A myriad of melt inclusions: a synchrotron microtomography study of melt inclusions and vapour bubbles from Colli Albani (Italy)

2021 ◽  
Author(s):  
Corin Jorgenson ◽  
Luca Caricchi ◽  
Michael Stueckelberger ◽  
Giovanni Fevola ◽  
Gregor Weber
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Fluid Phase ◽  
Volcanic Eruptions ◽  
Mineral Chemistry ◽  
Magma Ascent ◽  
Vapour Bubble ◽  
Electron Synchrotron ◽  
Colli Albani ◽  
Synchrotron Microtomography

<p>Melt inclusions provide a window into the inner workings of magmatic systems. Both mineral chemistry and volatile distributions within melt inclusions can provide valuable information about the processes modulating magma ascent and preceding volcanic eruptions. Many melt inclusions host vapour bubbles which can be rich in CO<sub>2</sub> and H<sub>2</sub>O and must be taken into consideration when assessing the volatile budget of magmatic reservoirs. These vapour bubbles can be the product of differential volumetric contraction between the melt inclusion and host phase during an eruption or indicate an excess fluid phase in the magma reservoir. Thus, determining the distribution of volatiles between melt and vapour bubbles is integral to our fundamental understanding of melt inclusions, and by extension the evolution of volatiles within magmatic systems.</p><p>A large dataset of 79 high-resolution tomographic scans of clinopyroxene and leucite phenocrysts from the Colli Albani Caldera Complex (Italy) was recently acquired at the German Electron Synchrotron (DESY). These tomograms allow us to quantify the volume of melt inclusions and associated vapour bubble both glassy and microcrystalline melt inclusions. Notably, in the glassy melt inclusions the vapour bubbles exist either as a single large vapour bubble in the middle of the melt inclusion or as several smaller vapour bubbles distributed around the edge of the melt inclusion. These two types of melt inclusions can coexist within a single crystal. We suggest that the occurrence of these rim- bubbles is caused by one of two exsolution pathways, either pre-entrapment and bubble migration or post entrapment with preferential exsolution at the rims. By combining the analysis of hundreds of melt inclusions with the chemistry of the host phase we aim to unveil magma ascent rates and distribution of excess fluids within the magmatic system of Colli Albani, which produced several mafic-alkaline large volume ignimbrites.</p>

Magma ascent and eruption forecasting at Deception Island volcano (Antarctica) evidenced by δD and δ18O variations

2020 ◽  
Author(s):  
Antonio M. Álvarez-Valero ◽  
Meritxell Aulinas ◽  
Adelina Geyer ◽  
Guillem Gisbert ◽  
Gabor Kereszturi ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
Magma Ascent ◽  
Explosive Eruptions ◽  
Deception Island ◽  
Essential Information ◽  
Local Modification ◽  
Isotopic Variations ◽  
Active Volcanoes

<p>Geochemistry of volatiles in active volcanoes provides insights into the magmatic processes and evolution at depth, such as magma evolution and degassing, which can be implemented into volcanic hazards assessment. Deception Island is one of the most active volcanoes in Antarctica, with more than twenty explosive eruptions documented over the past two centuries. Hydrogen and oxygen isotopic variations in the volatiles trapped in the Deception Island rocks (glass and melt inclusions in phenocrysts) provide essential information on the mechanisms controlling the eruptive history in this volcanic suite. Thus, understanding the petrological and related isotopic variations in the island, has the potential to foresee the possible occurrence and its main eruptive features of a future eruption.</p><p>Information from hydrogen and oxygen stable isotopes combined with detailed petrologic data reveal in Deception Island (i) fast ascent and quenching of most magmas, preserving pre-eruptive magmatic signal of water contents and isotopic ratios, with local modification by rehydration due to glass exposition to seawater, meteoric and fumarolic waters; (ii) a plumbing system(s) currently dominated by closed-system degassing leading to explosive eruptions; (iii) control on the interactions of ascending magmas with the surface waters producing hydrovolcanic activity throughout the two main fault systems in Deception Island. These results can be considered in further studies of volcanic monitoring to improve the capability to interpret geophysical data and signals recorded during volcanic unrest episodes, and hence, forecast volcanic eruptions and related hazards.</p><p>This research was partially funded by the following projects: POSVOLDEC (CTM2016‐79617‐P) (AEI/FEDER‐UE), VOLGASDEC (PGC2018-095693-B-I00) (AEI/FEDER‐UE) and Programa Propio Ib-2019 (USAL). This research is also part of POLARCSIC activities.</p>

