University of Southampton
New research suggests that artificial islands, known as crannogs, are much older than previously thought.
Archaeologists in Scotland have discovered new evidence that shows that the artificial islands known as crannogs they were built more than 5000 years ago, revealing an unexpectedly advanced level of prehistoric engineering during the Late Neolithic period.
The discovery, reports in a published in Advances in Archaeological Practice, centers on a crannog or Loch Bhorgastailon the Isle of Lewis in the Outer Hebrides of Scotland. Researchers from the University of Southampton used cutting-edge underwater imaging techniques to examine the structure’s submerged foundations, confirming that it was built between 3800 and 3300 BC. — thousands of years earlier than previously believed for many crannogs.
Crannogs are small artificial islands which are found in lakes in Scotland and Ireland. For decades, archaeologists assumed most dated to the Iron Age or medieval period. However, recent studies increasingly suggest that some of these structures originated much earlier, fundamentally reshaping understanding of prehistoric communities in Britain.
“Crannogs are small artificial islands that are usually thousands of years old,” said the archaeologist Stephanie Blanksheinmember of the research team. Hundreds of them remain scattered across Scotland, many still unexplored beneath remote lakes and waterways.
According to the , investigation of the Loch Bhorgastail archaeological site has proven particularly difficult because many of its key features are submerged in shallow, murky waters. Traditional aerial photogrammetry — a method that typically uses drones to create detailed 3D models — has proven to be ineffective due to poor visibility and the inability of satellite positioning signals to penetrate water.
To overcome this challenge, researchers developed a new underwater imaging approach. A diver equipped with two low-light wide-angle cameras, mounted on a frame, carefully swam around following a mapped route. The method allowed scientists to create highly accurate three-dimensional models of the submerged remains, offering unprecedented detail of the crannog’s structure.
The images guided subsequent excavations and radiocarbon datingwhich revealed the island’s original wooden foundations, buried beneath layers of stone. Researchers discovered that prehistoric builders initially created a circular wooden platform approximately 75 feet in diameter, reinforced with mats of oversized branches.
About 2000 years later, the structure was expanded and reinforced with more branches and stones. At some point, the builders also added a stone causeway connecting the island to the coast.
Although archaeologists are still uncertain about the crannog’s exact function, pottery fragments and other traces of human activity found nearby suggest that it was used repeatedly over many centuries.
