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Wyszukujesz frazę "palaeoenvironment" wg kryterium: Temat


Tytuł:
Analysis of the trace fossils from Paleogene formations of the Central Western Carpathian (Orava region)
Autorzy:
Simo, V.
Starek, D.
Tematy:
outcrop
palaeoenvironment
assemblage
Pokaż więcej
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/184756.pdf  Link otwiera się w nowym oknie
Opis:
Up to now only little attention was dedicated to the study of the trace fossils in the development of the Central Carpathian Paleogene Basin in the Orava region. Occasional trace fossils findings from the Central Carpathian Paleogene formations in the Orava and others regions were referred by Plička (1987). Other specialized works on trace fossils from these formations from the Orava region were not published. Study of trace fossils is strongly influenced by the existence of well exposed outcrops within individual formations. The best exposed outcrops are situated in the basal Borové Formation as well as in the higher parts of Paleogene sequences – mainly in the Zuberec Formation. This preliminary study shows a relatively rich diversity of trace fossils associations across the Central Carpathian Paleogene Basin. We present new finds of trace fossils, within which we have classified 7 ichnogenera, 11 ichnospecies and 2 types of trace fossils, which were not closely systematically classified. Many trace fossils identified in the Orava region are typical for some palaeoenvironments, which are characterized by a specific lithology, nature of the substrate, dynamics of the environment, amount of nutrients and stability or fluctuations of oxygen in the bottom waters. The trace fossils assemblages reflect changes of depositional systems during the tectonic and sequence stratigraphic development of the basin. Early Eocene shallow-sea environment of the Borové Formation including the rocky coast, sandy dynamic littoral, transition - al and internal shelf zones are characterized by findings of traces of Entobia, Gastrochaenolites, Nummipera, Ophiomorpha and Skolithos. On the contrary, a significant deepening of the deposition environment during the Oligocene, documented by turbidite sedimentation of Zuberec and Biely Potok formations is characterised by findings of graphoglyptids ( Spirorhaphe, Nereites, Paleodiction, Protopaleodictyon, Megagrapton ) or traces of deposit feeders ( Arthrophycus, Chondrites, Planolites, Phycodes, Scolicia, Zoophycos).
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion of carbonate speleothems by an allogenic river inferred from petrography and a weight loss experiment : a case study from the Demänová Cave System, Slovakia
Autorzy:
Sala, Przemysław
Bella, Paweł
Tematy:
Karst
carbonates
hiatus
dissolution
palaeoenvironment
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Wydawca:
Polskie Towarzystwo Geologiczne
Powiązania:
https://bibliotekanauki.pl/articles/27311293.pdf  Link otwiera się w nowym oknie
Opis:
The crystallization of speleothems can be interrupted by the invasion of allogenic water into cave passages. These interruptions were studied, both in speleothems currently submerged in an underground river and in speleothem sections, which were found at the lowermost fluvially active passage level of the Demänová Cave System. The interaction between speleothems and allogenic water, undersaturated with respect to calcite, is manifested in the presence of siliciclastic material and the corrosion of calcite crystals. The progressive development of corrosion features depends on the duration of the interaction of calcite crystals with allogenic water. Moreover, the movement of the water and siliciclastic deposition over the speleothems can influence the corrosion process. The estimated rate of corrosion, caused by the underground Demänovka River and measured by the weight loss of experimental tablets, is up to 0.029 mm/y. U-series dating indicated that the interaction of speleothems with allogenic water occurred during the Vistulian (Weichselian). The identification of corrosion episodes, caused by allogenic water, is a step towards understanding the origin of hiatuses and establishing criteria for recognition of them.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical characteristics of Neogene methane-bearing lignite of the Bełchatów region
Autorzy:
Maruta, M.
Zakrzewski, A.
Tematy:
tertiary lignite
geochemical analysis
palaeoenvironment
methane
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Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/299185.pdf  Link otwiera się w nowym oknie
Opis:
Coal beds could contain various amount of methane. This attribute might be dangerous in shafts or quarrying. Among other things, the works in the coal beds, including drilling, potentially there is a risk of exceeding the methane lower explosive limit. But on the other hand it is a source of unconventional hydrocarbon accumulations. In this paper geochemical characteristic of organic matter of tertiary brown coal from central part of Poland were performed. Geochemical surveys helps to know about genesis of methane from study area. The analysed samples contain various quantity of organic carbon, from 20,74 to 71.93 wt. %. Lignite from examine samples have weak hydrocarbon potential. In tertiary sediments prevails III type of kerogen with admixture of II type of kerogen. The thermal maturity of the tertiary organic matter changes within the interval from 354 to 419 in Tmax scale. Organic matter is immature. The composition of bitumens is different in various part of study area. Elemental analysis confirm that brown coal was comprised mostly by humic-group macerals. Coal samples contain methane with mixed genesis.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Turonian-Coniacian (Upper Cretaceous) of the Babadag Basin (North Dobrogea, Romania) : integrated biostratigraphy and microfacies succession
Autorzy:
Lodowski, Damian Gerard
Walaszczyk, Ireneusz Piotr
Grădinaru, Eugen
Tematy:
microfacies
petrology
inoceramids
ammonites
foraminifera
palaeoenvironment
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2058617.pdf  Link otwiera się w nowym oknie
Opis:
The Upper Turonian to Middle Coniacian (Upper Cretaceous) succession of the Babadag Basin (North Dobrogea, Romania) constitutes an apparently continuous fossiliferous carbonate succession. The presence of moderately rich inoceramid, ammonite and foraminiferal assemblages allows for the application of a precise biostratigraphic subdivision. The palaeoenvironmental conditions and evolution of the Babadag Basin during the Late Turonian-Middle Coniacian are inferred using microfacies analysis and foraminiferal spectra. Together, these suggest the Turonian-Coniacian Badabag Basin reflects relatively shallow-water conditions in a near-shore environment, punctuated by two regression events in the Late Turonian and in the Middle Coniacian.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Malacofauna of the Holsteinian lake deposits at Hrud II (Eastern Poland) and its palaeoecological significance
Autorzy:
Szymanek, M.
