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’, 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,
the uplift has been in the order of 285 m which is the highest known
''rebound''. The site affords outstanding opportunities for the
understanding of the important processes that formed the glaciated and
land uplift areas of the Earth''s surface.