MAGNETIC ANOMALY PATTERN OF CENTRAL-EUROPE

The magnetic anomalies represented on our map of Central Europe reflect the geological units and these anomalies are tentatively correlated with known geological structures. In Scandinavia strong magnetic anomalies caused by crystalline rocks of the East European Platform have been observed. Their southern boundary corresponds to the Elbe Line, the border between the mobile part of the East European Platform and the Dutch-German Platform. Here only some broader anomalies can be found and are caused by a magnetic basement (magnetization M = 2 A/m) under a 12-15 km thick layer of sediments. A southern margin of the Dutch-German Platform can be assumed along the W-E "Northern German Line" which is marked by local magnetic anomalies. Younger magmatic events are presumed to be the sources of these anomalies. The Rhenohercynian is located south of the Dutch-German Platform. Small NE-striking anomalies indicate a weak magnetic basement (M = 0.35 A/m). A magnetic relief varying between 9 and 15 km is obtained by relief calculations. West of the Rhenohercynian anomalies of relatively strong amplitudes prevail. These correspond to the Brabant Massif, the eastern boundary of which presumably influences the tectonically controlled anomalies of Erkelenz and Lingen. There is no magnetic indication of a continuation of the Brabant Massif into the Rhenohercynian. The Mid-German Crystalline Rise and the Saxothuringian zone of the Variscan belt are situated south of the Rhenohercynian. Both areas show strong magnetic anomalies. The southwestern border forms an arch around the Brabant Massif and ends at the Paris Basin Anomaly. This magnetic zone finds its equivalent in a magnetic belt, the Donau Anomaly, which can be followed to the Massif Central in the southwest. This is located in the middle of the Moldanubian, which is characterized by a relatively undisturbed magnetic field. The strong anomalies in the Saxothuringian and Donau magnetic belts point to an accumulation of magmatic rocks. These might be fragments of oceanic crust or ophiolites marking previous subduction or obduction zones. Another explanation may be the intrusion of predominantly basic material during former crustal thinning or stretching. With the exception of the Saxothuringian and Donau Anomaly magnetic belts there is no indication of oceanic crust in the magnetic anomaly map.