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Chapter 1

Introduction

The Aeolian volcanic province is one of the main geological fea- merging volcanological, petrological and structural data into an tures in the Mediterranean area. It consists of seven main islands accurate temporal framework to facilitate a better understanding (, , Salina, , , and ) of petrological, structural and volcanological problems; and forming a volcanic arc, and several seamounts (Eolo, Enarete, placing more cogent constraints on natural hazards from volcanism Sisifo, Lametini, Alcione and Palinuro). The Aeolian arc is a and related phenomena. most active volcanic structure, comprising a number of active Geological monographs and maps for the Aeolian archipelago (Stromboli and Vulcano) or dormant (Panarea and Lipari) volcanic were first presented by Cortese & Sabatini (1892) and Bergeat islands together with extinct volcanoes. (1899). In the first half of the 20th century these were followed Well known from prehistorical times, the by a wealth of contributions to particular problems of the stratigra- (Aeoliae Insulae from , the Greek god of wind) have phy, petrology and volcanic activity and dynamics of the Aeolian attracted the interest and fantasy of ancient and modern naturalists, volcanoes. Detailed mapping at 1:10 000 started under the stimu- historians, travellers and artists. Tucidides, , Pliny the lating leadership of Alfred Rittmann of the International Institute Elder, , Livy and Seneca gave early reports on volcanic of () in the early to mid-1960s. H. Pichler, activity in the Ancient World, followed by many medieval to J. Keller, L. Villari, G.R. Romano and M. Rosi contributed signifi- modern scientists such as De´odat de Dolomieu, Lord Hamilton cantly to geological mapping and establishing first-order features and . Papers by these authors represent mile- of the stratigraphy, petrology and volcanology of the Aeolian stones in the history of science, and the Aeolian archipelago can Islands. This work was compiled in the volume named ‘The be rightfully considered as the cradle of the scientific discipline Aeolian Islands: an active volcanic arc in the Mediterranean of Volcanology as shown by the definitions of the ‘strombolian’ Sea’ (Villari, 1980) and represented the last attempt to provide a and ‘vulcanian’ styles of eruptive activity. The Aeolian arc has coordinated, homogeneous geological framework for the whole attracted the attention of a great number of modern volcanologists, Aeolian Islands magmatic arc. Since the 1960s knowledge of tec- petrologists and structural geologists because of its complex suc- tonics (e.g. plate tectonics) and volcanology has increased steeply, cession of volcanic events, very variable structural setting and together with improved methods of chemical analysis that have wide range of magmatic compositions. All these characteristics allowed production of a great amount of major and trace element are closely related to each other, which stresses the need for inte- and isotopic data (both radiogenic and stable isotopes). Following grated multidisciplinary studies to understand the characteristics of the mapping of the 1960–70s, application of these advances facili- Aeolian volcanism. tated a wealth of petrological, volcanological and geophysical The Aeolian archipelago exhibits strong structural, volcanologi- studies by Italian and international research teams, greatly expand- cal and petrological variations. Active volcanoes are basically ing our knowledge of the structure of the Aeolian volcanoes, their restricted to the central (Vulcano and Lipari) and eastern (Strom- magmatic origins, evolutions and modes of eruption, and the geo- boli and Panarea) sectors of the Aeolian archipelago, where an dynamic setting of the arc. However, a complete set of geological extensional stress regime and a deep-focus earthquakes are maps of the whole Aeolian archipelago, compiled using modern detected as an effect of the north-westwards subduction of the criteria of stratigraphic nomenclature and considering the single Ionian lithospheric slab beneath the southern . By islands in the framework of the activity of the entire archipelago, contrast, no historical eruptions are recorded in the western was still lacking. Publications providing a synthesis of data at a Aeolian archipelago (Alicudi, Filicudi and Salina) where only regional scale have been few. Only a few data have been available shallow seismicity is detected in a compressional tectonic on the submarine portions of the Aeolian volcanoes (except for regime. A first-order lithospheric fault system, the so-called Stromboli) until now. –Letojanni Fault, divides the western and eastern sectors Here we present new geological maps of the Aeolian Islands at a of the Aeolian arc. This structural divide