GACR

Middle Devonian radiolaria were reported from the Barrandian formerly (Bouček, Petránek, Čejchan 1986, Braun & Budil 1999), indicating an ocurrence of a rich and diverse radiolarian fauna of quite unique stratigraphic position among the world's paleoziocradiolarian localities. However, this fauna has not been studied monographically yet. Both albaillellid and entactiniid polycystine radiolarians are present within the fauna. Previous studies indicate a presence of several evolutionary lineages ofceratoikiscids, with several new species characteristic of the Eifelian age. Radiolarian fauna is accompanied by megafauna of goniatites, bivalves, trilobites, etc., and, best of all, also by conodonts. Thus, the hopefully newly established localradiolarian zones would be able to be directly correlated with the standard conodont and goniatite zonations.

The main point of the project is the study of the development of the brachiopod assemblages through the Triassic x Jurassic boundary, and the detailed taxonomic revision of new finds of brachiopods with an accent on inner structures and variability ofthe external morphology of shells. The large comparative material of brachiopods from this stratigraphic span deposited in the collections in Innsbruck and Vienna will be also studied. Based on the detailed study of the characteristic localities andsections in the Northern Calcareous Alps, completed with the study of new brachiopod material, the changes in the representation of particular groups of brachiopods during the critical period of reduced marine asssemblages between the Uppermost Triassicand Lowermost Jurassic will be documented. The results of the palaeontological revision of brachiopods will be completed by new data gained recently by other geologists.

The durability of natural stone is assumed to be intimately related to pre-peak fracture process (crack initiation and damage), which can be derived from stress-strain behaviour during compression and/or tension. Compared to previous empirical evaluation (freeze-thaw cycles, salt crystallization, hydric dilation) of the durability of natural stone, in this new project this will be resolved through experimental rock mechanical tests employing acoustic emission monitoring. Testing will include rock fabric analyses prior and after the tests on porous rocks (sandstones, silicites, tuffites, bioclastic limestones) showing variable porosity (5-30 vol. %), pore size distribution, granulometry, degree of cementation, and physical properties. Prior to the rock mechanical tests, certain specimens will be artificially weathered and/or consolidated in order to evaluate effect of rock fabric modification on the mechanical properties. From the stress-strain curves, energetic parameters of deformational process will be derived as a key factor influencing the durability of natural stone.

Salt weathering is considered to be a key factor for evolution of many sandstone landforms. The grant project is aimed to characterize the properties and processes, which are critical for salt weathering, but they were not studied in detail under eld conditions. These are among others the migration of water, vapour and dissolved salts in surcial zone of sandstone/its crust. Hypotheses concerning fundamental role of evaporation rate temporary changes to cavernous weathering will be tested as well. In Strelec Quarry (active sandstone quarry with abandoned exposures of various ages including the incipient crusts) the methods adopted from laboratory techniques will be applied. Their results will be tested by fully destructive but proven techniques. Developed approach to study and characterize the processes in surface zone of sandstone will be consequently applied to natural sandstone exposures in the Czech Republic

Numerous fish fossil have been found in the Oligocene-Miocene deposits of the Carpathian Basins over the last decades. These findings have been taxonomically studied but especially juvenile and larval specimens gained only a minor attention. The goal of the present study is to fill the gap in this research by choosing the exceptional fish collection from the Hermanowa locality represented by several hundreds of specimens of different ontogenetic levels. Study of these specimens brings an opportunity of recognition of ontogenetic processes, one of key issues in these days. Information on ontogeny together with a detailed taxonomical study will serve as a basis for re-evaluation of the studied fish taxa from the systematic points of view. Furthermore, the complex description and analysis of the collection will provide palaeoecological data, which, in larger context of other localities in Carpathian Basins, can reveal new aspects of fish fauna changes during the Oligocene-Miocene time interval.

Moldavites are central European tektites genetically related to the Ries crater. However, source materials of moldavites and processes of their chemical fractionation are not properly constrained. Investigation of moldavites indicates that, in parallel to sedimentary rocks, plant biomass could have supplied significant portion of source matter as indicated by enrichments in contents of plant-essential elements, depletion in plant-non-essential elements and C and O isotope composition in moldavite glass. We aim at exploring this hypothesis by C and O isotope analysis in glass and fluid inclusions in moldavites, as well as Si, Ca, Mg and Li in moldavites and sedimentary units of the Ries area by means of isotope mass spectrometry. Selection of samples for detailed isotope analyses will be based on prior geochemical characterization. Further, Re–Os systematics, Cr and platinum group element contents will be studied in order to reveal any extraterrestrial signature in moldavites. These findings should constrain processes of tektite formation, with possible application in astrobiology.

During the last two decades, an increasing number of constructions affected by alkali-silica reaction (ASR) was found. In the Czech Republic, ASR was characterized deteriorating concrete pavements, airports, bridges, and dams. One of the arguments for the frequent occurrence of ASR damage is regarded to be in extensive use of quartz-rich aggregates in concrete and an insufficient knowledge of the parameters affecting their ASR. The project submitted proposes to measure the ASR of quartz-rich aggregates, employing chemical methods and an accelerated mortar bar test combined with acoustic emission analysis. Quartz crystallinity and deformation will be characterised quantitatively employing microscopic methods (SEM/EDS, CL, TEM, and FTIR). The approach mentioned above will enable the finding of those parameters responsible for the ASR of quartz. The project results will be published in scientific journals, and conferences. Their applications in the technical regulations concerning aggregate testing will contribute to the mitigation of ASR in new constructions in the Czech Republic.

Aim of this project is identification of the open system-processes in granitic rocks and reconstruction of p-T-x conditions before, during, and after the opening of particular magmatic system. We will study granitoids and rhyolites, which underwent different kinds of system opening: (i) mingling and mixing, (ii) subvolcanic intrusion connected with escape of volatiles and undercooling, (iii) volcanic eruption and recharge of magma chamber. The main methodological contribution of the project is a combination of modern imaging techniques (BSE and color CL), surface analytical methods ("mapping" using EMPA and LA-ICP-MS) and local microanalysis (EMPA, LA-ICP-MS). Beside this, methods of classical petrology and mineralogy (study of equilibrium vs. non-equilibrium rock textures), and methods of local geochronology (U/Pb by LA-ICP-MS) will be used. Models of magmatic evolution will be developed for each studied locality.

Existing global stratotype sections of the lower Silurian Aeronian and Homerian stages have been found inadequate with respect to modern high-resolution tools of stratigraphic correlation and even standard biostratigraphy. In response to current ISSS initiatives, Rhuddanian/Aeronian and Sheinwoodian/Homerian boundary sections exposed at Hlásná Třebaň and Kosov in the Prague Synform will be examined in detail as prospective candidates for new global stratotypes. Biostratigraphic description and correlation of the sections based upon graptolites will be supplemented by chitinozoan and limited conodont data. Horizons and biozones formerly selected to mark the base of the respective stages are well recognizable in these sections. Apart from biostratigraphic markers, geochemical and petro-physical proxies will be studied since trends in carbon isotopic composition and potential changes or cycles in organic productivity and rate of black-shale sedimentation can serve as likely proxies of global environmental changes of chronostratigraphic significance.

The project’s aim is to establish sequence-stratigraphic framework for the Devonian events in carbonates of the Barrandian area and Moravo-Silesian Zone, Bohemian Massif; with emphasis to sediments, facies, paleontological content and indicators of paleoclimate settings.