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EN
In the Paratethys Sea, isolation, the development of anoxia and stratification of the water column resulted in deposition of organic-rich sediments. In the Western Carpathians (Central Paratethys) these sediments now lie within the Menilite Formation. Whereas the Eocene-Oligocene transition has been studI ed in the Western Carpathians and is documented by dinoflagellate cyst assemblages, the dinoflagellate cyst stratigraphy of the Menilite Formation members has been uncertain. The Popiele Member and the Menilite Formati on exposed at Aksmanice (Boryslav-Pokuttya Nappe, Western Outer Carpathians) reflect palaeogeographic changes at the beginning of the Oligocene. These previously studied deposits have been assigned to lithostratigraphic units, though without biostratigraphic documentation. The age of the Menilite Fm. in the Carpathian sedimentary succession is particularly interesting dueto the diachronous character of the facies development. In this study we provide biostratigraphic data based on well-preserved organic-walled dinoflagellate cyst assemblages. The marker taxa recovered indicate a Rupelian age (Early Oligocene) for the Menilite Fm. A different assemblage occurs in the Popiele Member underlying the Menilite Fm. Here, the dinoflagellate cysts are more diverse and abundant, and represented by typical Eocene taxa attributed to Areosphaeridium spp. and Charlesdowniea spp. The Popiele Member may be assigned to the Priabonian (Late Eocene).
EN
Rocks deposited in the Oligocene Paratethys are recognized as one of the most important source rocks in the Flysch Carpathians. The Šitbořice Member (uppermost NP23 to lowermost NP25 zone) represents the upper part of the Menilite Formation in the Outer Flysch Carpathians of the Czech Republic. This paper presents results of bulk geochemical analysis, Rock-Eval pyrolysis and organic petrography. The geochemical evaluation, source rock potential, kerogen type and thermal maturity were studied using borehole cores. Based on the classification of Peters (1986), the evaluated Šitbořice Member is mostly classified as a “very good” source rock according to TOC and variable, mostly “poor” to “good” according to the petroleum potential. However, the average petroleum potential value assigned the member to “good” source rock which is in accordance with the TOC classification if the “live” TOC is used. A comparable distribution between kerogen type II and III has been indicated by HI. Unlike this, the organic petrography observations show the organic matter belongs to the kerogen type II which corresponds to the relationship of residual hydrocarbon potential versus TOC and HI calculated based on “live” organic carbon. Presumed immaturity was confirmed by Rr and Rock-Eval Tmax. Oxygen-restricted conditions ora dysoxic environment have been indicated by the TOC/TS ratio.
EN
Tourmaline populations studied from the Campanian-Maastrichtian part of the Ropianka (Upper Cretaceous-Paleocene) and Menilite (Oligocene) formations of the Polish Carpathians, represent a mixture of first-cycle and polycyclic grains. The tourmalines of the deposits studied display very strong resemblance in terms of optical features and chemical composition. They belong mostly to the schorl-dravite series with a minor contribution of tourmalines of foititic or Mg-foititic composition. Euhedral tourmalines originated from metasedimentary rocks, while the rounded grains crystallised in Li-poorgranitic rocks or in pegmatites, Al-poor and Al-rich metasedimentary rocks. Most of the tourmalines studied crystallised during a single igneous or metamorphic event. However, tourmal ines form ng in evolving chemical conditions as well as polymetamorphic grains (having a metamorphic detrital core and metamorphic overgrowths) are also present. The chemical composition of the metamorphic tourmalines studied indicates theirformation in medium-grade metamorphic conditions. This is supported by the crystallisation temperature of the garnet-biotite inclusion present in one of rounded metamorphic tourma l ines from the Ropianka Formation. The euhedral grains derive from metasediments, directly from a massif located close to the Skole Basin. The scarcity of euhedral grains in the tourmaline populations studied suggests that their source rocks were poor in these minerals. The direct sources of rounded tourmalines (most probably polycyclic grains), may have been Paleozoic and Mesozoic sedimentary rocks of the Skole Basin foreland or crystalline rocks of remote source areas. The initial igneous and metamorphic host rocks of the tourma l ines may have been crystall ine domains of the Bohemian Massif and/or the crystalline basement of Brunovistulicum.
EN
The study focused on the chemistry of detrital garnet and tourmaline from sediments of the Boryslav and Kliva Sandstone types in the Oligocene part of the Menilite Formation of the Skole Nappe (Western Outer Carpathians, Poland), with regard to provenance. Almandine and almandine-pyrope compositional varieties are the most common garnets, with minor almandine-pyrope-grossular garnet. Scarce garnet grains, with grossular and spessartine as the dominant end-members, are also present. The tourmaline belongs to the alkali tourmaline principal group and represents the schörl-dravite series. The detrital garnet and tourmaline display strong, compositional similarities to minerals, occurring in igneous and metamorphic rocks of the Bohemian Massif, as well as to detrital grains, deposited within the internal basins of the massif. This suggests that the primary rocks for the garnet and tourmaline may be crystalline complexes of the Bohemian Massif. However, other uplifted areas, similar to the complexes of the Bohemian Massif, cannot be ruled out. Such hypothetical areas could be located in the northern foreland of the Carpathian basins. Euhedral tourmaline and other minerals, occurring in the heavy- mineral assemblages studied, most probably were derived from eroded and presently not exposed, crystalline complexes, originally situated in the Skole Basin foreland or within the basin.
EN
Heavy minerals from sandstones belonging mostly to the Boryslav Sandstone and Kliva Sandstone members of the lower part of the Menilite Formation (Oligocene) in the northern part of the Skole Nappe, Polish Carpathians are characterized. In the study area, the sediments were deposited in the Rzeszów and Łańcut channel zones running from the northern margin of the basin. The most frequent heavy minerals in the sandstones examined include zircon, tourmaline, rutile, staurolite, kyanite and garnet. Single grains of andalusite, sillimanite, apatite, epidote, brookite and chrome spinel occur in some samples. The very small content of apatite is related to long, continental weathering in the source area, which is referred to the Paleozoic sedimentary cover of the Małopolska Block and the easternmost part of the Upper Silesian Block. Different preservation states, morphology, degree of roundness and colour varieties suggest that the heavy minerals studied derive from various petrographic types including metamorphic, igneous and sedimentary rocks. However, the Carboniferous and Permian conglomerates and sandstones seem to be the most probable source rocks.
EN
Two newly recognized sections (Jamna Dolna 2 and Wola Czudecka) of the Lower Oligocene Menilite Shales (Menilite Formation) in the Polish Outer (Flysch) Carpathians have recently yielded a small shark assemblage. It comprises teeth of Heptranchias howelli (Reed, 1946), not hitherto reported from Europe, as well as the remains of other sharks (teeth of ?Mitsukurina, Alopias, gillrakers of Cetorhinus) all contributing to the fish assemblage of the Carpathian Menilite Formation, which has long been famous mostly for its teleost content. The life environment of the studied sharks and the basin bottom conditions are briefly discussed.
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