Celem prowadzonych prac bylo określenie budowy geologicznej czapy anhydrytowej oraz nadkladu wysadu solnego „Damaslawek”. Podstawowym narzedziem badawczym byly wysokorozdzielcze dane sejsmiki refleksyjnej. Dodatkowo wykonano pomiary i interpretacje danych geoelektrycznych, oraz reinterpretacje archiwalnych danych grawimetrycznych i geofizyki otworowej. Uzyskane dane sejsmiczne charakteryzowaly sie wysoką jakością. Zintegrowana interpretacja geofizyczno-geologiczna pozwolila na bardzo precyzyjne określenie glownych i podrzednych deformacji tektonicznych, rozwinietych w obrebie czapy oraz w jej nadkladzie. Zidentyfikowano wiele reaktywowanych uskokow inwersyjnych, ktore najprawdopodobniej przynajmniej cześciowo byly związane z ruchami przesuwczymi. Analiza sejsmostratygraficzno-tektoniczna pokazala, iz niektore strefy uskokowe byly aktywne rowniez w czwartorzedzie.
GEOPHYSICAL-GEOLOGICAL STUDY OF CAPROCK AND OVERBURDEN OF THE DAMASŁAWEK SALT DOME (CENTRAL POLAND)
Summary
The goal of completed research project was to establish reliable geological model of cap rock and overburden of the Damaslawek salt dome. High-resolution reflection seismic profiling was main research method used for this project. Additionally, geoelectrical profilingand interpretation as we l! as reinterpretation of available gravity and well log data was completed. Acquired seismic data were ofvery high quality. Integrated geophysical-geological interpretation allowed the major and subordinate tectonic deformations present within cap rock and salt domes overburden to be precisely distinguished. Numerous inversion faults possibly at least partly related to strike-slip movements were identified. Seismostratigraphic-tectonic analysis showed that some of identified fault zones were active also during the Quaternary.
Przedstawiono wyniki pomiarow gestości skal wystepujących nad poziomem morza. Mapa w oryginalnej skali 1:500 000 zostala opracowana na podstawie wynikow oznaczen w 1370 punktach na calym obszarze Polski. Stanowi to podstawe kompleksowych interpretacji geofizycznych metodą strippingu i modelowania grawimetrycznego. THE MAP OF DISTRIBUTlON OF THE DENSITY OF ROCKS EXISTING ABOVE SEA LEVEL IN POLAND The maps of the gravity anomalies using Bouguer reduction are the starting gravimetric material for all the qualitative and quantitative analyses. To achieve the reduction, the knowledge of the density of the rock masses lying above sea level is necessary. The first trial of the serious synthesis of the data about the rock density above sea level was done in the year 1965. The laboratory measurements of the samples of rocks were done from the cores of about 90 boreholes drilled in the period 1954-1961. After elaborating of the dependence of the effective porosity on the density of the dry sample, the data from the fifties were corrected and the map of the density of rocks above sea level was put together in the scale 1:1 000 000. The map showed the existence of great regional differences of the density between 2.1-2.80 g/cm 3 . The weighted average for Poland was 2.25 g/cm 3 . In the end of the seventies, the work upon preparing the gravimetric bank of data, and evaluating of the uniform gravimetric map of Poland in the scale 1:50 000 and 1:200 000 has begun. To calculate the Bouguer anomalies it was accepted for the area of Polish Lowland the density 2.25 g/cm 3 ,and for Southern Poland the density 2.60 g/cm 3 . The present work is the synthesis of data achieved in the years 1962-1988 using the uniform method of measurements of the density. To put together the maps, the densities achieved in the laboratory measurements, executed mainly by the Enterprise for Geophysical Investigations, were used. The samples of rocks were achieved from the boreholes and from the exposures. For the scientific aims, the data achieved using the gamma-gamma radiometric method near the surface were used . The laboratory density measurements were made for the insufficient amount of boreholes. In the greater amount of boreholes, the density values were estimated, using the knowladge of the lithological