The Biancavilla-Montalto ingnimbrite (Etna,Sicily) |
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| Authors: | D De Rita G Frazzetta R Romano |
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| Institution: | (1) Dipartimento Scienze della Terra, Università  La Sapienza , I-00100 Roma, Italy;(2) CNR Istituto Internazionale di Vulcanologia, I-95123 Catania, Italy |
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| Abstract: | Stratigraphic, granulometric, and SEM grain texture studies have been carried out on pyroclastic deposits in the Biancavilla and Montalto areas on the lower SW flank of Etna. These studies support the interpretation that the deposits were emplaced as pyroclastic flows during the final stage of the Ellittico eruptive activity (14.18±26 ka). Based on the high percentage of juvenile components and granulometric characteristics, the deposits are classified as  normal ignimbrite. Four separate flow units have been distinguished based on the presence of fine-grained basal layers. A multivariate G-mode statistical analysis has been used to discriminate particle morphology populations between flow units and infer temporal changes in the nature of the eruptive processes. The initial flow (I) was emplaced at a high temperature and involved a juvenile gas phase exolved from the magma. Subsequent flows (II, III, IV) exhibit evidence for the interaction of external water. |
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