Plumbing System Research Articles

Driving Global Change One LIP at a Time

Earth’s history has been punctuated by extraordinary magmatic events that produced large igneous provinces (LIPs). Many LIPs induced global changes, including millennial-scale warming, terrestrial and oceanic mass extinctions, oceanic anoxic events, and even glaciations. Research over the past 20 years has shown that shallow crustal degassing is an important factor contributing to the environmental impact of LIPs. Contact metamorphism in sedimentary basins can generate huge gas volumes, and operates as a function of magma volume and the architecture of LIP plumbing systems. Numerous open questions remain concerning the role of LIPs in triggering rapid and lasting changes, whose answers require collaboration across geoscientific disciplines. In this issue, we present the status of five key research themes and discuss potential ways forward to better understanding these large-scale phenomena.

Zircon double-dating, trace element and O isotope analysis to decipher late Pleistocene explosive-effusive eruptions from a zoned ocean-island magma system, Ascension Island

In this first detailed study of zircon from Ascension Island, South Atlantic, we take a novel approach combining trace element and O isotope compositional data with double-dating (disequilibrium 238U–230Th and (U–Th)/He) to decipher timescales and dynamics of magmatic processes. The Echo Canyon (EC) sequence comprises small-volume explosive-effusive eruptions of trachyte that tapped a compositionally zoned magma system. Associated volcanic hazards may be constrained from the age of volcanism, duration of magma storage, and magma source and plumbing system character. Zircon U–Th–Pb dating of lithic lava clasts has revealed recurrent evolved volcanism at 1.34 and 0.6 Ma, and 95 ka. The (U–Th)/He zircon cooling ages indicate that most of the EC explosive-effusive sequence erupted in a brief episode at ca. 95 ka. Additionally, uniform 238U–230Th zircon crystallisation ages suggest moderately protracted magma storage with melt present at depth for at most 103–104 years before eruption. The enriched character of zircon trace element compositions, relative to MORB, in the absence of a continental crustal signature in the oxygen isotope values (δ18O range 2.67–5.63‰), suggests the presence of an enriched component in the EC magma source. Furthermore, low δ18O zircon compositions imply assimilation of high temperature hydrothermally altered country rock by the source magma. The mineral assemblage in crystal-poor pumices indicates equilibrium storage conditions: zircon saturation and Ti-in-zircon crystallisation temperatures are consistent with alkali feldspar-melt temperatures. Significantly, zircon crystals were preserved both as macrocryst inclusions and in the groundmass of EC explosive and effusive deposits. These rocks preserve evidence of magma evolution by fractional crystallisation. This process led to pre-eruptive compositional stratification, which is evidenced in the range of whole-rock major and trace element compositions and zircon Zr/Hf values. Notably, zircon crystallisation and cooling ages derived from pumice, lava, and accidental lithic lava clasts in highly explosive pyroclastic deposits, have revealed episodes of evolved magmatism that would otherwise have gone undetected. In addition, the zircon trace element and isotope compositions, in combination with the range of crystallisation ages, evidence progressively deeper tapping of less evolved magma stored in discrete lenses. Thus, a combined zircon geochronological-geochemical approach can place constraints on the ca. 0.6 Ma recurrence of past explosive-effusive pulses of millennial to decamillennial duration and their enriched magma sources. This information is relevant for assessing hazards and informing monitoring and forecasting efforts to assist in managing associated risks for small ocean island volcanoes with particularly vulnerable populations and infrastructure.

Translithospheric magmatic plumbing system of a late Early Cretaceous intraplate volcano in NE China: Insights from geochemistry and phenocryst composition

