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Explosive activity preceding the ~40 ka Campanian Ignimbrite (CI) eruption in the Neapolitan volcanic area, Southern Italy, has long been speculated based on the occurrences of widespread tephra layers, with a Campanian geochemical signature, such as the C-22, X-5, and X-6, preserved in Mediterranean Marine Isotope Stage (MIS) 5 sedimentary records. However, previous studies of pre-CI pyroclastic units occurring in close proximity of the Neapolitan volcanoes, including Campi Flegrei, Somma-Vesuvius, Ischia and Procida islands, did not allow a conclusive identification of the near-source equivalents of these tephra markers. Here we present a comprehensive characterization of four pyroclastic units from the Campanian Plain, comprising major and trace element glass compositions, Sr[sbnd]Nd isotopes and 40Ar/39Ar dating. Our data allowed the identification of the medial equivalents of the MIS 5 tephra markers, including the widespread C-22, X-5, and X-6 tephra, and their assignment to previously undocumented Campi Flegrei activity between 109 and 92 ka. In addition to substantially extending Campi Flegrei explosive activity deeper in time, and thus providing the basis for a revaluation of its history, our findings provide new precise radioisotopic dating to better constrain the chronology of the millennial scale climatic oscillations of the MIS 5c-d in the Mediterranean area and possibly on a larger scale.

The Fucino Basin, central Italy, with its long and continuous history of Quaternary sediment accumulation, is one of the richest Mediterranean Middle Pleistocene tephra records. Here, we present a new detailed investigation of tephra layers (tephras) of the 250–170 thousand years before present (ka) interval, corresponding to the entire Marine Isotope Stage (MIS) 7 and parts of the MIS 8 and MIS 6. The investigated tephras have been characterised in terms of major, minor and trace elements, Sr–Nd isotopic compositions and 40Ar/39Ar ages. For correlation purposes, glass compositions and several new 40Ar/39Ar ages of selected proximal pyroclastic units spanning the same temporal interval from Vulsini (Latera Volcanic Complex), Sabatini, and Vico volcanic systems, central Italy, were measured. The late MIS 8-early MIS 6 Fucino tephras were backtracked to their corresponding volcanic sources, which include the Vulsini, Vico, Sabatini, Roccamonfina, Ischia and Campi Flegrei volcanic systems. While some of these tephras have been correlated to specific eruption units, other layers are currently not documented or described in near-vent sections, thus highlighting previously unrecognised events generated by these volcanic systems. Furthermore, the new high precision 40Ar/39Ar ages provide improved temporal constraints for Fucino making it one of the most detailed and chronologically best constrained tephra records for central Mediterranean MIS 7 tephrochronology. The Fucino record thus provides new integrative information for reconstructing the explosive history of Italian volcanoes during the investigated time interval. Furthermore, the geochronological constraints provide the basis for future paleoclimatic investigations at local and regional scale.

Submarine felsic volcanoes are dominated by hyaloclastic piles hundreds of meters thick, the origin of which, in terms of how and when they form, is far from being completely understood. Here we present a study of the thermal remanent magnetization of the Miocene high-K dacitic El Barronal hyaloclastites (Cabo de Gata, Spain), showing that their formation is dominated by in situ fragmentation with small or negligible transportation and/or rotation of different clasts after their formation. Data indicate that fragmentation progressed down to 210-390 °C, well below the glass-transition temperature estimated at 560-750 °C depending on the water content of the high-K dacite. Hence, hyaloclastite fragmentation in thick lavas may occur over most of the cooling history, as a result of the progressive access of sea water toward the lava interior by development of a complex network of contraction fractures. © 2013 Geological Society of America.

The Los Frailes Formation lava-flow and dome complex is a Miocene succession that is part of the Cabo de Gata volcanic zone of SE Spain. The complex comprises dominantly dacitic, subaqueous dome rocks and interstratified sedimentary horizons emplaced over a few tens of thousands of years. Facies of the Los Frailes Formation include coherent lava, in-situ hyaloclastite, locally with microfossil-bearing siltstone matrix, pumiceous and block-rich tuff, and massive monomict breccia and megabreccia, in which clasts are locally several metres in diameter. The monomict megabreccias display both >block facies> and >matrix facies> architecture and show internal deformation at the block-matrix contacts. They are inferred to have derived from debris avalanches. Facies are divided into four volcanic units separated by fossiliferous marine sedimentary units emplaced during hiatuses in volcanism. The Los Frailes Formation lava-flow and dome complex were emplaced in a shallow setting that may have included emergent areas. Lava flows and the margins of dome edifices interacted with sea water to form hyaloclastite, and pyroclastic currents deposited pumiceous materials. Sector collapse of marine domes fed small-volume debris avalanches with generally the same facies and distribution of facies as the larger-scale equivalents on which traditional models are built. © 2012 Elsevier B.V.

This paper aims at describing some aspects of the Alps-Apennines orogens and their relationship in space and time with special focus on their junction area. After an historical outline of the subject, the main morphostructural, geophysical and tectonic domains of the system will be outlined. The result of recent research and a review of structural and thermochronometric data of the exhumed units in the mountain belts and on the sedimentation and deformation record in the surrounding basins will be used to constrain key events of the geological history. An analysis of crustal-scale cross sections across the Western Alps, Northern Apennine and Western Po Plain altogether with a presentation of the main exposed and buried boundary faults and their time activity are presented. We will try to constrain the evolution of the Western Alps/Northern Apennine junction area by analyzing and comparing the main elements of the growing and interfering segments of the orogens providing some remarks on recently proposed kinematic interpretations and point out open problems and ongoing research.

