A team of geologists from Britain have pinpointed the exact quarry that Stonehenge's innermost circle of rocks came from. It's the first time that a precise source has been found for any of the stones at the prehistoric monument.
Robert Ixer of the University of Leicester and Richard Bevins of the National Museum of Wales painstakingly identified samples from various rock outcrops in Pembrokeshire, Wales.
For nine months the pair used petrography -- the study of mineral content and textural relationships within rocks -- to find the origins of Stonehenge's rhyolite debitage stones. These spotted dolerites or bluestones form the inner circle and inner horseshoe of the site.
They found the culprit on a 65-metre-long outcropping called Craig Rhos-y-Felin, near Pont Saeson in north Pembrokeshire. It lies approximately 160 miles from the Stonehenge site.
The question remains though, as to how neolithic people transported huge chunks of rock from Wales to Wiltshire, some 5,000 years ago. Some historians reckon that these stone age builders quarried the stones in Pembrokeshire and brought them over to England, while others argue that giant glacial shifts moved the stones, hundreds of thousands of years earlier.
Ixer and Bevins hope that by finding the exact source for some of the monument's stones, they will be able to discover new clues as to when and how they made their 160 mile journey.
The more well-known and iconic stones, the huge sarsens, were incorporated into the monument several centuries later. They came from somewhere in the Marlborough Downs, 20 miles north of Stonehenge.