Klima, utečenci a proměna společnosti
Cílek, Václav
2015 - Czech
Keywords:
climate change; resources; migration
Available at various institutes of the ASCR
Klima, utečenci a proměna společnosti
Geologie Prahy
Mikuláš, Radek
2014 - Czech
Keywords:
geology; nature conservation; landscape; urban ecology; Prague
Available at various institutes of the ASCR
Geologie Prahy
Genius loci ve vinicích
Cílek, Václav
2013 - Czech
Keywords:
vine; landscape; climate change
Available at various institutes of the ASCR
Genius loci ve vinicích
Na Javorce Cave - a new discovery in the Bohemian Karst (Czech Republic): unique example of relationships between hydrothermal and common karstification.
Dragoun, J.; Žák, Karel; Vejlupek, J.; Filippi, Michal; Novotný, J.; Dobeš, J.
2013 - English
The Na Javorce Cave is located in the Bohemian Karst, Czech Republic, about 25 km SW of Prague. The cave was formed in vertically dipping layers of Lower Devonian limestone; it is 1,723 m long and 129 m deep, of which 9 m is permanently flooded. The cave is polygenetic, with several clearly separable evolutionary stages. Cavities discovered to date were mostly formed along the tectonic structures of two main systems. One of these systems is represented by vertical faults of generally N-S strike, which are frequently accompanied by vein hydrothermal calcite with crystal cavities. The second fault system is represented by moderately inclined west-dipping faults. Smaller tube-like passages of phreatic morphology connect the larger cavities. The fluid inclusion data obtained for calcite developed along both fault systems in combination with C and O stable isotope studies indicate that the hydrothermal calcite was deposited from moderately NaCl-type basinal fluids (0.5 to 8.7 wt. % NaCl equ
Keywords:
caves; karstification; karst; Bohemian Karst
Available at various institutes of the ASCR
Na Javorce Cave - a new discovery in the Bohemian Karst (Czech Republic): unique example of relationships between hydrothermal and common karstification.
The Na Javorce Cave is located in the Bohemian Karst, Czech Republic, about 25 km SW of Prague. The cave was formed in vertically dipping layers of Lower Devonian limestone; it is 1,723 m long and 129 ...
New localities of coarsely crystalline cryogenic cave carbonates in Slovakia
Orvošová, M.; Vlček, L.; Žák, Karel
2013 - English
Three new localities of coarsely crystalline cryogenic cave carbonates (CCCcoarse) have been recently discovered in the Western Carpathians, Slovakia. CCCcoarse are secondary mineral formations in the cave and belong to speleothems. They occur in the form of loose accumulations of calcite crystals and crystal aggregates freely deposited on the bottom of the cavities. Their genesis is interpreted as related to slow karst-water freezing in pools inside the caves, in relation to the existence of a permafrost zone during Quaternary glacials. The newly discovered CCCcoarse localities in Četníkova svadba Cave, Demänovská j. mieru Cave and Zlomísk Cave are characterized by description and photodocumentation of the present crystal forms, by preliminary C and O isotope data, and by their U-series ages. The ages of the cryogenic crystals are in the range between 47 and 12 ka BP, corresponding to the latter half of the Last Glacial. Any new locality of CCCcoarse formed during the Last Glacial represents an important source of information about paleoclimatic conditions of adjacent areas. The U-series ages of the new localities support the earlier conclusion that the formation of CCCcoarse is related to transitions from cold to warm climate periods within the Last Glacial.
Keywords:
caves; carbonates; cryogenic carbonates
Available at various institutes of the ASCR
New localities of coarsely crystalline cryogenic cave carbonates in Slovakia
Three new localities of coarsely crystalline cryogenic cave carbonates (CCCcoarse) have been recently discovered in the Western Carpathians, Slovakia. CCCcoarse are secondary mineral formations in ...
Miocene-Pliocene age of cave Snežna Jama na Raduhi, Southern Alps, Slovenia
Mihevc, A.; Horáček, I.; Pruner, Petr; Zupan Hajna, N.; Čermák, Stanislav; Wagner, Jan; Bosák, Pavel
2013 - English
Snežna jama cave is 1,600 m long horizontal cave at about 1,500 m a.s.l. in Raduha Massif (Kamnik-Savinja Alps) rich in cave deposits (both allogenic sediments and massive flowstones). The cave size, shape and deposits show (1) formation of the cave in different conditions, and (2) its substantial age. A 4.8 m deep pit was excavated in allogenic sediments. Samples were taken both for palaeomagnetic analysis and palaeontological screening. Sediments consist of rhythmically arranged layers deposited in phreatic conditions. Fragments of rodent teeth and a well-preserved molar of genus Baranomys were identified. Fossil remains indicate mammalian zone MN 16 and MN 14. A high-resolution palaeomagnetic analysis revealed total of 3 principal normal polarized and 2 principal reverse polarized magnetozones. If we accept the palaeontologic calibration, the deposition took place within Gauss and Gilbert chrons, from about 2.6 to more than 5 Ma. Long sedimentation period is in concordance with the cave rocky relief that shows phreatic and epiphreatic morphology and predates the main uplift of the area for about 900 m.