Olivine-Hosted Melt Inclusions: A Microscopic Perspective on a Complex Magmatic World

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Paul J. Wallace ◽  
Terry Plank ◽  
Robert J. Bodnar ◽  
Glenn A. Gaetani ◽  
Thomas Shea
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Volcanic Eruptions ◽  
Annual Review ◽  
Publication Date ◽  
Basaltic Melt ◽  
Recent Developments ◽  
Magma Crystallization ◽  
Detailed Record ◽  
Kinetics Of

Inclusions of basaltic melt trapped inside of olivine phenocrysts during igneous crystallization provide a rich, crystal-scale record of magmatic processes ranging from mantle melting to ascent, eruption, and quenching of magma during volcanic eruptions. Melt inclusions are particularly valuable for retaining information on volatiles such as H2O and CO2 that are normally lost by vesiculation and degassing as magma ascends and erupts. However, the record preserved in melt inclusions can be variably obscured by postentrapment processes, and thus melt inclusion research requires careful evaluation of the effects of such processes. Here we review processes by which melt inclusions are trapped and modified after trapping, describe new opportunities for studying the rates of magmatic and volcanic processes over a range of timescales using the kinetics of post-trapping processes, and describe recent developments in the use of volatile contents of melt inclusions to improve our understanding of how volcanoes work. ▪ Inclusions of silicate melt (magma) trapped inside of crystals formed by magma crystallization provide a rich, detailed record of what happens beneath volcanoes. ▪ These inclusions record information ranging from how magma forms deep inside Earth to its final hours as it ascends to the surface and erupts. ▪ The melt inclusion record, however, is complex and hazy because of many processes that modify the inclusions after they become trapped in crystals. ▪ Melt inclusions provide a primary archive of dissolved gases in magma, which are the key ingredients that make volcanoes erupt explosively. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 49 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals VESIcal Part II: A critical approach to volatile solubility modelling using an open-source Python3 engine

2021 ◽  
Author(s):  
Penny Wieser ◽  
Kayla Iacovino ◽  
Simon Matthews ◽  
Gordon Moore ◽  
Chelsea Allison
Keyword(s):  
Open Source ◽  
Melt Inclusions ◽  
Melt Inclusion ◽  
Volcanic Eruptions ◽  
Critical Approach ◽  
Co2 Solubility ◽  
Large Numbers ◽  
Plumbing Systems ◽  
Presentation Methods ◽  
Volatile Exsolution

Accurate models of H2O and CO2 solubility in silicate melts are vital for understanding volcanic plumbing systems. These models are used to estimate the depths of magma storage regions from melt inclusion volatile contents, investigate the role of volatile exsolution as a driver of volcanic eruptions, and track the degassing paths followed by magma ascending to the surface. However, despite the large increase in the number of experimental constraints over the last two decades, many recent studies still utilize the earlier generation of models, which were calibrated on experimental datasets with restricted compositional ranges. This may be because many of the available tools for more recent models require large numbers of input parameters to be hand-typed (e.g., temperature, concentrations of H2O, CO2, and 8--14 oxides), making them difficult to implement on large datasets. Here, we use a new open-source Python3 tool, VESIcal, to critically evaluate the behaviours and sensitivities of different solubility models for a range of melt compositions. Using literature datasets of andesitic-dacitic experimental products and melt inclusions as case studies, we illustrate the importance of evaluating the calibration dataset of each model. Finally, we highlight the limitations of particular data presentation methods such as isobar diagrams, and provide suggestions for alternatives, and best practices regarding the presentation and archiving of data. This review will aid the selection of the most applicable solubility model for different melt compositions, and identifies areas where additional experimental constraints are required

scholarly journals Degassing during quiescence as a trigger of magma ascent and volcanic eruptions

