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Wyświetlanie 1-15 z 279
Tytuł:
Sulphur, oxygen and strontium isotope compositions of Middle Miocene (Badenian) calcium sulphates from the Carpathian Foredeep, Poland: palaeoenvironmental implications
Autorzy:
Kasprzyk, A.
Pueyo, J.J.
Hałas, S.
Fuenlabrada, J.M.
Powiązania:
https://bibliotekanauki.pl/articles/2059523.pdf
Data publikacji:
2007
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Carpathian Foredeep
Badenian
sulphur
oxygen and strontium isotopes
sulphate deposits
Opis:
Sulphur, oxygen and strontium isotope compositions have been measured in sulphate (gypsum and anhydrite) sam ples from the Badenian evaporite complex in the Carpathian Foredeep Basin (Poland) to determine the origin of brines from which these sulphates were formed. Studied samples display the d values from +22.68 to +24.91‰ CDT for sulphur (ten samples) and from +12.26 to +13.63‰ SMOW for oxygen (ten samples), and 87Sr/86Sr ratios from 0.708915 to 0.716329 (six samples). Most samples show isotopic values (both d34S and 87Sr/86Sr) higher than contem poraneous (Badenian) sea water, and thus suggest that these sulphates were formed (i) from brines with a significant component of non-marine waters, (ii) in a restricted system, where an important role was played by meteoric water inputs as well as by bacterial sulphate reduction. The results of this study show clear differences in the isotopic signatures between sedimen tary (gypsum) and diagenetic (anhydrite) lithofacies. While sedimentary gypsum displays sulphur, oxygen and strontium isotope ratios close to contemporaneous (Badenian) sea water, diagenetic anhydrite values are largely elevated. The higher isotopic values (d34S, d18O and 87Sr/86Sr) for anhydrite when compared to gypsum are interpreted as reflecting different hydrological provenances of sulphate in the Badenian basin. Gypsum was formed from brines marine in origin that were subject to an important in flow of continental waters and a local bacterial sulphate reduction in arestricted, and there fore sulphate-limited basin, which is consistent with earlier interpre tations based on sedimentological and geochemical studies. Our study shows that brines from which anhydrite was formed had a highly-radiogenic non-marine (riverine, ground water) strontium component, which is a new contribution to the knowledge on the Badenian sulphate formation. The results reflect a lateral compositional evolution of parent waters during sulphate deposition and diagenesis in the Carpathian Foredeep Basin.
Źródło:
Geological Quarterly; 2007, 51, 3; 285-294
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anthropogenic changes of CO2, CH4, N2O, CFCI3, CF2Cl2, CCl2FCClF2, CHCl3, CH3CCI3, CCI4, SF6 and SF5CF3 mixing ratios in the atmosphere over southern Poland
Autorzy:
Różański, K.
Nęcki, J.
Chmura, Ł.
Śliwka, I.
Zimnoch, M.
Bielewski, J.
Gałkowski, M.
Bartyzel, J.
Rosiek, J.
Powiązania:
https://bibliotekanauki.pl/articles/2060461.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
atmosphere
monitoring
greenhouse gases
halogenated compounds
Opis:
An overview of long-term, sysiematic observations of trace gas composition of the atmosphere over southern Poland is given. Three major greenhouse gases (CO2, CH4, N2O) and selected halocarbons (freons F-11, F-12 and F-113; chloroform; 1,1,1-trichloroetane; carbon tetrachloride; sulphur hexafluoride and trifluoromethyl sulphur pentafuoride) were monitored. Measurements were performed at two locations of contrasting characteristics: (1) the high-mountain site Kasprowy Wierch, High Tatras, representing atmospheric conditions relatively free of local influences, and (2) two sites located in the Kraków agglomeration, representing a typical urban atmosphere. The data available for Kraków and Kasprowy Wierch were compared with the Mace Head data, representing a marine regional background. The impact of continental sources for some of the measured gases is clearly seen in the Kraków and Kasprowy Wierch records. The mean offset between CH4 concentrations recorded at Kasprowy Wierch and at Mace Head for the period 1998-2012 is 20.7 ppb and stems from continental emissions of this gas originating mainly from anthropogenic activities (leaks of natural gas distribution networks, landfills, livestock). For N2O, a similar offset of ca. 1 ppb for the period 2009-2012 was observed. Although the long-term concentration trends of selected halogenated compounds measured in Kraków coincide in general with the respective trends in Mace Head data, the Kraków records contain numerous spikes and periods of enhanced concentrations, reflecting the impact of local sources of these compounds. The impact of a legislative framework enforced in Poland in July 2002, regulating the trade, storage and disposal of ozone-depleting substances, is visible in the Kraków record of halogenated compounds.
