12 research outputs found

    Middlesex/punctata Event in the Rhenish Basin (Padberg section, Sauerland, Germany) – Geochemical clues to the early-middle Frasnian perturbation of global carbon cycle

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    A positive carbon stable isotope excursion of about 3‰is documented in the topmost lower Frasnian at Padberg, eastern Rhenish Massif, as a muted record of the worldwide early−middle Frasnian isotopic perturbation (punctata Event; up to 6–8‰ shift in both δ13Ccarb and δ13Corg elsewhere), comparable with the Appalachian δ13C curve. This German isotopic signature occurs in a 12 m thick calciturbidite succession and correlates well with the three-step chemostratigraphic pattern known from the Holy Cross Mountains, Poland. It is especially clear in the δ13Corg shifts, whilst δ13Ccarb (and elemental geochemical) proxies are partly biased by post-sedimentary alterations. The New York State, Polish, Nevada and Padberg conodont successions place the onset of the major positive δ13C excursion slightly beneath the early–middle Frasnian boundary, with Ancyrodella nodosa (previously Ad. gigas form 1) as the main conodont guide species, and coincident with the Middlesex transgression and spread of cold, nutrient-rich, poorly oxygenated water masses. In the light of geochemical proxies, enhanced primary production and oxygen deficiency occurred evidently in the Rhenish Basin during the punctata Event. Moderate Hg enrichments in the early Middlesex/punctata Event interval suggest a volcanic signature. However, conclusive data from other regions are required to differentiate between effects of the regionally wellknown synsedimenary magmatism and of a possible global volcanic trigger for the biogeochemical perturbation

    Integrated palynostratigraphy and magnetostratigraphy of the Middle and Upper Buntsandstein in NE Poland : an approach to correlating Lower Triassic regional isochronous horizons

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    Despite years of research, Lower Triassic deposits of the epicontinental Central European Basin still lack a detailed stratigraphy that would allow regional correlation of isochronous horizons. The best chronostratigraphic results have up to now been achieved by microspore-based biostratigraphy and magnetostratigraphy. Integrated palynostratigraphic and magnetostratigraphic investigations, carried out on Buntsandstein cores from northeastern Poland representing the eastern margin of the basin, have made precise correlations with the better-explored basin centre. The Lidzbark and Malbork formations of the Bartoszyce IG 1 borehole were examined by means of palynology and palaeomagnetic studies. Further palaeomagnetic studies were applied to the Lidzbark, Malbork and Elbląg formations of the Nidzica IG 1 borehole and the Elbląg Fm. of the Pasłęk IG 1. Two spore-poll en assemblages were distinguished representing the Densoisporites nejburgii Subzone of the D. nejburgii Zone within the lower part of the Lidzbark Fm. and the lowermost part of the Malbork Fm. Mostly reversed polarity was detected within the lower part of the succession investigated, whereas normal polarity prevailed within its upper part. A normal polarity local zone was correlated with the undivided Tbn6-Tbn7 standard magnetozones of western Poland. The reversely polarized part of the succession corresponds most probably to the Tbr5 standard magnetozone. The base of the Tbn6-Tbn7 magnetozone can serve as a good correlation horizon for regional reconstructions

    Devonian/Carboniferous boundary interval in Poland : multidisciplinary studies in pelagic (Holy Cross Mountains and Sudetes) and ramp (Western Pomerania) successions

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    A multidisciplinary study of the Devonian–Carboniferous boundary interval in pelagic successions of the Holy CrossMountains and Sudetes and the ramp successions in the Western Pomerania region (Poland) is presented herein. The analysis applies the results of new palaeontological and biostratigraphic studies based mainly on conodonts, ammonoids and palynomorphs, biostratigraphic results interpreted earlier by different authors that have been re-examined, and geochemical and mineralogical characteristics, as well as magnetic susceptibility measurements across the Devonian–Carboniferous boundary interval. The study is focused on the interval from the Famennian ultimus conodont Zone to the Tournaisian duplicata conodont Zone, and from the Famennian lepidophyta–explanatus (LE) miospore Zone to the Tournaisian verrucosus–incohatus (VI) miospore Zone, respectively. The paper highlights sections, which are the most representative for the Devonian–Carboniferous boundary in each region, illustrates and summarises current knowledge on the uppermost Famennian to lowermost Tournaisian in these regions, gives data and correlation of the important stratigraphic markers for each region, and briefly correlates them outside the region. The sedimentary successions and specific phenomena, together with microscale environmental perturbations, recognised close to the Devonian/Carboniferous boundary in Poland, display a pattern similar to that observed in many areas in Europe during the Hangenberg Event

