Monday , July 26 2021

The mysterious Mediterranean ash layer of volcanic ash 29,000 years ago traced to the volcano

Researchers from the University of Oxford have traced the origin of the prehistoric eruption that covered the Mediterranean ash region 29,000 years ago in the less-known volcano of Campi Flegre in Naples, located just west of the city.

Since the late 1970s, scientists have identified the same prehistoric volcanic ash in sedimentary cores extracted from 150,000 square kilometers of the central Mediterranean. This widespread layer of ash, dating back 29,000 years ago, covers the region and clearly shows a large volcanic eruption. Although the region is known for its many active volcanoes, such as Vesuvius, which in 79 AD. He demolished Pompey, scientists fail to enter confidently in this older, distant ash fields, to a particular volcano or eruption.

The study, led by Dr. Paul Albert, a research fellow at the Archaeological School, now identifies a field of ash-rich ash within the city of Naples, which is produced by the volcano Campy Flegre and has a chemical composition that matches prehistoric ash. traced in the Mediterranean region. The work was carried out in partnership with international researchers, including those from the National Institute of Geophysics and Vulcology (INGV), the National Council for Research in Italy, the Laboratoire des Sciences du Climate et de l'Environnement in France and the Berkeley Geochemical Center. in USA.

"Part of the challenge related to the credible attribution of this great fall to the ash of the volcano Campie Flegre is that there is limited evidence of a large eruption near the volcano," says Albert. "This is partly because the more recent large-scale volcano eruption has buried the Naples area in a dense ash deposit, which largely destroys or conceals the evidence of this earlier event," said Albert.

The team used a computer-based ash scattering model to reconstruct the eruption rate. "By linking the thickness of the ash deposits found in Naples to those stored in the Central Mediterranean nuclei, the model is able to demonstrate and provide important limitations on the magnitude of this large eruption of magnitude," said Albert.

This study marks the beginning of this unprecedented large-scale explosion of Campy Flegre between two well-known large-scale volcanic eruptions 15,000 and 40,000 years ago, drastically reducing the interval of repetition of large volcanic eruptions. ,

The study, published today in the journal Geology, also highlights the importance of looking at the diving events kept away from the volcano in the reconstruction of the weather and the scale of past explosions. "The fall of ash, hundreds of miles from the volcano, is critical to identifying and restoring this great eruption in Campie Flegre," says Albert.

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