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Társilo Girona ◽  
Fidel Costa ◽  
Gerald Schubert
Keyword(s):  
Volcanic Eruptions ◽  
Magma Ascent

Magmatic-Hydrothermal Fluids

Elements ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 401-406 ◽  
Author(s):  
Andreas Audétat ◽  
Marie Edmonds
Keyword(s):  
Metal Content ◽  
Fluid Phase ◽  
Volcanic Eruptions ◽  
Hydrothermal Systems ◽  
Ore Deposits ◽  
Hydrothermal Fluids ◽  
Geological Processes ◽  
Mineral Growth ◽  
Fluid Saturation ◽  
Fluid Phase Equilibria

Magmatic-hydrothermal fluids play a key role in a variety of geological processes, including volcanic eruptions and the formation of ore deposits whose metal content is derived from magmas and transported to the site of ore deposition by means of hydrothermal fluids. Here, we explain the causes and consequences of fluid saturation in magmas, the corresponding fluid-phase equilibria, and the behavior of metals and ligands during the transition from magma to an exsolved hydrothermal fluid. Much of what we know about magmatic-hydrothermal systems stems from the study of fluid inclusions, which are minute droplets of fluids trapped within minerals during mineral growth.

scholarly journals What lies beneath? Reconstructing the primitive magmas fueling voluminous silicic volcanism using olivine-hosted melt inclusions

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 504-508 ◽  
Author(s):  
Simon J. Barker ◽  
Michael C. Rowe ◽  
Colin J.N. Wilson ◽  
John A. Gamble ◽  
Shane M. Rooyakkers ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Taupo Volcanic Zone ◽  
Mantle Dynamics ◽  
Silicic Volcanism ◽  
Depleted Mantle ◽  
Basaltic Magmas ◽  
Show Evidence ◽  
Basaltic Melts ◽  
Eruptive Centers

Abstract Understanding the origins of the mantle melts that drive voluminous silicic volcanism is challenging because primitive magmas are generally trapped at depth. The central Taupō Volcanic Zone (TVZ; New Zealand) hosts an extraordinarily productive region of rhyolitic caldera volcanism. Accompanying and interspersed with the rhyolitic products, there are traces of basalt to andesite preserved as enclaves or pyroclasts in caldera eruption products and occurring as small monogenetic eruptive centers between calderas. These mafic materials contain MgO-rich olivines (Fo79–86) that host melt inclusions capturing the most primitive basaltic melts fueling the central TVZ. Olivine-hosted melt inclusion compositions associated with the caldera volcanoes (intracaldera samples) contrast with those from the nearby, mafic intercaldera monogenetic centers. Intracaldera melt inclusions from the modern caldera volcanoes of Taupō and Okataina have lower abundances of incompatible elements, reflecting distinct mantle melts. There is a direct link showing that caldera-related silicic volcanism is fueled by basaltic magmas that have resulted from higher degrees of partial melting of a more depleted mantle source, along with distinct subduction signatures. The locations and vigor of Taupō and Okataina are fundamentally related to the degree of melting and flux of basalt from the mantle, and intercaldera mafic eruptive products are thus not representative of the feeder magmas for the caldera volcanoes. Inherited olivines and their melt inclusions provide a unique “window” into the mantle dynamics that drive the active TVZ silicic magmatic systems and may present a useful approach at other volcanoes that show evidence for mafic recharge.

scholarly journals Petrogenesis of Ultramafic Lamprophyres from the Terina Complex (Chadobets Upland, Russia): Mineralogy and Melt Inclusion Composition

