Stonehenge rocks traced to source
A team of archaeologists in the United Kingdom says it has traced dozens of Stonehenge’s massive rocks to two quarries in west Wales.
The rocks were transported 290 kilometres – dragged on wooden sleds, the scientists suggest, by teams of strong men. These stones, called bluestones after their bluish-grey hue, form the inner circle of the monument that towers over Salisbury Plain.
Two bluestone quarries, named Carn Goedog and Craig Rhos-y-felin, were excavated around 3000BC, according to the authors of a study published in the journal Antiquity.
Excavations at the quarries from 2014 to 2016 recovered ancient charcoal and stone tools. In some places, the charcoal was mixed with dirt and stones to form flat platforms, which may have been used like loading bays to distribute the massive pillars, said Michael Parker Pearson, an archaeologist at University College London and an author of the study.
Prehistoric workers probably exploited natural weaknesses in the rock structures, Parker Pearson said. ‘‘They’re nearly vertical. All you’ve got to do is get a lasso around each one and pull.’’
With ropes and simple tools, such as sandstone wedges shoved into the outcrop’s joints, excavators may have plucked out a pillar as cleanly as a loose tooth. Those on top of the outcrop could have carefully slackened their ropes to control the pillar’s descent to a platform below, the authors wrote. From there, workers may have lowered a stone on to a wooden sled to haul it away.
Bluestones were big but not so big that a ‘‘burly group of Stone Age men’’ couldn’t drag them across the countryside, Pearce said.
The pillars were ‘‘the Ikea version of Neolithic megaliths’’, Parker Pearson joked – the stones peeled off the outcrop as though from ready-to-use kits. Unlike the people who crafted Egypt’s obelisks from much larger rocks, Stonehenge’s builders did not need to rework the bluestone pillars.
The bluestones, which are speckled with fingernail-size deposits of white minerals, form an inner horseshoe and ring at Stonehenge. Previous chemical studies had linked the bluestones to the Preseli Hills in Pembrokeshire, Wales. ‘‘That’s the only place you get that particular rock type,’’ said Nicholas Pearce, a geochemist at Aberystwyth University in Wales, who was not involved with the study.
Humans buried at Stonehenge probably came from that region of Wales, too. Remains at the site contain isotopes consistent with life near the quarries, which are only a few kilometres apart. The bluestones and early Welsh travellers could have arrived at Salisbury Plain together.
According to one hypothesis, prehistoric travellers floated the bluestones along the coast. An attempt to replicate a bluestone float failed spectacularly in 2000, however, when a raft carrying a stone sank. Parker Pearson and his colleagues suspect that the stones were transported over land instead.
– Washington Post