Źródło:
Geological Quarterly; 2014, 58, 4; 673--684
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudometeorite from Łapino (Pomerania, North Poland)
Autorzy:
Stępniewski, M.
Borucki, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059303.pdf
Data publikacji:
2001
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Łapino
morth Poland
iron silicide
pseudometeorite
Opis:
A boulder, found in a gravel pit by Łapino near Gdańsk in 1954, was noted as unusual. Among various erratics ice-derived from Scandinavia in the Quaternary, this one had an extraordinary appearance; unusually dark, heavy and strongly magnetic. An extraterrestrial origin was suggested. The border resembles an intrusive breccia with numerous periclase-bearing fragments in a magnetite-clinopyroxene-olivine matrix. A single grain with a metallic luster, a few centimetres in diameter, was identified as the iron silicide (Fe3Si). Only two natural occurrences of iron silicide have been described, both from meteorites. However, the isotopic analysis showed an absence of radiogenic nuclides (10Be, 26Al, 36Cl), and the ratio of oxygen isotopes (delta 17O and delta 18O) suggested a terrestrial origin. Thus the stone is probable artifact, presumably the product of an unidentified foundry.
Źródło:
Geological Quarterly; 2001, 45, 3; 343-348
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alabaster from the Carpathian Foredeep in the architecture of Cracow
Autorzy:
Rajchel, J. M.
Śliwa, T.
Wardzyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060059.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Carpathian Foredeep
Miocene
architecture
Cracow
Zhuravno
Opis:
Alabaster is a rock with low hardness, high coherence, fine-crystalline development and forms an optically “warm” surface when polished. It has been used as a sculpting, decorative and architectonic stone, often by civilizations of the Mediterranean Sea Basin. Alabaster in the architecture and sculpture of Kraków is mainly from the Middle Miocene (Badenian) and comes from deposits within the Ukrainian Carpathian Foredeep Basin, chiefly along its northern margin in the “Podolia rim”. It was quarried around the mid-part of the Dnister River and its tributaries, from Lviv (Lwów) to Khotyn (Chocim), and mostly at Zhuravno (Żurawno). The alabaster quarried here was called Ruthenian, Polish, or Lvov “marble”. Small quarries were also located at the front of the Carpathian overthrust, including the known deposit at Łopuszka Wielka. The Miocene alabaster has shades of white, yellow, green, brown, usually with differing spots or veins; often the rock is brecciated and partly semi-transparent. Alabaster has been quarried in the Polish Republic since the 16th century, peaking (also in finished stone products) between the world wars. The authors present examples of alabaster usage in ecclesiastical edifices of Kraków, for instance in the Wawel Cathedral, St. Mary’s Church, the churches of Dominican, Carmelite and Missionary clergy, and also in some secular buildings, e.g. the Jagiellonian Library.
Źródło:
Geological Quarterly; 2014, 58, 3; 597--616
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rekonstrukcja paleośrodowiska sedymentacji środkowojurajskich iłów rudonośnych Gnaszyna (Częstochowa) - wyniki wstępne
Autorzy:
Gedl, P.
Kaim, A.
Boczarowski, A.
Kędzierski, M.
Smoleń, J.
Szczepanik, P.
Witkowska, M.
Ziaja, J.
Powiązania:
https://bibliotekanauki.pl/articles/2061399.pdf
Data publikacji:
2003
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
paleośrodowisko
sedymentacja
iły rudonośne
szkarłupnie
paleoenvironment
sedimentation
ore bearing
echinoderms
Źródło:
Volumina Jurassica; 2003, 1, 1; 19-28
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chromian spinels from the Magura Unit (Western Carpathians, Eastern Slovakia) : their petrogenetic and palaeogeographic implications
Autorzy:
Bónová, K.
Špisiak, J.
Bóna, J.
