ausblenden:
Schlagwörter:
seismic facies; Northeast German Basin
DDC:
550 - Earth sciences
Zusammenfassung:
This PhD-work is a collaboration between of the University Potsdam and the GeoForschungszentrum Potsdam. It is part of the DEKORP project BASIN' 96. The main aim of this work is to improve the understanding of the evolution of the intracontinental NE Basin (NEGB). Together with other workers from other institutes a variety of aspects concerning the basin development will be investigated. Of special interest in this work is the role of pre-Permian structures on the distribution of Permian and Mesozoic/Cenozoic sediments and volcanics. Background geology The NEGB is one of a series of related intracontinental basins extending from the North Sea to Poland. The NEGB contains in excess of 12 km of Phanerozoic strata. The region was significantly influenced by the Caledonian and Variscan orogenies. Three broadly NW-SE-striking fault zones occur in the area (Fig. 1). From north to south these are: the Tornquist Zone (TZ), the Caledonian Deformation Front (CDF) and the Trans-European Fault (TEF). Crustal warping and block faulting in the late Stephanian was accompanied by extensive magmatism resulting in the deposition of a thick (ca. 2000m) volcanic succession of Permosilesian age. This was followed by the main phase of thermal subsidence extending from early Permian to Middle Triassic times. Following marine transgression an epicontinental southward migrating sea developed in Zechstein times. The overlying Triassic succession, as in much of Central Europe, is characterized by the Germanic tripartite facies comprising Lower Triassic fluviatile-dominated red-bed clastic sequences (Buntsandstein), followed by a Middle Triassic marine transgression during which the Muschelkalk platform carbonates were deposited. Eustatic sea-level lowering in Upper Triassic times (Keuper) led to renewed continental-type sedimentation, including playa and tidal flat deposits. At that times salt movement first occured. In Middle Triassic times, regional extension led to new NNE-SSW-trending basins (e.g. Gifhorn). In the Jurassic the NW part of NEGB was uplifted. During the Cretaceous, regional compression caused uplift of both basin margins. A final subsidence phase occured in the Cenozoic and was accompanied by renewed salt movement. Database and resuls Newly-obtained deep seismic data (DEKORP-campaign Basin'96) together with standard industrial profiles from the northern margin of the basin facilitate the detailed analysis of the sedimentary succession of the region. The network of available seismic profiles cover an area of about 120x80 km along the northern margin of the NEGB. A series of seismic reflectors will be interpreted and correlated throughout the region. In combination with deep bore holes a series of contour and isopach maps for the Mesozoic and Cenozoic cover sediments will be produced. More detailed analysis involve the recognition of characteristic seismic facies and facies associations, their regional correlation, and their interpretation in terms of specific depositional enviroments. Additionally, this seismic-stratigraphical approach allows the development of a series of detailed time-slices for the evolution of the region.
