The age of the beginning of the formation of the Valle del Bove of Etna and the chronology of the lateral eruptions following the collapse have been dated for the first time in absolute terms.
Stratigraphic and petrographic investigations, carbon-14 and paleomagnetic dating of the lava flows conducted in various quarries located at the mouth of the Valle del Bove have made it possible to date the age of the beginning of the formation of the valley and the chronology of the lateral eruptions following its formation . The research, the result of the multidisciplinary study "” conducted by a team of researchers from the National Institute of Geophysics and Volcanology (INGV) in collaboration with theUniversity of Urbino, was recently published in the scientific journal 'Journal of Volcanology and Geothermal Research'.
"The Valle del Bove is a depression located on the eastern flank of Etna, about 7 x 4,5 km wide, characterized by a typical horseshoe shape whose bottom is totally covered by lava flows generated by lateral eruptions that occurred during the last centuries”, explains Stefano Branca, Director of the Etna Observatory. “This depression is the result of multiple flank collapse phenomena and related erosional phenomena which during the Holocene generated the current morphological structure of this sector of Etna. In particular, the initial phase of the formation of the valley is due to a large collapse of the side of the volcanic edifice which produced a vast debris deposit that emerges in the area of the town of Milo, for an extension of 4,3 km2, which is partially covered by a lava and pyroclastic successionto ".
The team of researchers has defined for the first time the age of the landslide deposit thanks to the discovery inside it of fragments of trees, perfectly preserved, which have been dated with the carbon-14 technique.
"The analyzes carried out made it possible to date the landslide deposit between 7478 and 7134 BC At the same time, we studied the volcanic succession exposed in two quarries and, thanks to paleomagnetic dating, we reconstructed the sequence of eruptions which affected this sector of the volcano after the beginning of the Valle del Bove formation. In particular, paleomagnetic datings have shown that during the last 4000 years two lateral eruptions have occurred during the late Copper Age (2600-2400 BC) and two other lateral eruptions, not reported in historical sources, occurred in the Greek era -Roman and Medieval”, says Arianna Beatrice Malaguti, PhD candidate at the University of Urbino and co-author of the study.
The research is the result of the long and consolidated experience of the INGV researchers in the dating of lava flows through the investigations carried out in the highly specialized paleomagnetism laboratory in place at the Rome 2 section of the INGV, which is the main paleomagnetic laboratory in Italy and one of the most renowned internationally. The multidisciplinary research activities for the dating of the historical lava flows of Etna began in 2004 and have allowed us to deepen our knowledge of the eruptive activity of the volcano in prehistoric times.
This type of research activity, which combines the classic geological-stratigraphic investigations with paleomagnetic dating, will continue to be applied on Etna in order to reconstruct the chronology of the lateral eruptions which occurred during the last 4000 years, recognized in the geological map of the volcano at the 1:50.000 scale published in 2011, in order to improve understanding of volcanic hazard.
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ETNA | Discovered the age of Valle del Bove
The age of the formation of the Valle del Bove of Etna and the chronology of the flank eruptions following the collapse have been dated for the first time.
Stratigraphic and petrographic investigations, carbon-14 and paleomagnetic dating of the lava flows performed in various quarries located at the mouth of the Valle del Bove have made it possible to date the age of the early stage of the formation of the valley and the chronology of the subsequent flank eruptions. The multidisciplinary study”Age of the Valle del Bove formation and chronology of the post-collapse flank eruptions, Etna volcano (Italy)” conducted by a team of researchers from the National Institute of Geophysics and Volcanology (INGV) in collaboration with the University of Urbino, recently has been published in the scientific journal 'Journal of Volcanology and Geothermal Research'.
"The Valle del Bove is a depression located on the eastern flank of Etna, about 7 x 4.5 km wide, characterized by a typical horseshoe shape whose bottom is totally covered by lava flows generated by flank eruptions that occurred in the over the last few centuries”, explains Stefano Branca, Director of the INGV-Etna Observatory. “This depression is the result of multiple flank collapse phenomena and related erosional phenomena which during the Holocene generated the current morphological setting of this sector of Etna. In particular, the initial stage of the formation of the valley is due to a large collapse of the volcano edifice which produced a vast debris deposit which outcrops in the area of Milo village, for an extension of 4.3 km2, which is partially covered by a lava and pyroclastic succession”.
The team of researchers has defined for the first time the age of the landslide deposit thanks to the discovery inside it of tree fragments, perfectly preserved, which have been dated with the carbon-14 technique.
“The analyzes carried out made it possible to date the deposit of the landslide between 7478 and 7134 BC. At the same time, we studied the volcanic succession exposed in two quarries and, thanks to paleomagnetic dating, we reconstructed the sequence of eruptions that affected this sector of the volcano after the beginning of the Valle del Bove formation. In particular, the paleomagnetic datings have shown that during the last 4000 years two flank eruptions occurred during the late Copper Age (2600-2400 BC) and two other flank eruptions, not reported in historical sources, occurred in the Greek-Roman and Medieval epochs”, explains Arianna Beatrice Malaguti, PhD candidate at the University of Urbino and co-author of the study.
The research is the result of the long and consolidated experience of the INGV researchers in the dating of lava flows through the investigations carried out in the highly specialized paleomagnetism laboratory of Rome 2 section of the INGV, which is the main paleomagnetic laboratory in Italy and one of the most renowned internationally. The multidisciplinary research activities for the dating of the historical lava flows of Etna began in 2004 and have allowed us to deepen our knowledge of the eruptive activity of the volcano in prehistoric times.
This type of research activity, which combines the classic geological-stratigraphic investigations with paleomagnetic dating, will continue to be applied on Etna in order to reconstruct the chronology of the flank eruptions which occurred during the last 4000 years, recognized in the geological map of the volcano at the 1:50,000 scale published in 2011, in order to improve the knowledge of volcanic hazard.
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Photo – Valle del Bove, Etna. Photo credits, Stefano Branca, Director of the EO of INGV.
Picture - Valle del Bove, Etna. Photo credits, Stefano Branca, Director of the EO of INGV.