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The National Science Education Standards (NSES; National Research Council [NRC], 1996) include Science and Technology as one of the eight categories of content standards. The science and technology standards establish connections between the natural and designed worlds and provide students with opportunities to develop decision-making abilities. As a complement to the abilities developed in the science as inquiry standards, these standards call for students to develop abilities to identify and state a problem, design a solution--including a cost and risk-and-benefit analysis--implement a solution, and evaluate the solution. Both standards emphasize student development of abilities and understanding. Scientists in different disciplines ask different questions, use different methods of investigation, and accept different types of evidence to support their explanations. Many scientific investigations require the contributions of individuals from different disciplines, including engineering. Science often advances with the introduction of new technologies; solving technological problems, in turn, often results in new scientific knowledge. Further, new technologies often extend the current levels of scientific understanding and introduce new areas of research. In this article a volcano activity is presented using a Go! Temp temperature probe to support science and technology learning and teaching as incorporated in NSES.

When Mount St. Helens threatened to erupt again in 2004, it grabbed headlines and captured the imagination of the country. Science classrooms nationwide used the event as an opportunity to make real-world connections to Earth science concepts introduced in the classroom. Thanks to modern technology, teachers no longer have to wait for the next eruption to take advantage of students natural interest in volcanoes. Using a variety of media, classes can now explore these forces of nature in a variety of ways--all from a safe distance! This article describes a variety of resources for teachers can use to launch in-depth studies of volcanoes--far from any hot ash or lava flows--online, in print, and on-screen. Brief lists of related resources; Web sites; and lesson plan links are also included.

Volcanic activity will be experienced differently in a warmer world. Researchers need to understand these risks and how they could spiral. [ABSTRACT FROM AUTHOR]

Volcano deformation models contribute to hazard assessment by simulating magma system dynamics. Traditional magma reservoir pressure source shape assumptions often fail to replicate irregular, geophysically identified geometries. Uncertainties regarding the influence of reservoir geometry can limit the effectiveness of using deformation models to decipher unrest signals. Here, we aim to determine the feasibility of using a magma reservoir geometry directly derived from a seismic tomography survey in a volcano deformation model for Soufrière Hills Volcano, Montserrat. Three‐dimensional deformation models are created to simulate displacement using a pressure source geometry constrained from a low seismic velocity anomaly, inferred to be a region of partial melt, and contrasted against a traditional ellipsoid reservoir geometry. We also test a "hybrid" model combining a seismically inferred reservoir upper geometry and ellipsoidal base. Results of each model are evaluated against ground displacement observed on Montserrat from 2010 to 2022. Our results show that different reservoir geometries change the horizontal and vertical displacement fields across the island: the ellipsoid reservoir best reproduces vertical displacement magnitude, while the hybrid reservoirs best simulate horizontal displacement vectors and the region of maximum uplift. Overall, the ellipsoid‐shaped reservoir provides our best‐fit to the observed data, but we note this result could be biased due to prior years of optimization helping constrain the ellipsoid shape, size, and location. Our results show the potential for further use of geophysically constrained reservoir geometries in deformation modeling, and our methods could be applied to other deforming volcanoes worldwide. Plain Language Summary: Volcano deformation models are used to simulate volcanic processes at depth to inform hazard assessment in volcanically active areas by comparing modeled results to observed ground surface deformation. Traditional models use spherical or ellipsoidal magma reservoir geometries, not realistic compared to the irregular and complex structures identified in geophysical surveys. The study presented here uses a geophysically defined magma reservoir geometry in a deformation model for the case study area of Soufrière Hills Volcano, Montserrat. A traditional ellipsoid reservoir and two "hybrid" reservoirs that combine the upper surface of the geophysical reservoir with a simplified base are also modeled. The results of each model are compared to GPS data from 2010–2022 to identify the best fitting reservoir geometry to observed ground deformation. Our results indicate that changing the reservoir geometry changes the direction and magnitude of deformation, with the hybrid reservoir best reproducing the direction of horizontal displacement and the region of maximum uplift. Despite this, the ellipsoid reservoir best replicates overall deformation, but we note that years optimizing the shape, size and location of the reservoir may bias the result. Our results show it is feasible to use a geophysically derived magma reservoir in volcano deformation models. Key Points: We test seismically inferred magma reservoir geometries in a volcano deformation model, compared against typical simple geometries and hybrid combinationsSimple ellipsoid reservoir geometry best replicates total overall deformation at Soufrière Hills Volcano, but hybrid reservoir shows promiseDifferent reservoir geometries better replicate observed deformation at different parts of the island [ABSTRACT FROM AUTHOR]

