An artificial island older than Stonehenge has been found in a Scottish lake

Such artificial islands in Scotland and Ireland are called crannogs. For a long time it was thought that most of them were built and used from the Iron Age onwards. However, research in recent years has shown that some crannogs in the Outer Hebrides date back much earlier - as far back as the Neolithic period, around the 4th millennium BC.

The crannog at Loch Bhorgastail at first looked like a small stone island. But excavations and underwater research have revealed that underneath the stone part is a complex structure made of wood and kindling. According to the University of Southampton project, the artificial islands of the Outer Hebrides may have been built around 3640 -3360 BC, which is about 2,500 years earlier than thought for most crannogs.

Details

The researchers found that the earliest stage of Loch Bhorgastail was a circular wooden platform about 23 metres in diameter, covered with kindling. Later, as early as the Bronze Age, further layers of kindling and stone were added to the structure, and then the site was used again in the Iron Age. A stone causeway leads from the shore to the island, which is now under water.

Hundreds of fragments of Neolithic pottery have been found in the water around the crannog. Such finds may indicate that the island was used for general gatherings, cooking, feasting or ritual activities. However, archaeologists stress that the exact purpose of such islands is still a matter of research.

Why it matters

The find shows that Neolithic people could create complex artificial structures on the water long before the appearance of known megalithic monuments. Building such an island required large quantities of materials, organised labour and an understanding of how to work at the land-water interface.

Crannogs also change the way we think about Neolithic communities in the Outer Hebrides. These were not just small settlements by the water: people created artificial islands, perhaps as special places for meeting, exchange, ceremonies or collective meals.

One of the main difficulties of such monuments is that they are simultaneously above water, at the water's edge and underwater. Conventional land-based photography does not give a complete picture, and underwater photogrammetry does not work well at depths of less than a metre because of glare, turbidity, algae and light distortion.

The University of Southampton and University of Reading team used stereophotogrammetry: two waterproof cameras were mounted on a frame at a fixed distance from each other. This allowed them to create an accurate 3D model of the site in extremely shallow water and link the underwater data to aerial drone photography. The method is described in the journal Advances in Archaeological Practice.

Background

Stonehenge began to be built around the late 4th or early 3rd millennium BC, so the Neolithic crannogs of the Outer Hebrides are indeed from an earlier period. But the comparison with Stonehenge must be understood carefully: it is not a question of a similar monument, but of the fact that the artificial islands demonstrate a comparably ancient and complex building tradition.

The Islands of Stone project is studying the Neolithic crannogs of the Outer Hebrides and has already shown that such artificial islands may have been a more widespread part of the Neolithic landscape than previously thought.

Source

The study by Stephanie Blankshein and co-authors At the Water's Edge: Photogrammetry in Extreme Shallow-Water Environments is published in Advances in Archaeological Practice. The project is linked to the study of Neolithic crannogs in the Outer Hebrides by teams from the University of Southampton and the University of Reading.