Herculaneum, 79 AD The eruption of Vesuvius that buried Pompei and Herculaneum, under a blanket of ash and lapilli, left an extraordinary legacy: the vitrified brain of a victim of the ancient catastrophe.
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A unique case of its kind, the result of extreme conditions and an incredible conservation process. The mystery was revealed by an Italian-German research team led by volcanologist Guido Giordano of the University of Roma Tre, whose results were published in the journal Scientific Reports.
An exceptional find
The vitrified organic material was found inside the skull of a young adult, found lying on a bed in the Collegium Augustalium, a building in the Herculaneum Archaeological Park. The discovery is extraordinary because the vitrification of organic tissues, composed mainly of water, requires extremely specific conditions: rapid heating to very high temperatures, followed by equally rapid cooling. In nature, this process is extremely rare, so much so that it is the first documented case in the world of a human brain transformed into glass.
The vitrification process
The team's analyses, which included electron microscopy, Raman spectrometry, and calorimetric experiments, revealed that the brain was exposed to temperatures of at least 510 °C, followed by very rapid cooling. This allowed the formation of an organic glass that preserved the brain microstructures intact. "The brain material could not have vitrified if the individual had been heated only by the pyroclastic flows that buried Herculaneum," explains Giordano. "The deposits of these flows, with temperatures below 465 °C, cooled too slowly, destroying the organic material. Vitrification was only possible thanks to a cloud of very hot and dilute ash, which hit the city for a short but lethal interval of time."
An apocalyptic scenario
According to researchers, on the night of August 24 (or perhaps October 24, as recent studies suggest) in 79 AD, Herculaneum was hit by a first wave of pyroclastic flows. The ash cloud, with temperatures exceeding 510 °C, killed the inhabitants instantly, but its rapid dissipation allowed the victim's brain to cool quickly, triggering the vitrification process. Only later was the city buried under volcanic deposits, which have preserved the site to this day.
Historical and scientific implications
The discovery has not only historical and archaeological value, but also implications for civil protection. “This scenario highlights the extremely high danger of diluted pyroclastic flows, which can be lethal due to their extreme temperatures,” Giordano emphasizes. “Understanding these phenomena is crucial to developing effective prevention measures.”
Danilo Di Genova, of the Cnr-Issmc, highlighted the importance of the experimental analyses: “We recreated the thermal conditions of the vitrification process using sophisticated equipment, in collaboration with the University of Roma Tre and the Technische Universität Clausthal”. Pier Paolo Petrone, of the University of Naples Federico II, thanked the Ercolano Archaeological Park for the ten-year collaboration, underlining the exceptional nature of the discovery: “This vitrified cerebral and spinal material has no equal in the world. It is likely that the particular conditions of the eruption and the protection offered by the skull and the spinal column have allowed this unique preservation”.
A window to the past
The vitrified brain of Herculaneum is not only an extraordinary testimony to the destructive power of Vesuvius, but also a unique window into human history and the natural processes that have shaped our planet. A discovery that continues to amaze and provide new keys to understanding the past and protecting the future.
Article published on 27 February 2025 - 19:54
