Late Miocene to present day structural development of the Polish segment of the Outer Carpathians

This paper presents a few pieces of evidence on neotectonic structural evolution of the Polish segment of the Outer Carpathians. During the Late Neogene, structural development was largely controlled by normal faulting and block uplift. However, there are also indications of compressional stress setting, at least during the Pliocene and particularly within the medial and eastern parts of the belt. In the Quaternary, in turn, structural development has been mainly controlled by compressional stress arrangement, with \sigma _{1} orientated roughly perpendicular to the belt. The Pliocene-Quaternary tectonic mobility of the Polish Outer Carpathians has been relatively weak and mostly of thin-skinned character. Normal faults were formed on the margins of intramontane basins and in the western part of the belt. Rates of uplift of individual structures were variable and the amount of uplift was the greatest in the Late Pliocene and Early Quaternary times. Geomorphologically-detected zones of uplift are relatively narrow and arranged subparallel or under small angle in respect to the strike of principal thrusts and frontal parts of large slices. Such an arrangement is interpreted as resulting from the steepening of frontal thrusts due to horizontal compression within the overthrust flysch nappes. This hypothesis is confirmed by the results of recent break-out and GPS studies, as well as by focal solutions of some Outer Carpathian earthquakes

Recent tectonic stress field investigations in Poland : a state of the art

The paper summarizes up-to-date knowledge of the contemporary tectonic stress field in Poland and compares the results of geophysical measurements with mathematical models. The extensive set of data provided by borehole breakout analyses is supplemented by hydraulic fracturing tests, earthquake focal mechanism solutions and preliminary resolution of regional intraplate motions from GPS measurements. Frequent breakout presence shows that tectonically driven anisotropy of horizontal stress is a common feature in the study area. Roughly N-S direction of maximum horizontal stress (SHmaxx) in Eastern Poland differs significantly from Western European stress domain. This difference is produced by tectonic push of Alcapa, which is successively compensated within the Teisseyre-Tornquist Zone (TTZ) and in the Upper Silesian segment of the Outer Carpathians. In the western part of Poland stress directions are ambiguous due to interplay of several additional tectonic factors. Most of hydraulic fracturing data and earthquake focal mechanism solutions indicate strike-slip stress regime in Eastern Poland where stresses are in equilibrium with preferentially oriented faults of Iow friction (0.16). Limited data from Western Poland suggest normal fault stress regime. Good conformity between directions of 5Hm", and intraplate motions occurs from comparison of breakout and GPS data. Finite element modelling shows that the most important factor shaping the stress field in Eastern and Central Poland is the Adria push transmitted through the Pannonian region. Secondary, but still notable factors are differentiation of loads along the Mediterranean collision zone and changes in magnitude of the ridge push force along the NW Continental passive margin of Europe. Results of rheological modelling indicate that the crust is entirely decoupled from the mantle in the Fore-Sudetic Platform, partial uncoupling in the base or the upper crust is possible in the TTZ while in the East European Craton (EEC) the whole lithosphere is coupled. The comparison of different set of data and models presented here provides a comprehensive geodynamic scenario for Poland, however, a number of unresolved questions still remains to be addressed

Sources of the present-day tectonic stresses in Central Europe: inferences from finite element modelling

Adigital two – dimensional elastic model was built to investigate the recent tectonic forces and stresses in Central Europe. Stresses and deformations were calculated using finite element method. The structure of model includes geologically defined features: 32 tectonic blocks, 16 fault zones and 12 boundary segments. The loads were implemented in two ways: as the external boundary forces and the correction due to differences in gravitational potential energy. The calculated stress directions and regimes were satisfactorily matched to the complex stress pattern in Central Europe provided by the World Stress Map Database. Modelling permits evaluation of tectonic forces acting in the collision zone between Africa and Arabia on one side, and Europe on the other side. Also the Mid-Atlantic Ridge push differentiation on the NWEuropean passive margin was determined. For the centre of modeled area the magnitudes of tectonic stresses averaged over the changeable lithospheric thickness were computed. Obtained values of friction coefficients for the fault zones located in the southern part of Europe are significantly lower than those obtained for the northern Europe. The maximum acceptable stiffness contrast across the model reaches one order of magnitude

