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It turned out that the stones were mostly calcarenites, a type of clastic sedimentary rock that is characterised by its brittle nature. Because such rock is difficult to transport without damage, the results suggest that the builders were capable of erecting structures with a certain level of engineering sophistication.
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Transporting and placing such large stones would have required carefully planned engineering. For example, scaffolding and ropes would have been required to lift a capstone weighing around 150 tonnes, which was laid across the top of the chamber and served as a roof, and level roads would have been needed to transport it.
