Geology

The unique terrain of the Kvarken Archipelago is, to a large extent, formed by the last inland ice sheet and its melting process. Some landscape transformations have occurred later due to land uplift, wave erosion on ancient shores of the Baltic Sea stages (Ancylus Lake, Litorina Sea, and present) and the continuously growing peatlands.

The The Kvarken Archipelago, with its flat topography, extensive archipelagos, shallow coast areas, and large annual land addition area represents a shorter period of 2000 - 3000 years. The moraine formations reach 3-10 meter above the surroundings. Both Kvarken Archipelago and the High Coast world heritage sites display the spatial aspect of land uplift and dynamic landscape development. The Kvarken Archipelago contributes significantly to the measuring of time, facilitating a dating precision of about 10 years. This is also evident in the ecosystem development, illustrated by the plant communities that occur in distinct belts along topographical and hydrographical gradients. The steep topography of the High Coast site makes the plant communities more stable and influenced less by the land uplift timescale. Instead, species specialization and adaptation are favoured, as well as long-term survival of relict species. The succession reflects a timescale precision of 10-100 years.

World Heritage area

 Land uplift, brackish water environments, sea level fluctuations, and a lack of tide are features that the Kvarken Archipelago and High Coast have in common. Ecosystems and plant communities are also similar, but differences in topography and geomorphology imply different ways of adaptation to the ongoing land uplift in time and space.