An interpretation of the Magsat anomalies of central Europe

Abstract

Magsat studies of central Europe have revealed correspondence between tectonic elements /geological structures and long-wavelength satellite-altitude anomalies. The most striking correlation is the two Magsat anomalies (one positive and the other negative) associated with either side of the Tornquist-Teisseyre Zone (TTZ). The TTZ, which extends from the Black Sea to the Baltic Sea, represents the structural boundary (suture) between the younger, thinner, and hotter crust of the Hercynide or Paleozoic block (negative anomaly) and the older, thicker, and colder crust of the East European Precambrian Platform (positive anomaly). This produces a gradient of approximately 18 nT (peak-to-trough) and a half-wavelength of 720 km along a Magsat orbit at 325 km altitude. This anomaly pair is the result of the juxtaposition of these two significantly different crustal blocks. To model this field, two irregular three-dimensional bodies were used to represent the Precambrian and Paleozoic crust. The former was modeled with a normal magnetization vector while the latter was modeled with a reverse vector. Aeromagnetic anomalies in western Germany and rock magnetic measurements from Germany and Scandinavia support a model in which reversely magnetic geologic units, extending from upper-crustal metasediments to mid-crustal sources produce this negative anomaly.