Wyniki wyszukiwania - BazTech

1

Gravity measurements in the Pieniny Klippen Belt (Western Slovakia)

Bucova J., Bielik M., Pasteka R., Plasienka D.

Geology, Geophysics and Environment

|

2015

|

Vol. 41, no. 1

65

EN

The examined area is situated in the Púchov section of the Pieniny Klippen Belt (PKB) in western Slovakia. The main aim of our research was to broaden the present knowledge on geological structure of the PKB and on its tectonic connection to the surrounding regional units using the geophysical methods.The profile gravity measurements consist of two parallel profiles named prof_1 and prof_2 of roughly NNW-SSE direction. The eastern section prof_1 has a length of 6.36 km; the western profile prof_2 is about 3.84 km long. Measurements were carried out at intervals of 20 meters (overall 506 points were gauged) by gravimeters Scintrex CG3 and CG5. The acquire data were processed into the Bouguer gravity anomalies. The software package GM-SYS (Geosoft) was applied for the gravity modelling and the final geological-geophysical sections represent distribution of the lithological members with their specific density parameters (density values were determined by the own laboratory measurements of rock samples collected along the profiles). The density modelling was also based on the results obtained by the geoelectrical exploration (vertical electric sounding and resistivity profiling), new surface geological mapping and borehole interpretation (continuously cored bores MIK-1 and MIK-2). Presented detailed gravity measurements reflect density differences between klippen (rigid limestone blocks) and their mantle (predominant marlstone) and they demonstrate that the primary fold-nappe system of the PKB was destructed by the subsequent deformation, resulting in the formation of the positive flower structure and backthrusting. Summing up, the new density modelling confirmed complex geological structure of the studied area and helped us to better interpret the tectonic evolution of the PKB.

2

Density and magnetic models of the lithosphere along CELEBRATION 2000 profile CEL01

Grabowska T., Bojdys G., Bielik M., Csicsay K.

Acta Geophysica

|

2011

|

Vol. 59, no. 3

526-560

EN

The paper presents 2D density and magnetic models of the crust and upper mantle along the DSS line profile of the CELEBRATION 2000 project that crosses the most important geological units in Central Europe. These are the Alps-Carpathians-Pannonian (ALCAPA) region, the SE part of the Paleozoic Platform (PLZ), the Trans-European Suture Zone (TESZ) and a fragment of the SW portion of the East European Craton (EEC). The density and magnetic models were constructed on the basis of a 2D model of P-wave velocity converted into density model, geological data as well as geothermal data and the results of integrated geophysical modelling for the lithosphere-asthenosphere boundary. This allowed us to construct a comprehensive geophysical 2D model of the crust and enlargement the geophysical-geological characteristics of the lithosphere in the Pannonian basins, the Carpathian orogen, and in the transitional zone between the ALCAPA plate and the East European Craton (passing through the Paleozoic Platform). As a result, we have provided evidence for the heterogeneity of the density in the lithospheric mantle, terrane concept of the East European Craton foreland, and confirmed the possibility of rift events along the SW boundary of the Precambrian craton in SE Poland.

3

Calculation of a stripped gravity map with a high degree of accuracy: a case study of Liptovská Kotlina Basin (Northern Slovakia)

Szalaiová E., Bielik M., Makarenko I.

Geological Quarterly

|

2008

|

Vol. 52, No 2

103-103

EN

The paper deals with the construction and calculation of a stripped gravity map with a high de gree of accu acy. In the Western Carpathian basins such types of gravity maps represent the corrected Bouguer anomalies by the gravity effects of the Tertiary sedimentary masses. It means that the re sultant stripped gravity map reflects the gravity effects of den sity inhomogeneities, which are located beneath the pre-Tertiary basement. For determination of this map, the modern progres sive forward-mod elling gravity method was applied. The advantage of this method in comparison with previous approaches is that it is capable of calculating the 3D gravity effects of the geological bodies with real topography. A case study for presentation of a new and precise stripped gravity map, the Liptovská Kotlina Basin, was chosen, because it is one of the best-surveyed basins in the West ern Carpathians. This new gravity map represents, for this moment, the most accurate stripped gravity map in the whole Western Carpathians. It allows construction not only of a very precise 3D gravity model of the sedimentary fill but also enables interpretation of the sources of the gravity anomalies revealed in the stripped gravity map. This interpretation is based on all available geophysical and geological constraining data. It is also supported by 2D analysis of the gravity effects of the main tectonic units building the Liptovská Kotlina Basin.

4

Geophysical features of the Slovak Western Carpathians: a review

Bielik M.

Kwartalnik Geologiczny

|

1999

|

Vol. 43, Nr 3

251-262

EN

The article reviews the important results of the geophysical research in the Slovak Western Carpathians. As the Slovak Western Carpathians has been a target of intensive detailed gravimetric measurements for the last 20 years, an emphasis is given to the interpretation of gravity field. Analysis of the Bouguer gravity anomalies comes from density modelling in local isostatic equilibrium and 2 1/2 D forward density modelling. The results of density modelling together with other geophysical data were used for geological and geophysical interpretation of the lithospheric structure and its tectonics in the Slovak Western Carpathians. Rheology of the lithosphere based on extrapolation of failure criteria, lithology and temperature models is presented. Finally, the obtained results are discussed.

PL

Praca poświęcona jest podsumowaniu istotnych wyników badań geofizycznych słowackich Karpat zachodnich. Obszar ten był przedmiotem intensywnych, szczegółowych pomiarów grawimetrycznych w ostatnich 20 latach, stąd w artykule położono nacisk na interpretacje pól grawitacyjnych. Analiza anomalii Bouguera została wykonana na podstawie modelowania gęstości w warunkach lokalnej równowagi izostatycznej oraz na progresywnym modelowaniu gęstości 2 1 D. Wyniki modelowania gęstości wraz z innymi danymi geofizycznymi, w tym sejsmicznymi, są punktem wyjścia do geologicznej i geofizycznej interpretacji struktury litosfery na analizowanym obszarze. Przedyskutowano ponadto zagadnienia reologii litosfery na podstawie ekstrapolacji kryteriów zniszczenia litologii i modeli termicznych.