    The astronomical rhythm of Late-Devonian climate change (Kowala section, Holy Cross Mountains, Poland)

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    Rhythmical alternations between limestone and shales or marls characterize the famous Kowala section, Holy Cross Mountains, Poland. Two intervals of this section were studied for evidence of orbital cyclostratigraphy. The oldest interval spans the Frasnian-Famennian boundary, deposited under one of the hottest greenhouse climates of the Phanerozoic. The youngest interval encompasses the Devonian-Carboniferous (D-C) boundary, a pivotal moment in Earth's climatic history that saw a transition from greenhouse to icehouse. For the Frasnian-Famennian sequence, lithological variations are consistent with 405-kyr and 100-kyr eccentricity forcing and a cyclostratigraphic floating time-scale is presented. The interpretation of observed lithological rhythms as eccentricity cycles is confirmed by amplitude modulation patterns in agreement with astronomical theory and by the recognition of precession cycles in high-resolution stable isotope records. The resulting relative time-scale suggests that ∼800kyr separate the Lower and Upper Kellwasser Events (LKE and UKE, respectively), two periods of anoxia that culminated in massive biodiversity loss at the end of the Frasnian. Th/U and pyrite framboid analyses indicate that during the UKE, oxygen levels remained low for 400kyr and δ13Corg measurements demonstrate that more than 600kyr elapsed before the carbon cycle reached a steady state after a +3‰ UKE excursion. The Famennian-Tournaisian (D-C) interval also reveals eccentricity and precession-related lithological variations. Precession-related alternations clearly demonstrate grouping into 100-kyr bundles. The Famennian part of this interval is characterized by several distinctive anoxic black shales, including the Annulata, Dasberg and Hangenberg shales. Our high-resolution cyclostratigraphic framework indicates that those shales were deposited at 2.2 and 2.4Myr intervals respectively. These durations strongly suggest a link between the long-period (∼2.4Myr) eccentricity cycle and the development of the Annulata, Dasberg and Hangenberg anoxic shales. It is assumed that these black shales form under transgressive conditions, when extremely high eccentricity promoted the collapse of small continental ice-sheets at the most austral latitudes of western Gondwana

    Magnetic susceptibility and spectral gamma logs in the Tithonian-Berriasian pelagic carbonates in the Tatra Mts (Western Carpathians, Poland): Palaeoenvironmental changes at the Jurassic/Cretaceous boundary

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    International audienceUpper Tithonian–Berriasian pelagic carbonates in the Central Western Carpathians, Tatra Mts (southern Poland), with well-established bio- and magnetostratigraphy, provide excellent possibilities of testing magnetic and geochemical methods as proxies of palaeoenvironmental changes in the Western Tethys at the Jurassic/Cretaceous boundary. Magnetic susceptibility (MS), field spectral gamma-ray (GRS) as well as CaCO3, total organic carbon (TOC), and elemental analyzes were performed in the Pośrednie III section. MS reveals very good negative correlation with CaCO3 content as well as positive correlation with Al, Zr, Ti and other lithogenic elements and therefore it might be interpreted as a proxy of a detrital input into the basin. Abrupt MS variations correlate well with relative sea-level changes and indicate regressive intervals (MS highs) in the upper Tithonian/lowermost Berriasian (M20r to M19n2n) and upper Berriasian (M16n) and transgressive interval (MS low) in the lower to middle Berriasian (M18r to M17r). Long-term MS variations might be linked to a palaeoclimatic-controlled enhanced continental runoff. Geochemical data (P, Th/U, Mn, Cd, Ni, Mo and TOC content) point to a productivity increase and a slight oxygen deficiency in the lower and middle Berriasian, which corresponds to MS low values and typical calpionellid limestone sedimentation. Timing of major palaeoenvironmental turnovers might be correlated also with general palaeoclimatic trends in the Western Tethys and Western Europe: cooling in the late Tithonian followed by a temperature increase throughout the Berriasian and an important humidity increase in the middle Berriasian (M17n)

    Paleomagnetism and integrated stratigraphy of the Upper Berriasian hemipelagic succession in the Barlya section Western Balkan, Bulgaria : implications for lithogenic input and paleoredox variations