Tematy:
Quaternary
Holsteinian
lake deposits
molluscs
palaeoenvironment
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2058942.pdf  Link otwiera się w nowym oknie
Opis:
Mollusc-bearing deposits at Hrud II (Eastern Poland) accumulated in the western part of a palaeolake of Holsteinian age (MIS 11). The faunal assemblage is typical of freshwater environments and presumably represents a part of the interglacial climatic optimum (Carpinus–Abies Zone). On the basis of its varied composition, the evolution of the water body is described. Reinterpretation of the data from the eastern part of the lake (Hrud I) and combining of the results from both sites enable a wider palaeoecological reconstruction. Fluctuations in lake level, water dynamics and changes in the aquatic vegetation are inferred from quantitative relations between selected molluscs, especially Lithoglyphus jahni, Valvata piscinalis and Bithynia tentaculata, which prevail in the deposits investigated. A predominance of Valvata piscinalis indicates a rise in water level, whereas the communities with abundant Bithynia opercula are typical of a more shallow lake with rich reed fields. Amelioration of the trophic conditions between the pre-optimal and optimal part of the Holsteinian Interglacial can also be recognised.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Marine palynology and environmental interpretation of the Lower Cretaceous (Barremian?–Aptian) rock units in the Koppeh-Dagh Basin, NE Iran
Autorzy:
Sharifi, M.
Ghasemi-Nejad, E.
Sarfi, M.
Yazdi-Moghadam, M.
Tarjani-Salehani, M.
Akhtari, M.
Tematy:
Koppeh-Dagh
palynostratigraphy
palynofacies
palaeoecology
palaeoenvironment
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2059347.pdf  Link otwiera się w nowym oknie
Opis:
The Sarcheshmeh and Sanganeh formations are the Lower Cretaceous deep marine sequences of the Koppeh-Dagh sedimentary basin, which revealed a diverse assemblage of dinoflagellates. The paper discusses palynostratigraphy, palynofacies and palaeoenvironment of these rock units in a borehole drilled in the eastern part of this basin. Ninety-five ditch-cutting samples were prepared and studied palynologically, which resulted in recognition of 76 species of dinoflagellate cysts belonging to 29 genera. The recorded assemblages are in accordance with the Odontochitina operculata Zone suggesting a Barremian?–Aptian age for the formations. Palynological data extracted led to identification of five palynofacies types based on the categories of Tyson (1995). These indicate a marginal, proximal and distal shelf environment of deposition. The obtained data from calculated palaeoecological factors revealed a gradual sea level rise during the deposition of these rock units, resulting in replacement of the oxic/dysoxic Sarcheshmeh Formation by the dysoxic/anoxic Sanganeh Formation.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagenetic alteration in low-Mg calcite from macrofossils : a review
Autorzy:
Ullmann, C. V.
Korte, C.
Tematy:
diagenetic alteration
macrofossil calcite
isotopes
palaeoenvironment
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2059799.pdf  Link otwiera się w nowym oknie
Opis:
The quality of palaeoenvironmental reconstructions based on macrofossil carbonate critically depends on preservation of the shell material because post-depositional processes can modify its structural, chemical and isotopic composition, potentially overprinting or completely erasing palaeoenvironmental information. A suite of methods can be employed to evaluate the impact of diagenetic processes on the primary geochemical signatures of samples. Here we review the benefits and shortcomings of the most commonly employed optical (optical microscopy, cathodoluminescence microscopy, scanning electron microscopy) and chemical (trace element abundances, isotopic ratios) screening techniques used to assess the alteration degree of low-Mg calcite macrofossils and summarize the findings on diagenetic trends observed for elemental and isotopic systems in such materials. For a robust evaluation of the preservation state of biogenic calcite, it is advisable to combine a set of complementary techniques. Absolute limiting values of element and isotope ratios for discarding diagenetically altered materials cannot be universally applied, but should rather be evaluated on a case to case basis. The evaluation can be improved by analyses of diagenetic carbonate and altered fossil materials, which help constraining the diagenetic trajectories in the sampled specimens. Quantification of post-depositional alteration is possible, but in most cases the complexity of diagenetic systems hampers the possibility of retrieving original proxy values for palaeoenvironmental reconstructions from partially altered materials.
Dostawca treści:
Biblioteka Nauki
Artykuł

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