Can we store CO2 in gas-bearing shales and why? ShaleSeq Project financed by Norwegian funds

Properties of carbon dioxide are favourable for its storage in shale both in sorption within organic matter or free within the pore space and open fractures as supercritical fluid.Well fitted are partially depleted shale gas reservoirs, bearing a dense network of tectonic and hydraulically induced fractures, which is necessary for both gas drainage and injection of large volume of CO2. A previous analysis indicated that storage of significant amounts of CO2 in productive shale complexes in the USA is technologically possible, but requires very intense gas exploitation in a vast area of several states. CO2 injection in partially depleted shale gas reservoirs can contribute to the growth of gas production by approx. 5–10%. Given the current state of research and the most recent estimates of shale gas resources in Poland, one may recognoze that the storage of CO2 with stimulation of gas production is not a viable alternative to sequestration in saline aquifers in Poland. Interdisciplinary research, with Polish-Norwegian collaboration within the ShaleSeq Project, undertakes complex problems of physical and chemical interaction of CO2 with gas-bearing shales of Pomerania. In spite of the fate of CO2 storage in shales all over the world, the findings of this Project might also be relevant for conventional storage in reservoirs which are usual sealed with shale cap rock

Recent tectonic stress regime in Poland based on analyses of hydraulic fracturing of borehole walls

Magnitudes of the recent tectonic stress were estimated based on the hydraulic fracturing data from Poland. In spite of a low quality of the tests, consistent results for particular regions were obtained. For the Outer Carpathians three hydraulic fracturing tests indicate strike-slip stress regime with the local deviation towards the thrust fault regime. Along the front of the Carpathians within the foredeep complex and its basement, low intensity of strike-slip regime with local tendency towards normal fault regime is revealed from tests performed in four wells. Stable, strike-slip stress regime is determined for the Lublin Basin, based on fracturing tests from four wells. Singular result from the Fore-Sudetic Monocline suggests normal fault stress regime for the Permian complex below Zechstein evaporates. Heterogeneity of the stress field within each of these regions is presumably controlled by tectonic structures inherited after the Variscan and the Alpine epochs. For the SE part of Poland, an estimation of the general trend of stress increase with depth gives 2.9 MPa/km for the maximum horizontal stress and 1.9 MPa/km for the minimum horizontal stress

The Kock Fault Zone as an indicator of tectonic stress regime changes at the margin of the East European Craton (Poland)

Integrated tectonic interpretation of seismic data and core samples from boreholes in the vicinity of the Kock Fault Zone (KFZ) allowed us to identify several tectonic deformation events that were responsible for creating its complex structure. The KFZ is an example of a mechanically weak regional-scale tectonic structure that accumulated deformation over hundreds of millions of years and therefore is a good indicator of stress regime changes in a broader area. The KFZ is here regarded as a combination and superposition of two genetically and temporally different faults: the older Kock Fault, which is an inverted normal fault, and the younger, low-angle Kock Thrust. The first, Silurian stage of KFZ evolution occurred in a tensional stress regime that gave rise to the activation of a deeply rooted normal-slip precursor to the Kock Fault. Subsequently, this fault underwent inversion during the Late Famennian compressive/transpressive event. In the Early Carboniferous, the tectonic stress regime changed into tension/transtension, leading to extrusion of basalt magma and abundant mineralisation in the vicinity of the inverted Kock Fault, followed by tectonically relaxed sedimentation of Carboniferous strata. The deposition was terminated by a compressional event at the end of the Westphalian. Contraction resulted in the formation of the low-angle Kock Thrust decoupled in Silurian shale that cut across the upper part of the Kock Fault and displaced it towards the NE, over the East European Craton foreland

Polskie uregulowania prawne dotyczące wyboru miejsca lokalizacji elektrowni jądrowej w zakresie zagrożeń geodynamicznych na tle wybranych regulacji międzynarodowych