The magmatic plumbing systems of intraplate volcanoes are key to understanding the structure of intraplate continental crust. A late Early Cretaceous volcano in NE China provides an opportunity to reconstruct the magmatic plumbing system of an intraplate paleo-volcano. ArAr and zircon SIMS UPb dating results indicate that olivine basalts formed at 102.81 ± 0.17 Ma and hornblende andesitic rocks formed at 101.1 ± 1.1 Ma–102.84 ± 1.2 Ma. Compared with coeval olivine basalts, the hornblende andesitic rocks have lower rare earth element (REE) abundance and parallel REE patterns, indicating that the basalts and andesitic rocks have independent origins. Olivine phenocrysts only occur in the basalts and are often zoned, with cores of Fo78–86 and rims of Fo62–68, the crystalline temperatures of olivine cores are 1204–1234 °C. The plagioclases from the basalt groundmass have An = 62–63. There are two types of plagioclase phenocryst in the andesitic rocks. One has An = 62–50, the other has An = 27–34.The former is normally zoned crystals (An = 62–50 from the core to rim) with high-An rims (60–63), similar in composition to plagioclase in the groundmass of the coeval basalt. They formed at temperatures of 1140–1162 °C and pressures of 4.7–7.0 kbar, implying that they were crystallized from basaltic melt with H2O contents of 0.60–0.82 wt%. The latter is low-An phenocrysts (27–34) with high-An (∼44) rims, suggesting that they were crystallized from felsic melt and that the injection of mafic magma had happened. The orthopyroxene phenocrysts only occur in andesitic rocks and have Mg# of 80–82, and are estimated to have crystallized at 6.7–8.5 kbar, and 1206–1222 °C, implying that they were crystallized from basaltic melt. The hornblende phenocrysts in andesitic rocks are pargasite, tschermakite, magnesio-hornblende, and magnesio-hastingsite and formed at 2.4–3.5 kbar and 883–957 °C. The estimated pressure and temperature of orthopyroxene and plagioclase (An>55) phenocrysts indicate that mafic magma chambers was located at depths of over 31.0 km, whereas those of hornblende phenocrysts show that felsic magma chamber was located at 8.9–12.8 km and has H2O content of 5.8–7.3 wt%. Using these data, we construct a new model of translithospheric magmatic plumbing system for intraplate volcanoes. Mantle-derived mafic magma chamber was emplaced at the crust–mantle boundary and causes partial melting of the lower crust, which in turn produces felsic magma that would be stored in a magma chamber in the upper crust. The mafic magma chamber at the crust-mantle boundary does not crystallize in-situ, as mafic magma could occasionally rise and be repeatedly injected and mix into the felsic magma chamber in the upper crust.

The evolution of Martian fissure eruptions and their plumbing systems

On Earth, the investigation of fissure eruptions and their deposits provide fundamental insights into the evolution of the subsurface volcanic plumbing system. On Mars, we have limited evidence of the spatiotemporal evolution of fissure-fed volcanic systems, and thus the processes operating within their subsurface-feeding dykes remain poorly understood. The timescales of eruptive activity and the longevity of the associated plumbing systems remain unknown for Martian fissure-fed volcanism. Here, we performed high-resolution mapping and age dating of a ∼ 90-km long volcanic fissure system to uniquely unravel the evolution of the volcanic eruptions and the associated plumbing system both spatially and temporally. We show that through time, eruptive activity evolved from highly mobile lava flows that erupted along the entire fissure length to viscous lava flows that erupted at a single location and built up a cone. These observations suggest that the subsurface plumbing system became more chemically differentiated and the magma flow localized from a dyke-like, linear source to a point source with time. Our detailed reconstructions also suggest a long-lived (at least ≳ 9 Ma), and active volcanic plumbing system. Therefore, we argue that spatiotemporal mapping constitutes a powerful approach to understand the dynamic nature of subvolcanic plumbing systems on planetary bodies.

Trace element and Sr-Nd-Hf-Pb isotope evidence for a multi-magma chamber system beneath the Deccan Volcanic Province, India

