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We propose a new relative shore-level curve for the Aarhus Bugt area, an embayment in eastern Jylland, Denmark, based on a compilation of pub- lished and new radiocarbon ages of organic material. Lakes existed in the area during the Late Glacial and Early Holocene. Lake level rose gradually until the region was inundated by the sea at c. 9000 cal. years BP. The relative sea level reached a high stand at about 6000 cal. years BP, when the local relative sea level was c. 3 m above present-day mean sea level. The Aarhus Bugt area was inundated by the sea later than the Limfjord area in northern Jylland, but earlier than the Lillebælt region in southern Denmark. The shore- level curves for these areas differ partly because the glacio-isostatic uplift was more pronounced in the Limfjord area than farther south and partly because the northern regions were inundated by the sea earlier than the southern areas.

This paper presents new marine evidence of Lateglacial and Holocene environmental changes in the western part of Limfjorden, and provides a review of the geological history/development of this part of northern Jylland, Denmark. Lateglacial clay without fossils is widespread in the region and is probably a glaciolacustrine deposit. Limfjorden began to form as a strait in the Early Holocene due to rising relative sea level and the oldest marine shells are dated to c. 9300 cal. years BP. We propose a new relative sealevel curve for the region based on new and published data, which appear to confirm that the relative sea-level change was not extremely rapid, which was suggested earlier. During the Mid-Holocene a wide connection existed from the western part of Limfjorden to the North Sea in the west and more narrow connections existed between Limfjorden and Skagerrak in the north. The marine fauna included several species that indicate warmer and more salty waters than at present. Gradually, the connections to the North Sea and Skagerrak closed due to long-shore sediment transport and deposition of aeolian sand combined with a fall in the relative sea level during the Middle- to Late Holocene. During the Viking Age, 800–1050 CE (Common Era), the western connection to the North Sea was still open, but around 1200 CE it was closed by a coastal sandy barrier and the western part of Limfjorden became brackish. The coastal barrier was flooded on several occasions but soon formed again. After 1825 CE the western connection from Limfjorden to the North Sea has been maintained artificially.