The Söderfjärden Meteor Crater – Finland

I visited the Söderfjärden on a warm, rainy August morning.

The ten kilometers of road south from Vasa were perfectly clear except for two fearless foxes moving from one stand of Red Pine to the other.  I had spent the previous several days in Finland’s Kvarken Archipelago and had heard about the 520-560 million year old meteorite impact crater to the south. It sounded like it was worth the time.

Today, the Söderfjärden Meteor Crater is an open, fertile field of wheat and oats and, mostly, barley sitting about 250-300 meters below the surrounding pine-covered landscape. I also saw lines of potatoes. It is approximately 6.5 kilometers in diameter and chock full of bird life. During the fall migrations, cranes come to the Söderfjärden fields to rest by the tens of thousand making it perhaps the most important stopover on the migration.

When the meteorite hit it literally evaporated itself and the shallow sea floor it slammed into and caused a massive tsunami that pushed sediments away for hundreds of kilometers.  Over the Cambrian period the crater filled with sediments that were then molded into the structures you can find at the crater today.  Despite the scraping of glaciers and the sea floor uplift that brought the crater up to dry land the crater rim is still easy to find both with the eye and by the difference in geology between the inside and the outside of the crater.

Interestingly Söderfjärden is one of those places where the Earth’s geologic history can be traced way back into the way back.  When the meteor hit this area, Finland was actually in the southern hemisphere.  Over the course of tens of millions of years Söderfjärden came back north, went south again and then returned to the north where we find it today. Glaciation came and went. The geologic record is rich. Geologic core samples taken from Söderfjärden also show fragments of trilobites and brachiopods, species that help us trace the evolution of life on Earth.

For the archaeologist in me Söderfjärden also tells how people first came to this area and how the rising sea changed their food production techniques.  On the north edge of the crater there is the small hill Öjberget where 4000-year old tools have been excavated.  Closer to Sundom a small hut was found and dated to about 2000-years ago.  At that time, the hut was on an island far out in the sea.  During the Middle Ages when Söderfjärden was still under water the area was seine fished using nets.

Until the 1920’s, Söderfjärden was a wetland.  Arrowgrass and other sedges were harvested from the area for fodder.  Reeds were harvested for roofing materials. In the 1800’s much of Finland’s wetlands were drained for agriculture and the same happened here just after independence in 1918.  In this case the hot item was hay.  The 1950’s and 60’s in Finland saw a booming cattle business with lots of hungry animals. I found my way to a little pump-house still working away to keep the cultivated areas drained.  The canal that took the water away run towards the sea to the west. The pump house sported murals by Eivor Holm, an unexpected find.

At the center of the crater is a tiny visitor center that was closed when I arrived.  That was a little bit of a bummer considering the exhibit is said to be so nice and that they staff regularly runs and astronomical observatory on the site.  But that is Finland.  You never know when things are open or closed – even with posted opening hours online.

Still, I climbed the bird tower to watch the slowly migrating flocks pass and circle and land and go again until the rain came down again.  This time fierce.

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From Vasa, the Söderfjärden Meteor Crater is easy to get to. Use this map, bring a raincoat, a picnic and your birding gear.

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