The Eastern Pontide Orogenic Belt (EPOB), a well-preserved palaeo-magmatic arc, exists south of the Black Sea, from Bulgaria to Georgia. The region, which forms an essential part of the Alpine-Himalayan belt, contains volcanic rocks formed in the Late Cretaceous. This paper aims to investigate the petrogenesis of the Late Cretaceous volcanic rocks using both new and previously existing geochemical and geochronological data. Based on the geochemical features, the studied volcanics are divided into Group I (dacite/rhyolite) and Group II (basalt/basaltic andesite). According to LA-ICP-MS zircon U–Pb data, the crystallization age of Group I is 83.43 ± 0.87 Ma. The εNd(t) values of Group I are −1.4 and + 4.5, and the εNd(t) value of Group II is +3.0. The Lu–Hf isotope data from zircon shows that Group I have positive εHf(t) values (+14.20 - +12.15), and their crustal model age is 240–339 Ma. The εHf(t) values indicate that the Group I rocks are derived from the melting of a depleted mantle source. Whole-rock geochemistry data show that Group II samples were formed by partial melting of metasomatised spinel-bearing lherzolites at shallow depths. It is thought that the Late Cretaceous volcanic rocks are the products of arc magmatism associated with the northward subduction of the Neotethys oceanic lithosphere under the Eurasian plate, and the EPOB was an active continental margin arc during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

This study presents new analytical data for the Ulukale porphyritic dome located within the Neogene Tunceli volcanic rocks, as well as whole rock geochemistry and Sr–Nd isotope data for the Çağlarca radial dykes for the first time. The Ulukale porphyritic dome and the Çağlarca radial dykes, have trachyandesite composition. On trace element diagrams normalized to primitive mantle, samples from the dome and dykes have similar features. Whole-rock geochemistry data for the investigated volcanic rocks indicate they formed from low-degree of partial melting of spinel lherzolite at shallow depths. Accordingly magmatism forming the dome appears to have more acidic composition. Sr–Nd isotope data (εNd(T) value –2.0 and –1.7) for both rock groups indicate a lithospheric subcontinental mantle source. All geochemical data indicate these volcanic rocks had source magma with lherzolitic features which underwent low-degree of partial melting; however, fractional crystallization, magma mixing, contamination in the form of continental crust effects and the effect of subduction-linked sediment melts were shown to be important during magma differentiation. Additionally, all this data shows that these volcanic rocks have the same petrological features as the Tunceli Volcanics, the main product of this magmatism. [ABSTRACT FROM AUTHOR]

The northwestern part of the Sevan–Shirak structural formation zone of the Lesser Caucasus contains ultra-high-K siliceous ignimbrites dating back to the Late Eocene–start of Early Oligocene (?), which associate with high-K volcanics of the calc-alkaline and shoshonite series. During Eocene–Oligocene time the Sevan–Shirak zone was an ensialic island arc with a Hercynian metamorphic basement. The formation of high-K and especially ultra-high-K rocks was due to the effects of mantle fluids on the continental crust. [ABSTRACT FROM AUTHOR]

New mineralogical–petrographical and isotope-geochemical data, as well as numerical simulation results, suggest that high-magnesian basalts and basaltic andesites of the eastern block of the Talmi volcanic structure formed as a result of crystallization differentiation during the rapid ascent of mantle magmas to a depth of ∼7.5 km, under conditions of relatively low oxygen fugacity and water content. We consider acid volcanics (SiO2 ∼76–78 wt %) of the central block as crustal melts, the mixing of which with mantle melts in shallow peripheral chambers leads to the appearance of andesites with numerous mineralogical and geochemical signs of hybridism. The geodynamic position of Triassic volcanism is governed by a transtensional regime under conditions of regionally manifested submeridional compression. [ABSTRACT FROM AUTHOR]

