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Evolution of rhyolite melt production on Lipari

Dawid Szymanowski 1, Gabriel Rojas1, Francesca Forni2, Federico Lucchi3, Claudio A. Tranne3, Olivier Bachmann1

  • Affiliations: 1Institute of Geochemistry and Petrology, ETH Zurich, Switzerland; 2Dipartimento di Scienze della Terra "Ardito Desio", Università degli Studi di Milano, Milan, Italy; 3Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Alma Mater Studiorum - Università di Bologna, Bologna, Italy

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 241

  • Programme No: 1.1.27

  • Theme 1 > Session 1

Abstract

Making rhyolites in a volcanic arc requires a prolonged flux of primary magma to create thermal conditions conducive to extreme magma differentiation, a process which leaves behind a pile of crystal cumulates. How these processes operate, however, is often difficult to disentangle from complex volcanic systems with jumps in composition or eruptive style and overlapping edifices. On the island of Lipari (Aeolian Islands, Italy) rhyolitic volcanism developed following an extended magmatic buildup characterised by mafic to intermediate volcanism between ca. 267--81 ka. Then, following quiescence of ca. 40 ky, the magmatic system peaked by producing alternating dome-style effusive and explosive rhyolitic eruptions from ca. 43 ka to historical times. Eruptive centres progressively migrated from the S of the island, along the E coast, towards the N, where the most recent eruptions took place at 1243-1304 CE. This spatial development offers a unique opportunity to extensively sample the volcanic products, and through them understand the variable nature of the magmatic system developing under Lipari for the last ca. 40 ky. We will present new geochemical data probing the complete suite of rhyolitic eruptive products of Lipari, including glass and mineral compositions, revealing distinct spatio-temporal grouping of the magmatic products. New zircon U--Th disequilibrium ages will be used to refine the absolute time framework of eruptive activity. Our new data provide evidence of extensive fractionation (e.g. low Zr/Hf, Eu/Eu* in glass) en route to generating the rhyolites, indicating the existence of a heterogeneous cumulate body beneath Lipari.