New study challenges origin of Stonehenge Altar Stone

Credit: A. Sood/Unsplash

A recent study published in the¬†Journal of Archaeological Science: Reports challenges the long-standing belief regarding the origin of the largest stone in the inner circle of Stonehenge, known as the Altar Stone. Contrary to the established idea that this stone, like the other “bluestones,” came from the Preseli Hills in western Wales, new research suggests it may have originated from a more distant location, potentially in northern England or Scotland.

The traditional understanding of Stonehenge’s stone sources can be traced back to British geologist Herbert Henry Thomas’s influential 1923 study. In this work, Thomas identified the Preseli Hills in western Wales as the source of the bluestones within Stonehenge’s inner circle. These bluestones, so named due to their bluish hue when wet or freshly broken, were distinct from the outer circle’s “sarsen” stones. Among them was the Altar Stone, a massive, flat-lying gray-green slab measuring 4.9 metres (16 feet) in length.

For a century, this interpretation went unchallenged. However, the recent study led by Richard Bevins, an honorary professor of geology and Earth sciences at Aberystwyth University in Wales, suggests that Thomas’s assessment was flawed. Bevins and his team have proposed that while Thomas correctly identified the origins of some stones in western Wales, the Altar Stone might have come from an entirely different location, possibly an unidentified quarry in northern Britain.

Credit: A. Sood/Unsplash

Stonehenge, constructed during the Late Neolithic period approximately 4,000 to 5,000 years ago on Salisbury Plain in Wiltshire, southern England, underwent several phases of construction and modification over the millennia. The bluestones were transported over an extraordinary distance of 225 kilometres (140 miles) from western Wales to Stonehenge, making it one of the most remarkable prehistoric monument construction efforts known globally.

The Altar Stone has always stood out among the bluestones due to its larger size and different rock type. Notably, there is no archaeological evidence pinpointing when it was brought to Stonehenge, leaving the possibility open that it arrived during a later construction phase.

To investigate the Altar Stone’s origin, the researchers compared its geochemistry and mineralogy with 58 sandstone outcrops spanning from southern Wales to western England. However, this search failed to yield a conclusive match, prompting the researchers to consider alternative areas.

The Altar Stone [Credit: The Stones Of Stonehenge]

An unusually high barium content in the Altar Stone offered a new clue. According to Bevins, they intend to explore regions with known ancient Neolithic monuments, stretching from northern England to Scotland. This broader search horizon challenges the previously Wales-focused quest for the Altar Stone’s source.

The reevaluation of the Altar Stone’s classification as a bluestone has substantial implications for our understanding of Stonehenge’s history.

This study is not the first time that Bevins and his colleagues have challenged Herbert Henry Thomas’s century-old work. In 2018, they reported in the journal Antiquity that the bluestones originated from a different outcrop in the Preseli Hills than Thomas initially proposed.

Source: The Archaeology News Network [October 03, 2023]