Plagioclase phenocrysts in dacites from the high-K calc-alkaline CapraiaVolcano were investigated for major, trace element and Sr isotope variations in order to gain better insight into the proposed open-system behaviour of the volcano. Repeated dissolution zone in plagioclases from the early-erupted Monte Castello (MC) and later Monte Rucitello (MR) dacitic units are associated with a sharp increase in An content and variation in isotopic compositions (87Sr/86Sr=0.70872-0.71004), which argue for repeated magma mixing. In particular, petrographic and mineralogical evidence suggest that recharge with hot, basaltic magma occurred repeatedly during the lifetime of the Capraia volcanic system. We attempted to correlate shared crystallization and resorption histories using chemical (mol% An, Fe) and Sr isotopic zoning in plagioclase. In this correlation framework, the observed mismatch between chemical and isotopic data in some phenocrysts is interpreted to reflect either growth of phenocrysts in a separate magma chamber, or compositional zoning within a single magma chamber. A minor role of crustal contamination is inferred. Instead, the intra-crystal variations in isotopic composition in plagioclase reflect the existence of distinct components that may have thoroughly mixed at the end of the MC plagioclase growth history. The dominant radiogenic component is similar to lamproites occurring in Tuscany. Recharge with this component occurred throughout the genesis of the MR dacites, but was restricted to the early growth history of the MC dacites. The MR plagioclases are inferred to have crystallized from separate, more differentiated batches of magma that were likely to have evolved at the top of a zoned magma reservoir. Decrease in the An content after most dissolution zones in all phenocrysts, and low temperature estimates from zircon saturation thermometry (800 °C) also emphasize the importance of crystal fractionation during the evolution of

Plagioclase phenocrysts in dacites from the high-K calc-alkaline CapraiaVolcano were investigated for major, trace element and Sr isotope variations in order to gain better insight into the proposed open-system behaviour of the volcano. Repeated dissolution zone in plagioclases from the early-erupted Monte Castello (MC) and later Monte Rucitello (MR) dacitic units are associated with a sharp increase in An content and variation in isotopic compositions (87Sr/86Sr=0.70872-0.71004), which argue for repeated magma mixing. In particular, petrographic and mineralogical evidence suggest that recharge with hot, basaltic magma occurred repeatedly during the lifetime of the Capraia volcanic system. We attempted to correlate shared crystallization and resorption histories using chemical (mol% An, Fe) and Sr isotopic zoning in plagioclase. In this correlation framework, the observed mismatch between chemical and isotopic data in some phenocrysts is interpreted to reflect either growth of phenocrysts in a separate magma chamber, or compositional zoning within a single magma chamber. A minor role of crustal contamination is inferred. Instead, the intra-crystal variations in isotopic composition in plagioclase reflect the existence of distinct components that may have thoroughly mixed at the end of the MC plagioclase growth history. The dominant radiogenic component is similar to lamproites occurring in Tuscany. Recharge with this component occurred throughout the genesis of the MR dacites, but was restricted to the early growth history of the MC dacites. The MR plagioclases are inferred to have crystallized from separate, more differentiated batches of magma that were likely to have evolved at the top of a zoned magma reservoir. Decrease in the An content after most dissolution zones in all phenocrysts, and low temperature estimates from zircon saturation thermometry (800 °C) also emphasize the importance of crystal fractionation during the evolution of

Over the last several hundred years, Stromboli has been characterized by steady-state Strombolian activity. The volcanic products are dominated by degassed and highly porphyritic (HP-magma) black scoria bombs, lapilli and lava flows of basaltic shoshonitic composition. Periodically (about one to three events per year), more energetic explosive eruptions also eject light coloured volatile-rich pumices with low phenocryst content (LP-magma) that have more mafic compositions than the HP-magma. An in situ major and trace element and Sr isotope microanalysis study is presented on four samples chosen to characterize the different modes of activity at Stromboli: a lava flow (1985-1986 effusive event), a scoria bomb from the 'normal' present-day activity of Stromboli (April 1984), and a scoria and coeval pumice sample from a recent more explosive eruption (September 1996). Plagioclase (An

Over the last several hundred years, Stromboli has been characterized by steady-state Strombolian activity. The volcanic products are dominated by degassed and highly porphyritic (HP-magma) black scoria bombs, lapilli and lava flows of basaltic shoshonitic composition. Periodically (about one to three events per year), more energetic explosive eruptions also eject light coloured volatile-rich pumices with low phenocryst content (LP-magma) that have more mafic compositions than the HP-magma. An in situ major and trace element and Sr isotope microanalysis study is presented on four samples chosen to characterize the different modes of activity at Stromboli: a lava flow (1985-1986 effusive event), a scoria bomb from the 'normal' present-day activity of Stromboli (April 1984), and a scoria and coeval pumice sample from a recent more explosive eruption (September 1996). Plagioclase (An