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    A continuous Late Berriasian sedimentary and stratigraphic record is here presented from a hemipelagic succession from the Western Balkan (Barlya section, Bulgaria). The section, 39-m-thick, was stratigraphically calibrated using a variety of methods: biostratigraphy (calpionellids, calcareous nannofossils and calcareous dinocysts), magnetostratigraphy and carbon isotope stratigraphy. Additionally, chemostratigraphy and rock magnetic stratigraphy were applied in order to identify major paleoenvironmental changes: lithogenic input and paleoredox variations. Polarity zones from M17r to M14r were identified from the uppermost Lower Berriasian up to the Berriasian/Valanginian boundary (Elliptica to Darderi calpionellid subzones and NK-1 to NK-3 nannofossil zones). Late Berriasian calcareous dinocyst zones of Stomiosphaerina proxima, Stomiosphaera wanneri and Colomisphaera conferta were correlated with magnetostratigraphy for the first time. A carbon isotope profile correlates very well with the δ13C records from SE France and the Western Atlantic, documenting some well-resolved minima and maxima in a generally decreasing trend. Magnetic susceptibility (MS) reveals a very good positive correlation with lithogenic elements (e.g., Al, Ti, Zr, Th and others) and is regarded as a reliable proxy of detrital input. Influx of fine grained terrigenous material increases in the Upper Berriasian up to the Berriasian/Valanginian boundary. A prominent MS increase takes place in the lowermost part of polarity zone M16n (close to the Simplex/Oblonga subzonal boundary). The MS event can be traced in the Central Carpathian, Apennine and SE France sections, exactly in the same stratigraphic position. It is coeval with an important climatic turnover in Western Tethys; however, it might have been strengthened by a general regression and regional tectonic events in the Carpatho–Balkan area. Two oxygen deficient intervals were documented: the first in the Lower Berriasian (M17r to M16r); the second one in the uppermost Upper Berriasian up to the boundary with Valanginian (M15r to M14r). Both intervals correlate with an elevated sea-level in the Western Tethys

    New Opportunities for Oil and Gas Exploration in Poland—A Review

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    Reserves totaling ~142 BCM (5 TCF) of natural gas trapped in 306 fields and ~22 MTOE (~157 MMBOE) of crude oil in 87 fields have been discovered. The prospection, exploration, and production of hydrocarbons are licensed: an entity interested in these kinds of activities needs to have concession, which is granted by the Polish Ministry of Climate and Environment for 10 to 30 years according to one of two independent ways—international tender or open door procedure. In this review, the most prospective areas for oil and gas exploration in Poland, selected by the Polish Geological Survey, and announced as dedicated for the next 6th tender round, planned in the second half of 2022, are described. These are: Block 413–414, Block 208, Cybinka–Torzym, Zielona Góra West, and Koło areas. The main exploration target of these tender areas is related to conventional and unconventional accumulations of gas and oil in the Carpathian basement, Carpathian Foredeep, and Outer Carpathians (Block 413–414), as well as in the Carboniferous, Permian Rotliegend, Zechstein Main Dolomite (Block 208, Cybinka–Torzym, Zielona Góra West), and in the Mesozoic of the Polish Lowlands (Koło). The second way of granting concession in Poland is the so-called open door procedure, in which an entity may apply for a concession for any other area selected on its own

    Prospection and exploration of oil and gas fields in Poland : 6th tender round

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    On June 30, 2021 the Polish Minister of Climate and Environment announced the boundaries of five areas dedicated for the next, 6th tender round for hydrocarbon concessions in Poland, planned for the second half of 2022. These are: Block 413-414, Block 208, Cybinka-Torzym, Zielona Góra West, and Koto tender areas. The main exploration target of these areas is related to conventional and unconventional accumulations of gas and oil in the Carpathian basement, Carpathian Foredeep and Outer Carpathians (Block 413-414), as well as in the Carboniferous, Permian Rotliegend, Zechstein Limestone, and Main Dolomite (Block 208, Cybinka-Torzym, Zielona Góra West) and in the Mesozoic of the Polish Lowlands (Koto). The other way of granting hydrocarbon concessions in Poland is the open door procedure, in which an entity may apply for concessions for any other area

    An account of the bio- and magnetostratigraphy of the Upper Tithonian-Lower Berriasian interval at Le Chouet, Drôme (SE France).

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    24 pagesInternational audienceThis paper discusses the results of a study of the Le Chouet section, its lithologies, facies, magnetic properties and fossil record (ammonites, calcareous nannofossils, calpionellids and calcareous dinoflagellates). Data obtained have been applied to give a precise biostratigraphy for this carbonate sequence as well as a paleoenvironmental reconstruction. Its relationship to magnetostratigraphy, based on a modern study of a French site, is important. Investigation of the micro- and macrofossils shows that the site comprises a sedimentary sequence in the Microcanthum to Jacobi ammonite Zones, and the Chitinoidella, Crassicollaria and Calpionella Zones. Several calpionellid and nannofossil bioevents have been recorded on the basis of the distribution of stratigraphically important planktonic organisms. The site allows us to calibrate the levels of various biomarkers and biozonal boundaries, and correlate them with the magnetozones M20n, M19r and M19n
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