is mirrored by along-arc scale of 1:10 000. These maps and related explanatory notes are variations of compositions becoming increasingly the focus of this Memoir and are the result of a decade of geologi- enriched in silica toward the central islands and more rich in pot- cal and structural fieldwork together with studies of aerial and sat- assium and radiogenic Sr from west to east. ellite images and numerous analytical data on the petrology and The Aeolian arc is therefore a key location where the relation- geochemistry (and even palaeomagnetic features) of the Aeolian ships between volcanism, geodynamics and magmatism can be rocks. Geological mapping has, to a considerable part, been pro- investigated. Problems that have been focused on during the last duced by the research team of the University of Bologna. It is pri- decades are many and include: (1) the nature and timing of volca- marily based upon the concept of unconformity-bounded units nic phenomena (such as eruptions, and lateral collapses) (supersynthems, synthems, subsynthems) combined with informal and landslides; (2) the origin and evolution of and their lithosomes and the classical lithostratigraphic units. This is a mul- relationships to geodynamics and volcanology; and (3) the tidisciplinary approach aimed at merging different features of a hazard from subaerial and submarine eruptions and collapses in volcanic setting such as the lithology and composition of volcanic the archipelago and surrounding areas. Implications for volcanic rocks, the geometry of rock bodies and their genetic features and hazard are primarily related to the currently active volcanoes of the unconformities which subdivide volcanic successions. Stromboli and Vulcano, but also include the hydrothermal field Special emphasis is placed on widespread marine deposits and of Panarea and the island of Lipari since recognition of its tephra layers that provide a general and synthetic framework of medieval-age Monte Pilato–Rocche Rosse eruption. Most, if not regional correlations into which the individual volcanic succes- all, of these problems can be better tackled if the stratigraphy sions are arranged. Accordingly, we provide a new perspective and mapping of each volcanic centre is known in detail. Such an on the geological history of the Aeolian Islands as the result of approach offers the possibility of: reconstructing the volcanic the interplay among volcanic activity of local and external pro- history of the single islands and of the entire archipelago; venance, -tectonic processes, sea-level fluctuations and

From:Lucchi, F., Peccerillo, A., Keller, J., Tranne,C.A.&Rossi, P. L. (eds) 2013. The Aeolian Islands Volcanoes. Geological Society, London, Memoirs, 37, 1–2. http://dx.doi.org/10.1144/M37.1 # The Geological Society of London 2013. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://mem.lyellcollection.org/ by guest on September 26, 2021

2 INTRODUCTION regional fault systems, with a special look at the primary interlayered with and cutting through the volcanic successions. role played by volcano-tectonic and tectonic structures in control- Chapters 7 to 13 by Federico Lucchi, Francesca Forni, Gianfi- ling the localization of eruptive vents and eruptive processes lippo De Astis, Lorella Francalanci and co-workers deal with through time. Bathy-morphological maps of the submerged por- the stratigraphy, structural evolution, volcanology and petrology tions of the Aeolian Islands are also included in this Memoir, of the different islands of the Aeolian Archipelago. Each paper and provide important insights on the main volcanological and reports on the newly determined stratigraphy and mapping, and structural features that control the evolution of the Aeolian the history of eruptive activity and volcano-tectonic events of volcanoes. the Aeolian Islands. Information on rock compositions and the pro- The early maps and monographs could only use a limited cesses of magma origin and evolution is also provided for each number of radiometric age determinations from the mid-1960s, island, together with models of the volcanic plumbing systems which was the ‘dawn’ of radiometric dating. Now this Memoir and their evolution through time. These models are far from integrates, evaluates and discusses a considerable number of radio- being conclusive, but represent working hypotheses whose main metric age data (mostly 14C, K–Ar, Ar/Ar, fission track) and aim is that of stressing the importance of integrated structural, stra- archeomagnetic constraints, which have been used to support the tigraphic, petrological-geochemical and geobarometric studies for stratigraphic analysis. The K–Ar dates issued by Pierre-Yves understanding how the volcanoes have been working in the past Gillot (University of Paris XI) and his co-workers were