The stones were originally thought to be from another Preseli hill called Carn Meini, but the new research shows that they actually came from Carn Goedog.
A team of three geologists including Dr Richard Bevins, Keeper of Natural Sciences at the National Museum of Wales in Cardiff, have identified a hill called Carn Goedog as the site from which 11 stones known as spotted dolerites were somehow transported to Stonehenge in Wiltshire.
Dr Bevins, one of the world’s leading authorities on volcanic rocks, has been studying the Preseli Hills since he was a PhD student in the late 1970s.
For the latest research, he and his colleagues took as their starting point a ground breaking paper published by the academic HH Thomas in 1923 which first put forward the theory that the so-called blue stones of Stonehenge came from Pembrokeshire.
Thomas expressed the view that the stones came from another Preseli hill called Carn Meini, a mile away from Carn Goedog and ever since archaeologists have assumed that to be the case.
But Dr Bevins said: When Thomas was doing his research, it wasn’t possible to be as precise as it is now. By x-raying dolerites from Stonehenge and comparing them with dolerites from Carn Goedog, we know with some degree of certainty that’s where the blue stones originated.
Dr Bevins said he would not speculate on how the stones got from Preseli to Wiltshire.
Further research is ongoing that could pinpoint the origin of the stones with even greater precision.