Inversion tectonics at the northern margin of the North German Basin: Cretaceous to recent reactivation of Triassic normal faults (iTec-NGB)

晚更新世（可能是全新世）地层中的近地表断裂位于横跨Langeland岛（波罗的海丹麦部分）的西向东走向地堑的东部延伸，与三叠纪和白垩纪地层中的深根断裂相关。这些断裂位于Ringkøbing-Fyn隆起的基底基底构造之上，标志着北德意志盆地（NGB）的北缘。本项目旨在通过地震解释研究兰格兰岛以东NGB北部边缘的构造演化及其与后二叠纪至NGB近期演化的关系。研究区在三叠纪早期以盆地边缘正断层的伸展和相应发育为主导的盆地形成阶段，在晚白垩世和新生代盆地反转期间，盆地边缘正断层的挤压再活化为逆断层，以及近期可能的构造运动和冰川后均衡调整。2020年，在Langeland以东收集了27个高分辨率多通道反射地震和参数回声测深剖面。为了揭示NGB北部边缘复杂的多期演化，必须在构造框架内对这些数据进行处理、解释和讨论。第一个数据例子表明，正断层重新激活，包围倾斜的三叠纪块体，作为逆断层，抬升上覆的白垩纪地层并刺穿上覆的更新世单元。然而，故障系统的确切轮廓仍然未知。将更多的地震资料纳入解释将提高对断裂系统演化的认识，揭示其确切轮廓及其与Ringkøbing-Fyn高的深层构造的联系。断层位移的定量分析需要通过高质量的速度模型得到地震深度剖面。采用一种基于衍射提取技术的创新处理流程来建立偏移速度模型。该技术利用衍射波前属性计算横向变速信息，即使是短偏移地震数据。此外，提取的衍射将有助于识别断层，并提高对断层系统及其几何形状的理解。在生产深度剖面中可见的生长断层将允许对构造运动的活跃阶段进行量化，这将在已知的盆地沉降阶段和来自NGB其他地区和中欧盆地系统邻近子盆地的反转阶段的背景下进行讨论。

Near-surface faults within late Pleistocene, possibly Holocene strata are located in the eastern prolongation of a west-east striking graben across Langeland Island (Danish sector of the Baltic Sea) and correlate with deep-rooted faults within Triassic and Cretaceous strata. These faults are located above a prominent basement horst structure of the Ringkøbing-Fyn High, which marks the northern margin of the North German Basin (NGB). This project strives for investigating the tectonic evolution of the northern NGB margin east of Langeland Island and its relation to the post-Permian to recent evolution of the NGB by means of seismic interpretation. The study area allows investigating the early phases of basin formation dominated by extension and corresponding development of basin margin normal faults during the Triassic, their compressional reactivation as reverse faults during Late Cretaceous and Cenozoic basin inversion, and possible recent tectonic movements as well as post-glacial isostatic adjustments. In 2020, 27 high-resolution multi-channel reflection seismic and parametric echosounder profiles have been collected east of Langeland. To reveal the complex multiphase evolution of the northern NGB margin, these data have to be processed, interpreted and discussed within the tectonic framework. A first data example indicates the reactivation of normal faults, bounding tilted Triassic blocks, as reverse faults that uplifted overlying Cretaceous strata and pierce into overlying Pleistocene units. However, the exact outline of the fault system remains unknown. Incorporating more seismic data into the interpretation will improve the understanding of fault system evolution and reveal its exact outline and connection to deep-seated structures of the Ringkøbing-Fyn High. The quantitative analysis of fault displacement requires seismic depth sections obtained by high-quality velocity models. Migration velocity model building will be achieved by using an innovative processing flow based on a diffraction extraction technique. This technique uses diffraction wavefront attributes to calculate lateral variable velocity information even for short-offset seismic data. Additionally, extracted diffractions will help to identify faults and improve the understanding of the fault system and its geometry. Growth faulting visible in the produced depth sections will allow quantification of active phases of tectonic movement, which will be discussed in the context of the known phases of basin subsidence and inversion from other areas of the NGB and adjacent sub-basins of the Central European Basin System.