Brighton scientists unlock the secret of the Stonehenge stones

Their two-year investigation has discovered that most of the large stones that make up the iconic main sarsen circle and inner trilithon horseshoe of the monument came from around 15 miles to the north, in West Woods on the edge of the Marlborough Downs, Wiltshire.

The research, published in the journal Science Advances, was led by Professor David Nash, the university’s Professor of Physical Geography. He said: “Archaeologists and geologists have been debating where the sarsen stones used to build Stonehenge came from for more than four centuries. 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.”

The research team used geochemical data to show that 50 of the 52 sarsen stones at Stonehenge share a consistent chemistry and by inference originated from a common source area. They then compared the geochemical signature of small fragments of a core extracted from one of these sarsens – Stone 58 – with equivalent data for sarsens from across southern Britain. This information was used to identify that most of the sarsen stones at Stonehenge originated from West Woods.

Professor David Nash

Dr Jake Ciborowski analysing a sarsen lintel stone using a portable x ray fluorescence spectrometer. Photograph by Professor David Nash.

The core was drilled from Stone 58 during conservation work at Stonehenge in 1958. The location of the core remained a mystery until last year when Robert Phillips, a representative of the company who did the drilling work, returned it to the UK from his home in Florida.

Susan Greaney, Senior Properties Historian for English Heritage, the charity that cares for Stonehenge, said: “This research provides a fantastic leap forward in our knowledge about Stonehenge, as we can finally answer the question of where the iconic sarsen stones were brought from. We’re so pleased that the core from Stone 58, which the Phillips family returned to Stonehenge last year, has enabled the team to undertake a small amount of destructive sampling, adding a crucial piece of evidence to the jigsaw.”

English Heritage granted permission for the University of Brighton to conduct the research and in 2018 scientists began chemical analysis of the sarsens at Stonehenge. Non-invasive analyses at the monument used a portable x-ray spectrometer that can identify chemical concentrations of a range of elements. Analyses of the core fragments and of sarsens from the university’s extensive rock collection used a high precision mass spectrometer.

Professor Nash, from the university’s School of Environment and Technology, said: “The origins of the smaller bluestones near the centre of Stonehenge have attracted most attention over the years. These stones 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.

“Although we now understand where most of the sarsen megaliths at Stonehenge originated, there remain mysteries to solve. We still don’t know where two of the 52 remaining sarsens at the monument came from. These are upright Stone 26 at the northernmost point of the outer sarsen circle and lintel Stone 160 from the inner trilithon horseshoe. It is possible that these stones were once more local to Stonehenge, but at this stage we do not know.

“We also don’t know the exact areas of West Woods where the sarsens were extracted. Further geochemical testing of sarsens and archaeological investigations to discover extraction pits are needed to answer these questions.”

Professor Nash and colleagues Dr Jake Ciborowski and Dr Georgios Maniatis from the School of Environment and Technology undertook the study as part of a project funded by the British Academy and the grant-making foundation the Leverhulme Trust. Partners in the project included Susan Greaney (English Heritage), Katy Whitaker (Historic England), Professor Timothy Darvill (Bournemouth University) and Professor Mike Parker Pearson (University College London).

Click here to read the full Science Advances paper.

Professor David Nash analysing the sarsen core extracted from Stone 58 at Stonehenge. Photo by Sam Frost, English Heritage.