With a size of over 500,000 km2, the Deccan Volcanic Province (DVP) covers a large area of the Indian subcontinent. Stratigraphically continuous lava flows piled up to 3000 m record about five million years of volcanic activity. The peak activity of one million years coincides with the migration of the Indian subcontinent across the Réunion plume. Previous studies inferred an isotopic “common signature” for most DVP basalts that is best explained by a mixture of early Réunion plume-related melts and melts from the depleted upper mantle. Further chemical variability of the DVP sequence was explained by the incorporation of material from the lithospheric mantle and continental crust possibly within a single magma chamber system. Yet, indications for a complex crustal magmatic system have also been brought forward by earlier studies and find recently more support in explaining the magmatic plumbing system of the DVP and Large Igneous Provinces in general.This study presents new major and trace element data, including high-precision concentration measurements of high-field strength elements by isotope dilution and Sr-Nd-Hf-Pb isotope compositions for basaltic samples that cover nearly the complete DVP main section. Based on significant variations in Nb/Th (and Th/Ta) over a wide range of MgO concentrations we identified three distinct magma differentiation trends. The distinct differentiation trends result from three types of parental melts that are best explained by different proportions of lower and upper mantle melts indicated by diluted Réunion plume-like trace element and isotope compositions. During their ascent, these separate melts assimilated variable amounts of metasomatized lithospheric mantle and crustal material. Most likely the assimilation occurred before any major differentiation events, thus fixing the Nb/Th (and Th/Ta) of each group regardless of the degree of differentiation. The chemical trends can also be replicated using a statistical numerical approach, confirming that their geochemical signature truly reflects individual differentiation of three distinct parental melts. Field relations require that lavas related to these three unique differentiation trends erupted contemporaneously. This is in contrast to the idea of a gradually evolving single magma chamber system and the concept of a general chemostratigraphy for the DVP main plateau. Rather, our study reveals fast-changing contributions of different mantle reservoirs and provides new insight into the magma-plumbing systems of Large Igneous Provinces that may be more complex.

Impact of fixture purging on water age and excess water usage, considering stochastic water demands

Higher water ages are linked with water quality decline as chlorine dissipates, temperatures become more favorable for microbial growth, and metals and organic matter leach from the pipes. Water fixtures with automated purging devices can limit water age in premise plumbing systems, but also increase water use. To develop purging strategies that lower age while also minimizing water use, the stochastic nature of water demands must be considered. In this research, a hydraulic plumbing network model, with stochastic demands at fixtures, was used to compare water age and water use for five purging conditions: purging at regular intervals, “smart” purging (considering the time of last use), purging with different volumes of water, purging at different fixtures, and the purging with different levels of home occupancy. Higher purging frequency and volume resulted in lower water ages, but higher water use. Purging greatly reduced the variability in water ages, avoiding extreme ages entirely. Water age was minimized by scheduling the purging around occupancy behavior, such as before the occupants wake up or return from work. Scheduled purging used more water than smart purging. Purging after 12 h of nonuse used only 55% of the additional water required for purging every 12 h. Purging after 24 h of nonuse at the kitchen tap and shower used only 38% of the additional water required for purging every 24 h, while maintaining lower water ages and removing the variability in water ages. While larger purging volumes had a greater impact on water age, there were diminishing returns. Purging has a larger impact on low-occupancy homes because fixtures have less frequent use. Overall, this research provides a methodology to compare purging strategies that minimize both water age and water use. While the numerical results presented here are only valid for the specific layout and usage habits, they provide insights and trends applicable to other cases.

Magma plumbing architectures and timescales of magmatic processes during historical magmatism on the Reykjanes Peninsula, Iceland

