The Lateglacial and Holocene in Central Europe: a multi‐proxy environmental record from the Bohemian Forest,Czech Republic

The Hercynian mountain ranges were islands of mountain glaciation and alpine tundra in a Central European ice‐free corridor during the Late Pleistocene. Today they are notable areas of glacial landforms, alpine‐forest free areas, peatlands and woodlands. However, our knowledge of the Lateglacial and early Holocene environmental changes in this region is limited. We present a new multi‐proxy reconstruction of a mid‐altitude environment in the Bohemian Forest spanning this period. A core (5.2 m length) in the ?erné Lake cirque (1028 m a.s.l.) was subjected to lithological, geochemical, pollen and macrofossil analysis supplemented by two optically stimulated luminescence (OSL) and 10 AMS radiocarbon dates. We determined the impact of regional and supraregional climate changes on the environment. The two most significant changes in sedimentation during the Lateglacial (17.6 and 15.8–15.5 cal. ka BP) were synchronous with regional glacial chronostratigraphy. Unlike Central European mountain ranges, in the Bohemian Forest the Younger Dryas was not coincident with glacier re‐advance, but was a dry, cold episode with low lake levels, which prevailed until the early Preboreal. Plant macrofossils indicate local establishment of Betula nana and Betula pendula/pubescens at 15.4–13.4 cal. ka BP. Comparison with Holocene records from Central Europe shows a similar immigration history of vegetation at mid and higher altitudes. The tree line exceeded an altitude of ~1000 m a.s.l. around 10.5 cal. ka BP and coincided with rapid geochemical changes in the sediment. The 8.2 ka BP event did not have any response in the sedimentary record, but corresponded to stabilization of the Picea abies population and expansion of Fagus. Fagus colonized the Bohemian Forest earlier than other Hercynian mid‐mountains, but never predominated in the composition of the forest at higher elevations. Abies alba was the last tree species that immigrated to the study area.     

Expected changes in agroclimatic conditions in Central Europe

During the past few decades, the basic assumption of agroclimatic zoning, i.e., that agroclimatic conditions remain relatively stable, has been shattered by ongoing climate change. The first aim of this study was to develop a tool that would allow for effective analysis of various agroclimatic indicators and their dynamics under climate change conditions for a particular region. The results of this effort were summarized in the AgriClim software package, which provides users with a wide range of parameters essential for the evaluation of climate-related stress factors in agricultural crop production. The software was then tested over an area of 114,000 km² in Central Europe. We have found that by 2020, the combination of increased air temperature and changes in the amount and distribution of precipitation will lead to a prolonged growing season and significant shifts in the agroclimatic zones in Central Europe; in particular, the areas that are currently most productive will be reduced and replaced by warmer but drier conditions in the same time the higher elevations will most likely experience improvement in their agroclimatic conditions. This positive effect might be short-lived, as by 2050, even these areas might experience much drier conditions than observed currently. Both the rate and the scale of the shift are amazing as by 2020 (assuming upper range of the climate change projections) only 20?C38% of agriculture land in the evaluated region will remain in the same agroclimatic and by 2050 it might be less than 2%. On the other hand farmers will be able to take advantage of an earlier start to the growing season, at least in the lowland areas, as the proportion of days suitable for sowing increases. As all of these changes might occur within less than four decades, these issues could pose serious adaptation challenges for farmers and governmental policies. The presented results also suggest that the rate of change might be so rapid that the concept of static agroclimatic zoning itself might lose relevance due to perpetual change.     

Reproducing kernel and Galerkin��s matrix for the exterior of an ellipsoid: Application in gravity field studies

In the introductory part of the paper the importance of the topic for gravity field studies is outlined. Some concepts and tools often used for the representation of the solution of the respective boundary-value problems are mentioned. Subsequently a weak formulation of Neumann??s problem is considered with emphasis on a particular choice of function basis generated by the reproducing kernel of the respective Hilbert space of functions. The paper then focuses on the construction of the reproducing kernel for the solution domain given by the exterior of an oblate ellipsoid of revolution. First its exact structure is derived by means of the apparatus of ellipsoidal harmonics. In this case the structure of the kernel, similarly as of the entries of Galerkin??s matrix, becomes rather complex. Therefore, an approximation of ellipsoidal harmonics (limit layer approach), based on an approximation version of Legendre??s ordinary differential equation, resulting from the method of separation of variables in solving Laplace??s equation, is used. The kernel thus obtained shows some similar features, which the reproducing kernel has in the spherical case, i.e. for the solution domain represented by the exterior of a sphere. A numerical implementation of the exact structure of the reproducing kernel is mentioned as a driving impulse of running investigations.     

Numerical behaviour of the downward continuation of gravity anomalies

The numerical results of downward continuation (DWC) of point and mean gravity anomalies by the Poisson integral using point, single mean, and doubly averaged kernel are examined. Correct evaluation of the integral in its innermost zone is a challenging task. To avoid instabilities, an analytical planar approximation is used in the innermost integration zone. In addition it is shown that the single mean mode has the minimum discretization error. Downward continuation of point and mean anomalies by singly and doubly averaged kernel are the same mean anomalies on the geoid.     

