A group of researchers from the UK and South Africa has found that most of the hulking sandstone boulders — known as sarsens — that make up the well-known Stonehenge monument seem to share a popular origin 25 km (15.five miles) away in West Woods on the edge of the Marlborough Downs, Wiltshire.
Stonehenge. Image credit: Regina Wolfs.
The origins of the stones employed to create Stonehenge about 2500 BCE and their transportation strategies and routes have been the topic of debate amongst archaeologists and geologists for more than 400 years.
Two most important varieties of stones are present at the monument: the sarsen stones that kind the major architecture of Stonehenge and the bluestones close to the center of the monument.
The smaller sized bluestones have been traced to Wales, but the origins of the sarsens have remained unknown, till now.
“Archaeologists and geologists have been debating where the sarsen stones used to build Stonehenge came from for more than four centuries,” stated Professor David Nash, a scientist in the School of Environment and Technology at the University of Brighton and the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand.
“These 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-ton stones were transported.”
Stonehenge in context: (A) distribution of silcrete boulders across southern Britain, which includes sarsens and conglomeratic variants recognized as puddingstone (B) sampling internet sites and topography in the Stonehenge-Avebury location, along with proposed transportation routes for the sarsen stones (C) strategy of Stonehenge displaying the location of the monument enclosed by earthworks plus numbered peripheral sarsen stones (D) detail of the most important Stonehenge monument displaying the remaining bluestones and numbered sarsen stones. Image credit: Nash et al, doi: 10.1126/sciadv.abc0133.
To find out exactly where the enormous boulders came from, Professor Nash and colleagues employed transportable x-ray fluorescence spectrometry (PXRF) to initially characterize their chemical composition, then analyzed the information statistically to identify their degree of chemical variability.
Next, they performed inductively coupled plasma mass spectrometry (ICP-MS) and ICP-atomic emission spectrometry (ICP-AES) of samples from a core previously drilled by means of one particular sarsen stone — Stone 58 — and a variety of sarsen boulders from across southern Britain.
After comparing these signatures, they have been in a position to point to West Woods as the sarsens’ earliest house.
The purpose the monument’s builders chosen this web page remains a mystery, even though the scientists recommend the size and good quality of West Woods’ stones, and the ease with which the builders could access them, might have factored into the choice.
“We still don’t know where two of the 52 remaining sarsens at the monument came from,” Professor Nash stated.
“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.”
The analysis is published in the journal Science Advances.
David J. Nash et al. 2020. Origins of the sarsen megaliths at Stonehenge. Science Advances six (31): eabc0133 doi: 10.1126/sciadv.abc0133