Kováčik, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060358.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Western Carpathians
Magura Basin
provenance
detrital chromian spinel
geochemistry
Opis:
Detrital chromian spinels in sedimentary rocks provide much information concerning the tectonics of their parental ultrabasic rocks. Chromian spinels occurring in the Eocene to Oligocene depos its from the Magura Nappe were exam i ned to provide some constraints on the history of the Magura Basin. The Magura Nappe is a part of the Flysch Belt belonging to the External Western Carpathians. The Magura Nappe is separated by a narrow zone associated with the Pieniny Klippen Belt and is divided into three principal tectono-lithofacies units (from the S to N): the Krynica, Bystrica and Rača units. Cr-spinel is a common accessory mineral (2.3-5.9 vol% of heavy mineral spectra) in the siliciclastic rocks of the Rača and Krynica units. In terms of texture and chemical composition, two types of Cr-spinels were recognized: unaltered and altered. Unaltered spinels were found to contain silicate inclusions such as chromio-pargasite, enstatite, diopside, pargasite, plagioclase and olivine (forsterite). The chromian spinels show wide variations in compositional parameters such as Cr# (0.3-0.7), Mg# (0.3-0.7), TiO2 (<0.03-1.9 wt.%) and Fe2+/Fe3+ (2.5-13) whereas the differences between the Rača and Krynica units are in- significant. These parameters suggest a peridotitic and volcanic origin of the spinels, respectively. The ophiolite source consisting of harzburgitic mantle peridotites was developed mainly in a supra-subduction zone setting; volcanic spinels indicate an origin in mid-ocean ridge basalts, back-arc basin basalts and sporadically in ocean-island basalts. Concerning their geochem i cal features, we propose that during the Eocene to Early Oligocene, the ophiolitic detritus in the eastern part of the Magura Basin deposits may have been derived from a source area located in the Fore-Marmarosh Suture Zone (Eastern Carpathians) that is considered an equivalent of the Black Flysch and Ceahlau units. Some Cr-spinels found in the Eocene sedimentary successions may have resedimented from older Late Cretaceous-Paleocene formations of the Magura Unit, which are considered as reworked sedimentary material from the Pieniny Klippen Belt.
Źródło:
Geological Quarterly; 2017, 61, 1; 3--18
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie modelowania geochemicznego do ilościowej oceny denudacji chemicznej
Quantitative estimation of chemical denudation by using geochemical modelling
Autorzy:
Szostakiewicz, M.
Małecki, J.J.
Powiązania:
https://bibliotekanauki.pl/articles/2074430.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
denudacja chemiczna
modelowanie
geochemia
chemical denudation
geochemical modelling
Inner Carpathians
Opis:
Chemical denudation is an essential factor of the circulation of elements on the Earth. Its intensity is related to several processes, of which the most important are dissolution and precipitation of minerals. Chemical denudation considerably bears on physicochemical proprieties of surface waters and groundwaters in the hypergenesis zone. The paper presents the use of geochemical models for quantitative estimation of chemical denudation. The geochemical models allow considering in calculations such parameters as different solubilities of minerals and the reaction of dissolution of carbonates in the presence of carbon dioxide
Źródło:
Przegląd Geologiczny; 2006, 54, 11; 1007-1010
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetostratigraphy and paleopoles of the Kayenta Formation and the Tenney Canyon Tongue
Autorzy:
Steiner, M.
Tanner, L.
Powiązania:
https://bibliotekanauki.pl/articles/2077334.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Pliensbachian magnetostratigraphy
Kayenta Formation
paleopole
J-1 cusp
North America
formacja Kayenta
szpic J-1
Ameryka Północna
Opis:
The Kayenta Formation is the third in a series of stratigraphic units making up the Glen Canyon Group that were sampled along US Hwy 89 in southern Utah. The Kayenta is dominantly reversed polarity with a number of very short normal polarity intervals. Above the Kayenta and interbedded in the Navajo Sandstone is the Tenney Canyon Tongue of the Kayenta Formation. The lower half of the Tenney Canyon Tongue was also sampled and is dominantly normal polarity with three short reversed polarity intervals. The dominantly reversed magnetostratigraphy of the Kayenta appears to match that of Early Pliensbachian polarity interval “e-Pli R.” The dominance of normal polarity of the Tenney Canyon Tongue suggests that the Tenney Canyon may have been deposited in the upper half of the Pliensbachian polarity interval “ePli-N.” The suggested polarity matches indicate that the Kayenta and Tenney Canyon Tongue strata are 187–190 Ma in age. The paleopoles of the two units are statistically identical. The combined data of the Kayenta-Springdale-Whitmore Point show that the J-1 cusp terminated before the deposition of the Kayenta Formation. The North American continent/pole returned to its Late Triassic position during/after Springdale time, apparently along the same path used to reach the apex of the J-1 cusp.
