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

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

2021 ◽  
Author(s):  
Corin Jorgenson ◽  
Luca Caricchi ◽  
Michael Stueckelberger ◽  
Giovanni Fevola ◽  
Gregor Weber

<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>


Author(s):  
Paul J. Wallace ◽  
Terry Plank ◽  
Robert J. Bodnar ◽  
Glenn A. Gaetani ◽  
Thomas Shea

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.


2020 ◽  
Author(s):  
Daniel Smith ◽  
Lori Burns ◽  
Andrew Simmonett ◽  
Robert Parrish ◽  
Matthew Schieber ◽  
...  

<div> <div> <div> <p>Psi4 is a free and open-source ab initio electronic structure program providing Hartree–Fock, density functional theory, many-body perturbation theory, configuration interaction, density cumulant theory, symmetry-adapted perturbation theory, and coupled-cluster theory. Most of the methods are quite efficient thanks to density fitting and multi-core parallelism. The program is a hybrid of C++ and Python, and calculations may be run with very simple text files or using the Python API, facilitating post-processing and complex workflows; method developers also have access to most of Psi4’s core functionality via Python. Job specification may be passed using The Molecular Sciences Software Institute (MolSSI) QCSchema data format, facilitating interoperability. A rewrite of our top-level computation driver, and concomitant adoption of the MolSSI QCArchive Infrastructure project, make the latest version of Psi4 well suited to distributed computation of large numbers of independent tasks. The project has fostered the development of independent software components that may be reused in other quantum chemistry programs. </p> </div> </div> </div>


Geology ◽  
1999 ◽  
Vol 27 (8) ◽  
pp. 691 ◽  
Author(s):  
Vadim S. Kamenetsky ◽  
Rohan C. Wolfe ◽  
Stephen M. Eggins ◽  
Terrence P. Mernagh ◽  
Evgeniy Bastrakov

Author(s):  
Ruben van Wendel de Joode ◽  
Sebastian Spaeth

Most open source software is developed in online communities. These communities are typically referred to as “open source software communities” or “OSS communities.” In OSS communities, the source code, which is the human-readable part of software, is treated as something that is open and that should be downloadable and modifiable to anyone who wishes to do so. The availability of the source code has enabled a practice of decentralized software development in which large numbers of people contribute time and effort. Communities like Linux and Apache, for instance, have been able to connect thousands of individual programmers and professional organizations (although most project communities remain relatively small). These people and organizations are not confined to certain geographical places; on the contrary, they come from literally all continents and they interact and collaborate virtually.


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 ◽  
...  

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.


Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 419 ◽  
Author(s):  
Ilya Prokopyev ◽  
Anastasiya Starikova ◽  
Anna Doroshkevich ◽  
Yazgul Nugumanova ◽  
Vladislav Potapov

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.


2020 ◽  
Vol 105 (8) ◽  
pp. 1270-1274
Author(s):  
Francis M. McCubbin ◽  
Jessica J. Barnes

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.


2020 ◽  
Author(s):  
Penny Wieser ◽  
Marie Edmonds ◽  
John Maclennan ◽  
John Wheeler

&lt;p&gt;Distorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawai'i, Iceland, Andean Southern Volcanic Zone). At K&amp;#299;lauea volcano, distorted olivines are commonly attributed to ductile creep within dunitic bodies located around the central conduit, or within the deep rift zones (~5&amp;#8211;9 km depth). However, a recent suggestion that lattice distortions are produced by an early phase of branching dendritic growth, followed by textural ripening and the merging of misoriented crystal buds, has gained considerable traction.&lt;/p&gt;&lt;p&gt;A quantitative examination of the microstructures in distorted olivines by electron backscatter diffraction (EBSD) reveals striking similarities to microstructures observed in deformed mantle peridotites, but significant differences to the crystallographic signatures of dendritic growth. This suggests that lattice distortions record the application of differential stresses at high temperatures within the magmatic plumbing system, rather than rapid crystal growth. Previous petrological work has suggested that differential stresses are produced by ductile creep within K&amp;#299;lauea&amp;#8217;s deep rift zones. Crucially, this has fuelled suggestions that significant quantities of magma must travel along these rift zones in order to acquire distorted olivines, despite the paucity of geophysical evidence for these magma transport paths. In contrast, we show that the spatial distribution of eruptions containing distorted olivines is consistent with their derivation from the main magma storage reservoir. This model not only aligns petrological and geophysical observations at K&amp;#299;lauea, but also accounts for the occurrence of distorted olivines in a wide variety of basaltic systems worldwide (which lack deep rift zones).&lt;/p&gt;&lt;p&gt;Application of piezometers developed for mantle peridotites reveals that distorted olivines have experienced differential stresses of ~3&amp;#8211;12 MPa. Assuming that mush piles behave as granular materials, and form force chains, these stresses can be generated within cumulate piles of ~180&amp;#8211;720 m. Based on available constraints on the magma supply rate and the geometry of K&amp;#299;lauea&amp;#8217;s summit reservoir, these thicknesses accumulate in a few centuries (consistent with residence times inferred from melt inclusion records).&lt;/p&gt;&lt;p&gt;Overall, we demonstrate that microstructural investigations of erupted olivine crystals by EBSD generates rich datasets which provide quantitative insights into crystal storage within mush piles. Under the increasingly prevalent view that crustal magmatic systems are mush-dominated, constraining the geometry and dynamics of crystal storage regions is crucial to further our understanding of magmatic plumbing systems. The presence of distorted olivines in many different volcanic settings highlights the global applicability of the methods developed in this study. Furthermore, assessments of deformation conditions using EBSD need not be restricted to olivine-bearing lavas. Microstructural fabrics types in natural and experimental samples have been established for a wide variety of igneous phases (e.g. diopside, plagioclase, hornblende), so similar approaches may be utilized in more evolved volcanic systems.&lt;/p&gt;


2021 ◽  
Author(s):  
David Molik ◽  
Caroline DeVoto ◽  
Daniel Molik

(1) Motivation: A long standing problem in Environmental DNA has been the inability to compute across large number of datasets. Here we introduce an Open Source software frame work that can store a large number of Environmental DNA datasets, as well as provide a platform for analysis, in an easily customizable way. We show the utility of such an approach by analyzing over 1400 arthropod datasets. (2) Results: This article introduces a new software framework, met, which utilizes large numbers ofmetabarcode datasets to draw conclusions about patterns of diversity at large spatial scales. Given more accurate estimations on the distribution of variance in metabarcode datasets, this software framework could facilitate novel analyses that are outside the scope of currently available similar platforms. (3) Availability: All code are published under the Mozilla Public License ver 2.0 on the met project page: https://doi.org/10.17605/OSF.IO/SPB8V


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