Land‐To‐Sea Mapping of the Glacial Erosion Unconformity Reveals Evolution of the Jasmund Glacitectonic Complex East of Rügen Island (SW Baltic Sea).

Glacial movements shaped vast northern parts, offering critical insights into glacial dynamics in a changing climate. Located on the island of Rügen in NE Germany, the Jasmund Glacitectonic Complex (JGC) is a key area to study the dynamics of past glaciations. Previous reconstructions focused primarily on the onshore realm, resulting in some areas remaining unexplored. Here we use more than 140 high‐resolution marine multi‐channel seismic profiles to map the erosional unconformity surrounding the JGC for the first time. Submarine glacial features match features observed onshore, allowing a consistent land‐to‐sea reconstruction of the evolution of the JGC. Our results indicate a single SW‐directed Weichselian glacier advance, suggesting that the JGC formed through three distinct glacier lobes exerting pressure from multiple directions. The ice advance encircled the Jasmund peninsula and overthrusted Cretaceous sediments on the JGC perpendicularly and laterally. Plain Language Summary: The Jasmund Glacitectonic Complex on Rügen island, northeast Germany, is a popular tourist destination and a key area for studying how deformations and erosion by former ice sheets shape our landscapes. Previous studies were limited to the onshore area and suggested that the complex formed in three separate phases. Our study uses marine seismic imaging techniques that suggest an alternative development. By creating detailed maps of the proposed glacial erosional surface from seismic data, we discovered depressions of different shapes that were carved by glaciers moving southwestwards during the last ice age. The erosional feature is 100 m deep and matches earlier predictions of the ground's response to glacial movement. The mapping indicates that the glacial traces on the seabed extend onto the land. We propose that a single glacier movement was responsible for shaping the entire area in one dynamic phase. This shows that the sediments were compressed and displaced in varying directions during the ongoing (single) ice advance. Key Points: Seismic mapping, offshore channels and depressions, thrust‐fault structures, ice advance dynamics, Jasmund Glacitectonic Complex, Rügen Island and surrounding Baltic Sea, NE Germany [ABSTRACT FROM AUTHOR]