In the past 4000 years, three rifting episodes have occurred on the Reykjanes Peninsula (RP, SW Iceland) at time intervals of about 800-1000 years, with the activation of four of the five volcanic systems on the peninsula: Reykjanes, Svartsengi, Krýsuvík and Brennisteinsfjöll. In 2021 AD, 2022 AD and 2023 AD, three eruptions occurred in the Fagradalsfjall volcanic system, the only volcanic system that remained inactive during these past rifting episodes. Considering the eruptive history of the peninsula, this could mark the onset of a new eruptive episode. Although extensive petrochemical datasets have emerged from past rifting episodes, little is known about magma plumbing configuration and timescales of pre-eruptive magmatic processes. In this work, we focus on 16 basaltic lava units erupted across RP during a well-established rifting episode: the 800-1240 AD Fires. We analysed major and minor element contents of glasses, mineral phases and melt inclusions, and we reconstruct plumbing system architecture and constrain mixing-to-eruption timescales, with the goal of assessing likely eruption scenarios of a possible future eruptive episode. Mineral-melt equilibria suggests that most of crystal cores are antecrysts that did not crystallize from the magmas that carried them to the surface, but instead were scavenged from disaggregating mush layers genetically related to the erupted magmas. Magmas erupted in the easternmost part of the RP reveal larger contributions from geochemically enriched mantle-derived melts. However, MIs that record various extents of mixing of geochemically enriched and depleted components throughout the entire peninsula appear devoid of any spatial control of the underlying mantle. Independent clinopyroxene-melt and melt-based barometry, after correction for microlite crystallization, show consistent results and suggest that magmas from the western part of the peninsula were extracted from reservoirs located at about 7-10 km depth. In contrast, and similar to observations from recent eruptions at Fagradalsfjall, the easternmost system, Brennisteinsfjöll, was fed from deeper crustal reservoirs, at about 14-21 km depth. Fe-Mg diffusion chronometry applied to olivine rims suggests short mixing-to-eruption timescales on the order of days to weeks and likely faster ascent rates of magmas underneath Brennisteinsfjöll. Compared to 2021 AD Fagradalsfjall, mixing-to-eruption timescales were considerably shorter during the 800-1240 AD Fires. With inferred eruption durations on the order of months, the short olivine rim diffusion records are consistent with several discrete eruptive phases, which eventually assembled the individual magmatic units. In the light of possible future eruptive episodes on the RP, our work suggests that magmas are likely to accumulate at persistent depths across the RP, with key implication for interpreting pre-eruptive signals and eruption mitigation.

Capturing Mayotte's deep magmatic plumbing system and its spatiotemporal evolution with volcano-tectonic seismicity

Since 2018 an unexpected number of earthquakes have been occurring offshore Mayotte, in the Mozambique Channel. They are linked to the eruption of the Fani Maoré submarine volcano. Using a recently-developed comprehensive automatic catalog, we explore two years of volcano-tectonic (VT) seismicity between March 2019 and March 2021 and analyse in detail the active structures of the magmatic plumbing system using ~33,000 events. The VT earthquakes highlight three magma storage zones and two aseismic conduits that had never been observed before. The temporal evolution of the seismicity reveals a probable regime change in March 2020. While before, the plumbing system reacted to the drainage of magma from a deep reservoir and to the migration of magma towards the seafloor, it is now responding to new migrations of fluids and to the redistribution of the stress-load across the system's pre-existing faults. This analysis is key to better understand long-term volcanism worldwide.

Basaltic sills emplaced in organic-rich sedimentary rocks: Consequences for organic matter maturation and Cretaceous paleo-climate

Many continental large igneous provinces coincide with climate perturbations and mass extinctions. When basaltic plumbing systems traverse carbon-rich sedimentary rocks, large volumes of greenhouse gases may be generated. We document how intrusive sills of the Mesozoic High Arctic Large Igneous Province affected surrounding fine-grained, organic-rich siliciclastic rocks of the Sverdrup Basin in the Canadian Arctic Archipelago. Petrographic and X-ray diffraction data from samples located near sills show the presence of high-temperature metamorphic phases (diopside, andalusite, garnet, and cordierite). Raman thermometry on organic matter yields peak temperatures of 385−400 °C near sill contacts, tailing off to far-field temperatures of ≤230 °C. Samples located >20 m from sills show no systematic change in vitrinite reflectance and have a VRo eq% value of ∼2.5%, which indicates a temperature of ∼210 °C. The finite element thermal modeling tool SUTRAHEAT was applied to the 17-m-thick Hare Sill, emplaced at 3 km depth at 1105 °C. SUTRAHEAT results show that contact-proximal rocks attain temperatures of >700 °C for a brief period (∼1 year). By 5 years, the Hare Sill is completely solidified (<730 °C), and the temperature anomaly collapses rapidly thereafter as the thermal pulse propagates outward. By 10 years, all rocks within 10 m of the Hare Sill are between 450 °C and 400 °C, rocks at 20 m from the contact attain 200 °C, yet far-field temperatures (>50 m) have barely changed. When multiple sills are emplaced between 4 km and 6 km depth, all rocks between sills reach ∼250 °C after 100 years, showing that it is possible to raise regional-scale background temperatures by ∼150 °C for the observed High Arctic Large Igneous Province sill density. Vitrinite reflectance data and pyrolysis results, together with SILLi thermal modeling, indicate that much of the hydrocarbon-generating potential was eliminated by High Arctic Large Igneous Province intrusions. The SILLi model yields ∼20 tonnes/m2 of organic equivalent CO2 (all carbon gas is reported as CO2) from the Hare Sill alone when emplaced into Murray Harbour Formation rocks with 5.7 wt% organic carbon, and ∼226 tonnes/m2 by emplacement of multiple sills throughout the 2-km-thick Blaa Mountain Group with 3 wt% organic carbon. On a basin scale, this yields a total of ∼2550 Gt CO2 from the Hare Sill, with ∼13,000 Gt CO2 being generated by the multiple sill scenario, similar to estimates from other large igneous provinces. Much of the Blaa Mountain Group rocks now have organic carbon contents of <1 wt%, which is consistent with large volumes of carbon-species gas having been generated, likely a mixture of CO2, CH4, and other species. However, organic-rich Murray Harbour Formation rocks show no obvious reduction in organic carbon content toward the Hare Sill intrusive contacts, which suggests that not all of the carbon was lost from the sedimentary package hosting High Arctic Large Igneous Province magmas. We suggest that some of the gas generated by contact metamorphism failed to drain out for lack of high-permeability conduits, and then back-reacted to form calcite cements and pyrobitumen during cooling.