Keywords:
caves; karst; Miocene; Pliocene
Available at various institutes of the ASCR
Miocene-Pliocene age of cave Snežna Jama na Raduhi, Southern Alps, Slovenia
Snežna jama cave is 1,600 m long horizontal cave at about 1,500 m a.s.l. in Raduha Massif (Kamnik-Savinja Alps) rich in cave deposits (both allogenic sediments and massive flowstones). The cave size, ...
Magnetic fabric and mineralogy of cave deposits in Botovskaya Cave (Eastern Siberia, Russian Federation)
Kadlec, Jaroslav; Hercman, H.; Chadima, Martin; Lisá, Lenka; Oberhänsli, H.; Osintsev, A.
2013 - English
The Botovskaya Cave is a typical example of a two-dimensional maze with a total length of explored passages exceeding 60 km, which represents the longest limestone cave system in the Russian Federation. The clastic cave sediments filling the cave passages differ in both mineral and mineral magnetic properties and were deposited under different hydrological conditions. The older portion of the clastic cave fills was derived from overlying sandstones, whereas the properties of younger cave sediments show closer affinity to the soils and weathering products originating on the sandstone plateau above the cave. The cave sediments underwent repeated periods of deposition and erosion during the Tertiary and Pleistocene.
Keywords:
caves; magnetic fabric; mineralogy; cave deposits
Available at various institutes of the ASCR
Magnetic fabric and mineralogy of cave deposits in Botovskaya Cave (Eastern Siberia, Russian Federation)
The Botovskaya Cave is a typical example of a two-dimensional maze with a total length of explored passages exceeding 60 km, which represents the longest limestone cave system in the Russian ...
Trendy 2030 - dobrý život v obtížné době
Cílek, Václav
2013 - Czech
Keywords:
global change; energy; resources
Fulltext is available at external website.
Trendy 2030 - dobrý život v obtížné době
Výzkum sedimentů a speleotém ve Zbrašovských aragonitových jeskyních
Bosák, Pavel; Šlechta, Stanislav; Hercman, H.; Pruner, Petr
2013 - Czech
Numerické datování termominerálních speleotém (koblih) z okolí lokality U krokodýla poskytlo poněkud starší data než dosud udávaná v literatuře: 123 až 127 tisíc let (s rozptylem 108 až 144 tisíc let). Speleotémy se tvořily v průběhu klimatického optima vrcholné poslední doby meziledové (eem), tj. v mořském izotopovém stupni (MIS) 5e. Jemnozrnné klastické sedimenty z výkopu U Krokodýla mají normální paleomagnetickou polaritu vzorků s téměř současnými paleomagnetickými směry. S ohledem na skutečnost, že sedimenty leží na bloku ze stěny utržených termominerálních speleotém, jsou pak jistě mladší než 108 tisíc let. The numerical dating of hydrothemal speleothems (doughnuts) from locality At Crocodile gave older data than was published in the literature: 123 to 127 thousand years (with range 108 to 144 thousand years). Speleothems crystallized in the time of climatic optimum of the last interglacial period (Eemian) corresponding to the marine isotope stage (MIS) 5e. Clastic sediments from excavations in the area At Crocodile show normal paleomagnetic polarity in all samples with nearly recent magnetic field directions. Studied sediments cover block of hydrothermal speleothems fallen from the wall and therefore they must be younger than 108 thousand years.
Keywords:
Cave sediments; speleothems; U-series dating; paleomagnetism and magnetostratigraphy; Eemian; Hranice Karst (Czech Republic)
Available at various institutes of the ASCR
Výzkum sedimentů a speleotém ve Zbrašovských aragonitových jeskyních
Numerické datování termominerálních speleotém (koblih) z okolí lokality U krokodýla poskytlo poněkud starší data než dosud udávaná v literatuře: 123 až 127 tisíc let (s rozptylem 108 až 144 tisíc ...
Cave formation initiated by dissolution of carbonate cement in qartzose sandstones
Adamovič, Jiří; Mikuláš, Radek; Navrátil, Tomáš; Mertlík, J.
2013 - English
Besides cavities of irregular shape, European sandstones also feature symmetrical cavities of spherical, ellipsoidal or teardrop shapes. Most of them are tens of centimetres across but some reach as much as 2–3 m in diameter and may coalesce into large caves tens of metres in length. Their origin has not been clearly explained yet. Based on the field comparison between such cavities in quartzose sandstones and incompletely developed cavities in carbonate-cemented sandstones, it can be demonstrated that the symmetrical cavities form by carbonate dissolution within the limits of former carbonate concretions. The diagnostic features of post-concretionary cavities include their circular or elliptical cross-section, a uniform orientation of their long axes across the region, and the presence of a set of parallel vertical joints or grooves/ribs on their inner walls. In some sandstone areas (e.g., Petite Suisse area in Luxembourg, Kokořín area in the Czech Republic), a wide variety of transitional forms can be found between the cavities and concretions forming positive relief on a vertical cliff face, depending on the position of the carbonate dissolution front in the present landscape.
Keywords:
caves; sandstones; carbonate cement
Available at various institutes of the ASCR
Cave formation initiated by dissolution of carbonate cement in qartzose sandstones
Besides cavities of irregular shape, European sandstones also feature symmetrical cavities of spherical, ellipsoidal or teardrop shapes. Most of them are tens of centimetres across but some reach as ...
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