Blue, complexly zoned, (Na,Mg,Fe,Li)-rich beryl from quartz-calcite veins in low-grade metamorphosed Fe-deposit Sk��ly near Ryma?ov, Czech Republic

Syn-tectonic quartz-calcite veins containing blue beryl are enclosed in hematite > magnetite-rich portions of the low-grade metamorphosed Fe-deposit Skály near Ryma?ov, Czech Republic. Aggregates of pale to deep blue beryl, up to 2?cm in diameter, are associated with euclase, clinochlore, hematite, albite and dravite. Complexly zoned beryl crystals consist of skeletal aggregates of beryl I randomly distributed within volumetrically dominant beryl II with narrow rims of beryl III. All types of beryl have similar contents of Na (0.32?C0.49 apfu) and Mg (0.31?C0.41 apfu) but variable contents of Fe_tot (0.05?C0.34 apfu) and Al (1.20?C1.62 apfu). The LA-ICP-MS study yielded elevated contents of Li, up 1,314?ppm (0.28?wt.% Li₂O) in beryl I. The quartz-calcite veins represent an unusual type of low-T metamorphic-hydrothermal vein related to Fe-ore deposit characterized by single-stage fracturing and mobilization in a closed system at T~200?C300°C and CO ₃ ^2- as a major complexing agent for the mobility of Be.     

Simultaneous determination of the source mechanism and the seismic wave energy

Summary It is necessary to know the source mechanism for the determination of the seismic energy of seismic waves from the seismogram recorded at one station. For sparse data (selected events of the 1985/86 Western-Bohemia earthquake swarm) the source mechanisms cannot be determined fromP-wave first motions. Therefore, a new method of determining the source mechanism simultaneously with the energy calculated from observations at two stations has been developed. The method is described and tested. Advantages, disadvantages and the stability of the method are discussed.     

Regional development and the disintegration of Czechoslovakia

The breakup of Czechoslovakia on 31 December 1992 resulted in the emergence of a newly independent Slovakia and Czech Republic. The split is often interpreted as the result of ethnic nationalism. In contrast, this paper attempts to assess the influence of regional inequalities and uneven economic development on the split. Pre-World War Two Czechoslovakia was unable to address large regional differences between the Czech lands and Slovakia. The economic policies pursued by the state socialist governments following 1948 were directed toward the elimination of these differences through rapid industrialization of Slovakia. The economic transformation in Czechoslovakia after the collapse of state socialism resulted in reemergence of uneven development between Slovakia and the Czech lands, which contributed to the disintegration of the country. The links between economic issues and politics are discussed, and the paper shows how the regional inequalities and economic issues were used to justify the necessity of Slovak and Czech independence.     

The second most disastrous windstorm of the nineteenth century in the Czech Lands, 26-27 October 1870

Theoretical and Applied Climatology - One of the most disastrous windstorms to take place over the Czech Lands occurred on the night of 26/27 October 1870. It is here analysed through the use of...     

Geochemical history of a Lower Miocene lake,the Cypris Formation,Sokolov Basin,Czech Republic

The intracontinental Lower Miocene Cypris paleo-lake originated during progressive subsidence in the Sokolov Basin, part of the Cenozoic Oh?e Rift, after the deposition of coal seams. The Cypris Fm. consists almost entirely of lacustrine clays with variable mineral composition and organic matter, where this succession is 70–120 m thick. The main objective of this study was to interpret the geochemical history of the Lower Miocene Cypris Fm. using high-resolution, down-core geochemical records and study of the organic matter. This work revealed that the lower part of the lacustrine sediment sequence was deposited in a freshwater lake, in an open hydrological system. An increase in the K/Zr and K/Ti ratios towards the upper part of the Cypris Fm. indicates a gradual increase in the pelitic fraction of the local sediments and/or a decline in input of volcanic material. Simultaneously, increasing Ca/K and Sr/K ratios indicate the precipitation of carbonates, predominantly dolomite and siderite. In the upper part of the Cypris Fm., there is a significant increase in Na/K, Na/Zr, and Na/Ti ratios, suggesting increasing salinity (alkalinity) of the paleoenvironment in a closed hydrological system. Reaction between the Na-rich water and clastic components of the sediment in an alkaline medium gave rise to the formation of zeolites, mixed-layer clay minerals and smectite. Abundant remains of aquatic organisms, especially algae, increased with greater salinity in the upper part of the Cypris Fm. This is reflected in the greater hydrogen index (HI_{Rock Eval}), and the growing proportion of liptinite group macerals of aquatic origin in the bulk organic matter. During the entire history of sedimentation in the Miocene lake, repetitive changes in the sediment geochemistry occurred at both micro- and macroscales, and fluctuations of K/Ti, K/Zr, and Sr/Ca ratios over meters to tens of meters are observed. These changes probably reflect either long-term climate fluctuations during the Lower Miocene or oscillations caused by changes in the rate of subsidence of the basin floor. Variations in the elemental composition of sediments can be used to correlate individual boreholes across the entire sedimentary basin.