particu- and could behave in the future. Chapter 14 by Mauro Rosi and co- larly helpful. Data produced by these authors since the late workers is a reappraisal of the main features of the eruptive 1970s have greatly increased our understanding of the timing of activity of the currently active craters of Stromboli, with insights Aeolian volcanism and have been amply confirmed by successive into the evaluation of natural hazards of this unstable and persist- work by other research groups. The evolution of the exposed por- ently active volcano. Chapter 15 by Angelo Peccerillo and co- tions of the Aeolian volcanoes is now defined within a timespan of workers provides a synthesis of the regional variations of major, a few hundred thousand years, with the oldest products exposed on trace element and isotopic composition of magmatism for the Lipari (c. 270 ka), Salina (c. 250 ka) and Filicudi (c. 250 ka). The Aeolian Islands and seamounts, and discusses magma origin and most recent activities have occurred in historical to present times evolution processes at the regional scale and the relationships on the active islands of Vulcano (AD 1888–90) and Stromboli with mantle source evolution and geodynamics. (until present) and the active hydrothermal system of Panarea, A CD-ROM is attached to this Memoir containing geological whereas eruptions in medieval times are recorded on Lipari (AD maps of the Aeolian Islands, along with bathymetric maps of the 776–1220). The western Aeolian volcanoes are considered western, central and eastern Aeolian sectors and an extended extinct with the latest activities having occurred before the Holo- dataset of geochemical compositions. cene on Salina (c. 15 ka), Alicudi (c. 28 ka) and Filicudi (c. 30 ka). Future radiometric age determinations will certainly help to Over the past decades we have benefited from exchange, input and discussions determine a more complete chronostratigraphic picture for the with many friends and colleagues from many different countries who have Aeolian archipelago. worked extensively on the islands and achieved important detailed results on This Memoir is organized into a further 14 chapters after this which we could build our geological reconstructions. We recall in particular introduction. Seven chapters are dedicated to the volcanological, Pierre-Yves Gillot, Rosanna de Rosa, Guido Giordano, Sonia Calvari and Piero structural and petrological-geochemical features of each of the Dellino, but many other colleagues contributed to discussions and understanding Aeolian islands (Lipari, Salina, Filicudi, Alicudi, Panarea, Vulcano of many problems. and Stromboli), representing the extended explanatory notes of the This Memoir would not have seen the light without the professional engage- associated geological maps. Additional chapters deal with general ment of Angharad Hills and Philip Leat. Constructive reviews by many colleagues aspects of the volcanic islands and seamounts. Chapter 2 by Guido were vital in improving early versions of the manuscripts. They are acknowledged at the end of the relevant chapters. Ventura summarizes the geodynamic setting of the Aeolian vol- Research on Aeolian volcanism has been possible thanks to the financial canism based on geophysical and structural data. In Chapters 3 support of many institutions. We wish to acknowledge funds from the INGV, and 4, Claudia Romagnoli and co-workers present an updated MIUR-PRIN 2008, University of Perugia, University of Bologna and Regione bathymetry of the Aeolian seafloor based on recently acquired Sicilia. Help from other institutions is acknowledged at the end of multibeam swath bathymetry data. The new detailed bathymetric relevant chapters. maps are the basis for understanding the structure and morphology of the volcanism hidden below the sea. This represents the largest part of the erupted magmas and its study is fundamental for References increasing the present knowledge on the arc, which was previously mostly based on subaerial portions. Chapter 5 by Federico Lucchi Bergeat, A. 1899. Die aeolischen Inseln Stromboli, Panaria, Salina, describes the methodology of stratigraphic analysis and geological Lipari, Vulcano, Filicudi und Alicudi geologisch beschrieben. fieldwork which has been the basis for the mapping of the Aeolian Abhandlungen der Bayerishen Akademie der Wissenschaften, 20 islands. A general chapter (Chapter 6) by Federico Lucchi and co- (1899/1900) I, Abt. 1–274, Mu¨nchen. workers deals with the regional stratigraphic correlations across Cortese,M.&Sabatini, V. 1892. Descrizione geologico-petrografica the Aeolian Archipelago. This is based on inter-island relation- delle Isole Eolie. Memorie Descrittive della Carta Geologica ships, distal tephrochronology and correlation of marine deposits d’Italia, Tipografia Nazionale, 7, pp. 131.