The Mamonia Mélange in the Ayia Varvara area (southwestern Cyprus) is characterized by a matrix supported mélange which is composed of tectonized siltstones and mudstones with numerous blocks that were derived from the Mamonia Allochthonous Complex (Petra tou Romiou Formation reefal limestones, Phasoula Formation volcanics, Kholetria Member pelagic limestones, Akamas Member sandstone, Parekklisha Member sandstone, Ayia Varvara Formation metamorphics and Episkopi Formation radiolarian cherts). Subordinate blocks were derived from the Troodos Ophiolite Complex: serpentinites, gabbro, pillow lavas and cherty umbers (Perapedhi Formation). Radiolarian assemblages from chert blocks display a broad spectrum in age, ranging from the Late Triassic (latest Carnian–early Norian) to the youngest Cenomanian. The composition of the mélange in the Ayia Varvara area differs from the one described in the Petra tou Romiou area (SW Cyprus), as various lithologies were recorded (like Akamas Member sandstone and Parekklisha Member sandstone) which were not detected previously. The Mamonia Mélange was formed during the Late Cretaceous, most probably after the end of deposition of the Perapedhi Formation (late Santonian–early Campanian). [ABSTRACT FROM AUTHOR]

Magma fragmentation is an essential process driving explosive volcanic eruptions, generating a distribution of pyroclasts with characteristic shape and grain size. These characteristics are often used to inform on the energetics of magma fragmentation and the associated eruption style and intensity. However, a portion of these pyroclasts, droplets when still in the molten state, are likely to be generated through impact mechanisms (i.e., collisions), and subsequent secondary fragmentation (i.e., splashing). Here, we successfully apply and dynamically scale concepts and findings of liquid droplet impacts in engineering to magma fragmentation processes in volcanology. We compile and model physical data for two mafic melt compositions (kimberlite and basalt) and use specific eruption examples from Igwisi Hills, Kīlauea and Stromboli volcanoes to define composition‐specific impact dynamics. Pyroclast impact dynamics have a direct control on in‐conduit processes, eruption dynamics, and ash dispersal. For low viscosity mafic melts such as kimberlite and basalt, pyroclast impacts can lead to both splash and deposition on the conduit wall, resulting either in conduit clearing or conduit narrowing, respectively. In both cases, shifting the impact regime toward surface deposition will lead to an inexorable decay in explosiveness, potentially switching the eruption style to effusive behavior. This has direct consequences for the transport of volcanic ash at the surface and inferring magma fragmentation processes (e.g., energies) from the depositional record. Plain Language Summary: During explosive eruptions, magma is ripped apart to form a distribution of incandescent fragments, termed pyroclasts, of different sizes and shapes. These characteristics are often used to forensically reconstruct eruption dynamics. For explosive volcanic eruptions of low viscosity magmas, fragmentation dynamics often resemble water spraying with the generation of droplets. In volcanoes, and under certain conditions, magma droplets can impact a surface or each other and further fragment, splashing into finer droplets. Such liquid impact dynamics have been long researched in engineering but seldom considered in volcanology. Here, we apply and scale the concepts of liquid impacts from engineering to volcanic processes. We compiled data for ultramafic and mafic magma compositions, which are characterized by different physical properties that influence the impact outcomes (e.g., splash vs. surface deposition). Droplet impacts may lead to splashing or sticking against the conduit wall. For example, under prolonged deposition conditions, progressive narrowing of the conduit could lead to eruption termination or switch to pure lava effusion. Finally, we show that droplet impacts are likely to control the final size of pyroclasts produced during ultramafic and mafic explosive eruptions, and therefore must be considered when interpreting the rock record from related past events. Key Points: Liquid droplet impacts are relevant to magma fragmentation processes in volcanologyMagma composition and ejection velocity are the main factors controlling pyroclast impact dynamicsTransitions between pyroclast splash and deposition can contribute to eruption style transitions and eruption dynamics [ABSTRACT FROM AUTHOR]

