Storage and evolution of mafic and intermediate alkaline magmas beneath ross Island, Antarctica

We present the results of phase equilibrium experiments carried out on basanite and phonotephrite lavas from Ross Island, Antarctica. Experiments were designed to reproduce the P-T-X-fO₂ conditions of deep and intermediate magma storage and to place constraints on the differentiation of each of the two predominant lava suites on the island, which are thought to be derived from a common parent melt. The Erebus Lineage (EL) consists of lava erupted from the Erebus summit and the Dry Valley Drilling Project (DVDP) lineage is represented by lavas sampled by drill core on Hut Point Peninsula. Experiments were performed in internally heated pressure vessels over a range of temperatures (1000-1150°C) and pressures (200-400 MPa), under oxidized conditions (NNO to NNO+3, where NNO is the nickel-nickel oxide buffer), with X_Η2O of the H₂O-CO₂ mixture added to the experimental capsule varying between zero and unity. The overall mineralogy and mineral compositions of the natural lavas were reproduced, suggesting oxidizing conditions for the deep magma plumbing system, in marked contrast to the reducing conditions (QFM to QFM -1, where QFM is the quartz-fayalite-magnetite buffer) in the Erebus lava lake. In basanite, crystallization of spinel is followed by olivine and clinopyroxene olivine is replaced by kaersutitic amphibole below 1050°C at intermediate water contents. In phonotephrite, the liquidus phase is kaersutite except in runs with low water content (XH₂O^fluid <0·2) where it is replaced by clinopyroxene. Experimental kaersutite compositions suggest that the amphibole-bearing DVDP lavas differentiated below 1050°C at 200-400MPa and NNO+1·5 to NNO+2. Olivine- and clinopyroxene-bearing EL lavas are consistent with experiments performed above 1050°C and pressures around 200 MPa. The plagioclase liquidus at <1-2 wt % H₂O suggests extremely dry conditions for both lineages (XH₂O^fluid approaching zero for EL,∼0·25 for DVDP), probably facilitated by dehydration induced by a CO₂-rich fluid phase. Our results agree with previous studies that suggest a single plumbing system beneath Ross Island in which DVDP lavas (and probably other peripheral volcanic products) were erupted through radial fractures associated with the ascent of parental magma into the lower crust. The longer travel time of the DVDP lavas through the crust owing to lateral movement along fractures and the lack of a direct, sustained connection to the continuous CO₂-rich gas flux that characterizes the main central Erebus conduit is probably responsible for the lower temperatures and slightly wetter conditions and hence the change in mineralogy observed.Fieldwork in Antarctica was supported by the Office of Polar Programs (National Science Foundation) (ANT1142083). Experimental research was supported by Labex Voltaire (ANR-10-LABX-100-10); and by the University of Cambridge Department of Geography Phillip Lake and William Vaughn Lewis grants

VESIcal: 2. A Critical Approach to Volatile Solubility Modeling Using an Open-Source Python3 Engine

Abstract: 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 path followed by a 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 an 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 behaviors 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 on volatile solubility are required

VESIcal Part I: An Open-Source Thermodynamic Model Engine for Mixed Volatile (H<inf>2</inf>O-CO<inf>2</inf>) Solubility in Silicate Melts

Abstract: Thermodynamics has been fundamental to the interpretation of geologic data and modeling of geologic systems for decades. However, more recent advancements in computational capabilities and a marked increase in researchers' accessibility to computing tools has outpaced the functionality and extensibility of currently available modeling tools. Here, we present VESIcal (Volatile Equilibria and Saturation Identification calculator): the first comprehensive modeling tool for H 2 O, C O 2 , and mixed ( H 2 O‐ C O 2 ) solubility in silicate melts that: (a) allows users access to seven of the most popular models, plus easy inter‐comparison between models; (b) provides universal functionality for all models (e.g., functions for calculating saturation pressures, degassing paths, etc.); (c) can process large datasets (1,000s of samples) automatically; (d) can output computed data into an Excel spreadsheet or CSV file for simple post‐modeling analysis; (e) integrates plotting capabilities directly within the tool; and (f) provides all of these within the framework of a python library, making the tool extensible by the user and allowing any of the model functions to be incorporated into any other code capable of calling python. The tool is presented within this manuscript, which may be read as a static PDF but is better experienced via the Jupyter Notebook version of this manuscript. Here, we present worked examples accessible to python users with a range of skill levels. The basic functions of VESIcal can also be accessed via a web app (https://vesical.anvil.app). The VESIcal python library is open‐source and available for download at https://github.com/kaylai/VESIcal, or it can be installed using pip. It is recommended to read and interact with this manuscript as an executable Jupyter Notebook, available at https://mybinder.org/v2/gh/kaylai/vesical-binder/HEAD?filepath=Manuscript.ipynb

