What makes Stonehenge so strong? These ancient monuments have withstood harsh weather, climate change and much more. Scientists have finally unravelled the mystery behind their strength.
This is the first comprehensive scientific analysis of Stonehenge megaliths.
Researchers with the help of a battery of examinations provided a glimpse inside one of Stonehenge’s 52 sandstone megaliths, known as sarsens. It gives us so much information about its geology and chemistry.
Scientists studied a core sample extracted from one of the sarsens, called Stone 58. It was only after the 1950s conservation work that it returned to Britain for research in 2018.
These sarsens are made of stone called silcrete. This apparently formed gradually within a few meters of the ground surface as a result of groundwater washing through buried sediment.
This has further clarified Stone 58’s internal structure. It shows that the silcrete is comprised of mainly sand-sized quartz grains. These are cemented tightly together by an interlocking mosaic of quartz crystals.
Since Quartz is extremely durable, it just does not easily crumble or erode. Even when exposed to eons of wind and weather it can withstand harsher climatic conditions.
Science behind Stonehenge: A Neolithic age wonder
This is the main reason behind the stone’s resistance to weathering.
One can call it a remarkable engineering achievement by the late Neolithic people. These sarsens were erected at the site in Wiltshire, England around 2500 BC.
Stone 58 is one of the giant upright sarsens at Stonehenge’s centre. It stands about 7 meters tall, with another 2 meters underground, and an estimated above-ground weight of 24 tons.
The core sample is a rod of stone, roughly a yard (meter) long. Its cream colour is brighter than the pale-grey exterior of the megaliths, which have been exposed to the elements for millennia.
Researchers used CT-scanning, X-rays, microscopic analyses and various geochemical techniques to study fragments. It also involved wafer-thin slices of the core sample.
However, it remains unclear when the rock formed. Researchers found that some embedded sand grains dated as long ago as the Mesoproterozoic Era.
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