Submarine volcanic eruptions can induce major local and regional tsunami hazards through varied source mechanisms. Large‐scale experiments of tsunamis generated by submarine volcanic eruptions are conducted to study the cylindrical wave generation and propagation in a three‐dimensional wave basin. A unique volcanic tsunami generator (VTG) was deployed at the bottom of the wave basin to generate volcanic tsunamis with repeatable and controlled source parameters. The physical modeling is based on the generalized Froude number defined with the VTG velocity and the near source water depth. The pneumatically driven vertical stroke motion generates leading elevation waves in the wave basin. The tsunami waves generated by the VTG are measured with a wave gauge array. The wave maker performance is characterized by the dimensionless leading wave amplitudes and periods. The experimental data show the variations of the leading wave amplitude, period, and celerity along the radial propagation distance. The generated cylindrical waves belong to the weakly nonlinear wave regime in the near field with decaying wave amplitude along radial propagation. The attenuation rate of the leading wave exceeds the range from the linear wave theory in runs with higher Froude numbers. The dimensionless leading wave period increases with the dimensionless propagation distance due to the dispersion relation. Empirical equations for the characteristic wave parameters such as amplitudes and periods are derived. The experimental results contribute to the understanding of volcanic tsunami generation processes and may serve rapid volcanic tsunami hazard assessments as well as the advancement and validation of numerical models. Plain Language Summary: Tsunami hazards generated by non‐tectonic sources such as submarine volcanic eruptions have received more attention recently to understand their generation mechanisms and advance tsunami warning systems. Underwater eruptions with explosive energy can trigger catastrophic tsunamis such as the 1883 Krakatau and 2022 Tonga events. It's generally dangerous to directly observe an eruption and particularly challenging to collect remote sensing field data for underwater or partially submerged volcanoes. In order to understand the tsunami generation, an individual mechanism is isolated. A submarine volcano is physically modeled in the wave basin with a unique pneumatically driven volcanic tsunami generator. The tsunami waves generated with the experimental setup are measured with cameras and wave gauges. Based on the measured data, predictive equations are compared with existing studies. The experimental results can support the development of rapid tsunami hazard assessments for future events. Key Points: A volcanic tsunami generator with pneumatically controllable vertical motion is deployed for physical modeling of point source tsunamisExperiments encompassing submerged, daylighting, and surface piercing scenarios are conducted to measure the cylindrical wave parametersEmpirical equations are proposed to evaluate the wave characteristics of the cylindrical leading elevation waves [ABSTRACT FROM AUTHOR]

Late Permian to middle Triassic volcanic activities were very strong, however, volcanic records in the early Triassic strata are less reported than those of the Permo-Triassic boundary and the Triassic Olenekian-Anisian boundary in the Yangtze plate, especially within the Sichuan basin. We conduct zircon U-Pb dating and geochemical analysis of the tephra which was first found in the early Triassic Jialingjiang Formation from the Maliuping section, Hechuan, Chongqing. The volcanic ash in the paper yields the new 248.5 ± 0.7 Ma U-Pb age consistent with those of volcanic ashes in these contemporaneous strata in the Yangtze plate. Geochemical characters of whole-rock samples show lower contents in SiO2, K2O and higher components in Al2O3, CaO, MgO, relatively enriched LREE and depleted HREE with distinct negative Eu anomaly, and conspicuous Ba, Nb, Ta, Sr, P, Ti depletion and Th, U, K, Nd enrichment, which is similar to those of the Mung Bean rock of the Triassic Olenekian-Anisian boundary, and those of acidic volcanics from the Sanjiang orogenic belt and Shiwandashan-Qiangfang suture zone during the Early-Middle Triassic. Trace elements of whole rock and analysed zircons of the tuff imply its primary magma derived from Rhyodacite/Dacite and its tectonic setting of volcanic arc granite with continental crust affinity. The early Triassic volcanism during the syn-collision stage of the Paleo-Tethys evolution was less active than those of the Permo-Triassic boundary and the Triassic Olenekian-Anisian boundary, while the volcanic event may have a crucial effect on prolonging fully biotic recovery and entirely ecosystem turnover soon after the Permian-Triassic mass extinction. [ABSTRACT FROM AUTHOR]

