Structural Evolution at the Northeast North German Basin Margin: From Initial Triassic Salt Movement to Late Cretaceous‐Cenozoic Remobilization

Abstract

In this study, we investigate the regional tectonic impact on salt movement at the northeastern margin of the intracontinental North German Basin. We discuss the evolution of salt pillows in the Bay of Mecklenburg in the light of thick‐ and thin‐skinned tectonics, including gravity gliding, and differential loading using seismic imaging. Stratigraphic and structural interpretation of a 170 km long, multichannel seismic line, extending from the Bay of Mecklenburg to northeast of Rügen Island, incorporates well information of nearby onshore wells. This new high‐resolution seismic line completely images the stratigraphic and tectonic pattern of the subsurface, from the base of the Zechstein to the seafloor. Our analysis reveals that subsidence during Late Triassic to Early Cretaceous at the northeastern basin margin was associated with transtensional dextral strike slip movement within the Trans‐European Suture Zone. We reinterpret the Werre and Prerow Fault Zones west of Rügen Island as an inverted, thin‐skinned normal fault system associated with the formation of the Western Pomeranian Fault System. Salt movement in the Bay of Mecklenburg was initiated in the Late Triassic and lasted until the Early Jurassic. A second phase of salt pillow growth occurred during the Coniacian until Cenozoic and correlates with compression‐related regional basin inversion due to the onset of the Africa‐Iberia‐Europe convergence. Thin‐skinned extensional initialization of salt pillow growth and compressional salt remobilization explains salt pillow evolution in the Bay of Mecklenburg. Additionally, we discuss an impact of gravity gliding on salt pillow evolution induced by basin margin tilt.

A comprehensive model of seismic velocities for the Bay of Mecklenburg (Baltic Sea) at the North German Basin margin: implications for basin development

“…We performed this analysis for eight layers, from the seafloor down to the base of Fig. 2 Litho-stratigraphic chart of the NGB (modified after Ahlrichs et al (2020)). Layer numbers (in red) refer to the here presented migration velocity analysis (in red), corresponding regional reflectors after Reinhardt (1993).…”

“…1). The northeastern end of the Bay spatially correlates with the NGB margin (Ahlrichs et al 2020, and references there in). The NGB was affected by repeated phases of subsidence and uplift during its complex basin history from Palaeozoic to Cenozoic times (e.g.…”

“…Maystrenko et al 2008). In the Bay of Mecklenburg, the structural style is affected by salt movement and the development of some salt pillows (Hansen et al 2007;Zöllner et al 2008;Scheck-Wenderoth et al 2008;Hübscher et al 2010;Ahlrichs et al 2020). These salt structures consist of late Permian Zechstein evaporites, which were deposited during arid climate conditions and Fig.…”

“…2). During Middle to Upper Jurassic times, the development of the Central North Sea Dome (Ziegler 1990b;Underhill and Partington 1993) caused large-scale uplift, leading to erosion of much of the Jurassic strata in the Bay of Mecklenburg (Zöllner et al 2008;Ahlrichs et al 2020). Sedimentation was re-established in the Lower Cretaceous (Albian).…”

“…As a result, the area was again affected by uplift, erosion and the reactivation of pre-existing basement faults as reverse faults. Uplift of the nearby Grimmen High was approximately 400-500 m (Kossow and Krawczyk 2002;Ahlrichs et al 2020). During the Paleogene, the study area underwent gentle subsidence in conjunction with the rapid subsidence of the North Sea Basin (Ziegler 1990b).…”