In the article tourist management in two national parks in the Czech-German borderland are being compared,namely Bohemian ’Switzerland’(also known as Czech ’Switzerland’) and Saxon’Switzerland’.Situated on eithe...In the article tourist management in two national parks in the Czech-German borderland are being compared,namely Bohemian ’Switzerland’(also known as Czech ’Switzerland’) and Saxon’Switzerland’.Situated on either side of the state border,they feature the same type of geographical environment.Transport accessibility,transborder links and the hiking trail network are analyzed using methodology sourced from graph theory.The result of the analyses is a classification of tourist hubs and tourist centers,as well as an indication of the main directions of tourist flow.The German national park is decidedly more accessible but with a detrimental effect on the natural environment primarily due to its fragmentation by a dense network of tourist trails.In both parks trails enter the core zone(in theory a strict protection area) but this occurs on a larger scale on the German side.In the Czech national park a greater number of positive examples of managing tourist movements can be identified.Additionally,larger areas managed for dispersion,or from which tourists are generally excluded,are located there.展开更多
The Pb isotope composition of the upper mantle beneath Central Europe is heterogeneous due to the subduction of regionally contrasting material during the Variscan and Alpine orogenies.Late Variscan to Cenozoic mantle...The Pb isotope composition of the upper mantle beneath Central Europe is heterogeneous due to the subduction of regionally contrasting material during the Variscan and Alpine orogenies.Late Variscan to Cenozoic mantlederived melts allow mapping this heterogeneity on a regional scale for the last ca.340 Myr.Late Cretaceous and Cenozoic anorogenic magmatic rocks of the Bohemian Massif(lamprophyres,volcanic rocks of basanite/tephrite and trachyte/phonolite series) concentrate mostly in the Eger Rift.Cretaceous ultramafic lamprophyres yielded the most radiogenic Pb isotope signatures reflecting a maximum contribution from metasomatised lithospheric mantle,whereas Tertiary alkaline lamprophyres originated from mantle with less radiogenic ^(206)Pb/^(204)b ratios suggesting a more substantial modification of lithospheric source by interaction with asthenosphericderived melts.Cenozoic volcanic rocks of the basanite/tephrite and trachyte/phonolite series define a linear mixing trend between these components,indicating dilution of the initial lithospheric mantle signature by upwelling asthenosphere during rifting.The Pb isotope composition of Late Cretaceous and Cenozoic magmatic rocks of the Bohemian Massif follows the same Pb growth curve as Variscan orogenic lamprophyres and lamproites that formed during the collision between Laurussia,Gondwana,and associated terranes.This implies that the crustal Pb signature in the post-Variscan mantle is repeatedly sampled by younger anorogenic melts.Most Cenozoic mantle-derived rocks of Central Europe show similar Pb isotope ranges as the Bohemian Massif.展开更多
The Variscan Bohemian Massif in Central Europe,resulting from continent-continent collision,was long considered a potential UHP terrain due to numerous occurrences of high-pressure granulites,eclogites and
Underground storage systems are currently being used worldwide for the geological storage of natural gas （CH4）, the geological disposal of CO2, in geothermal energy, or radioactive waste disposal. We introduce a com...Underground storage systems are currently being used worldwide for the geological storage of natural gas （CH4）, the geological disposal of CO2, in geothermal energy, or radioactive waste disposal. We introduce a complex approach to the risks posed by induced bedrock instabilities in deep geological underground storage sites. Bedrock instability owing to underground openings has been studied and discussed for many years. The Bohemian Massif in the Czech Republic （Central Europe） is geologically and tectonically complex. However, this setting is ideal for leaming about the instability state of rock masses. Longterm geological and mining studies, natural and induced seismicity, radon emanations, and granite properties as potential storage sites for disposal of radioactive waste in the Czech Republic have provided useful information. In addition, the Czech Republic, with an average concentration radon of 140 Bq m-3, has the highest average radon concentrations in the world. Bedrock instabilities might emerge from microscale features, such as grain size and mineral orientation, and microfracturing. Any underground storage facility construction has to consider the stored substance and the geological settings. In the Czech Republic, granites and granitoids are the best underground storage sites. Microcrack networks and migration properties are rock specific and vary considerably. Moreover, the matrix porosity also affects the mechanical properties of the rocks. Any underground storage site has to be selected carefully. The authors suggest to study the complex set of parameters from micro to macroscale for a particular place and type of rock to ensure that the storage remains safe and stable during construction, operation, and after closure.展开更多
文摘In the article tourist management in two national parks in the Czech-German borderland are being compared,namely Bohemian ’Switzerland’(also known as Czech ’Switzerland’) and Saxon’Switzerland’.Situated on either side of the state border,they feature the same type of geographical environment.Transport accessibility,transborder links and the hiking trail network are analyzed using methodology sourced from graph theory.The result of the analyses is a classification of tourist hubs and tourist centers,as well as an indication of the main directions of tourist flow.The German national park is decidedly more accessible but with a detrimental effect on the natural environment primarily due to its fragmentation by a dense network of tourist trails.In both parks trails enter the core zone(in theory a strict protection area) but this occurs on a larger scale on the German side.In the Czech national park a greater number of positive examples of managing tourist movements can be identified.Additionally,larger areas managed for dispersion,or from which tourists are generally excluded,are located there.