Rejuvenated volcanism is a worldwide phenomenon occurring on many oceanic islands in all of the major ocean basins. This plume-related volcanism follows the main edifice-building stage after a hiatus of variable duration (e.g. 0.6–2 Myrs in Hawai'i). The Honolulu Volcanics (HV), the classic case of rejuvenated volcanism, involved monogenetic eruptions from at least 48 vent areas. Previous studies inferred these vents were aligned along 3 to 11 rifts oriented orthogonal to the propagation direction of the Hawaiian plume. HV basalts are known for having high MgO contents (>10 wt %) and upper mantle xenoliths. Thus, HV magmas are assumed to be relatively primitive and to have ascended rapidly (<1 day) through the crust. However, new analyses of olivine cores in basalts from 24 HV vents are mostly too low in forsterite content (74–86 mol %) to be in equilibrium with mantle melts. Olivine and clinopyroxene in HV basalts commonly show reverse zoning indicating magma mixing prior to eruption. These results are inconsistent with the rapid ascent of HV magmas directly from their mantle source. Many of the HV magmas underwent storage (probably in the lower crust or uppermost mantle), crystal fractionation and magma mixing prior to eruption. New 40Ar/39Ar dates were determined for 11 HV lavas to evaluate their eruptive history. These ages, 80 to 685 ka, combined with our previous and other 40Ar/39Ar ages for HV lavas reveal long gaps (>50 kyr) between some eruptions. Our comprehensive, whole-rock major and trace element database (63 XRF analyses, 57 ICPMS analyses) of basalts from 37 vents show remarkable compositional diversity with no obvious spatial pattern or temporal trends. The two most recent eruptive sequences have the greatest diversity (basanite and melilitite compositions). HV basanites show systematic trace element trends that may reflect mixing of multiple source components. The nephelinites and melilitites require a complex source history that may have involved residual accessory minerals during mantle melting and a metasomatic component that was not carbonatitic. The new ages and geochemical data show eruptions along most of the previously proposed rift systems were unrelated (except for the Koko Rift). Therefore, geodynamic models that relate HV volcanism to these rift systems are invalid. Lava volumes for two HV eruptions were estimated at 0.11 and 0.23 km3 using surface mapping and water well data. Similar size, recent monogenetic eruptions in Auckland, New Zealand, were inferred to have lasted several months. Thus, if another HV eruption were to occur, which is possible given the long hiatus between eruptions, it would be extremely disruptive for the nearly 1 million residents of Honolulu. None of the existing geodynamic models fully explain the age duration, volumes and the locations of Hawai'i's rejuvenated volcanism. Thus, the cause of this secondary volcanism remains enigmatic. [ABSTRACT FROM AUTHOR]

This text provides a summary of various scientific studies and discoveries in the field of geology. It begins by discussing the recent volcanic activity of Mount Etna and Stromboli in Sicily, which has caused disruptions for travelers and locals. It then moves on to the discovery of a well-preserved dinosaur on the Isle of Wight, shedding new light on the diversity of dinosaurs in the UK. Billionaire Ken Griffin's purchase of the largest Stegosaurus fossil ever found is also mentioned. The text then highlights a study on Greenland's ice sheet, which reveals its fragility and the potential rise in sea levels due to greenhouse gas emissions. It concludes by discussing various geological features and discoveries, including impact craters, pterosaur tracks, and traces of flea infestation in extinct animals. The text also mentions the significance of Roman saltworks in ancient society. [Extracted from the article]

The International Network for Volcanology Collaboration (INVOLC) is a network formalised by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) with the specific ambition to enhance volcanology globally through improved international collaboration. IAVCEI-INVOLC was created with a focus on volcano scientists working in resource-constrained contexts, including those based in low- or middle-income countries. After a community-wide online survey and inaugural workshop during which INVOLC's ambitions were discussed, a series of challenges, as commonly experienced by those working in resource-constrained settings, were identified. These challenges may present barriers to participation in volcano science in an international context and are related to both organisational resources (financial, human, technical) and inclusion in research collaborations. In this perspectives paper, we present a series of 15 guidelines for best-engagement protocols in international collaboration in volcanology that may be adopted during times of quiescence, volcanic unrest and/or an eruption and its aftermath. Our aspiration is that these guidelines will help build more respectful, equitable and sustainable partnerships that will ultimately advance the science of volcanology. [ABSTRACT FROM AUTHOR]