Heterogeneous mush-dominated plumbing system and mantle sources of alkaline lamprophyres in Tuoyun Basin, SW Central Asian Orogenic Belt

Lamprophyres are spatially and temporally widespread in continental belts, but their magmatic differentiation process and melting dynamic mechanisms remain subjects of debate. In this study, we report mineral chemistry, bulk-rock compositions, and Sr-Nd-O isotopes of the alkaline lamprophyres (including monchiquite and camptonite) from the Tuoyun Basin of the southwestern Central Asian Orogenic Belt. Based on the P-T estimates, transcrustal magmatic reservoirs from the lower crust to upper crust are revealed for monchiquite and camptonite. These magmatic reservoirs were potentially connected, and the magmatic recharge and mixing processes that occurred were recorded by zoned clinopyroxene and amphibole. The diverse crystal populations are suggested to have originated from multiple batches of magmas, which were then involved in forming the subsequent magmas. The Sr-Nd isotopic compositions are relatively depleted, with (87Sr/86Sr)i = 0.70390−0.70452 and εNd(t) = 5.46−6.49 for the monchiquite, while the values for camptonite are 0.70391−0.70463 and 4.71−5.02. Moreover, the olivine in situ O isotopes in the monchiquite show δ18OV-SMOW values of 4.81‰−5.40‰, which are comparable to those of the mantle peridotite. Compared with the experimental melts, a hybridized mantle source of hydrous peridotite + silica-depleted pyroxenite is proposed, and partial melting of this component was induced by the upwelling asthenosphere. Ultimately, our study highlights the critical role of the magmatic plumbing system and hydrous mantle source in the formation of Tuoyun lamprophyres.

Concealed architecture, volcanism and tectonics of Deccan LIP related alkaline complexes of Rajasthan, NW India: Constrained from high resolution aero-geophysical data

In the north-western Indian shield two important alkaline complexes (Sarnu-Dandali and Mer-Mundwara) are linked to end-Cretaceous Deccan large igneous province (LIP) bear significance for REE mineralization, CO2 outgassing and mass extinctions near the K-Pg boundary. Although both of them bear numerous similarities, but, the geomorphology and magmatic emplacement are quite conflicting. Here, the subsurface crustal architecture of these two alkaline complexes is reported for the first time on the basis of high resolution airborne geophysical anomaly data (magnetic and spectrometric). Aeromagnetic anomalies distinguish prominent NW-SE and E-W trending linear deep seated crustal structures in the Sarnu-Dandali alkaline complex. The E-W trending structure mimics the older tectonic tendencies of the regional crustal-scale Narmada-Tapti tectonic zone. The NW-SE trending linear are linked to subsurface rift-oblique networks of fault systems of the petroliferous Barmer basin. The ensemble of numerous fracture patterns at various depths may attest to the rejuvenation of fracture systems and recurrent magmatism, leading to the polychronous nature of Sarnu-Dandali alkaline complex. On the contrary, the Mer-Mundwara alkaline complex exhibits broad magnetic circular features representing the deeper sections of a magmatic plumbing system. The geometry also resembles the subsurface magma chambers for Deccan basalt volcanism, occurring as rootless cones. Paleo stress pattern is derived from the fractures and when compared with the results obtained from geophysical data, these analyses demonstrate a high degree of compliance, reinforcing the validity and accuracy of both methods. Further, the inversion modeling, profile depth analysis and computed Euler depth solutions led us to infer that the subsurface magma sources of the Sarnu-Dandali are deeper than those of the Mer-Mundwara alkaline complex.