Evidence for partial melt in the crust beneath Mt. Paektu (Changbaishan), Democratic People's Republic of Korea and China

Mt. Paektu (also known as Changbaishan) is an enigmatic volcano on the border between the Democratic People's Republic of Korea (DPRK) and China. Despite being responsible for one of the largest eruptions in history, comparatively little is known about its magmatic evolution, geochronology, or underlying structure. We present receiver function results from an unprecedented seismic deployment in the DPRK. These are the first estimates of the crustal structure on the DPRK side of the volcano and, indeed, for anywhere beneath the DPRK. The crust 60 km from the volcano has a thickness of 35 km and a bulk $V_\text{P}$/$V_\text{S}$ of 1.76, similar to that of the Sino-Korean craton. The $V_\text{P}$/$V_\text{S}$ ratio increases ~20 km from the volcano, rising to >1.87 directly beneath the volcano. This shows that a large region of the crust has been modified by magmatism associated with the volcanism. Such high values of $V_\text{P}$/$V_\text{S}$ suggest that partial melt is present in the crust beneath Mt. Paektu. This region of melt represents a potential source for magmas erupted in the last few thousand years and may be associated with an episode of volcanic unrest observed between 2002 and 2005.This work was supported by the Richard Lounsbery Foundation. The UK seismic instruments and data management facilities were provided under loan number 976 by SEIS-UK at the University of Leicester. The facilities of SEIS-UK are supported by the NERC under Agreement R8/H10/64. J.O.S.H. was supported by an NERC Fellowship NE/I020342/1

Quantifying gas emissions from the "Millennium Eruption" of Paektu volcano, Democratic Peoples Republic of Korea/China

Paektu volcano (Changbaishan) is a rhyolitic caldera that straddles the border between the Democratic People’s Republic of Korea and China. Its most recent large eruption was the Millennium Eruption (ME; 23 km$^{3}$ dense rock equivalent) circa 946 CE, which resulted in the release of copious magmatic volatiles (H$_{2}$O, CO$_{2}$, sulfur, and halogens). Accurate quantification of volatile yield and composition is critical in assessing volcanogenic climate impacts but is challenging, particularly for events before the satellite era. We use a geochemical technique to quantify volatile composition and upper bounds to yields for the ME by examining trends in incompatible trace and volatile element concentrations in crystal-hosted melt inclusions. We estimate that the ME could have emitted as much as 45 Tg of S to the atmosphere. This is greater than the quantity of S released by the 1815 eruption of Tambora, which contributed to the “year without a summer.” Our maximum gas yield estimates place the ME among the strongest emitters of climate-forcing gases in the Common Era. However, ice cores from Greenland record only a relatively weak sulfate signal attributed to the ME. We suggest that other factors came into play in minimizing the glaciochemical signature. This paradoxical case in which high S emissions do not result in a strong glacial sulfate signal may present a way forward in building more https://symplectic.admin.cam.ac.uk/objectedit.html?cid=1&oid=876954generalized models for interpreting which volcanic eruptions have produced large climate impacts.K.I. was supported by the NSF under award no. 1349486 and by AAAS. Fieldwork was supported by the Richard Lounsbery Foundation

Similar levels of efficacy of two different maintenance doses of adalimumab on clinical severity and quality of life of patients with hidradenitis suppurativa

Adalimumab is the only biologic agent approved for the treatment of moderate-to-severe hidradenitis suppurativa (HS) patients (i.e., with Hurley II or III), which is recommended in two different maintenance doses (i.e., 40 mg weekly or 80 mg every two weeks). We conducted a prospective multicentric study to measure outcomes related to the severity of disease and quality of life (QoL) of patients affected by moderate-to-severe HS, treated with adalimumab at a maintenance dosing of 40 mg or 80 mg. Assessments were performed at baseline (T0) and after 32 weeks of treatment (T32). We enrolled 85 moderate-to-severe HS Italian patients, 43 men (50.6%) and 42 women, aged between 16 and 62 years (median 31 years, interquartile range 24.4-43.8). Statistically significant improvements were observed for clinical status (with a mean reduction of 7.1 points for the International Hidradenitis Suppurativa Severity Score System (IHS4)), pain levels (3.1 mean decrease in VAS), and QoL (3.4 mean improvement in DLQI score). Patients with no comorbidities, and those with higher levels of perceived pain showed significantly greater improvement in QoL than their counterpart from T0 to T32. As for the proportion of patients who at follow-up reached the minimal clinical important difference (MCID) in QoL, significantly higher proportions of success were observed for age (patients in the 29-39 category), pain (patients with higher reported pain), and Hurley stage III. While both treatment regimen groups (i.e., 40 vs. 80 mg) improved significantly, no statistical differences were observed when comparing the two treatment dosages

