Lithospheric structure in Central Europe: Integrated geophysical modelling

Abstract

The main aim of this thesis is to gain new knowledge about the lithospherical structure and tectonics of the Carpathian-Pannonian Basin region. We applied three different methods: 1D automatic modelling, 2D integrated geophysical modelling and 3D inversion to achieve this goal. These methods are similar concerning the used databases but differ by used processing and interpretation. At first we apply 1D automatic modelling to get a very first overview of the studied region. Secondly, we apply 2D integrated modelling of the lithosphere which combines the interpretation of surface heat flow, geoid, gravity, and topography data in the Carpathian-Pannonian Basin region and surrounding areas. This approach is able to constrain the complicated lithospheric structures of the studied region better than interpreting each data set on its own. We present four 2D integrated models of the lithosphere in the Carpathian-Pannonian Basin region and surrounding areas. Finally, based on the 3D Inversion algorithm, we present the geophysical models of the lithosphere in the Carpathian-Pannonian region. The algorithm returns the density structure of the lithosphere from joint inversion of free air gravity, geoid and topography data based on a Bayesian approach. The models are based on different input data sets and constrained by different a priori data. Based on our modelling we cannot confirm the extreme thinning (less than 70 km) of the Pannonian Basin lithosphere proposed by other authors. On the other hand, the results show the increasing trend of the lithospherical thickness of the Carpathian Arc from the Western Carpathians toward the Eastern Carpathians which confirms the previous theories about the propagation of subduction process. We got some controversial results in the area of the Southern Carpathians. The results based on 3D inversion show extremely thin lithosphere in the area; on the other hand, the results based on 2D integrated modelling do not support such thinning. However both methods indicate that it is probable that the Moesian Platform is bend and underthrusted underneath the Southern Carpathians. The southeastern edge of the Pannonian Basin based on 3D inversion shows unexpected and surprisingly thin lithosphere. Since the area is quite large, we could exclude an effect of flexure, therefore this area might be potentially interesting for further investigation.

Automatic 1D integrated geophysical modelling of lithospheric discontinuities: a case study from Carpathian-Pannonian Basin region

“…The 1D modelling provides a very fast but preliminary view of the lithosphere structure (Grinč, 2013). Since the reference geoid N 0 (see Eq.…”

“…From a scientific point of view, it is 1D modelling and therefore only valid for large-scale structures but on the other hand, when doing this 1D analysis on many vertical columns covering an area, it gives us a 3D initial estimate of the main boundaries that we are interested in the studied area (Grinč, 2013).…”

“…The coordinates of the study regions are (17 • /28 • E -43 • /51 • N) so that the area includes the whole Carpathian-Pannonian Basin region and its surrounding tectonic units (Grinč, 2013). In the N and E these are the North and the East European Platform, in the S the Moesian Platform and the Dinarides, and the Eastern Alps and the Bohemian Massif in the W.…”

3D density modelling of Gemeric granites of the Western Carpathians

“…In recent years, new data on the deep physical boundaries, such as the boundary between the upper and lower crust, Moho discontinuity and lithosphere-asthenosphere boundary have been obtained (e.g., Zeyen et al 2002;Dérerová et al 2006;Grad et al 2006Grad et al , 2009Środa et al 2006;Alasonati Tašarová et al 2008, 2016Hrubcová et al 2008;Csicsay 2010;Janik et al 2011;Grinč et al 2013). Therefore, if the density modelling of the studied area on a regional scale will be done in the future, then it will be necessary to take into account the above mentioned lithosphere discontinuities, since it can be expected that their influences on the observed gravity field will play an important role.…”

Joint interpretation of gravity and magnetic data in the Kolárovo anomaly region by separation of sources and the inversion method of local corrections

“…A possible explanation is that the up-thrusted lower crustal mafic material is magnetically heterogenous, or not entirely magnetic. The Curie temperature isotherm in this area lies just above the Moho boundary (Dérerová et al 2006;Grinč et al 2013), so an intrusive body would start losing its magnetization only at depths approaching the Moho.…”