Post-rift magma plumbing system in the northern Great South Basin, New Zealand

Late Cretaceous magmatism has been widely documented in the Great South Basin (GSB) of New Zealand, which is mainly relevant to the Gondwana break-up (105–83 Ma) and the separation of Zealandia from Australia and Antarctica (83–66 Ma). However, the magma plumbing system in the GSB is still poorly understood. In this study, we used a high-resolution 3D seismic reflection data to investigate the igneous intrusions that developed in the northern part of GSB. These igneous intrusions occurred from ∼75 Ma to ∼58 Ma that corresponded to the spreading of the Tasman Sea and the Southern Ocean. Most of the igneous intrusions developed above listric faults which formed during rifting stage. Moreover, dykes are also observed between the listric faults and igneous intrusions. Listric faults, dykes and sills formed the magma plumbing system of GSB. This study explored the possible origin of post-rift magmatism in the GSB, and addressed the post-rift magma plumbing system in detail, which greatly promoted the understanding of GSB’ evolution, resource exploration and marine geological hazard assessment.

The space-time architecture variation of the shallow magmatic plumbing systems feeding the Campi Flegrei and Ischia volcanoes (Southern Italy) from halogen constraints

The space-time architecture variation of the shallow magmatic plumbing systems feeding the Campi Flegrei and Ischia volcanoes (Southern Italy) from halogen constraints

Flushing Home Plumbing Pipes Contaminated with Aqueous Film-Forming Foam Containing Per- and Polyfluoroalkyl Substances.

Per- and polyfluoroalkyl substances (PFAS) from aqueous film forming foam (AFFF) can be accidentally backflushed into drinking water systems during firefighting operations or at industrial facilities. If this contaminated water enters household plumbing systems, homeowners may need to decontaminate their plumbing. This study examines the persistence of PFAS from AFFF on home plumbing, along with the effects of flushing and stagnation. Two sources of AFFF were investigated, representing older formulations (that contain longer chain PFAS) and newer formulations (that contain shorter chain PFAS). Experiments were conducted in copper, polyvinyl chloride (PVC), and cross-linked polyethylene (PEX) pipes with flushing after contamination followed by intermittent flow and periods of stagnation meant to mimic typical household use. Flushing immediately reduced the PFAS concentration in water leaving the pipe by 99.95% to 99.99%. However, PFAS concentration increased after periods of stagnation, corresponding to slow release of adhered PFAS. Flushing may be a valuable part of the decontamination process, but flushing parameters and duration need to be optimized for local conditions.

Alkaline magmas in shallow arc plutonic roots: a field and experimental investigation of hydrous cumulate melting in the southern Adamello batholith

