Joint analysis of the magnetic field and Total Gradient Intensity in Central Europe

Abstract

Abstract. In the European region, the magnetic field at satellite altitudes (~ 350 km) is mainly defined by a long-wavelength magnetic-low called here the Central Europe Magnetic Low (CEML), located to the southwest of the Trans European Suture Zone (TESZ). We studied this area by a joint analysis of the magnetic and total gradient (∇T) anomaly maps, for a range of different altitudes of 5 km, 100 km and 350 km. Tests on synthetic models showed the usefulness of the joint analysis at various altitudes to identify reverse dipolar anomalies and to characterize areas in which magnetization is weak. By this way we identified areas where either reversely or normally magnetized sources are locally dominant. At a European scale these anomalies are sparse, with a low degree of coalescence effect. The ∇T map indeed presents generally small values within the CEML area, indicating that the Palaeozoic Platform is weakly magnetized. At 350 km altitude, the TESZ effect is largely dominant: with intense ∇T highs above the East European Craton (EEC) and very small values above the Palaeozoic Platform, this again denoting a weakly magnetized crust. Small coalescence effects are masked by the trend of the TESZ. Although we identified sparsely located reversely magnetized sources in the Palaeozoic Platform of the CEML, the joint analysis does not support a model of a generally reversely magnetized crust. Instead, our analysis strongly favors the hypothesis that the CEML anomaly is mainly caused by a sharp contrast between the magnetic properties of EEC and Palaeozoic Platform.

East Antarctica magnetically linked to its ancient neighbours in Gondwana

“…E.g. the long to mid wavelength field is often used to estimate the Curie isotherm 31 , but can also relate to differences in crustal architecture 32 , upper mantle magnetisation 33 or a combination of thermal and structural properties 34 . For this area, the pattern partially correlates with some of the main tectonic features of the area such as the boundaries of the Kaapvaal Craton to its surrounding.…”