Scotland’s vitrified forts – the biggest mystery of them all?
Archaeologists have begun the latest attempt to solve a riddle that has baffled both experts and conspiracy theorists, says Alison Campsie
Archaeologists have returned to an ancient Iron Age hillfort in the shadows of Ben Nevis in a further attempt to unravel the great mystery surrounding the construction of the 2,500-year-old settlement and others like it.
Dun Deardail, a hilltop fort in Glen Nevis, is dated to 500 BC and likely served as a Celtic fort and then a Pictish citadel.
It continues to defy explanation given it was made from stone and timber burnt at such intense heat that the rocks melted and fused together in a process known as vitrification.
Theories on how its inhabitants were able to create such temperatures – around 1,000 degrees Celsius – over long periods and in such remote locations have divided opinion among archaeologists and geologists for decades. Conspiracy theorists are also interested in the answer, with science fiction writer Arthur C Clarke hailing the vitrified forts of Scotland as one of the great unsolved mysteries of the world.
This month, a team from AOC Archaeology, Nevis Landscape Partnership and Forestry Commission Scotland have returned to Dun Deardail for the third time to carry out excavation work with the assistance of Stirling University PHD student Amanda Dolan.
A spokeswoman for Nevis Landscape Partnership said: “Vitrified forts, like Dun Deardail in Glen Nevis, continue to bewilder even the sharpest mind but this month Nevis Landscape Partnership & Forestry Commission Scotland will attempt to understand this fascinating process and the people who inhabited this impressive Iron Age settlement when we begin our third and final year of excavations.”
Dun Deardail sits on the West Highland Way on an elevated rocky knoll to the west side of Glen Nevis.
The hillfort is overlooked by Ben Nevis and has breathtaking views over the surrounding glen.
It is around one of 60 vitrified forts in Scotland – with others including Tap O’ North in Aberdeenshire and Ord Hill near Inverness.
Similar structures are found in parts of France, Germany Wales and Ireland.
Remains of other vitrified forts can be found along the Great Glen Way with Dun Deardail providing a defensive site – and probably a status symbol – for its elite occupants.
Andy Heald of AOC Archaeology said several explanations have been given as to why the rock was burnt at such places.
Mr Heald said: “Some people think vitrification was a status symbol, some people think a settlement would be set alight and inadvertently vitrified in the process by attackers and some people think it’s a structural thing to do with strengthening the walls of the fort.”
With no clear answer, conspiracy theorists have their own ideas.
In addition, Arthur C Clarke took an interest in Scottish vitrified forts in the early the 1980s and recreated and earlier experiment with archaeologist Dr Ian Ralston at Tap O’ North.
A rampart wall of stone and timber beams was built with around six tonnes of wood burnt on top of it for more than 22 hours.
Some vitrification took place but the test could not explain how the process could work on the scale of a fort – or how such large amounts of fuel could be transported to a hilltop during prehistoric times.
Clarke, when asked in 2004 what he considered to be his biggest unsolved mystery, said: “The oddest thing is these vitrified forts in Scotland. I just thought, how? After all, lasers were not common in the Stone Age.”
Vitrified rock has also been found at the Incan fort of Sacsayhuaman in Peru.
Conspiracy theorists have suggest- ed the feat of engineering could have been achieved using a vast network of mirrors and lenses to concentrate sunlight – or that an alien invasion could have been responsible. Perhaps the truth is out there for the Nevis Landscape Partnership.