profile and using the density characteristics for separate rocks from the defined region. After the determination of the bulk density of Cainozoic rocks lying above sea level, the state of full saturation of pore space and argillaceous rock contraction during drying were taken into account. In the case of the pre-Cainozoic rocks these elements were not taken into consideration. The results were represented on the map in scale 1:500 000. The isolines corresponding to the increase of 0.05 g/cm 3 , and in the part of Sudetes and Fore-Sudetic Block of 0.10 g/cm 3 were drawn. This map contains the data from the measurements of density in 413 boreholes, the estimation of density in 957 boreholes and the measurements of density in the samples from about 1000 exposures. Omitting the exposures, we obtain the data frequency of 1 point to about 230 km 2 , that is in the accepted scale, 1 point to 9 cm 2 . The image of the distribution of the density is connected with the geological structure of the area. The density of rocks lying above sea level depends mainly on their age, lithology, water content and so on. The density of rocks in Polish Lowland is contained in the intervall 2.00-2.30 g/cm 3 , and in Lower Silesia - above 2.50 g/cm 3 , in Holy Cross Mountains - above 2.40 g/ cm3 , in Carpathian Mountains - in the interval 2.60-2.70 g/cm 3 , and in the transiton regions such as Silesian-Cracovian Monocline and Upper Silesian Trough - it achieves 2.60-2.70 g/cm 3 . The average densities for the separate sheets of the map 1:500 000 amount to: for NW -2.11 g/cm 3 , for NE - 2.16 g/cm 3 , for SW - 2.20 g/cm 3 , and for SE - 2.30 g/cm 3 , what shows the strict dependance on the type of rocks, laying above sea level. The average density for the whole Poland equals 2.22 g/cm 3 . While drawing the isolines the rule of linear interpolation, and in the mountainous regions the geological structure, were beeing taken into account. In summary, it can be stated that the great differentiation of the density of rocks lying above sea level shows the necessity of using the variable density in the Bouguer reduction. The constant density may be used for maps in greater scales and it is proposed to use for the lowland area the density 2.15 g/cm 3 , on the Silesian-Cracovian Monocline - 2.30-2.50 g/cm 3 , and in the Sudetes, part of the Fore-Sudetic Block, in the Carpathian Mountains and Holy Cross Mountains - about 2.60 g/cm 3 . Contemporaneously, the observation of the amount of points of measurements shows the insufficient degree of the survey, and allows to state, that farther investigation of the density of rocks is necessary.
THE ANALYSIS OF SEMIDETAILED GRAVITY SURVEY IN GORZOW BLOCK (WESTERN POLAND) AREA FOR RECOGNITION OF THE SUBSURFACE SEDIMENTS.
Summary
The local gravity anomalies were calculated using two different radii. Obtained gravimetric image was correlated with borecores and results of resistivity and high resolution seismic data. Final conclusions inform on morphology of Quaternary bottom and tectonics of the Cainozoic basement.
Rozszerzenie prac badawczych w obrebie wysadu solnego i jego okolicy, polegalo na analizie archiwalnych opracowan: tellurycznego i termicznego. Wcześniejsze badania sejsmiczne zostaly uzupelnione o modelowania wzdluz profili. Wyniki przeprowadzonych analiz uzupelnily wiedze o tektonice czapy wysadu i utworow otaczających wysad. W powiązaniu z informacjami geologicznymi pochodzącymi z wiercen i wcześniejszych badan geofizycznych, uzyskano pelniejszy obraz budowy geologicznej badanej struktury.
COMPREHENSIVE STUDY OF GEOLOGICAL SUBSURFACE STRUCTURE OF DAMASŁAWEK SALT DOME AND ITS SURROUNDING WITH ANALYSIS OF GEOPHYSICAL AND GEOLOGICAL DATA
Summary
Analysis of archive materials on telluric and thermal investigations preformed just above the Damaslawek salt dome and its surroundings as well as modelling along the former seismic sections expanded the knowledge of tectonics of dome caprock and adjacent deposits. These informations, together with earlier well and geophysical data allowed to reconstruct the salt dome structure in greater detail.
