THE 400-year-old mystery of where the 20-tonne stones used to build Stonehenge came from has been unravelled by a team of academics.

David Nash, Professor of Physical Geography at the University of Brighton, has led a two-year investigation and chemical analysis of the stones.

The team discovered most of the large stones in the main circle and inner horse shoe of the ancient monument came from West Woods on the edge of the Marlborough Downs in Wiltshire, about 20 miles north of the site.

Professor Nash said: “Archaeologists and geologists have been debating where the Sarsen stones used to build Stonehenge came from for more than four centuries.

The Argus:

“This significant new data will help explain more of how the monument was constructed and perhaps offer insights into the routes by which the 20 to 30 tonne stones were transported.”

There are two types of stone at Stonehenge – the larger Sarsen stones, a type of sandstone found scattered across southern England, and the smaller “bluestones”.

Professor Nash said: “The origins of the smaller bluestones near the centre of Stonehenge have attracted most attention over the years, and these have been shown to originate from parts of Wales.

“However, virtually no work had been done until now on the sources of the larger Sarsen megaliths that form the primary architecture of Stonehenge.”

The Argus:

The research team were able to use the core drilled from one of the Sarsen stones, Stone 58, during conservation work in 1958.

But the location of the Stone 58 core had remained a mystery until Robert Phillips, a representative of the company who did the drilling work, returned it to the UK from his home in Florida last year.

Professor Nash’s team used geochemical data to show that 50 of the 52 Sarsen stones at Stonehenge share a consistent chemistry and originated from a common source area. They compared the geochemical signature of small fragments of the core extracted from Stone 58 with data for Sarsens from across southern Britain, and found that most of the stones at Stonehenge originated from West Woods.

Professor Nash said there are still mysteries to solve, however. He said: “We still don’t know where two of the 52 remaining Sarsens came from. It’s possible these stones were once more local to Stonehenge. We also don’t know the exact areas of West Woods where the Sarsens were extracted. Further investigations are needed.”