Pomerania Gravity Low at the East European Craton margin – granitic batholith or a Paleoproterozoic impact structure ?

Abstract

The Pomerania Gravity Low is a regular large-amplitude, oval-shaped anomaly of a disputable origin located at the East European Craton margin. In the past it was interpreted as a Proterozoic crustal keel or Early Paleozoic/Permian-Mesozoic depocenter. The origin of the anomaly has been reconsidered based on a reinterpretation of previous potential fields, seismic and magnetotelluric data and recent gravimetric modelling results. New alternative interpretations are proposed and discussed: felsic intrusion related to the Transscandinavian Igneous Belt and a large impact structure ca. 1.6-1.8 Ga old. In view of the presented data and regional comparisons the impact origin seems more probable. Nevertheless, a prolonged erosion, deep burial and metamorphic overprint hamper verification of this hypothesis, e.g. by finding impact ejecta or shock-affected minerals.