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Wyświetlanie 1-5 z 5
Tytuł:
Acritarch assemblages from the Silurian Pomeranian Caledonides and their foreland
Autorzy:
Jachowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059448.pdf
Data publikacji:
2000
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Pomeranian Caledonides
Silurian
acritarch assemblages
Opis:
Comprehensive palynological studies of the Silurian rocks of the Pomeranian Caledonides are described, the first since Eisenack's (1972) work. 250 clastic rock samples were analysed, all from deep boreholes. Three of these boreholes (Lębork IG 1, Gdańsk IG 1 and Kościerzyna IG 1) are located NE of the Teisseyre-Tornquist Zone (TTZ) and contain horizontal successions of the western, marginal part of the East European Craton. Other boreholes studied (Bydgoszcz IG 1, Klosnowo IG 1 and Stobno 1) penetrated folded Lower Palaeozoic sediments, and lie SE of the TTZ. The investigations included a complete Silurian profile from the Llandovery to the Poidoli, which is documented in detail by graptolites. Associations of microflora (Acritarcha, Prasinophyceae, Sporites) and microfauna (Chitinozoa, Scolecodonta) varied in quality and quantity. There was considerable variability in the preservation and thermal maturity of the organic-walled microfossils. Detailed investigations of the acritarchs are described. 7 characteristic acritarch assemblages have been distinguished, and these are correlated with the graptolite biozones. Llandovery rocks contain assemblages with Domasia, Ammonidium and Tylotopalla genera. Wenlock deposits include Tylotopalla, Leptobrachion and Cymbosphaeridium. The Upper Ludlow deposits contain well preserved assemblages with Visbysphaera, Veryhachium, Onondagella and Leoniella, accompanied by Neoveryhachium carminae, Geron gracilis, and some Deflandrastrum and Visbysphaera species generally considered characteristic of Gondwana. Throughout the Silurian profile, individual specimens of typical Ordovician genera such as Acanthodiacrodium, Frankea, Striatotheca and Coryphidium occur. The acritarch assemblages overall show mixed characters, typical of both Baltica and Gondwana.
Źródło:
Geological Quarterly; 2000, 44, 3; 317-331
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molluscs in Eemian-Vistulian deposits of the Kolodiiv section, Ukraine (East Carpathian Foreland) and their palaeoecological interpretation
Autorzy:
Alexandrowicz, W.P.
Dmytruk, R.
Powiązania:
https://bibliotekanauki.pl/articles/2059489.pdf
Data publikacji:
2007
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Ukraine
Halye Basin
Vistulian
loess
molluscan assemblages
Opis:
A profile of loess several metres thick with palaeosoils, underlain by calcareous gyttja, out crops in Kolodiiv, Ukraine. Rich and diverse assemblages of molluscs have been found in these deposits. Three types of mollusc communities can be distinguished. The oldest is dominated by freshwater taxa and corresponds to calcareous gyttja of Eemian age. The next two assemblages contain only snails typical of loess. The first of these indicates a cold and dry climate and open environment of arctic steppe type, with rapid accumulation of loess; the second assemblage represents a cold and humid climate and a relatively moist, open environment of tundra type.
Źródło:
Geological Quarterly; 2007, 51, 2; 173-178
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural and anthropogenic changes in the environment during the Holocene at the Kraków region (Southern Poland) from study of mollusc assemblages
Autorzy:
Alexandrowicz, Witold Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2058731.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
mollusc assemblages
environmental changes
anthropogenic pressure
Holocene
Southern Poland
Opis:
Malacological analysis was used to reconstruct Holocene environmental changes from profiles of calcareous tufa and fluvial deposits exposed in the Kobylanka stream valley, several kilometres west of Kraków in southern Poland. The abundant and diversified mollusc fauna was characterized by clear variability within the vertical succession where five types of molluscan assemblages were distinguished. The pattern of sedimentary and molluscan facies allowed characterization of two main intervals of environmental change during Holocene. In the lower interval, until the end of the Middle Holocene, human activity was not detected and environmental processes were controlled by natural factors. In the upper interval, corresponding to the Late Holocene, human impact can be seen, in the form of rapid deforestation and agricultural development. Anthropogenic impact has been particularly evident during the last millennium. The mollusc assemblages studied allowed accurate reconstruction of natural and anthropogenic factors affecting the natural environment.
Źródło:
Geological Quarterly; 2021, 65, 1; 9
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molluscan assemblages in Late Holocene tufa cones in the Pieniny Mountains (southern Poland)
Autorzy:
Alexandrowicz, W. P.
Powiązania:
https://bibliotekanauki.pl/articles/2059741.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
calcareous tufa
molluscan assemblages
historic period
Pieniny Mts.
South Poland
Opis:
Limestone rock walls of various inclination form a favourable substrate for the deposition of calcareous tufas that form cone-shaped structures located at the foot of slopes or fill niches within them. Such carbonate deposits usually contain rich and diversified molluscan assemblages, whose composition and structure closely correspond to the ambient environmental conditions in the immediate vicinity. The study of the Pieniny Mountains area revealed 10 sites with such deposits. The identified malacofouna was subjected to detailed analysis. It enabled identification of three types of faunistic assemblages (Bythinella austriaca assemblage, Pyramidula pusilla assemblage, and a shade-loving species assemblage), which are related to the conditions prevailing during the deposition. Tufa cones found in the Pieniny Mountains represent the historic period (Late Holocene). The deposits provide a record of two climatic phases: warmer and colder. The former (Medieval Warm Period) involved the intensified deposition of carbonate material and the rapid growth of tufa cones. The latter – the Little Ice Age – entailed the slow degradation of cones and slower sedimentation of tufas, while the intensified physical weathering led to the increase in the clast material proportion (sharp-edged limestone fragments). Tufas accumulated in the zone unaffected by high anthropogenic pressure and thus represent a record of natural environmental changes during the historic period
Źródło:
Geological Quarterly; 2014, 58, 2; 269--280
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of palaeoclimate and the green house effect on Hettangian clay mineral as sem blages (Holy Cross Mts. area, Polish Basin)
Autorzy:
Brański, P.
Powiązania:
https://bibliotekanauki.pl/articles/2059218.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Hettangian
Holy Cross Mountains
margin
clay mineral assemblages
palaeoclimate
greenhouse effect
Opis:
Hettangian clay mineral assemblages from the Holy Cross Mts. margin (south eastern part of the epicontinental Polish Basin) were mostly controlled by climaticcon ditions and weathering regime. Hettangian claystones and mudstones were deposited in continental and marine-margin palaeoenvironments in a warm climate, mostly with year-round humidity. The pronounced, long-term green house conditions intensified chemical weathering in the hinterland. Reworking and redeposition of ancient sediments caused by tectonics and/or by sea-level changes and early diagenesis may have modified the clay mineral content in the earliest Hettangian. Burial diagenesis and telodiagenesis changed the clay mineral composition only locally.
Źródło:
Geological Quarterly; 2009, 53, 3; 363-368
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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