Źródło:
Volumina Jurassica; 2014, 12, 2; 31--38
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two spinel-bearing compound chondrules from the Baszkówka meteorite
Autorzy:
Borucki, J.
Stępniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059304.pdf
Data publikacji:
2001
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Baszkówka
meteorites
ordinary chondrites
spinel
Opis:
The present paper describes two compound chondrules labelled panda and chevron, discovered in the Baszkówka meteorite. Optical microscope, electron microscope and electron microprobe studies revealed an unusual mineral composition and fabric. Both chondrules include "primary" and "secondary" components. The panda and chevron chondrules have apparent diameters of ~0.86 and ~0.54 mm respectively with spinel dominant in primary components and olivine-plagioclase in secondary components overlain by thin microcrystalline rims. Euhedral or subhedral Mg, Fe2+/Al, Cr-spinel crystals from the panda's primary component (zoned, cavernous or homogeneous) were not found in Mg-Fe chondrules in Baszkówka, where Cr occurs exclusively as chromite. Olivine crystals from panda's primary (Fa27.1) and secondary (Fa26.5) component have similar compositions to those from panda's rim (Fa26.4) and comparable to olivine from other Baszkówka Mg-Fe chondrules (average ~Fa25.7). The Ca-plagioclase laths from the groundmass of panda's primary component has an extremely variable composition (~An49 to ~An60), evidently more calcic than those in other chondrules of the meteorite (mean ~An13). The primary components of the two spinel-bearing chondrules may have been formed in a fireball generated by powerful impact during early accretion of a protoplanet. After crystallisation the spinel crystals were abraded and polished, probably during rapid flight through a dense cloud of interplanetary dust. The moderately reducing conditions of the hypothetical fire ball were replaced by a more reducing environment during the condensation of the rims of both chondrules.
Źródło:
Geological Quarterly; 2001, 45, 3; 281-288
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical analysis of petrophysical parameters of Middle Miocene rocks from the Polish Carpathian Foredeep
Autorzy:
Bala, M. J.
Jarzyna, J. A.
Mortimer, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2060540.pdf
Data publikacji:
2012
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Middle Miocene
Carpathian Foredeep
fractal correlation dimension
statistical analysis
well logging data
Opis:
Sarmatian thin-bedded sandstone and shales have been a subject of statistical studies to differentiate between good and poor reservoir rocks and to show gas-saturated layers in comparison to water-saturated strata. Statistical studies including fractal analysis were performed on well logging data from the Sędziszów 34 borehole drilled in a belt of hydrocarbon deposits that continue below the northern edge of the Carpathian–Stebnik overthrust. Lithological variability and porosity differentiation and changes in water saturation were traced on the basis of the results of well logging interpretation. Basic statistics and histograms of petrophysical parameters have been analysed. A generalized second order fractal correlation dimension was calculated for all parameters and analysed as for a time series. Fractal dimensions did not correlated with the parameters, but good positive correlations between them and the parameters were observed and showed that the curves analysed had the same type of complexity. High correlation coefficients showed pairs of fractal dimensions for those parameters which had similar variability and the same curve roughness. The fractal correlation dimension described the type of complexity of the parameter (curve roughness) and indicated, for example, how shaliness influenced the reservoir properties of the local Middle Miocene. Therefore, the results were also useful in practice, which gave extra information on thin-bedded reservoir rocks.
Źródło:
Geological Quarterly; 2012, 56, 4; 665--680
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Znaczniki środowiskowe w wodach termalnych niecki podhalańskiej
Environmental tracers in thermal waters of Podhale Basin
Autorzy:
Chowaniec, J.
Duliński, M.
Mochalski, P.
Najman, J.
Śliwka, J.
Zuber, A.