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 419 ◽  
Author(s):  
Ilya Prokopyev ◽  
Anastasiya Starikova ◽  
Anna Doroshkevich ◽  
Yazgul Nugumanova ◽  
Vladislav Potapov
Keyword(s):  
Mineral Composition ◽  
Fractional Crystallization ◽  
Fluid Inclusions ◽  
Siberian Craton ◽  
Melt Inclusions ◽  
Melt Inclusion ◽  
Inclusion Composition ◽  
Accessory Minerals ◽  
Secondary Minerals ◽  
Peridotite Mantle

The mineral composition and melt inclusions of ultramafic lamprophyres of the Terina complex were investigated. The rocks identified were aillikites, mela-aillikites, and damtjernites, and they were originally composed of olivine macrocrysts and phenocrysts, as well as phlogopite phenocrysts in carbonate groundmass, containing phlogopite, clinopyroxene and feldspars. Minor and accessory minerals were fluorapatite, ilmenite, rutile, titanite, and sulphides. Secondary minerals identified were quartz, calcite, dolomite, serpentine, chlorite, rutile, barite, synchysite-(Ce), and monazite-(Ce). Phlogopite, calcite, clinopyroxene, Ca-amphibole, fluorapatite, magnetite, and ilmenite occurred as daughter-phases in melt inclusions. The melt inclusions also contained Fe–Ni sulphides, synchysite-(Ce) and, probably, anhydrite. The olivine macrocrysts included orthopyroxene and ilmenite, and the olivine phenocrysts included Cr-spinel and Ti-magnetite inclusions. Crystal-fluid inclusions in fluorapatite from damtjernites contain calcite, clinopyroxene, dolomite, and barite. The data that were obtained confirm that the ultramafic lamprophyres of the Terina complex crystallized from peridotite mantle-derived carbonated melts and they have not undergone significant fractional crystallization. The investigated rocks are considered to be representative of melts that are derived from carbonate-rich mantle beneath the Siberian craton.

The chlorine-isotopic composition of lunar KREEP from magnesian-suite troctolite 76535

2020 ◽  
Vol 105 (8) ◽  
pp. 1270-1274
Author(s):  
Francis M. McCubbin ◽  
Jessica J. Barnes
Keyword(s):  
Isotopic Composition ◽  
Melt Inclusions ◽  
Melt Inclusion ◽  
Isotopic Fractionation ◽  
Magma Ocean ◽  
Geochemical Composition ◽  
Isotopic Compositions ◽  
Stable Isotopic ◽  
Lunar Samples

Abstract We conducted in situ Cl isotopic measurements of apatite within intercumulus regions and within a holocrystalline olivine-hosted melt inclusion in magnesian-suite troctolite 76535 from Apollo 17. These data were collected to place constraints on the Cl-isotopic composition of the last liquid to crystallize from the lunar magma ocean (i.e., urKREEP, named after its enrichments in incompatible lithophile trace elements like potassium, rare earth elements, and phosphorus). The apatite in the olivine-hosted melt inclusion and within the intercumulus regions of the sample yielded Cl-isotopic compositions of 28.3 ± 0.9‰ (2σ) and 30.3 ± 1.1‰ (2σ), respectively. The concordance of these values from both textural regimes we analyzed indicates that the Cl-isotopic composition of apatites in 76535 likely represents the Cl-isotopic composition of the KREEP-rich magnesian-suite magmas. Based on the age of 76535, these results imply that the KREEP reservoir attained a Cl-isotopic composition of 28–30‰ by at least 4.31 Ga, consistent with the onset of Cl-isotopic fractionation at the time of lunar magma ocean crystallization or shortly thereafter. Moreover, lunar samples that yield Cl-isotopic compositions higher than the value for KREEP are likely affected by secondary processes such as impacts and/or magmatic degassing. The presence of KREEP-rich olivine-hosted melt inclusions within one of the most pristine and ancient KREEP-rich rocks from the Moon provides a new opportunity to characterize the geochemistry of KREEP. In particular, a broader analysis of stable isotopic compositions of highly and moderately volatile elements could provide an unprecedented advancement in our characterization of the geochemical composition of the KREEP reservoir and of volatile-depletion processes during magma ocean crystallization, more broadly.

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