Geologia
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ISSN 0138-0974
e-ISSN: 2353-0782
Issue Date
2010
Volume
T. 36
Number
Nr 1
Description
Journal Volume
Geologia
T. 36 (2010)
Projects
Pages
Articles
Wstępna ocena macierzystości wybranych utworów paleozoiku Gór Świętokrzyskich
(Wydawnictwa AGH, 2010) Malec, Jan; Więcław, Dariusz; Zbroja, Stanisława
The hydrocarbon potential of selected Paleozoic lithostratigraphic complexes of the Holy Cross Mountains was determined based on the results of Rock-Eval pyrolysis of 47 samples. For investigations only rocks in dark colours from Cambrian, Ordovician, Silurian, Carboniferous and Permian strata were selected. The Cambrian and Ordovician strata from the Łysogóry Region have poor source-rock parameters. Among the Silurian strata, the claystones of the Bardo Beds (ca. 3 wt. % TOC) are the richest in total organic carbon (TOC). The claystones of the Zaręby Formation (Carboniferous - Visean and Tournaisian) have mean TOC content ca. 2.8 wt. % and the Zechstein Limestone (Permian) ca. 1.6 wt. % TOC. In the Early Paleozoic strata marine kerogen (Type-II) is present. It dominates also in the Upper Paleozoic strata. Local inputs of the terrigenous Type-III kerogen were confirmed in the Zaręby Formation (Carboniferous). The Cambrian and Ordovician strata in the Łysogóry region are overmature. Maturity of the investigated Silurian, Carboniferous and Permian strata corresponds with the initial and middle phases of the »oil window«. The NW margin of the Holy Cross Mountains, where the Paleozoic complexes rich in the organic matter are covered by the Mesozoic complex, is perspective area for hydrocarbon exploration.
Sekwencje modalne w analizie profili litologicznych - spojrzenie metodyczne
(Wydawnictwa AGH, 2010) Doktor, Marek; Krawczyk, Andrzej J.
The Markov chains theory is a tool commonly applied to sedimentological studies. Unfortunately, this method does not provide fully credible conclusions concerning the cyclicity of sedimentation. Such cyclicity is documented, among others, by the appearance of modal sequences, i.e., sequences many times repeated in the lithological profile and having unequivocal genetic interpretation. The paper proposes the statistical permutation test, which can verify the hypothesis of the randomness of layers succession in a given lithological profile. Applying the Monte Carlo simulation method, the probability is estimated that in a random sequence composed of the same layers as the studied profile the given number of particular sequences of layers will occur. Such attempt allows the researcher to distinguish the modal sequences, i.e., those indicating the important features of sedimentation process, from sequences whose frequent appearance results exclusively from the dominance of particular lithological varieties of rocks.
Model entropii dla węglonośnych utworów karbonu górnego Zagłębia Górnośląskiego i próba jego geologicznej interpretacji
(Wydawnictwa AGH, 2010) Doktor, Marek; Krawczyk, Andrzej J.
The paper presents the model of entropy for the coal-bearing formations of the Upper Silesian Coal Basin. The coal-bearing formations include exclusively continental (fluvial) sediments in their upper parts and paralic sediments in the lower parts, the latter composed of partly continental, partly near-shore deposits laid down in broadly understood sea coast environment (shoreline, sand bars, beaches, etc.). For studies 18 boreholes were selected in which both the continental and the paralic successions were represented. For all lithofacies distinguished in all successions the normalized, pre- and post-depositional entropies were calculated. Then, successions were categorized on the basis of these calculations. The dendrogram shows three groups of successions from which the first corresponds almost exclusively to the Paralic Series and the second one - to the Mudstone Series. The third group differs distinctly from the first two groups and represents the sediments of the Krakow Sandstone Series.
Badania zmineralizowanego drewna z Arabii Saudyjskiej i z północnych Czech
(Wydawnictwa AGH, 2010) Pitera, Helena; Wojewoda, Jurand
In this study two samples of silicified wood were examined. One sample was found on a desert in Saudi Arabia, and the second one was taken in the Czech Republic. The first sample represents the Cretaceous period (Wasia), and the second one - Carboniferous. Both specimens were subjected to the macroscopic inspection, microscopic analysis (in the transmitted light and the scanning microscope). Some point analyses were also carried out, and in the case of the first sample the X-ray analysis was made. In the mineralised wood from Saudi Arabia polluting with organic compounds was detected, as well as presence of calcite and admixtures of clay minerals, and cryptocrystalline pigment of dark brown colour (probably haematite). The sample from the Czech Republic (an outcrop near Trutnov) is strongly silicified. The quartz and chalcedony observed in it are effects of this process. This allows for a conclusion about the presence of two generations of the silica in the sample. The first, earlier generation is represented by quartz, and the later, second generation of silica is the chalcedony. In the case of this sample concentration of fine-grained pigment of brown-red colour is also visible on surfaces of quartz or chalcedony.
Piaskowce modyfikowane związkami krzemoorganicznymi oraz zmiany ich porowatości i wytrzymałości na zginanie pod działaniem siły skupionej
(Wydawnictwa AGH, 2010) Rembiś, Marek
The sandstone samples representing 24 deposits localized in various geological regions of Poland were impregnated with liquid polymers, in which esters of the orthosilicic acid are active agents. Such preparations are commonly applied as stone strengtheners in conservation practices. The products of condensation of these polymers formed in the course of seasoning of the impregnated stone samples for 4 weeks have developed diversified microstructures. Their presence has lowered the porosity of the sandstones and changed the structure of the rock pore spaces. As a result, the sandstones have been strengthened as indicated by their values of the flexural strength under concentrated load. A distinct change of this parameter should be linked to exceeding of the threshold value of tetraetoxysilan oligomers concentration (percolation threshold) in the sandstones in question, mainly in their Liassic, Cretaceous and Istebna varieties. It has taken place in the samples with the porosity lowered at 41-66%. The percolation threshold has not been achieved in this part of the impregnated Magura, Krosno and Godula sandstones, in which their porosity has decreased at the value not exceeding 10%. In these cases, the value of the flexural strength under concentrated load remains at the same level as it was measured prior to impregnation.