基金financially supported by the institutional project RVO 67985831 of the Institute of Geology of the Czech Academy of Sciencesby the Brno University of Technology project LO1408“AdMaS UP-Advanced Materials,Structures and Technologies”supported by the Ministry of Education,Youth and Sports of the Czech Republic under the“National Sustainability Programme I”。
文摘The Pb isotope composition of the upper mantle beneath Central Europe is heterogeneous due to the subduction of regionally contrasting material during the Variscan and Alpine orogenies.Late Variscan to Cenozoic mantlederived melts allow mapping this heterogeneity on a regional scale for the last ca.340 Myr.Late Cretaceous and Cenozoic anorogenic magmatic rocks of the Bohemian Massif(lamprophyres,volcanic rocks of basanite/tephrite and trachyte/phonolite series) concentrate mostly in the Eger Rift.Cretaceous ultramafic lamprophyres yielded the most radiogenic Pb isotope signatures reflecting a maximum contribution from metasomatised lithospheric mantle,whereas Tertiary alkaline lamprophyres originated from mantle with less radiogenic ^(206)Pb/^(204)b ratios suggesting a more substantial modification of lithospheric source by interaction with asthenosphericderived melts.Cenozoic volcanic rocks of the basanite/tephrite and trachyte/phonolite series define a linear mixing trend between these components,indicating dilution of the initial lithospheric mantle signature by upwelling asthenosphere during rifting.The Pb isotope composition of Late Cretaceous and Cenozoic magmatic rocks of the Bohemian Massif follows the same Pb growth curve as Variscan orogenic lamprophyres and lamproites that formed during the collision between Laurussia,Gondwana,and associated terranes.This implies that the crustal Pb signature in the post-Variscan mantle is repeatedly sampled by younger anorogenic melts.Most Cenozoic mantle-derived rocks of Central Europe show similar Pb isotope ranges as the Bohemian Massif.
文摘The Variscan Bohemian Massif in Central Europe,resulting from continent-continent collision,was long considered a potential UHP terrain due to numerous occurrences of high-pressure granulites,eclogites and
基金supported by the long-term conceptual development research organization RVO grant 67985891the Ministry of Industry and Trade of the Czech Republic (FR-TI1/367)
文摘Underground storage systems are currently being used worldwide for the geological storage of natural gas （CH4）, the geological disposal of CO2, in geothermal energy, or radioactive waste disposal. We introduce a complex approach to the risks posed by induced bedrock instabilities in deep geological underground storage sites. Bedrock instability owing to underground openings has been studied and discussed for many years. The Bohemian Massif in the Czech Republic （Central Europe） is geologically and tectonically complex. However, this setting is ideal for leaming about the instability state of rock masses. Longterm geological and mining studies, natural and induced seismicity, radon emanations, and granite properties as potential storage sites for disposal of radioactive waste in the Czech Republic have provided useful information. In addition, the Czech Republic, with an average concentration radon of 140 Bq m-3, has the highest average radon concentrations in the world. Bedrock instabilities might emerge from microscale features, such as grain size and mineral orientation, and microfracturing. Any underground storage facility construction has to consider the stored substance and the geological settings. In the Czech Republic, granites and granitoids are the best underground storage sites. Microcrack networks and migration properties are rock specific and vary considerably. Moreover, the matrix porosity also affects the mechanical properties of the rocks. Any underground storage site has to be selected carefully. The authors suggest to study the complex set of parameters from micro to macroscale for a particular place and type of rock to ensure that the storage remains safe and stable during construction, operation, and after closure.
