Millennia-old pits found at Stonehenge offer new insight into human activity at the monument

Scientists are forming new theories about how the prehistoric monument Stonehenge was used after recently discovering hundreds of previously unknown large pits, and thousands of smaller ones, that were potentially excavated thousands of years ago.

A team of researchers from the University of Birmingham in the United Kingdom and Ghent University in Belgium used geophysical sensors, excavations and computers to reveal the prehistoric land use of the Stonehenge site, including one large pit more than 10,000 years old that measured more than four metres wide and two metres deep, dug into chalk bedrock.

The results were published earlier this month in the Journal of Archaeological Science.

"When used correctly, geophysical sensors do not 'lie,'" Henry Chapman, a professor of archeology at the University of Birmingham, said in a news release.

"They represent a physical reality. Converting that observed reality to archeological knowledge, however, is not a straightforward process. As archeologists, we need information on aspects such as chronology and function as a basis for understanding past human behaviour. That puzzle contains pieces that can only be retrieved through excavation."

The team identified more than 400 possible large pits, each more than 2.5 metres in diameter, and excavated six. The pits range in age from the Early Mesolithic period around 8,000 BC to the Middle Bronze Age around 1,300 BC.

The researchers say the Mesolithic pit stands out in particular, with its size and shape suggesting it was probably dug as a hunting trap for large game, such as the extinct cattle species aurochs, red deer and wild boar.

This pit, dating back to between 8,200 and 7,800 BC, is not only one of the earliest of the few Mesolithic sites found near Stonehenge, the researchers say it is also the largest one known in northwest Europe.

Nick Snashall, an archeologist for the Stonehenge and Avebury World Heritage Site, said the research team has revealed "some of the earliest evidence of human activity yet unearthed in the Stonehenge landscape."

"The discovery of the largest known Early Mesolithic pit in northwest Europe shows that this was a special place for hunter-gatherer communities thousands of years before the first stones were erected."

The study's authors say mapping of the large pits shows they cluster in parts that were repeatedly revisited for thousands of years, namely on the higher ground to the east and west of Stonehenge.

The distribution of these pits provided extensive vistas overlooking Stonehenge, the researchers say.

"What we're seeing is not a snapshot of one moment in time. The traces we see in our data span millennia, as indicated by the 7,000-year timeframe between the oldest and most recent prehistoric pits we've excavated," said Paul Garwood, senior lecturer in prehistory at the University of Birmingham.

"From early Holocene hunter-gatherers to later Bronze Age inhabitants of farms and field systems, the archeology we're detecting is the result of complex and ever-changing occupation of the landscape."