When Did The Bluestones Arrive at Stonehenge

Stonehenge: New Study Challenges Timeline For Construction Of Ancient Monument

Ancient people probably assembled the massive sandstone horseshoe at Stonehenge more than 4,600 years ago, while the smaller bluestones were imported from Wales later, a new study suggests.

The conclusion, detailed in the December issue of the journal Antiquity, challenges earlier timelines that proposed the smaller stones were raised first.

"The sequence proposed for the site is really the wrong way around," said study co-author Timothy Darvill, an archaeologist at Bournemouth University in England. "The original idea that it starts small and gets bigger is wrong. It starts big and stays big. The new scheme puts the big stones at the center at the site as the first stage."...

Though only some of the stones remain, at the center of the site once sat an oval of bluestones, or igneous rocks (those formed from magma) that turn a bluish hue when wet or freshly cut. Surrounding the bluestones are five giant sandstone megaliths called trilithons, or two vertical standing slabs capped by a horizontal stone, arranged in the shape of a horseshoe.

Around the horseshoe, ancient builders erected a circular ring of bluestones. The sandstone boulders, or sarsens, can weigh up to 40 tons (36,287 kilograms), while the much smaller bluestones weigh a mere 4 tons (3,628 kg). ...

Like past researchers, the team believes that ancient people first used the site 5,000 years ago, when they dug a circular ditch and mound, or henge, about 361 feet (110 meters) in diameter.

But the new analysis suggests around 2600 B.C. the Neolithic people built the giant sandstone horseshoe, drawing the stone from nearby quarries. Only then did builders arrange the much smaller bluestones, which were probably imported from Wales. Those bluestones were then rearranged at various positions throughout the site over the next millennium, Darvill said.

"They sort out the local stuff first, and then they bring in the stones from Wales to add to the complexity of the structure," Darvill told LiveScience

From the sheer engineering point of view I thought the consensus has always been the big five trilithons first, then the sarsen ring and then infill with Bluestones. It is hard to see how they could have erected the big stones if they had to work round the Welsh stones. So I see nothing new there. But what is new is the idea that the Bluestones were not onsite or had not been used at Stonehenge before. Not in the QR holes nor in the Aubrey holes, nowhere.

Without access to the paper I don't know what they base this idea on.

Gowland's report from 1901 describes in detail the stones found when he dug round Stone 56 and under 55. He found Bluestone chippings at depth in all the holes, suggesting that the stones were erected when there was Bluestone debitage on the surface.  This would support the idea that the Bluestones arrived before the Sarsens and had been used and worked before they were removed from their holes to allow the erection of the Sarsens and the remodelling of Stonehenge and then put back in their present positions, plus or minus some further fine tuning.