GA AV

The main goal of the project is the determination of relations of parent plants and their spores from Czech and Polish parts of the Upper Silesian Basin by the combination of macropalaeobotanical and palynological methods. The comparison and correlation of the occurrences of fertile and sterile parts of Carboniferous plants and their spores will be made in both parts of the basin. The combination of micro- and macropalaeobotanical methods will determine the classification and stratigraphical ranges of Carboniferous plants of the Upper Silesian Basin. The synonymisation of plant taxa will be proposed. Another goal of the project is the reconstruction of the coal-forming vegetation at the whole area of the Upper Silesian Basin during the sedimentation from the Namurian to the Westphalian D.

The Králův Dvůr Formation represents an important lithostratigraphic unit of the Ordovician in the Prague Basin (Barrandian area). Widely extended and important changes in sedimentary and fossil record took place during its sedimentation. Trends in biodiversity dynamics are particularly substantial for understanding all effects of the Late Ordovician global climatic changes. Such knowledge is of actualistic significance for models of modern climatic changes. In spite of worldwide interest in study of global changes in the Late Ordovician, not very intense attention has been paid to upper Katian in the Prague Basin. The proposed project is focused on filling of this information gap.

Proposal is aimed to determination of longitudinal and shear wave velocity propagation in magmatic rocks, specification of dynamic moduli of these rocks and their anisotropy. Experiments will be carried out in laboratory and field conditions. Laboratory testing of sphere samples is based on ultrasonic sounding and monitoring of velocity changes in dependence on increasing hydrostatic pressure. Space distribution of sensors enables to determine elastic anisotropy under uniaxial loading. Rocks will be sampled from localities, where impact source seismic measurement will be realized. Field space dependence of velocities P and S waves will be examined analogically as in laboratory conditions. The question of S waves record will be solved by applying of special sensors and suitable orientation of seismic wave excitation. Sources of anisotropy under laboratory and field conditions (scaling factor) will be analysed and conversion relation between laboratory and field values will be assessed.

During the low temperature measurements of selected enstatite chondrites we discovered that certain iron and manganese bearing sulfide minerals present within extraterrestrial material undergo various magnetic transitions at low temperatures and thus have significantly different magnetic properties at temperatures of the cold environment than at terrestrial conditions. This opens us a new way to look on extraterrestrial material and to interpret its properties and interactions with magnetic fields in Solar System. In the proposed extensive study a set of he samples representing extraterrestrial material, terrestrial mineral samples as well as synthetic mineral analogues (including single crystals) will be prepared. First a detailed mineralogical and chemical characterization will be done. In the second step a detailed research of the low temperature magnetic propeties will be performed. Special emphasis will be taken on the role of impurities in the samples on the magnetic properties.Certain iron and manganese bearing sulfide minerals present within extraterrestrial material undergo various magnetic transitions at low temperatures and thus have significantly different magnetic properties at temperatures of the cold interplanetary environment compared to terrestrial conditions. This opens us a new look on asteroids and comets and on their interactions with magnetic fields in Solar System. Detailed research of the low temperature magnetic properties of such sulfides is being done with natural and synthetic samples. Data are used to model and interpret magnetic observations and magnetic properties of Solar System minor bodies.

Continental intraplate magmatism is commonly expressed in subvolcanic complexes, for which it is important to characterize the mantle sources. That necessitates distinguishing the effect upon mantle signature of fractional crystallization and assimilation processes during magma ascent and residence in the crust before final emplacement. To achieve that goal, major, minor and trace element data, together with Sr and Nd isotope systematics will be determined. An excellent case area is provided by the subvolcanic rock association of the Roztoky Intrusive Centre, which comprises a hypabyssal low-alkali series of essexite-monzodiorite-sodalite-syenite and dykes of both high- and low-alkali character. Existing data on the genetically related basaltic lava piles and felsic intrusions of the České středohoří Mts. will provide a valuable comparison. Temperature-time profiles of individual subvolcanic rock types will be constructed using fission-track methodology on apatites.

The project seeks a new approach to the study of weathering patterns on siliciclastic sediments. Various morphofacies typical for humid temperate climate will be outlined based on the presence of characteristic micro- and mesoforms of sandstone relief. Further on, their relationship to outcrop position, architecture and tectonic deformation of the sandstone body, grain-size parameters, cement composition, porosity and mechanical properties of sandstone will be studied. Special attention will be given to the degree of silica dissolution and to salt weathering. Interrelationships between such parameters and the resulting morphofacies will open way towards a genetic classification of micro- and mesoforms of sandstone relief, and contribute to the understanding of the sedimentary microrelief on Mars. The project will benefit from outcrop documentation in the Bohemian Cretaceous Basin and elsewhere in Europe, petrographic study, electron microscopy and microanalysis, and laboratory tests.

Aim of project is to obtain new data on salt karst in Zagros Mts., Iran with focuse on: 1)Water flow in salt diapers and their surrounding, including study of dissolution and deposition in unsaturated zone of salt karst, and 2) Dating of inland diapir surfaces to depict the history of salt diapers and salt karst evolution. Several methods will be used for describtion of water flow and its residence time in underground (chemical and isotopic analyses, dating ba means of environmental tracers). Diapir surfaces will be dated by means of OSL method and AMS dating of wood twigs in surface/ cave fluvial deposits. Project is successor of grant project GAAV No. B301110501.

The proposed project is focused on a detailed record of waterborne and aeolian erosions in Strážnické Pomoraví on the lower reach of Morava River in the Holocene, in particular in the last millennium. The main aim is to estimate how the erosion was affected by natural and anthropogenic factors during the fall of the Great Moravian Empire, during Mediaeval colonization, and in the current extensive agricultural land use. Erosion processes recorded in the flood and aeolian sediments will be reconstructed using sedimentological, geophysical, mineralogical, and geochemical means and pollen analysis, supplemented by (14)C, dendrochronological, and OSL dating. The results will be compared with the historical records on the land use and historical-climatologic information on extreme windstorms and flood events. The targeted multidisciplinary study of that natural archive completed by historical data will permit reconstruction of the climate evolution in Central Europe in the last millennium.

Aims of this project are: 1. to bring together people dealing with fractionated granites and pegmatites through the Czech geological institutes and to bring different technologies of melt inclusions (MI) study in routine use in Czech geological institutes. 2. to realise detail study of MI in quartz from subsequent evolutionary stages from three typical, geologically well documented magmatic systems in the Bohemian Massif: highly peraluminous tin-bearing granite, mildly peraluminous subvolcanic granite, and a complex pegmatite. Study of MI from early to late quartz generations enables to interpret the enrichment/depletion of water and volatiles in melt during complex history of evolution of granite system. Comparison of both shallow–seated granite systems with relatively deep-seated pegmatite may demonstrate influence of pressure on the fractionation of evolved granitic melt.

The stromatactis cavities are present in fine-grained carbonate sediments in the nature, forming the specific shapes and reticulate arrays. However, the mechanisms behind the origin of these cavities are subjects of heated discussions in geology for 125 years. Numerous biotic and abiotic factors were considered, but with unclear results. Most recently, our team produced a critical analysis of these sedimentary structures and formulated a new hypothesis that these cavities would likely originate during the rapid deposition of extremely polydisperse and multimodal granular mixtures. Although the first experiments simulated the production of these cavities with a considerably high level of similarity, there is a lot of work to be done if we wish really explain these unique phenomena in terms of hydrodynamics. The proposed interdisciplinary study is novel, and the results would be fundamental for sedimentology and hydrodynamics, with possible implications in related technologies.