Powiązania:
https://bibliotekanauki.pl/articles/2074700.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
niecka popdhalańska
wody termalne
wiek wody
gazy szlachetne
Podhale basin
thermal waters
water age
noble gases
Opis:
Tritium and stable isotope data delta exp.18 O and delta exp.2H) for wells near the recharge area of the thermal system of the Podhale Basin indicate the presence of modern waters recharged at the lowest altitudes of the outcrops of water bearing formations. In turn, delta exp.18O and delta exp.2H values obtained for deep part of the basin may be interpreted as either the result of a high altitude recharge or a cold climate. Helium contents are in general unusually high but can not be interpreted quantitatively at the present stage of the study. The noble gas temperatures (NGT) values obtained from Ne and Ar data disagree with temperatures deduced from the known dependence of air temperature on altitude and altitudes of recharge areas found from the stable isotope data. High concentrations ofHe (ca. 10-4 cm3STP/g), and low NGT deduced from Ne and Ar concentrations suggest the presence of pre-Holocene water in the northeastern part of the basin, which means slow movement of water. Stable isotope and exp.14C data indicate the presence of much younger Holocene waters in the western part of the basin.
Źródło:
Przegląd Geologiczny; 2009, 57, 8; 685--693
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water ages in thermal system of the Podhale Basin (Inner Carpathians, southern Poland)
Autorzy:
Chowaniec, J.
Duliński, M.
Mochalski, P.
Najman, J.
Śliwka, I.
Zuber, A.
Powiązania:
https://bibliotekanauki.pl/articles/2062981.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
thermal waters
environmental tracers
water age
Podhale basin
Inner Carpathians
Opis:
Karstified carbonates which outcrop in the Tatras, Inner Carpathians, southern Poland, and dip to the north under the flysch sediments of the Podhale Basin, represent the largest known renewable reservoir of thermal waters in the country, with temperatures up to about 80°C. Measurements of He excess, Ne and Ar unexpectedly revealed the existence of glacial age waters in the northeastern part of the basin, and late Holocene age waters in other parts. The noble gas data are shown to be in accordance with newly interpreted earlier long-term records of 3H, δ18O and δ2H in waters of the karstic springs, and with available determinations of 3H, δ18O, δ2H, 14C and δ13C in cold and thermal well waters.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2010, 441 Hydrogeologia z. 10; 7--17
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New magnetostratigraphy and paleopole from the Whitmore Point Member of the Moenave Formation at Kanab, Utah
Autorzy:
Steiner, M.
Powiązania:
https://bibliotekanauki.pl/articles/2077331.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
hettangian magnetostratigraphy
Moenave Formation
normal polarity
paleopole
J-1 cusp
Formacja Moenave
normalna polaryzacja
szpic J-1
Opis:
The entire Whitmore Point Member of the Moenave Formation was sampled in close stratigraphic sequence (+0.3 m) from a vertical exposure in southwestern Utah. The polarity sequence in the Whitmore Point Member is essentially normal polarity, with five or more very short reversed intervals interspersed and a <1 m reversed interval at the top of the sequence. This polarity pattern dates the Whitmore Point Member as Hettangian. In the earliest Jurassic, the North American plate rotated even further westward from its Late Triassic position, and the movement appears to have been accompanied by an abrupt increase in plate motion because of the similarity in position of many Late Triassic paleopoles. The Moenave pole forms the ‘J-1 cusp’ of the North American apparent polar wander curve. The paleopole obtained by this study is somewhat further westward than those of previous studies. Within the 27 m of a mostly normal polarity sequence, the data show multiple, exceedingly short polarity intervals. The magnetization carrier is a maghemite-magnetite mineral, with the magnetization of an additional hematite carrier superposed. The lithostratigraphic sequence of the Moenave Formation is terminated by an unconformable surface, overlain by the Springdale Sandstone. Paleomagnetic directions of the Whitmore Point Member are exceedingly similar to those of the overlying Springdale Sandstone. Even though the two lithologic bodies are separated by a clear disconformity, the similarity in pole positions suggests that the two are closely related in time. It is possible that this disconformity represents the termination of the westward excursion of North America in earliest Jurassic time.The entire Whitmore Point Member of the Moenave Formation was sampled in close stratigraphic sequence (+0.3 m) from a vertical exposure in southwestern Utah. The polarity sequence in the Whitmore Point Member is essentially normal polarity, with five or more very short reversed intervals interspersed and a <1 m reversed interval at the top of the sequence. This polarity pattern dates the Whitmore Point Member as Hettangian. In the earliest Jurassic, the North American plate rotated even further westward from its Late Triassic position, and the movement appears to have been accompanied by an abrupt increase in plate motion because of the similarity in position of many Late Triassic paleopoles. The Moenave pole forms the ‘J-1 cusp’ of the North American apparent polar wander curve. The paleopole obtained by this study is somewhat further westward than those of previous studies. Within the 27 m of a mostly normal polarity sequence, the data show multiple, exceedingly short polarity intervals. The magnetization carrier is a maghemite-magnetite mineral, with the magnetization of an additional hematite carrier superposed. The lithostratigraphic sequence of the Moenave Formation is terminated by an unconformable surface, overlain by the Springdale Sandstone. Paleomagnetic directions of the Whitmore Point Member are exceedingly similar to those of the overlying Springdale Sandstone. Even though the two lithologic bodies are separated by a clear disconformity, the similarity in pole positions suggests that the two are closely related in time. It is possible that this disconformity represents the termination of the westward excursion of North America in earliest Jurassic time.
