WASHINGTON (AP) 鈥 The ancient ritual meaning of Stonehenge is still a mystery, but researchers are one step closer to understanding how the famous stone circle was created.
The unique stone lying flat at the center of the monument was brought to the site in southern England from near the tip of northeast Scotland, in the journal Nature. It鈥檚 not clear whether the 16-foot (5-meter) stone was carried by boat or across land 鈥 a journey of more than 460 miles (740 kilometers).
鈥淚t鈥檚 a surprise that it鈥檚 come from so far away,鈥 said University of Exeter archaeologist Susan Greaney, who was not involved in the study.
For more than a hundred years, scientists believed that Stonehenge鈥檚 central sandstone slab 鈥 long called the 鈥渁ltar stone" 鈥 came from much closer Wales. But a study last year by some of the same researchers showed that the stone didn鈥檛 match the geology of Wales鈥 sandstone formations. The actual source of the stone remained unknown until now.
For the study, the team was not permitted to chip away rocks at the site, but instead analyzed minerals in bits of rock that had been collected in previous digs, some dating back to the 1840s. They found a match in the sandstone formations of Orcadian Basin in northeast Scotland, a region that includes parts of the tip of the Scottish peninsula as well as the Orkney Islands.
鈥淭hat geological 鈥榝ingerprint鈥 isn鈥檛 repeated in any other area of sediment in the U.K.,鈥 said Aberystwyth University geologist Nick Pearce, a study co-author.
Greaney said the difficult logistics of moving the stone such a long distance show a high level of coordination and cultural connection between these two regions of ancient Britain.
Stonehenge was constructed around 5,000 years ago, with stones forming different circles brought to the site at different times. The placement of stones allows for the sun to rise through a stone 鈥渨indow鈥 during summer solstice. The ancient purpose of the altar stone 鈥 which lies flat at the heart of Stonehenge, now beneath other rocks 鈥 remains a mystery.
鈥淪tonehenge isn鈥檛 a settlement site, but a place of ceremony or ritual,鈥 said Heather Sebire, senior curator at English Heritage, who was not involved in the study. She said that past archaeological excavations had not uncovered evidence of feasting or daily living at the site.
Previous research has shown cultural connections 鈥 such as similarities in pottery styles 鈥 between the area around Stonehenge and Scotland鈥檚 Orkney Islands. Other stones at Stonehenge came from western Wales.
While Britain is dotted with other Neolithic stone circles, 鈥渢he thing that鈥檚 unique about Stonehenge is the distance from which the stones have been sourced,鈥 said Aberystwyth University鈥檚 Richard Bevins, a study co-author.
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