Państwowy Instytut Geologiczny w badaniach budowy geologicznej Polski

Abstract

Rozpoznanie budowy geologicznej kraju jest podstawowym zadaniem Państwowego Instytutu Geologicznego od chwili jego powstania w 1919 r. Do 1939 c badano głównie obszary pozbawione grubej pokrywy osadów czwartorzędu, tj. Karpaty. Górny Śląsk, Góry Świętokrzyskie i Wołyń. Po drugiej wojnie światowej, począwszy od 1945 r., znacznie zintensyfikowano prace geologiczno-kartograficzne oraz badania geofizyczne i prace wiertnicze. Przystąpiono do badan wgłębnej budowy geologicznej zarówno Niżu Polskiego, pokrytego grubym płaszczem osadów czwartorzędu, jak i Karpat, Dolnego i Górnego Śląska oraz Gór Świętokrzyskich. Podjęto także badania geologiczne osadów dennych południowej części Morza Bałtyckiego i wgłębnej budowy geologicznej tego regionu.STATE GEOLOGICAL INSTITUTE IN STUDIES OF GEOLOGICAL STRUCTURE OF POLAND 1919-1944 The State Geological Institute was among the first research institutes that have been established after the First World War by the reborn country of Poland. Geological structure of the country, partitioned for many years before by the occupants, was known differently in that time. Only the southern part of the country had a complete geological map in a scale of 1:75,000. This map was prepared in 1886-1911 by the Polish Academy of Science. Studies of a geological structure of country, firstly the mapping, belonged to the principal tasks of the State Geological Institute. The first geological map of the whole Polish territory was published by the Institute in a scale of 1:750,000 in 1926. Already during the first years of the Institute activity, the works over sets of geological maps in scales of 1: 100,000 and 1:50,000 have been initiated. In the Upper Silesia the edition of geological maps in a scale of 1:25,000 was started. Vast areas of the country were covered by intensive studies that formed the basis for a rapid increase after 1938 of set cartographic publications. But cartographic materials of many authors that needed only the editorial preparation, were not published due to the outbreak of the Second World War. Such was the destiny of many cartographic materials from the Polish Lowland, Carpathians, Upper Silesia, Vol hynia, Podolia, Polesie and Vilnius region.Regional and stratigraphic studies of the Stare Geological Institute before 1939, have been mainly but not exclusively focused in areas without a thick cover of Quaternary deposits. Such concentration of works was due to geological technics of that time. The most intensive have been carried through in the Carpathians and their foreland. They remained in a strict connection with interests of the oil industry. The Carpathian foreland was the first region in which the State Geological Institute applied geophysical measurements in geological investigations. Studies in the Holy Cross Mts resulted in preparation of numerous sections and maps that illustrate complex tectonics of the region. Well documented stratigraphical schemes of the Holy Cross region were correlated with international stratigraphic standards. The Upper Silesia was very intensively examined. Geologists from the State Geological Institute prepared a uniform stratigraphic subdivision of the Carboniferous of the Polish Coal Basin, concordant with the most up-to-date international scheme of that time. Deep geological structure of the Polish Lowland, covered with a thick mantle of Cainozoic sediments, have been the subject of theoretical considerations until the end of the twenties. Starting from 1930, the State Geological Institute initiated drilling and geophysical works in Kujawy i.e. in the central part of the Polish Lowland. In 1939-1944 (during the war) geologists of the State Geological Institute kept working. Materials were collected with hope to use them with profit to the country after a renewed independence. Every-thing possible was done to make the works demanded by the occupant go slowly and without any profits for him. 1945-1989 Just after the Second World War, in 1945-1946, geologists of the State Geological Institute delimited main directions of studies of geological structure of Poland within its new frontiers. Mapping, geo-physical works and studies of deep geological structure of areas with thick mantle of Quaternary sediments were put ahead. GEOLOGICAL MAPPING In 1946 a uniform geological map of Poland in a scale of 1:300,000 was initiated. This map is composed of two sets: A - covered (with Quaternary) and B - uncovered (without Quaternary) ones. Both sets of the map had been published until 1953. In 1964 the State Geological Institute started to prepare a geological map of Poland in a scale of 1:200,000. This map is also published in two sets, covered and uncovered. Geological map of Poland in a scale