmuration, as well as the first record of gastropod eggs from the Cretaceous.

17

Late Cretaceous foraminiferids from sections in the Zabratówka area (Skole Nappe, Outer Carpathians)

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Kowalczewska O. , Gasiński A.

Annales Societatis Geologorum Poloniae

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2018

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tom Vol. 88, No. 1

71--85

EN

Well preserved Late Cretaceous–Palaeogene planktonic and benthic foraminiferal assemblages were studied in the Zabratówka section of the Ropianka Formation in the Skole Nappe. The Racemiguembelina fructicosa and Abathomphalus mayaroensis standard foraminiferal biozones were distinguished. The K-T boundary was recognized within the interval between samples ZB10B–ZB9A, mainly composed of marly mudstones, interlayered with thin-bedded sandstones, and is characterized by the disappearance of planktonic taxa and an abundance of agglutinated species. Foraminiferal assemblages, collected from the turbiditic flysch-type sediments, indicate a primary depositional environment on the outer shelf to the upper part of the continental slope, with shallowing during the Maastrichtian in the part of the Skole Basin studied. The foraminiferids correspond to the assemblages of a palaeobiogeographical “transition” zone, located between the Boreal and Tethyan domains.

18

Halszka Osmolska [1930-2008]

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Borsuk-Bialynicka M. , Maryanska T.

Acta Palaeontologica Polonica

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2008

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tom 53

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nr 2

19

New data on anatomy of the Late Cretaceous multituberculate mammal Catopsbaatar

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Kielan-Jaworowska Z. , Hurum J. H. , Currie P. J. , Barsbold R.

Acta Palaeontologica Polonica

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2002

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tom 47

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nr 3

EN

The Gobi Desert is famous for providing one of the worlds best preserved Cretaceous terrestrial faunas, including dinosaurs and mammals. Beginning with the Central Asiatic Expeditions in the 1920s, through the Polish−Mongolian Expeditions in the 1960s–1970s, Soviet−Mongolian Expeditions in 1970s, and finally the Mongolian Academy−American Museum Expeditions in the 1990s–2000s, the number of complete skulls (see Kielan−Jaworowska et al. 2000 for review) of Cretaceous mammals often associated with postcranial skeletons, found in Mongolia increased to several hundred. In addition to these professional expeditions, there have been other types of trips to Mongolia, also aimed at collecting fossils. The Nomadic Expeditions Company in USA organizes one of these, and has made trips to Mongolia since 1996. During the 1999 Nomadic Expedition, a skull associated with parts of the postcranial skeleton of the multituberculate mammal Catopsbaatar catopsaloides was found. The specimen is more complete than others previously known of this species and brings new data on multituberculate anatomy and ontogenetic variation. In this note we discuss the new data on the structure of C. catopsaloides; the details of its anatomy will be described in subsequent papers by the two first authors.

20

Środowisko sedymentacji i domniemane źródło materiału detrytycznego w górnokredowej formacji red-bed Ashua (Peru)

63%

Paulo A. , Ciesielczuk J. , Racki G. , Żaba J. , Gaidzik K.

Przegląd Geologiczny

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2019

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tom Vol. 67, nr 3

189--191

EN

Ashua Formation was deposited in Coniacian-Early Santonian time near shore of a shallow sea and in a plethora of continental arid environments. Its main component is fine-grained siliciclastic materialforming lithic and subordinate arkosic graywackes. Limestones are frequent in the lower member, and in the upper one gypsum and halite are present. Based on sedimentary textures and detailed petrographic studies, nine general microfacies were identified: shallow sea, beach, brackisch and mud flats, lagoon, sabkha and playa, deltaic, alluvial, mud flows, dunes at shoreline of an agitated water basin. The present authors suggest that the main source of detritus was pyroclastic deposits. They probably belong to the heavily eroded Lower Cretaceous Matalaque Formation.