Poly morphological analysis of the Cenozoic geology along the western part of the Esrum Sø, Denmark based on interpretation of Vibro seismic data

Esrum Sø geomorphology has previously been due to a buried glacier eventually melting into a lake. In the recent study, a glaciotectonic complex was found based on a detailed interpretation on a 6.3 km high resolution, vibro seismic profile collected along the northwestern bank of the Esrum Sø. The detailed seismic interpretation is supplemented by information of nearby wells, among which some is intersected by the seismic profile. The interpreted seismic profile was differentiated into five sections, characterizing the distal to the proximal structures of the development of the complex. The complex was deformed across a stepwise décollement surface. That is situated at the deepest level of 95 meter b.s.l. in the northern proximal section and the décollement surface shallows toward the southern, distal section. The glaciotectonic complex consists of ramps and flats related to hanging walls and footwalls positions, and in addition, a few folded structures such as hanging wall anticlines. In the part of seismic section that corresponds to the chalk, two major fault trenches are recognized and are located at Gravervang in the south and the other at Krogdal Vang in the north. The glaciotectonic complex was formed by gravity spreading during two proglacial events, during the advance of the Scandinavian Ice sheet of Late Weichselian (23,000-18,000 B.P.).The first event deposited large amounts of Quaternary sediments, which were later thrusted into piggyback duplexes. This was followed by a recession of the ice, such that meltwater deposits ahead of the ice would form a lake. New glaciotectonic structures across the older structures were deformed during the second advance. The thinned-skinned thrust fault duplexes is situated at positions that are located above two tectonic trenches. The tectonics are identified as wrench tectonics and can conceivable be connected with the glaciotectonic complex. Comparing the seismic profile to geomorphological maps the tecton