of 1:50,000 forms a huge undertaking which is supervised by the State Geological Institute. Its systematic preparation was started in the Institute in 1954. Realization of the map granted by the State Geological Institute, is carried through by scientists from universities, Polish Academy of Sciences and by workers of geological enterprises. Up to the present amongst the total number of 1025 sheets, over 25% have been mapped and over 20% are published. Basic studies carried through by the State Geological Institute formed the subject of many synthetic monographs what is expressed by geological atlases. They comprise: Geological Atlas of Poland in scales 1: 1,000,000 and 1:2,000,000, Lithologic-paleogeographical Atlas of Platform Areas in a scale of 1:2,000,000, Lithofacial-paleogeographical Atlas of the Permian of Platform Areas in scales of 1:1,000,000 and 1:2,000,000, and Geological Atlas of Crystalline Bedrock in the Polish Part of the East--European Platform in a scale of 1:2,000,000. Besides the atlases, geologists from the State Geological Institute prepared numerous separate maps in small scales that illustrate various aspects of a geological structure of the country. Among them the most important are: tectonic maps of Poland that are frag-ments of two editions of the International Tectonical Map of Europe in a scale of 1 :5,000,000. Geological Map of Poland and Adjacent Countries without Cainozoic, Mesozoic and Permian Sediments in scale of 1:1,000,000, Photogeoiogicai Map of Poland in a scale of 1: 1 ,000,000. Geological Map of Poland in a scale of 1 :500,000 (two versions: without and with the Quaternary cover). Already in 1953 the general geophysical maps started to be published by the State Geological Institute. Geophysicists from the Institute prepared the seismic map of Poland in a scale of 1:500,000 and uniform magnetic and gravimetric maps in scales: 1:500,000, 1 :300,000 and 1 :200,000. REGIONAL STUDIES In 1945 the problem of deep structure of the Polish Lowland created a great challenge for the Polish geology which has been picked up by the State Geological Institute. During the first post-war decade numerous diapirs of the Zechstein salts were located in a substrate of the Polish Lowland and data on structure of the Mesozoic-Cainozoic structural complex were collected. In the half of the fifties the Institute as well as the oil industry started systematic investigations with a use of deep boreholes (at first to 3000 m and then also over 5000 m deep) and geophysical methods. Such works are continued up to the present. Due to collected data the scientists from the State Geological Institute prepared the basis for lithostratigraphy of Precambrian and Paleozoic sediments in the Polish part of the East-European Platform. Presence of the Devonian and Carboniferous sediments was noted in southeastern Poland. In northwestern, northern and central Poland sediments of the Permian sedimentary basin were recognized. They are in a substrate of the Polish Lowland the most prospective formations from a point of view of occurrence of natural oil and gas deposits. A lithostratigraphy of the Mesozoic complex has been also studied, either in the area of the East-European Platform or outside its limits, in the remaining part of a substrate of the Polish Lowland. Basing on analyses of thicknesses and facies of studied sediments, a development of three great diastrophic sedimentary cycles was reconstructed in a substrate of the Polish Lowland i.e. the Lower Paleozoic, Devonian-Carboniferous and Permian-Mesozoic ones. Among the problems which are still not determined, there are: running of the southwestern border of the East-European Platform, origin of the Teisseyre-Tornquist's tectonic zone, outer zone of the Variscites. Cartographic works connected with a geological map in a scale of 1 :50,000 resulted in a considerable recognition of the Cainozoic cover of the Polish Lowland. In the State Geological Institute the attempts to prepare a synthesis of stratigraphy of the Polish Quaternary were undertaken. During the post-war period the works of the Institute in the Carpathians were predominated by mapping. In the sixties deep studies of a geological structure of the Carpathians have been initiated and arc continued until nowadays. Surface and deep investigations of the Institute in the Carpathians resulted in a preparation of a detailed lithostratigraphic subdivision within all the geological units of the region. Main tectonic units of the Carpathians were recognized, secondary ones were discovered as well as tectonic rafts from the zones that separate the Carpathian basins. Deep boreholes enabled to find deep transversal shortening of the Carpathian geosyncline. Studies of a platform substrate of the Carpathian Foredeep and of the