An international team of archaeologists has discovered traces of early Stone Age settlement under a lake called Kuolimojärvi (Kuolimo) in south-eastern Finland.

Scientists have long known about the presence of humans of Finland. They were roaming in the region more than 10,000 years ago, but due to nature’s way of things, there has been a massive 4,000 year-long gap in the archaeological evidence of human activity. This is exactly what the latest discovery from more than 8,000 years ago aims to solve.

Drone Photo over Kammarlahti Drone photo over Kammarlahti, the site studied in the latest work. The raft anchored in the research area. Photo: Jesse Jokinen/Museovirasto

During the early Stone Age, the water levels of Lake Kuolimo were several meters below what they are at the moment. However, the gradual upliftment of land raised those levels, covering dry land and several Stone Age sites in the process. The levels came down some 6,000 years ago.

“This means that there is a huge gap in our archaeological knowledge of this particular area because we have not yet found the earliest Stone Age sites,” Satu Koivisto, the lead researcher behind the latest expedition, said in a statement.

The mystery prompted Koivisto and team — researchers from Sweden, Denmark, and Nordic Maritime Group — to launch an underwater expedition to Kuolimo and hunt Stone Age traces buried at the bottom of the lake or its littoral deposits.

They started off with a region of the lake best sheltered by waves and winds, which could have helped in preserving prehistoric evidence. The idea proved correct as the team found a number of pits as the first evidence of a submerged Stone Age settlement to be discovered in Finland.

“In one of the test pits, we found a distinct layer of burned soil, charcoal and burned rocks,” Koivisto added. Other pits located nearby had flakes of quartz, which indicated that people living at the site were engaged in making quartz artifacts.

As the hearth feature and other related traces were seen nearly a meter below the lake, the team thinks this is an evidence from before the rise of sea level or some 9,000 to 8,000 years ago. The closest Stone Age sites similar to this one are located in northwestern Russia and southern parts of Scandinavia.

That said, it is worth noting that further archaeological analysis is still required to shed more light into the exact timeline of settlement and gain more insight into human activity back in the day. The researchers have taken samples of the burnt soil and are using sophisticated analytical for the task.

The researchers also believe further observation of traces buried beneath other lakes could reveal more about Finnish Stone Age.

"With the excavation equipment tested in the underwater research at Kammarlahti [the studied lake site], we may also be able to find other submerged sites at similar locations,” Koivisto concluded. “Many of our large lakes, such as Vanajavesi, Pielinen, and Oulujärvi have also gone through similar fluctuations in water levels. This means that a huge and largely untapped archaeological resource is hidden in Finnish lakes.”