PhD defence: Carina Bendixen

Carina Bendixen defends her thesis,

Aspects of the Quaternary evolution of the southern Kattegat and the central North Sea based on interpretation of 2D and 3D marine reflection seismic profiles

Supervisors:
Associate Professor Lars Ole Boldreel, IGN
State Geologist Jørn Bo Jensen, GEUS
Associate Professor Ole Rønø Clausen, Aarhus University

Assessment committee:
Professor Svante Björck, GeoBiosphere Science Centre, Lund University
Professor Karl Stattegger, Christian-Albrehcts-Universität zu Kiel
Professor Lars Nielsen (chair), IGN

Summary:
In this PhD study interpretation of 2D shallow seismic data in the Kattegat region and 3D conventional seismic data in the central North Sea, combined with sediment core interpretation and radiocarbon dating has been carried out in order to outline the geological development of the southwestern part of the Kattegat region in from the Late Weichselian to Early Holocene and investigate the potential of using 3D seismic in Quaternary geology. Within the study area of the Kattegat region Late Weichselian
(Lateglacial) sediments are widespread unit and they drape the surface of the underlying till and followed by postglacial (Holocene) sediments. During early Holocene, the southwestern part of Kattegat was characterized by multiple funnel-shaped estuaries with spits and bars, connected to the freshwater palaeo-Great Belt channel. This took place simultaneously with the occurrence and drainage of the Ancylus Lake through the Great Belt. The drainage of the Ancylus Lake was interpreted as non-catastrophic water flow. With a continuous Holocene sea-level rise landwards retreat of the coastal systems occurred, followed by flooding of the northern Great Belt threshold and major erosion took place. Within the study area of the central North Sea, interpretation of 3D-seismic data has led to the identification of an unknown well-preserved glaciotectonic complex. It is suggested that the glacial thrust complex is evidence for an extensive Pre-Elsterian glaciation. The interpreted thrusts blocks plot well within the range of the thrusts associated with the Weichselian glaciation.

The thesis is available at the PhD administration office, 04.1.417