Metasomatised mantle is considered a prerequisite for the formation of many major ore deposits. Since magnetotellurics (MT) is strongly sensitive to mantle metasomatism, MT is a useful tool for analysis of mineral systems that incorporate a metasomatised mantle as a key ingredient. In this work, we combine recently reported kimberlite-hosted mantle xenocryst data from the southern Gawler Craton and Adelaide Superbasin with AusLAMP MT models. We find good correlations between mantle MT conductors and geochemical indicators of mantle metasomatism from clinopyroxene xenocrysts, with the most metasomatically enriched lithospheric mantle beneath the Adelaide Superbasin and more depleted mantle beneath the Gawler Craton. There is a significant step in lithospheric thickness across the Adelaide Superbasin, and particularly around the Terowie kimberlite cluster. Combined with the fertile mantle, this helps explain this region's prospectivity for sediment-hosted copper deposits. High mantle resistivities and depleted geochemical compositions towards the central Gawler Craton on and north of the Eyre Peninsula are consistent with melting of previously metasomatised mantle, including during production of the Gawler Range Volcanics and Hiltaba Suite Large Igneous Province. Most of the major iron oxide copper gold (IOCG) and gold deposits in the region lie on the edge of this zone of mantle melting, consistent with mineral systems models that require melting of previously metasomatised mantle in the generation of these deposits. [ABSTRACT FROM AUTHOR]

Before the rise of the Northern Andes in Cenozoic time, Triassic to Jurassic extensional basins in northwestern South America accommodated predominantly continental strata partly intercalated with volcanic rocks. Coeval plutonism is attributed to a magmatic arc related to the subduction of the Farallon plate beneath South America. The basins later became involved in the Andean orogeny and are now partially exposed in the Eastern Cordillera and Middle Magdalena Valley of Colombia. We have employed (U/Pb) geochronology on zircons from Triassic-Jurassic felsic to intermediate volcanic and volcaniclastic rocks. Most of the ten samples have a substantial proportion of detrital zircons, but only three had no Mesozoic grains. The Mesozoic ages obtained range from ca. 201 Ma to ca. 177 Ma and overlap with published crystallization ages (K/Ar; Ar/Ar; U/Pb) from plutonic bodies. Volcanics from the Jordán and Girón formations are latest Triassic to Early Jurassic and synchronous with major plutonic activity. These ages constrain the early evolution of the extensional basins that formed from about the Triassic-Jurassic transition in an intra-arc position and facilitated the preservation of sediment and arc-derived volcanics. Middle Jurassic ages from the Noreán Fm. are synchronous with sparse plutonism west of the Middle Magdalena Valley. At this time, the magmatic arc had migrated westward, while intrusive activity in the Eastern Cordillera ceased. A geochemical rift signature only appears in scarce Early Cretaceous mafic intrusions that resumed magmatic activity in the Eastern Cordillera. This magmatism, now in a back-arc position, coincides with maximum subsidence of the large Cretaceous basin that extended across the older intra-arc rift basins. Extension and lithospheric thinning ceased by the end of the Early Cretaceous. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic Jahaj–Govindpura Formation of the Raialo Group of Delhi supergroup, India exposes volcanic and volcaniclastics rock at multiple stratigraphic levels and hence, provides a unique scope for the study of volcaniclastics of varying rheology and their bearing on the tectono-magmatic setting of the basin. From a detailed field study in three spatially disparate sections, associated sedimentary facies types and textural evidences such as clast annealing, deformation in pumice fragments, eutaxitic foliation and shattered crystals, the volcaniclastics are documented as pyroclastic flow (VLC 1), welded tuff (VLC 2), clast-/matrix-supported boulder pyroclastic conglomerate (VLC 3), and pyroclastic fall deposits (VLC 4). Whereas, VLC 1 and VLC 2 are identified as subaqueous, VLC 3 and VLC 4 are grouped under subaerial categories. The facies distribution of volcaniclastics and eastward paleocurrent motif from associated sedimentary facies is indicative of proximal-distal relationship varying between subaerial to sub-marine depositional settings. From collation and comparison of available geochemical data (major, trace element, and REE) of volcanic rock and new geochemical data generated from volcaniclastics under the present study, it is inferred that the source magma was more basic (low SiO2 and high MgO) resembling tholeiitic to calc-alkaline island-arc source composition while a more intermediate to felsic composition is posited for the volcaniclastics. Considering the ca-1876 Ma time frame of the basin and a subduction-related magmatic character for the volcaniclastics, a possible Orosirian subduction margin, related to the 'Columbia' supercontinent, in the vicinity of the Bayana sub-basin in North Delhi fold belt is suggested. Highlights: Primary subaerial to subaquous volcaniclastics described from Paleoproterozoic Bayana sub-basin, North Delhi Fold Belt, India. Unequivocal petrological features allowed subaerial and subaquous emplacement of volcaniclastics. Depending on associated sedimentary facies and paleocurrent motif a proximal-distal relationship established between different volcaniclastic facies. Whereas volcanics register tholeiitic to calc-alkaline composition, a more intermediate to felsic composition is inferred for the volcaniclastics. From geochemical signature, an overall compressional tectonic set-up is suggested with riftogenic Bayana basin a part of it. It is argued that in terms of tectonic and depositional setting, the Bayana basin shares a common geological history with contemporary basins in North China Craton. [ABSTRACT FROM AUTHOR]

