Papers by Gianfilippo Astis
Nature Communications
Open-conduit basaltic volcanoes can be characterised by sudden large explosive events (paroxysms)... more Open-conduit basaltic volcanoes can be characterised by sudden large explosive events (paroxysms) that interrupt normal effusive and mild explosive activity. In June-August 2019, one major explosion and two paroxysms occurred at Stromboli volcano (Italy) within only 64 days. Here, via a multifaceted approach using clinopyroxene, we show arrival of mafic recharges up to a few days before the onset of these events and their effects on the eruption pattern at Stromboli, as a prime example of a persistently active, open-conduit basaltic volcano. Our data indicate a rejuvenated Stromboli plumbing system where the extant crystal mush is efficiently permeated by recharge magmas with minimum remobilisation promoting a direct linkage between the deeper and the shallow reservoirs that sustains the currently observed larger variability of eruptive behaviour. Our approach provides vital insights into magma dynamics and their effects on monitoring signals demonstrating the power of petrological ...
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Frontiers in Earth Science
Italy is the land of iconic volcanoes, whose activity has been witnessed, described and portrayed... more Italy is the land of iconic volcanoes, whose activity has been witnessed, described and portrayed for centuries. This legacy has greatly contributed to shaping the public perception of volcanoes and their impact, well beyond the national borders. Stories about famous eruptions overlap and nowadays easily mix up with the impressive footage that is readily available from ongoing eruptions worldwide. As a result, the public discourse may flatten the wide spectrum of possible phenomena into an oversimplified sketch of volcanic eruptions and their impact, where all events seem equally probable and look alike. Actual volcanoes differ in size, eruption magnitude, state of activity, eruptive style, geographical position, and each is located within a specific social and cultural context. All these elements combine in defining the consequences of volcanic activity as well as in determining the severity of the damage and the size of the impacted area. How can we convey such a complexity to the...
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Geothermics, 2022
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Chemical Geology, 2015
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IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2014
ABSTRACT This paper shows the main outcomes of the Puyehue volcano (Chile) eruption monitoring by... more ABSTRACT This paper shows the main outcomes of the Puyehue volcano (Chile) eruption monitoring by means of multisensor remote sensing instruments working from thermal infrared (TIR) to microwave (MW) spectral range. Thanks to the use of Synthetic Aperture Radar (SAR) and the Moderate Resolution Imaging Spectroradiometer (MODIS), the eruption evolution was observed, capturing the deformations of volcano edifice, the lava extension, as well as the information on ash and gas emitted. On the one hand, SAR Interferometry applied to ENVISAT-ASAR data allowed the estimation of the deformation occurred just before the beginning of the eruption and the subsequent deflation, with monthly sampling. On the other hand, with the combined use of the very highresolution (VHR) images taken by COSMO-SkyMed X-band SAR, and ENVISAT-ASAR ones, we were able to follow the lava deposition during the most intense phase of the eruption. Additionally, the joined exploitation of SAR and optical MODIS images allowed ash detection, also in cloudy sky conditions. Finally, the information gathered by both types of sensors allowed to highlight some volcanological features of the eruption and the relationship between surface deformation and the amount of ash and gases emitted by the volcano.
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Mineralogy and Petrology, 2007
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Geology, 2006
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Chemical Geology, 2011
We present a study of olivine-hosted glass/melt inclusions (MIs) in the most primitive rocks erup... more We present a study of olivine-hosted glass/melt inclusions (MIs) in the most primitive rocks erupted at Procida Island, within the Phlegraean Volcanic District (PVD), Southern Italy. MIs were analyzed by combined Scanning Electron Microscopy coupled with Energy Dispersive X-ray-detectors, Wavelength Dispersive X-ray-equipped Electron Microprobe and Fourier Transform Infrared (FT-IR) Spectroscopy; notably, the novel Focal-Plane-Array mode provided high-resolution FT-IR images evidencing
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Geological Society, London, Memoirs, 2013
Stromboli is famous for its persistent volcanic activity consisting of periodic discrete explosio... more Stromboli is famous for its persistent volcanic activity consisting of periodic discrete explosions alternating with lava effusion and more violent explosions. This paper presents a detailed reconstruction of the geological history of Stromboli and description of the characteristics and distribution of the volcanic units and structural features. Six main growth stages (Eruptive Epochs 1–6), in addition to the c. 200 ka activity of Strombolicchio, are recognized between c. 85 ka and the present day, displaying a magma composition ranging from calc-alkaline to potassic series which usually varies with changing Eruptive Epochs. The Epochs are subdivided into sequences of eruptions and characterized by dominant central-vent summit activity with episodic phases of flank activity along fissures and eccentric vents. The activity was repeatedly interrupted by erosional and destructive phases driven by recurrent vertical caldera-type (cc1–5) and sector (and flank) collapses (sc1–7) and gener...
