Analysis of the inverted Stonehenge core helps explain the durability of the megalith

A team of researchers affiliated with a multitude of institutions in the UK and one from South Africa and another from Belgium have discovered why the famous stone structure Stonehenge has survived for so long. They wrote an article describing their analysis of a core taken from one of the ancient pillars half a century ago, now posted on the open access site. PLOS ONE.

Stonehenge is a megalithic monument located on Salisbury Plain in Wiltshire, England. Due to its protected status, it cannot be pierced, cut or subjected to chemical analysis, which makes it difficult to study its composition. However, the monument was not always so well protected – in 1958, workers hired to restore the monument pierced one of the stones and extracted carrots. Parts of one of the cores were discovered in a museum in 2019; another was kept as a souvenir by a worker who immigrated to the United States; and the third has never been found. Three years ago, the souvenir sample was returned to England and is under review as part of this new effort.

The work consisted of cutting part of the core into very thin slices, which allowed for a wide variety of geochemical studies. The researchers also subjected the samples to CT scans, X-rays and microscopy.

They found that the stone was 99.7% quartz and there were different grain sizes. One of them, which they describe as medium in size, formed “a mosaic of interlocking crystals”, which the researchers said served as a kind of cement and explained how the stones that make up Stonehenge managed to survive. so long. Researchers suggest that the Neolithic people who erected the monument may have known about the durability of the stones and chose them for their longevity.

The researchers also found that the sediment from which the stones formed were about 66 to 23 million years old. Some of the grains could be dated to 66 to 252 million years ago, and a few formed 1 billion years ago.

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