Reconstructing Magma Storage Depths for the 2018 Kı̄lauean Eruption From Melt Inclusion CO ₂ Contents: The Importance of Vapor Bubbles

The 2018 lower East Rift Zone (LERZ) eruption and the accompanying collapse of the summit caldera marked the most destructive episode of activity at Kı̄lauea Volcano in the last 200 years. The eruption was extremely well-monitored, with extensive real-time lava sampling as well as continuous geodetic data capturing the caldera collapse. This multiparameter data set provides an exceptional opportunity to determine the reservoir geometry and magma transport paths supplying Kı̄lauea’s LERZ. The forsterite contents of olivine crystals, together with the degree of major element disequilibrium with carrier melts, indicates that two distinct crystal populations were erupted from Fissure 8 (termed high- and low-Fo). Melt inclusion entrapment pressures reveal that low-Fo olivines (close to equilibrium with their carrier melts) crystallized within the Halema’uma’u reservoir (∼2-km depth), while many high-Fo olivines (>Fo81.5; far from equilibrium with their carrier melts) crystallized within the South Caldera reservoir (∼3–5-km depth). Melt inclusions in high-Fo olivines experienced extensive post-entrapment crystallization following their incorporation into cooler, more evolved melts. This favored the growth of a CO2-rich vapor bubble, containing up to 99% of the total melt inclusion CO2 budget (median = 93%). If this CO2-rich bubble is not accounted for, entrapment depths are significantly underestimated. Conversely, reconstructions using equation of state methods rather than direct measurements of vapor bubbles overestimate entrapment depths. Overall, we show that direct measurements of melts and vapor bubbles by secondary-ion mass spectrometry and Raman spectroscopy, combined with a suitable H2O-CO2 solubility model, is a powerful tool to identify the magma storage reservoirs supplying volcanic eruptions. Key Points Petrological, gaseous and geophysical observations can be reconciled by a model where Fissure 8 was supplied from two summit storage reservoirs (∼1–2- and 3–5-km depth) Extensive post-entrapment crystallization of melt inclusions within high-Fo olivines (Fo > 81.5) caused ∼90% of the CO2 to enter the vapor bubble Raman analyses of vapor bubbles combined with choice of a suitable H2O-CO2 solubility model is required to accurately determine magma storage depths Plain Language Summary Pockets of frozen magma trapped within olivine crystals, termed “melt inclusions,” can provide information about the depths at which magma is stored beneath the surface prior to a volcanic eruption. This is because the amount of CO2 and H2O that can be dissolved in a melt is dependent on the pressure, and therefore the depth. We examine melt inclusions from lava flows produced during the 2018 eruption of Kı̄lauea Volcano. Previous work, based on geophysics, has shown that magma is stored in two main reservoirs at Kı̄lauea, located at ∼1–2- and ∼3–5-km depth. However, because many melt inclusions host almost all of their CO2 within a vapor bubble, which is rarely measured, previous petrological estimates of magma storage depths at Kı̄lauea do not align with the depths of the two reservoirs identified by geophysics. In this study, we measure the amount of CO2 in the glass and the bubble using secondary-ion mass spectrometry and Raman spectroscopy, respectively. By adding these two measurements together, we can reconstruct the amount of CO2 that was present when melt inclusions were trapped. Calculated depths align remarkably well with geophysical estimates, and demonstrate that the 2018 eruption was supplied by both magma storage reservoirs

The transcriptional programme controlled by Runx1 during early embryonic blood development

AbstractTranscription factors have long been recognised as powerful regulators of mammalian development yet it is largely unknown how individual key regulators operate within wider regulatory networks. Here we have used a combination of global gene expression and chromatin-immunoprecipitation approaches during the early stages of haematopoietic development to define the transcriptional programme controlled by Runx1, an essential regulator of blood cell specification. Integrated analysis of these complementary genome-wide datasets allowed us to construct a global regulatory network model, which suggested that key regulators are activated sequentially during blood specification, but will ultimately collaborate to control many haematopoietically expressed genes. Using the CD41/integrin alpha 2b gene as a model, cellular and in vivo studies showed that CD41 is controlled by both Scl/Tal1 and Runx1 in fully specified blood cells, and initiation of CD41 expression in E7.5 embryos is severely compromised in the absence of Runx1. Taken together, this study represents the first global analysis of the transcriptional programme controlled by any key haematopoietic regulator during the process of early blood cell specification. Moreover, the concept of interplay between sequentially deployed core regulators is likely to represent a design principle widely applicable to the transcriptional control of mammalian development