How were the skerry islands along the Swedish and Finnish coasts formed?

The skerry islands along the Swedish and Finnish coasts were formed primarily through the retreat of the massive ice sheet that covered northern Europe during the Pleistocene Epoch glaciations.1

As the glaciers melted and retreated toward the Arctic, they left behind significant geological features and deposited materials. The subsequent removal of the immense weight of these glaciers triggered a process of post-glacial land uplift, where the land began to rebound. This ongoing uplift, combined with the complex topography left by glacial activity, created the characteristic fragmented coastal landscapes known as skerries. While eskers—winding ridges of sand and gravel deposited by subglacial meltwater streams—are notable features found in Sweden resulting from this same glacial retreat, the formation of the skerry archipelagos is fundamentally tied to the interplay between glacial erosion, the resulting uneven terrain, and the long-term crustal rebound of the region.12