Despite the first-order importance of crystallisation–differentiation for arc magma evolution, several other processes contribute to their compositional diversity. Among them is the remelting of partly crystallised magmas, also known as cumulate melting or ‘petrological cannibalism’. The impact of this process on the plutonic record is poorly constrained. We investigate a nepheline-normative dyke suite close to the Blumone gabbros, a large amphibole-gabbro unit of the Tertiary Southern Alpine Adamello igneous complex. The compositions of the studied dykes are characterised by low SiO2 (43–46 wt. %), MgO (5.0–7.2 wt. %), Ni (18–40 μg/g), and high Al2O3 (20.2–22.0 wt. %) contents. Phenocrystic plagioclase in these dykes exhibits major, trace, and Sr isotope compositions similar to Blumone cumulate plagioclase, suggesting a genetic link between the nepheline-normative dykes and the amphibole-gabbro cumulates. We tested this hypothesis by performing saturation experiments on a nepheline-normative dyke composition in an externally heated pressure vessel at 200 MPa between 975 and 1100 °C at fO2 conditions close to the Ni–NiO buffer. Plagioclase and spinel are near-liquidus phases at and above 1050 °C, contrasting with the typical near-liquidus olivine ± spinel assemblage in hydrous calc-alkaline basalts. The alkaline nature of the dykes results from the abundance of amphibole in the protolith, consistent with melting of amphibole-gabbro cumulates. We modelled the heat budget from the repeated injection of basaltic andesite into a partly crystallised amphibole-gabbro cumulate. The results of this model show that no more than 7% of the cumulate pile reaches temperatures high enough to produce nepheline-normative melts. We propose that such nepheline-normative dykes are a hallmark of hydrous cumulate melting in subvolcanic plumbing systems. Therefore, ne-normative dykes in arc batholiths may indicate periods with high magma fluxes.

Frontiers of thermobarometry: GAIA, a novel Deep Learning-based tool for volcano plumbing systems

The anatomy of the plumbing system of active volcanoes is fundamental to understand how magma is stored and channeled to the surface. Reliable geothermobarometric estimates are, therefore, critical to assess the depths and temperatures of the complex system of magmatic reservoirs that form a volcano apparatus. Here, we developed a novel Machine Learning approach (named GAIA, Geo Artificial Intelligence thermobArometry) based upon Feedforward Neural Networks to estimate P-T conditions of magma (clinopyroxene) storage and migration within the crust. Our Feedforward Neural Network method applied to clinopyroxene compositions yields better uncertainties (Root-Mean-Square Error and R2 score) than previous Machine Learning methods and set the basis for a novel generation of reliable geothermobarometers, which extends beyond the paradigm associated to crystal-liquid equilibrium. Also, the bootstrap procedure, inherent to the Feedforward Neural Network architecture, permits to perform a rigorous assessment of the P-T uncertainty associated to each clinopyroxene composition, as opposed to the Root-Mean-Square Error representing the P-T uncertainty of whole set of clinopyroxene compositions.As a test, we applied GAIA to assess P-T conditions of five Italian volcanoes (Somma-Vesuvius, Campi Flegrei, Etna, Stromboli, Volcano), which are among the most dangerous volcanic centres in Europe. The results on the depths of the plumbing systems are in excellent agreement with those obtained with independent geophysical and geodetic surveys, and provide further evidence to current models of volcano plumbing systems consisting of physically-separated reservoirs interconnected by a network of conduits channelling magma en route to the surface. The results on the magma (clinopyroxene crystallization) temperatures are also in agreement with other estimates, albeit obtained considering - mainly but not only - thermodynamically-based clinopyroxene-liquid geothermometers.GAIA can set robust estimates of magma storage, segregation, and ascent conditions within the plumbing system of active volcanoes, helping to unravel P-T variations, if any, during their eruptive history and providing robust clues to volcanic hazard assessment.

Shotgun Metagenomics Reveals Impacts of Copper and Water Heater Anodes on Pathogens and Microbiomes in Hot Water Plumbing Systems.

Hot water building plumbing systems are vulnerable to the proliferation of opportunistic pathogens (OPs), including Legionella pneumophila and Mycobacterium avium. Implementation of copper as a disinfectant could help reduce OPs, but a mechanistic understanding of the effects on the microbial community under real-world plumbing conditions is lacking. Here, we carried out a controlled pilot-scale study of hot water systems and applied shotgun metagenomic sequencing to examine the effects of copper dose (0-2 mg/L), orthophosphate corrosion control agent, and water heater anode materials (aluminum vs magnesium vs powered anode) on the bulk water and biofilm microbiome composition. Metagenomic analysis revealed that, even though a copper dose of 1.2 mg/L was required to reduce Legionella and Mycobacterium numbers, lower doses (e.g., ≤0.6 mg/L) measurably impacted the broader microbial community, indicating that the OP strains colonizing these systems were highly copper tolerant. Orthophosphate addition reduced bioavailability of copper, both to OPs and to the broader microbiome. Functional gene analysis indicated that both membrane damage and interruption of nucleic acid replication are likely at play in copper inactivation mechanisms. This study identifies key factors (e.g., orthophosphate, copper resistance, and anode materials) that can confound the efficacy of copper for controlling OPs in hot water plumbing.