Carpathian overthrusts were initiated. The Holy Cross region belongs to the areas that are very intensively studied. It is due to the fact that about three fourth of all the 80 sheets of geological map in a scale of 1:50,000 and covering this region, have been already prepared. In the nearest years the Holy Cross Region is supposed to be entirely covered by a detailed geological mapping. During the studies of a structural evolution of the Holy Cross Mts a dislocation of the wave of the Late Caledonian deformations from the south northwards since the Ludlovian until the Emsian has been noted among other things. Besides, the influence of the Breton movements on development of sedimentary basins was defined and the Variscite structural plan of the region was reconstructed. The main although not the only target of regional studies of the Institute in the Upper Silesia comprises a recognition of the Carboniferous sediments and of a geological structure of coal beds in that area. Geologists from the State Geological Institute are the authors of the numerical nomenclature of the coal beds. This system was accepted in mining practice and forms a reference pattern for structural maps of conventional correlation horizons of the coal-bearing Carboniferous sediments. Recently the State Geological Institute started to prepare a new atlas of the Upper Silesian Coal Basin in a scale of 1: 100,000. Already the maps that present typical thermic conditions of the basin and maps of coal quality have been published. Works over geological-structural maps are continued. Principal geological studies carried by the Institute were collected in a special monograph, sacrificed to sediments of the Upper Silesia Coal Basin.Due to investigations with deep boreholes and geophysical methods, the substrate of the Upper Silesian Coal Basin is composed of massif of Precambrian consolidation. A substrate of the Mesozoic sediments in the northeastern margin of the Upper Silesian Coal Basin comprises the Cracow branch of the Variscides. According to other opinions this area has the Caledonian consolidation. The Sudetes are the only (up to the present) region of Poland covered by geological mapping in a scale of 1:25,000. This mapping, supervised by the State Geological Institute, is almost finished at present. At the turn of sixties and seventies the Institute published a geological atlas of the Lower Silesian Coal Basin in a scale of 1: 100,000. Cartographic works and deep regional studies of the Lower Silesia have been accompanied by a progress in recognition of lithology, stratigraphy and tectonics of the area. The central Sudetes were found among others to indicate a sedimentary continuity of sediments of the Upper Visean and Lower Namurian and so, the absence of symptoms of the Sudeten phase of the Variscite orogeny. Lately the geologists of the State Geological Institute suggested a participation of fragments of the ocean crust in structure of the Lower Silesia. The opinion on probable occurrence of terranes in the Variscite substrate of southwestern Poland is also presented. Due to deep boreholes and geophysical investigations a dislocation zone of the Middle Odra was examined. Deep regional studies were also carried through in the Bardo Mts., Mid-Sudetic Synclinorium and in the Fore-Sudetic area. In the end of the sixties, the State Geological Institute started studies of a new region i.e. the Polish part of the Baltic Sea. Works over a geological map of the bottom of the Baltic Sea in a scale of 1 :200,000 are ahead. Mapping and accompanied studies of a geological structure are carried through on the basis of collected surface samples and cores of bottom sediments. Both are subjected to detailed laboratory analyses. They are supplemented by seismoacoustic works. Significant achievements of the Institute in geological investigations of the bottom of the southern part of the Baltic Sea comprise: separation of main lithostratigraphic units of the Pleistocene and Holocene sediments and studies of present conditions of deposition of bottom sediments. Deep geological structure of the bottom of the southern Baltic Sea was recognized by geologists from the State Geological Institute on the basis of geophysical investigations (marine seismics included) and deep boreholes located in northernmost Poland. A synthesis of these works was enclosed in a geological atlas of the southern Baltic Sea in a scale of 1:75.000. A total length of boreholes done in 1950-1988 within the deep regional investigations of the Institute considerably exceeds I min meters. Geophysical works done in connection with regional investigations of the Institute in 1945-1988 reach about 55,000 km of seismic soundings. The whole territory of Poland has been covered by gravimetric and magnetic measurements.