They discovered that the largest volcanic eruption of the past 5,000 years had taken place in Argentina.

A team of Argentinian and Spanish scientists discovered that the largest volcanic eruption in the last 5,000 years was at Cerro Blanco in the Andes some 4,200 years ago.

As reported in the research published in the journal Geological Studies, the studied eruption revealed a cloud of gas and ash reaching 32 km high, extending over an area of ​​500 000 km 2, which corresponds almost all over Spain.

"The data we have today are the most important of the period," Spanish geologist José Luis Fernández Turiel of the JSC's Institute of Earth Sciences Jaume Almera told El Pais. One of the scientists who participated in the study. l & # 39; investigation.

Cerro Blanco is located 4,400 meters above sea level, at the southern tip of the Andean plateau, which today corresponds to the province of Catamarca, in the north-east of the country. The researchers found ash from this eruption 400 kilometers from the volcano, near the city of Santiago del Estero.

"Accidental" discovery

Initially, research conducted by Fernández Turiel aimed to determine the connection between arsenic in water and volcanic ash. However, by collecting dozens of ash samples in this Andean region, scientists discovered that almost all of them came from a single eruption.

"The works are changing the model of active volcanism that we had in the Andean region.Until now, it was thought that in the central volcanic area everything worked in the same way as in the southern zone: many volcanoes with many eruptions over time.We found that there were few eruptions, but with a high volume of magma and a very high explosivity, "said Fernández Turiel in El País.

About the eruption

The scientists estimated that the eruption of Cerro Blanco had a volcanic explosive index of 7, similar to the one that destroyed 3,600 years ago the Minoan civilization of Thera, the known Greek island. today under the name of Santorini.

The magma volume doubled that of the Tambora Indonesia volcano eruption of 1815, responsible for the decrease in global temperature, as indicated in the survey. The eruption of Cerro Blanco caused the collapse of the back of the volcano and formed a boiler six kilometers wide.

The magma and volcanic ash have ended with all the life around them. Therefore, in the area, they found no evidence of the presence of hunter-gatherer societies, according to Argentina Norma Ratto, archaeologist of the Institute of Cultures of the University of Buenos Aires and Conicet (Council National Scientific and Technical Survey).

"About 80 kilometers from here, in Antofagasta, there are records of occupation 10,000 years ago, but in the region where we work, the oldest dates from the year 1000 BC, that is about 3,000 years ago, "says Ratto.

"Throughout the region, there are high-rise sanctuaries with volcano offerings that reflect the ritual of the people, which combines eruptions with the wrath of the gods," he adds.

L & # 39; study

The researchers studied 62 outcrops in the area and collected more than 230 ash samples in different campaigns.

The samples were badyzed by different petrological and geochemical techniques to determine their origin.

Spain and Argentina

The University of Las Palmas de Gran Canaria and the Institute of Natural Resources and Agrobiology of Salamanca (Spain), as well as the National University of Mar del Plata and the University of Tucumán (Argentina) also participated in these workshops.