Surfactant-Assisted Synthesis of Bismuth Oxychloride Nanoflowers for Electrochemical Sensing of Heavy Metal Ions

Heavy metal ion contamination of drinking water is a significant, invisible threat to public health which requires active and decentralized monitoring with high sensitivity, accuracy and reliability. The government and regulatory agencies actively survey and maintain established limits on heavy metal contamination, but generally prioritizing localized hotspots in high-risk communities. Their characterization techniques are typically expensive and inaccessible to the public, requiring specialized training and extended sample shipping times, with a purview restricted to public infrastructure. As plumbing systems corrode and contaminants leach into drinking water systems, independent means of oversight are becoming increasingly vital in effectively identifying and mitigating toxic exposure. In this work we propose the development and application of a high surface area bismuth oxychloride nanoflower for the electrochemical detection of zinc and lead ions in drinking water. The flower structure was synthesized via hydrolysis of bismuth chloride salt in a micellar environment of sodium dodecyl sulfate, followed by aqueous chemical reduction and transformation to metallic bismuth. The size and uniformity of the synthesized nanoflower was characterized with scanning electron microscopy (SEM), and the composition and microstructure were investigated using energy dispersive x-ray spectroscopy (EDS) analysis and x-ray diffraction (XRD). The nanoflowers were deposited onto a glassy carbon electrode and coated with a protective Nafion layer, prior to cyclic voltammetry analysis of analyte ion reactivity, achieving detection of lead and zinc ions in buffer and practical drinking water samples. These results indicate the viability of bismuth-based nanoflower structures for portable, accessible detection of heavy metal ions, with enhanced sensitivity.

Comparative Study of Bill of Quantity Planning and Actual Work Mechanical, Electrical and Plumbing Construction of Hospital Buildings

One important aspect in the planning process of a project is the calculation of the volume of work or commonly known as the Bill of Quantity (BoQ). BoQ itself is a document detailing the type of work, volume and unit of measurement of all work items to be carried out to determine the final estimated value of a construction job. Calculation of the volume of work will be carried out based on the Work Plan and Conditions (RKS) and drawings that have been approved by the owner. In the construction industry, MEP or Mechanical, Electrical, and Plumbing is an important factor to realize a building or buildings whose installation system is safe and of good quality. MEP itself is the expertise to plan, design, and manage mechanical, electrical, and piping systems in a building. The actual BoQ results were 5.74% greater than the planned BoQ caused by changes in the work of installing the plumbing system. As well as the most influential factors were changes in design drawings that did not match the conditions in the field and incomplete design drawings.

Hydrogeologic and magmatic controls on phreatomagmatism at the La Garrotxa monogenetic volcanic field (NE of Iberian Peninsula)

Phreatomagmatism caused by direct interaction of erupting magma and groundwater is a common phenomenon accompanying monogenetic volcanism. The controls on the type of phreatomagmatic phases and deposits that can be observed in such eruptions have been attributed to magma ascent rate, magma rheology, magma discharge, magma vesiculation, water availability, and the properties of the interacting aquifer (i.e., permeability, pore water pressure, recharge rate, etc.). The La Garrotxa monogenetic volcanic field displays a wide variety of eruption sequences and deposits among its 50 volcanoes, half of them including phreatomagmatic phases with very distinct characteristics. Using the characteristics of the phreatomagmatic deposits, including the lithology and content of the accidental lithic fragments, and the substrate stratigraphy and its hydrogeology through the analysis of available information on the water wells and boreholes of the area, it is evident that several aquifers with very different lithologic and hydraulic properties have interacted with the erupting magmas. Moreover, these same data show that all the phreatomagmatic explosions nucleated at a maximum depth of 200 m. These results suggest that pressure variations inside the eruptive conduit, caused by changes in the recharge rate from the magmatic plumbing system, have played a major role in controlling phreatomagmatism, rather than due to variation of the lithological and hydraulic properties of aquifers.