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Contributions to Mineralogy and Petrology
Understanding the mechanisms responsible for the generation of chemical gradients in high-volume ... more Understanding the mechanisms responsible for the generation of chemical gradients in high-volume ignimbrites is key to retrieve information on the processes that control the maturation and eruption of large silicic magmatic reservoirs. Over the last 60 ky, two large ignimbrites showing remarkable zoning were emplaced during caldera-forming eruptions at Campi Flegrei (i.e., Campanian Ignimbrite, CI, ~ 39 ka and Neapolitan Yellow Tuff, NYT, ~ 15 ka). While the CI displays linear compositional, thermal and crystallinity gradients, the NYT is a more complex ignimbrite characterized by crystal-poor magmas ranging in composition from trachy-andesites to phonolites. By combining major and trace element compositions of matrix glasses and mineral phases from juvenile clasts located at different stratigraphic heights along the NYT pyroclastic sequence, we interpret such compositional gradients as the result of mixing/mingling between three different magmas: (1) a resident evolved magma showing geochemical characteristics of a melt extracted from a cumulate mush dominated by clinopyroxene, plagioclase and oxides with minor sanidine and biotite; (2) a hotter and more mafic magma from recharge providing high-An plagioclase and high-Mg clinopyroxene crystals and (3) a compositionally intermediate magma derived from remelting of low temperature mineral phases (i.e., sanidine and biotite) within the cumulate crystal mush. We suggest that the presence of a refractory crystal mush, as documented by the occurrence of abundant crystal clots containing clinopyroxene, plagioclase and oxides, is the main reason for the lack of erupted crystal-rich material in the NYT. A comparison between the NYT and the CI, characterized by both crystal-poor extracted melts and crystal-rich magmas representing remobilized portions of a “mature” (i.e., sanidine dominated) cumulate residue, allows evaluation of the capability of crystal mushes of becoming eruptible upon recharge.
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Lithos
Abstract The Miocene “Corte Blanco Tuff” rhyolite deposit is the product of a large volume and hi... more Abstract The Miocene “Corte Blanco Tuff” rhyolite deposit is the product of a large volume and high intensity Plinian eruption from the solitary and monogenetic Ramadas Volcanic Centre (Central Andes, Province of Salta, NW Argentina). The “Corte Blanco Tuff” consists of vitreous tube pumices with rare euhedral sub-millimetric Mn-garnet phenocrysts, typically hosting inclusions of U-phases as zircon and monazite. Here, we present new textural, major and trace elemental analyses of garnet, zircon and glass that, combined with in situ U-(Th)-Pb zircon and monazite dating, are used to reconstruct the thermobaric environment of formation, age and longevity of the magmatic plumbing system of the Ramadas magma. The results indicate to a crystallization path of a peraluminous rhyolitic melt at shallow crustal levels (≤6 km), as sequentially tracked by the initial nucleation of zircon (780 °C at 9.16 Ma) and garnet (above or at ca. 700 °C), to the final monazite growth (660–670 °C, at 8.70 Ma) in a water-saturated (H2O = 3–5 wt%) environment, shortly before the eruption started. These data (1) define for the first time the primary magmatic origin of Mn-garnet in a rhyolitic volcanic setting; (2) provide new partition coefficients of rare earth elements (REE) between natural garnet, zircon and rhyolitic melts; and (3) permit reconstruction of the magmatic processes that resulted in the Ramadas eruption. On a wider scale, our results document the spatio-temporal (P-T conditions, timing and longevity) time scales involved in the petrogenesis of a shallow peraluminous water-saturated rhyolitic magmatic plumbing system that is able to generate the conditions for extremely explosive Plinian eruptions.
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Lithos
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Lithos
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Energies
This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the C... more This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal ...
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Geological Field Trips
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JOKULL
Katla is one of the most active volcanoes in Iceland and is characterised by persistent seismicit... more Katla is one of the most active volcanoes in Iceland and is characterised by persistent seismicity. It is partly covered by the Mýrdalsjökull glacier and its historic activity is dominated by phreatomagmatic eruptions within the caldera associated with catastrophic glacial floods. In July 2011 a sudden jökulhlaup was released from the glacier, associated with tremor, elevated seismicity inside the caldera and a new cluster of seismicity on the south flank. This was likely caused by a hydrothermal or magmatic event, possibly a small subglacial eruption. Similar unrests occurred in 1955 and 1999. We have identified changes of the seismicity pattern coinciding with the 2011 unrest, suggesting a modification in the volcanic system. It may be speculated that if the persistent seismicity at Katla is an indication of a pressurized magma system ready to erupt, small events like those of 1955, 1999 and 2011 may trigger larger eruptions in the future. We have also conducted a pilot study of ...
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Journal of Volcanology and Geothermal Research
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Landslides
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Journal of Volcanology and Geothermal Research
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Papers by Gianfilippo Astis