Emplacement and flow dynamics in a small volcanic dyke swarm: The example of Mount Calanna (Etna, Italy)

• Published in: Journal of volcanology and geothermal research Vol. 449; p. 108069
• Main Authors: Shajahan, Rasia, Harris, Andrew, Mana, Sara, Nicotra, Eugenio, Test, Claudio Robustelli, Van Wyk de Vries, Benjamin, Zanella, Elena
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024
• Subjects: AMS; Dyke swarm; Etna; Magma flow; Petrographic fabric; Shallow plumbing system; Magma flow; Shallow plumbing system; Dyke swarm; Etna; AMS; Petrographic fabric
• ISSN: 0377-0273; 1872-6097
• DOI: 10.1016/j.jvolgeores.2024.108069

The emplacement mechanism and flow dynamics of small dyke swarms associated with monogenetic eruptive centres are less well studied than those of large swarms associated with shield volcanoes and flood basalts. This is due to their limited exposure and ease of reworking by later events. However, the study of small dykes helps to better constrain the forces controlling dyke propagation and thus reconstruct the emplacement history of the volcanic system. This study presents a multidisciplinary analysis of Mount Calanna (Mount Etna, Italy) where we sampled a total of 11 dykes among the two groups: 1) sub-vertical dykes from the lower part of the system, and 2) sub-horizontal dykes from the upper part. To infer the magma flow direction, we used Anisotropy of Magnetic Susceptibility (AMS) and compared the results to the Shape Preferred Orientation (SPO) of the plagioclase crystal fabric. To quantify the relative timing of dyke emplacement, and to characterise the magma plumbing system, we also used the palaeomagnetic and geochemical signature of the sampled dykes. The fabric analysis highlights a NE-SW flow direction in the sub-vertical dykes, and a NE-SW and NW-SE direction in the sub-horizontal dykes. Dykes emplaced at the lowest levels in the swarm show sub-vertical to inclined magma flow, whereas those towards the top of the Mount Calanna show inclined to sub-horizontal flow. The combined structural and geochemical analyses suggest the Mount Calanna swarm is a coherent intrusive complex associated with a phase of activity of Ancient Alkaline centre (AAC), with Mount Calanna representing an example of the uppermost portion of a shallow plumbing system in which intrusion orientations are controlled by regional tectonics. •Forces controlling magma flow in dykes.•Emplacement of small dyke swarm.•Multidisciplinary study to better constrain AMS data.