Deep CO₂ in the end-Triassic Central Atlantic Magmatic Province

Large Igneous Province eruptions coincide with many major Phanerozoic mass extinctions, suggesting a cause-effect relationship where volcanic degassing triggers global climatic changes. In order to fully understand this relationship, it is necessary to constrain the quantity and type of degassed magmatic volatiles, and to determine the depth of their source and the timing of eruption. Here we present direct evidence of abundant CO2 in basaltic rocks from the end-Triassic Central Atlantic Magmatic Province (CAMP), through investigation of gas exsolution bubbles preserved by melt inclusions. Our results indicate abundance of CO2 and a mantle and/or lower-middle crustal origin for at least part of the degassed carbon. The presence of deep carbon is a key control on the emplacement mode of CAMP magmas, favouring rapid eruption pulses (a few centuries each). Our estimates suggest that the amount of CO2 that each CAMP magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21st century. Such large volumes of volcanic CO2 likely contributed to end-Triassic global warming and ocean acidification

Massive methane fluxing from magma–sediment interaction in the end-Triassic Central Atlantic Magmatic Province

Exceptional magmatic events coincided with the largest mass extinctions throughout Earth’s history. Extensive degassing from organic-rich sediments intruded by magmas is a possible driver of the catastrophic environmental changes, which triggered the biotic crises. One of Earth’s largest magmatic events is represented by the Central Atlantic Magmatic Province, which was synchronous with the end-Triassic mass extinction. Here, we show direct evidence for the presence in basaltic magmas of methane, generated or remobilized from the host sedimentary sequence during the emplacement of this Large Igneous Province. Abundant methane-rich fluid inclusions were entrapped within quartz at the end of magmatic crystallization in voluminous (about 1.0 × 106 km3) intrusions in Brazilian Amazonia, indicating a massive (about 7.2 × 103 Gt) fluxing of methane. These micrometre-sized imperfections in quartz crystals attest an extensive release of methane from magma–sediment interaction, which likely contributed to the global climate changes responsible for the end-Triassic mass extinction

On Complex Value Relations in Hive

International audienceIn this paper, we raise the question how data architects model their data for processing in Apache Hive. This well-known SQL-on-Hadoop engine supports complex value relations, where attribute types need not be atomic. In fact, this feature seems to be one of the prominent selling points, e.g., in Hive reference books. In an empirical study, we analyze Hive schemas in open source repositories. We examine to which extent practitioners make use of complex value relations and accordingly , whether they write queries over complex types. Understanding which features are actively used will help make the right decisions in setting up benchmarks for SQL-on-Hadoop engines, as well as in choosing which query operators to optimize for

An experimental and kinetic modeling study on nitric oxide formation in premixed C3 alcohols flames

This study provides new quantitative NO concentrations measurements in n-propanol + air and i-propanol + air flames together with a new combustion kinetic model. The heat flux method was employed to stabilize propyl alcohols flames and the initial gas conditions were set to 323 K, 1 atm, and ϕ=0.7-1.4. Saturated laser-induced fluorescence was employed to measure NO concentration in the post-combustion region. The presented and literature models, namely the POLIMI and Bohon et al. (2018) kinetic mechanisms, were assessed against new experimental data. Experimental results showed a higher NO formation in the thermal zone for n-propanol flames, whereas i-propanol flames indicate a higher amount of NO formed at fuel-rich conditions. Overall among the tested models, the present mechanism exhibited the best agreement in emulating NO experimental profiles; conversely, numerical simulations from the POLIMI model showed significant inconsistencies at fuel-rich conditions and the Bohon et al. (2018) model was unable to reproduce the measured data, notably underpredicting experimental values at all investigated conditions. However, the present model manifested some uncertainties in reproducing NO formation in the prompt region; therefore, in connection with this important aspect, the new experimental data obtained in this work will provide a valid support to further develop more reliable kinetic models

Functional characterisation of the antioxidant system in Drosophila melanogaster, after metals exposure.

Reactive oxygen species (ROS) are a normal byproduct of aerobic metabolism playing an important role in cell signaling and immunity when their production is regulated or controlled by antioxidant enzymes. Reduced expression and/or activity of these proteins lead to an excess of ROS production and oxidative stress, accelerating aging and neurodegeneration. For example, amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by motoneuron loss and some familial cases (fALS) are linked to mutations of superoxide dismutase type-1 (SOD1). Many animal models, such as Drosophila melanogaster, are used as useful tool to study this disease, focusing the attention on the different mutant SOD1s but not considering the complex relationships of functional complementarity between SOD1 and the other components of the enzymatic antioxidant system. In the present work we study, for the first time, the gene expression, by qRT-PCR, of SOD1 together with that of superoxide dismutase type-2, catalase, glutathione peroxidases and peroxiredoxins in wild type D. melanogaster, exposed to various concentration of copper or cadmium, used as pro-oxidants. The aim was to determine the adequate experimental condition to employ with D. melanogaster SOD1 mutants. On the basis of our results, copper is the major inducer of all considered enzymes, and the dose of 1.0 mM seems to be the more suitable. Catalase is temporally co-expressed with SOD1, at least in males and the gene expression of other enzymes seems to be temporally uncorrelated to SOD1. Other important indication will be obtained by biochemical quantification of activity for all considered enzymes and the evaluation of ROS production, that are now in progress

Massive methane fluxing from magma–sediment interaction in the end-Triassic Central Atlantic Magmatic Province

Exceptional magmatic events coincided with the largest mass extinctions throughout Earth’s history. Extensive degassing from organic-rich sediments intruded by magmas is a possible driver of the catastrophic environmental changes, which triggered the biotic crises. One of Earth’s largest magmatic events is represented by the Central Atlantic Magmatic Province, which was synchronous with the end-Triassic mass extinction. Here, we show direct evidence for the presence in basaltic magmas of methane, generated or remobilized from the host sedimentary sequence during the emplacement of this Large Igneous Province. Abundant methane-rich fluid inclusions were entrapped within quartz at the end of magmatic crystallization in voluminous (about 1.0 × 106 km3) intrusions in Brazilian Amazonia, indicating a massive (about 7.2 × 103 Gt) fluxing of methane. These micrometre-sized imperfections in quartz crystals attest an extensive release of methane from magma–sediment interaction, which likely contributed to the global climate changes responsible for the end-Triassic mass extinction