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Zasady klasyfikacji stratygraficznej czwartorzędu Polski i jej główne kategorie

Marks Leszek

Przegląd Geologiczny

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2023

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Vol. 71, nr 10

485--502

EN

A reliable stratigraphic subdivision of the Quaternary is extremely important, dependent firstly on primary significance of its deposits in geological investigations and every-day life of human societies. In the Cenozoic, the Quaternary is a period of the same stratigraphic rank as the Palaeogene and the Neogene, but it is much shorter. Traditional stratigraphic schemes of the Quaternary were based mostly on other criteria than of the older periods, because studies of the Quaternary were focused mainly on more easily accessible terrestrial deposits and a decisive role in their formation was played by climate-induced processes. These factors forced a specific approach to define the stratigraphic units and to create the stratigraphic subdivisions of the Quaternary. In the Quaternary investigations in Poland, several categories of stratigraphic classification are used, particularly lithostratigraphy (with pedostratigraphy and cryostratigraphy), morphostratigraphy, biostratigraphy (including palynostratigraphy, malacostratigraphy, teriostratigraphy and anthropostratigraphy), magnetostratigraphy, chronostratigraphy (synchronized with geochronology) and climatostratigraphy (combined with oxygen isotope stratigraphy). The main climatostratigraphic units can be treated as corresponding to the chronostratigraphic ones and it enables correlation in a regional and global scale. Acritical overview of the applied stratigraphic categories and the updated stratigraphic subdivision are presented for Poland.

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Biostratigraphy, magnetostratigraphy, C and O isotope distribution around the J/K boundary, the Brodno section (Kysuca Unit of the Pieniny Klippen Belt)

Michalik J., Rehakova D., Halasova E., Lintnerova O.

Volumina Jurassica

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2006

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Vol. 4, no. 1

190-191

EN

Detailed litho- and biostratigraphy of the Brodno section in contact zone of the Outer and the Central Western Carpathians was given by Michalík et al. (1990), VaĘíçek et al. (1992). Kimmeridgian and Tithonian condensed sequence of red nodular limestones (the Ammonitico Rosso facies) is referred to as the Czorsztyn Limestone Fm. Calcareous dinoflagellates Carpistomiosphaera borzai and Stomiosphaera moluccana indicate its Kimmeridgian age; Parastomiosphaera malmica, Carpistomiosphaera tithonica and Colomisphaera pulla indicate Early Tithonian age; calpionellids Chitinoidella boneti, Praetintinnopsella andrusovi, Crassicollaria intermedia, Crassicollaria brevis, Crassicollaria parvula, Crassicollaria colomi, confirm Middle to Late Tithonian age of this formation. Lower Berriasian part of this succession is represented by pale biomicritic wackestone (Pieniny Limestone Fm) with abundant Calpionella alpina. Strong subsidence and acceleration of “planktic rain” of nannofossils started on the Early/Middle Tithonian boundary where Polycostella beckmannii appeared. Helenea chiastia together with first small nannoconids are typical of the Middle and Late Tithonian. The Late Tithonian interval was specified by the FO of Rotelapillus laffitei and Litraphidites carniolensis. The Tithonian/Berriasian boundary was characterized by the FO of Nannoconus wintereri together with small nannoconids and by the FO of Nannoconus steinmanni minor. There is good correlation between the calcareous nannofossils distribution and the magnetostratigraphic zonation (HouĘa et al. 1996). In the M 20-M 19 interval, two distinct nannoevents were recognized: the dominance of Polycostella beckmannii (Chitinoidella Zone) and the appearance of calcareous nannofossil association with Helenea chiastia (Crassicolaria Zone). Carbon isotope curve from bulk carbonates of the J/K boundary sequence shows smooth trends resulted from equilibrated measure of bio-productivity and organic matter burial. The ä13C value ranges from 1.3 to 1.5‰ (PDB). The authentic character of the limestone record is underlined by relative high and conservative ä18O values (-2.27 to -0.88) of the same beds. These signals can be useful in global stratigraphic correlation in deep water carbonates.

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A potential stratotype for the Oxfordian/Kimmeridgian boundary: Staffin Bay, Isle of Skye, UK

Wierzbowski A., Coe A., Hounslow M., Matyja B., Ogg J., Page K., Wierzbowski H., Wright J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

17-33

EN

A coastal exposure of the Staffin Shale Formation at Flodigarry, Staffin Bay, Isle of Skye, Scotland, UK fulfils the criteria for definition as the Global Stratotype Section and Point (GSSP) for the base of the Kimmeridgian Stage (Upper Jurassic). This marine shale succession was deposited during a long-term transgression, and is part of a complete, relatively well-expanded stratigraphic succession. A rich fauna of ammonites above and below the Oxfordian/Kimmeridgian boundary allows recognition of the Evoluta Subzone (Pseudocordata Zone) and Rosenkrantzi Subzone (Rosenkrantzi Zone) of the Subboreal and Boreal uppermost Oxfordian, and the Densicostata Subzone (Baylei Zone) and the Bauhini Zone of the Subboreal and Boreal lowermost Kimmeridgian). A suitable level for the boundary is thus marked by the replacement of the Subboreal Ringsteadia (M)/Microbiplices (m) by Pictonia (M)/Prorasenia (m), and by the first appearance of Boreal Amoeboceras (Plasmatites). Detailed study of the microfossils reveals an excellent dinoflagellate succession. A variety of stratigraphically important dinoflagellates are found, the assemblages being intermediate in character between Boreal and Subboreal ones. The magnetostratigraphic data, though rather troublesome to extract, shows a polarity pattern which can be confidently correlated to other UK boundary sections. The upper boundary of a normal magnetozone falls at, or very near, the proposed Oxfordian/Kimmeridgian boundary. The 87Sr/86Sr ratio at the boundary, based on an analysis of belemnites, lies between 0,70689 and 0,70697, averaging 0.70693. Matching worldwide trends, no distinct change in the ratio is seen across the boundary. A lack of variations in the carbon isotope composition of belemnites across the Oxfordian/Kimmeridgian boundary does not indicate perturbation in the global carbon cycle. However, high ?13C values and their scatter suggest the influence of local fractionation affecting isotope composition of dissolved inorganic carbon (DIC) in the partly isolated Boreal sea. A fall in the belemnite ?18O values in the Upper Oxfordian and Lower Kimmeridgian compared to the Mid Oxfordian suggests a slight rise in seawater temperature.