The nuclear power plant site was determined following the formal analysis of the Polish economy and energy supply, with respect to societal reality. Beforehand, comprehensive studies were carried out covering essential geological factors and terrain circumstances. Every country undertakes sovereign decisions regarding nuclear power plants, based on legitimate regulations. In practice, guidance regarding general requirements, technical solutions and safety measures are derivative from experiences in other countries published by the International Atomic Energy Agency (IAEA) and the US Nuclear Regulatory Commission. The paper presents interrelations between the international guidelines and the Polish legal instructions

Key issues for public consultation on carbon underground storage in Poland

The paper dealswith thematter of underground, geological storage of carbon dioxide in Poland. The state of research, legal and especially public acceptance of this issue is presented. Possibile conflicts of interest as well as phenomena related to the underground storage of carbon dioxide and their possibile impact to environment and local populace living conditions are discussed. Disinformation circulating in the media and local communities is exposed

A technical-economic analysis of wind farms

W pracy omówiono parametry techniczne i ekonomiczne farm wiatrowych. Są one szczególnie ważne, ponieważ wiele farm zostało wzniesionych w miejscach o niekorzystnych warunkach, bez wiedzy teoretycznej i eksperckiej a także tła legislacyjnego. Analiza właściwości techniczno-ekonomicznych sugeruje wyznaczenie związków parametrów istotnych dla procesu podejmowania decyzji dotyczących konstrukcji farmy wiatrowej w rozważanej lokalizacji. Najważniejszym czynnikiem decydującym czy wspomniany rejon jest odpowiedni dla budowy farmy wiatrowej jest szybkość wiatru, która musi być określona doświadczalnie. Uzyskane wyniki analizy techniczno-ekonomicznej mogą być zastosowane zarówno dla Republiki Czeskiej jak i innych krajów europejskich. Szczególnie interesujące jest porównanie analiz dla krajów śródlądowych (np. Republika Czeska) oraz nadmorskich (np. Polska), szczególnie w przypadku państw sąsiadujących ze sobą.The paper discusses technical and economic parameters of wind farms. They are particularly important as a number of wind farms have been erected in localities with unfavourable wind conditions being unaware of theoretical and expert knowledge and legislative background. The analysis of technical-economic parameters implies a determination of links among the parameters vital for the decision-making process related to a construction of a wind farm in a considered locality. The most important parameter to decide whether the given locality is suitable for construction of a wind farm is the wind speed which must be identified in the locality in question. The stated results of the technical-economic parameter analysis may be applied both for the Czech Republic as well as for other European countries. What is especially interesting is to compare analyses for inland countries (e.g. the CR) and seaside countries (e.g. Poland), particularly in case of neighbouring countries

Diagenetic and tectonic processes controlling reservoir properties of the Frasnian dolostones in the central part of the Lublin Graben [Eastern Poland]

Petrological studies of core samples, integrated with mesostructural analysis of cores, and coupled with results of seismic data interpretation allowed to interpret evolving reservoir properties of dolostones of the Frasnian Werbkowice Mb. These crystalline and partly vuggy rocks form main reservoir horizons of the Ciecierzyn and Mełgiew A gas fields in the central Lublin Graben. The optimum reservoir properties were attained following the main phase of regional dolomitization and accompanying CaCO3 dissolution. These processes occurred after renewed subsidence in Viséan and before main phase of the Variscan inversion in late Westphalian. In Late Silesian, after the onset of hydrocarbon generation, porosity was partly filled by a dolomite cement. The most important agent of porosity destruction, however, was a precipitation of anhydrite cement preceding main phase of compressional deformations. The latter led to a localized development of open fracture systems which, however, were soon filled with various cements related to dissolution-reprecipitation processes. After compressional event, the stress regime evolved towards strike-slip and extensional, which created fractures allowing migration of hydrocarbons to newly formed structural traps. Several observed structures indicate negligible post- inversion deformations, thus facilitating preservation of earlier formed hydrocarbon accumulations. However, successive stages of secondary migration could have occurred during indefinite time under strike-slip and extensional regime recorded as a distinct set of mesostructures