High Coast / Kvarken Archipelago
The Kvarken Archipelago (Finland) and the High Coast (Sweden) are situated in the Gulf of Bothnia, a northern extension of the Baltic Sea. The 5,600 islands of the Kvarken Archipelago feature unusual ridged washboard moraines, ‘De Geer moraines’, which under an Old Earth theory supposedly formed by the melting of the continental ice sheet, 10,000 to 24,000 years ago.
The Archipelago is continuously rising from the sea in a process of rapid glacio-isostatic uplift, whereby the land, previously weighed down under the weight of a glacier, lifts at rates that are among the highest in the world. As a consequence islands appear and unite, peninsulas expand, and lakes evolve from bays and develop into marshes and peat fens.
The High Coast has also been largely shaped by the combined processes of glaciation, glacial retreat and the emergence of new land from the sea. Since the last retreat of the ice from the High Coast 9,600 years ago, again under an Old Earth theory. The uplift has been in the order of 285 meters which is the highest known rebound. Some argue that this affords outstanding opportunities for the understanding of the important processes that formed the glaciated and land uplift areas of the Earth's surface.