Źródło:
Volumina Jurassica; 2014, 12, 2; 13--22
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Mšeno-Roudnice Basin: problems of reconstruction of fossil stream pattern (Central Bohemian Coal Basins, Czech Republic)
Autorzy:
Skopec, J.
Pesek, J.
Kobr, M.
Powiązania:
https://bibliotekanauki.pl/articles/1204888.pdf
Data publikacji:
2002
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
seismic profiles
ancient river valleys
Mšeno-Roudnice Basin
Opis:
The Mšeno-Roudnice Coal Basin is an eastern part of the Central Bohemian Carboniferous Coal Basins. The total thickness of the Carboniferous sediments is ranging from several tens of metres in the south up to nearly 1 km in the basin centre. The basin was explored by nearly 55 deep boreholes with the aim to explore coal reserves. The seismic exploration in the basin has been carried out, too. Fossil stream pattern was reconstructed, of which rivers eroded the upper part of the Slaný Formation sediments during the intra-Stephanian hiatus between the Slaný and Líně Formation (Stephanian B/C). The project could have been realized due to some drilling close to seismic profiles, and also at least due to locally favourable seismological conditions. The results allowed to decipher the anomalous depositional structure of the Slaný and Líně formations that was difficult to be defined earlier. The results showed that some tectonic movements occurred towards the end of the Stephanian B which resulted in giving rise of erosional activity of ancient streams.
Źródło:
Polish Geological Institute Special Papers; 2002, 7; 229-236
1507-9791
Pojawia się w:
Polish Geological Institute Special Papers
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
U-Pb zircon age of the Krásné Loučky tuffite : the dating of Visean flysch in the Moravo-Silesian Paleozoic Basin (Rhenohercynian Zone, Czech Republic)
Autorzy:
Jirásek, J.
Wlosok, J.
Sivek, M.
Matýsek, D.
Schmitz, M.
Sýkorová, I.
Vašíèek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2060438.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
volcaniclastic sediment
Horní Benešov Formation
Variscan foreland
Viséan
Carboniferous
chronostratigraphy
Opis:
The only previous U-Pb zircon date for the the Early Carboniferous flysch sequence of the Moravo-Silesian Paleozoic Basin was published in 1987 from tuffogenic material from Kobylí Quarry at Krásné Loučky near the town of Krnov (Silesia, Czech Republic). The measured age of 319 Ma did not agree with its stratigraphic position, and was used as the basis for a hypothesized block of Late Carboniferous paralic molasse incorporated during a later tectonic event. During a survey of the still active quarry in 2010, volcaniclastic horizons were identified and sampled. Direct correspondence of the tuff units to those sampled in 1987 cannot be proved but is likely. High precision chemical abrasion - thermal ionization mass spectrometry (CA-TIMS) U-Pb dating of zircon from this new material has yielded an age of 340.05 ± 0.22 Ma, which correlates to the previously inferred stratigraphic age of the locality and the current calibration of the Early Carboniferous geologic time scale. The newly established age corresponds to the Visean stage and dates the boundary between the Horní Benešov and Moravice formations that can be correlated with other foredeep basins of the Culm in the European Variscides. A population of detrital Cambro-Ordovician zircons and a single 2.0 Ga old zircon crystal from the same volcaniclastic layer dated by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) are consistent with the known age of source material in the Variscan orogenic front.
Źródło:
Geological Quarterly; 2014, 58, 4; 659--672
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 279

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