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Wyszukujesz frazę "karst" wg kryterium: Wszystkie pola


Wyświetlanie 1-4 z 4
Tytuł:
New isotopic data on karst development in the northern Kraków-Wieluń Upland (southern Poland)
Autorzy:
Hercman, H.
Gąiorowski, M.
Sujka, G.
Powiązania:
https://bibliotekanauki.pl/articles/191296.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Kraków-Wieluń Upland
caves
speleothems
U-series dating
karst development
Opis:
The Kraków-Wieluñ Upland is one of the major palaeokarst regions in Poland. However, the stages of karst development in this area are neither well documented nor reconstructed. A series of samples from a new location in the vicinity of Raciszyn was analysed. On the basis of the results of U-series dating, four phases of speleothem deposition were distinguished: (1) older than 600 ka, (2) from more than 600 ka to 290 ka, (3) around 150 ka, and the youngest (4), younger than 3 ka. On the basis of all geochronological data from the region, eight stages of karst development were described. The structure of the oldest speleothems indicates even more stages of deposition and erosion that cannot be recognized using the 230Th/234U dating method. These results indicate that the initial creation of empty spaces in the limestone took place in pre-Pleistocene time. After 600 ka ago, climatic conditions were stable for more than 300 ka, allowing the continuous deposition of speleothems. Several episodes of erosion, deposition of clastic sediments and speleothem growth during the Middle and Early Pleistocene were described. This variability of the sedimentation regime clearly reflects climate changes during that period.
Źródło:
Annales Societatis Geologorum Poloniae; 2016, 86, 4; 429-436
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cryogenic carbonates and cryogenic speleothem damage in the Za Hájovnou Cave (Javoříčko Karst, Czech Republic)
Autorzy:
Žak, K.
Lipták, V.
Filippi, M.
Orvošová, M.
Hercman, H.
Matouškova, Š.
Powiązania:
https://bibliotekanauki.pl/articles/2060084.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
cryogenic cave carbonates
speleothem damage
Javoříčko Karst
U-series dating
Opis:
A new locality of coarse-grained cryogenic cave carbonates has been found in the Za Hájovnou Cave in Javoříčko Karst in Central Moravia, Czech Republic. Crystals and crystal aggregates, usually up to 15 mm in size, form typical loose accumulations on the surface of large fallen limestone blocks and clays covering the bottoms of several cave chambers distant from the cave entrance. The cryogenic origin of the carbonates is supported by their mode of occurrence, specific crystal and aggregate morphology, and C and O stable isotope data. U-series dating of one sample of cryogenic carbonate (age 29.5 ±0.1 ka) indicated that a period of karst water freezing occurred in marine isotope stage (MIS) 3, within the Weichselian. The cave also hosts numerous examples of speleothem damage. As shown in this paper, some of these are clearly connected with freezing conditions and cave ice action.
Źródło:
Geological Quarterly; 2018, 62, 4; 829--839
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland
Autorzy:
Gradziński, M.
Jach, R.
Hercman, H.
Powiązania:
https://bibliotekanauki.pl/articles/2059838.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
cave deposits
speleothems
weathering
Palaeogene
Opis:
Sparry limestone, ferruginous muddy limestone and limestone breccia have been found in the Western Tatra Mts. They occur within Jurassic rocks of the Choč Nappe just below red conglomerates of probable Eocene age. The deposits found bear strong resemblance to the infill of subterranean karst forms. They differ significantly from Quaternary karst deposits of the Tatra Mts. The δ18O values of spelean carbonates suggest crystallisation at relatively high temperatures (over 20°C) whereas their relatively negative δ13C values imply the presence of soil-derived CO2 linked with vegetation dominated by C3 pathway plants. The karst forms and their infill were formed before the Eocene transgression, which shows unequivocally that the Tatra Mts. were subjected to karstification at that time.
Źródło:
Geological Quarterly; 2016, 60, 2; 291-300
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Holocene tufa in the Slovak Karst : facies, sedimentary environments and depositional history
Autorzy:
Gradziński, M.
Hercman, H.
Jaśkiewicz, M.
Szczurek, S.
Powiązania:
https://bibliotekanauki.pl/articles/2060325.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
fluvial tufa
perched spingline tufa
radiocarbon dating
Quaternary
late Holocene tufa decline
Central Carpathians
Opis:
Several tufa complexes are known in the Slovak Karst which is a typical karst area of a temperate climate. This area is built of Mesozoic carbonates, mainly Triassic in age. The karst systems drain carbonate plateaux and lead water to resurgences located in valleys which are up to 300 m deep. Below the resurgences there are Holocene fossil tufa deposits that exceed 12 m in thickness. The tufas include stromatolite, moss, phytoclastic, oncoidal, and intraclastic facies. Extensive barrages which once dammed the upper reaches of the streams were formed in narrow valleys. They are composed predominantly of moss facies and stromatolites, with subordinate oncoidal and phytoclastic facies. Phytoclastic, oncoidal and intraclastic facies are dominant in dammed segments of streams, and include gastropod shells and charcoal fragments. Some small moss cushions are also developed. Barrages and dammed areas formed in a longitudinal fluvial depositional system. Conversely, below resurgences located on plateau slopes tufas of a perched springline depositional system were formed. These comprise deposits of prograding cascades constructed by moss, phytoclastic and stromatolitic facies. Presently, the tufas analysed are inactive. They stopped growing in the Late Holocene time, after which there was abrupt incision of the streams. This caused downcutting into Holocene tufas, in some places reaching Mesozoic bedrock. At present tufa is being precipitated from streams in all the sites studied.
Źródło:
Geological Quarterly; 2013, 57, 4; 769--788
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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