Unravelling Mount Etna’s early eruptive history by three-dimensional magnetic modeling

Abstract

Evidence of Mount Etna’s early volcanism is hidden by the products of its continuously intense volcanic activity. Etna’s volcanism has buried most of the onshore geological record, and the poorly known offshore extent of these volcanic deposits further limits understanding the volcano’s history. We obtained and analyzed new high-resolution offshore aeromagnetic data along the Ionian continental margin of Mount Etna and combined these with recent paleomagnetic data and available geological information. Specifically, we calculated a three-dimensional (3-D) magnetic inversion model of the thickness variations of the offshore Etnean volcanic system. The inversion model highlights E-W and N-S tabular lava flows associated with the Basal Tholeiitic (ca. 500 ka) and Timpe (ca. 220–110 ka) volcanic phases. These early Etna products, considering the onshore and offshore sectors, achieved total volumes of ~26 km3 and 77 km3, respectively. Moreover, the magnetic anomalies reveal several gravitational collapses that may be indicative of the submarine instabilities of Etna’s eastern flank. The findings shed new light on the history of Mount Etna and its early offshore phases. The observed geometry of these early products links the magma distribution to a recently discovered system of faults that can be associated with the presence of a lateral slab-tearing mechanism during the Ionian subduction.