Seismo-geological model of the Baltic Basin (Poland)

Abstract

The aim of this study is to construct a seismo-geological model of the western part of the Baltic Syneclise. This model enables reconstruction of the tectonic processes taking place in this area, which had a significant impact on the formation of prospective zones for the occurrence of unconventional hydrocarbon accumulations. The two seismic surveys Opalino 3D and Kościerzyna–Gdańsk 2D, together with borehole data available in the vicinity, were used for the research. Well data were used not only for the seismic-to-well tie, but also for the construction of well cross-sections (including balanced ones). The structural interpretation of seismic boundaries enabled the separation of four structural stages: Precambrian; Caledonian, Permian–Mesozoic and Cenozoic. The seismic interpretation of the Opalino 3D survey indicates the presence of block-style tectonics in this area. This system is considered to be a part of a large block system, also extending throughout the area of the 2D survey. The Caledonian interval shows the greatest degree of structural complexity. Most of the large Palaeozoic dislocations already had been formed in the Cambrian. They underwent reactivation and/or inversion in the Silurian, or in the final stages of the Caledonian and/or Variscan Orogeny, at the latest. The current shape and structure of the Baltic Syneclise and the development of the Palaeozoic sedimentary cover were significantly influenced by the processes taking place in the Teisseyre-Tornquist Zone (TTZ). The dislocations of the Lower Palaeozoic stage are characterized by general NW–SE and NE–SW trends, although the first of these seems to be dominant.