A major challenge in mantle geochemistry is determining the source composition and melt fraction involved in melting. We provide a new Rare‐Earth Element (REE) inverse model that provides source concentration, source and melt mineral modes, and melt fraction based on the difference between separate determinations of bulk distribution coefficients and constrained by boundary conditions. An analytical inverse of the batch melting equation provides expressions for source, Coi ${C}_{o}^{i}$, and bulk distribution coefficient of the mantle, Doi ${D}_{o}^{i}$, with two unknowns, the initial concentration of La in the mantle, CoLa ${C}_{o}^{La}$, and Pi, the bulk distribution coefficient of the melt. We traverse through a range of CoLa ${C}_{o}^{La}$ steps and examine thousands of melt modes, Pi, at each step. Thousands of trial melt modes fail by generating Doi ${D}_{o}^{i}$ that are inconsistent with partition coefficients. Many surviving trials cannot be inverted to estimate a mantle mode. Other boundary conditions eliminate even more trials. Surviving trials are ordered by the difference between Doi ${D}_{o}^{i}$ calculated from the REE data of a lava suite and Dci ${D}_{c}^{i}$ calculated from partition coefficients and mantle mode. We select the solution with the closest fit that passes all the boundary conditions. We tested our new model with lava suites from Hawaii where different lines of evidence suggest that they melted from different mantle sources, Mauna Kea representing shield‐stage lava and submarine Kiekie representing rejuvenated stage lava. Our inverse determination of mantle composition and melting parameters was consistent with earlier models based on assumptions of HREE composition. Plain Language Summary: Determining the composition of our planet's interior is a major goal of geochemistry. The most common approach is to make forward models based on reasonable assumptions about the source composition and the melting process to calculate synthetic compositions that match the observed lava. Successful forward models may be difficult to achieve, but nevertheless remain dependent on initial assumptions. In principle, inverse models make fewer assumptions and achieve more objective results. Even so, most published inverse models for mantle melting require assumptions about the source. The inverse modeling described here relies on boundary conditions and the match between observed and calculated bulk distribution coefficients to determine the behavior of mantle parameters as a function of the initial lanthanum concentration (CoLa ${C}_{o}^{La}$). Certain behavior patterns allow determination of the optimum CoLa ${C}_{o}^{La}$, allowing a complete inverse. Successful inverse models for Hawaiian lava suites define two distinct mantle types, in agreement with past observations about these volcanoes. Key Points: Melt modes and mantle La concentrations generate trial source and bulk distribution profiles, but most solutions fail boundary conditionsTrial solutions are ranked by comparing observed and calculated bulk distribution profiles. The best fit over a range of La is the solutionOptimum source and bulk distribution profiles provide melt extents for shield stage Hawaiian tholeiites and rejuvenated basalts [ABSTRACT FROM AUTHOR]

Lascar volcano, located in northern Chile, is among the most active volcanoes of the Andean Central Volcanic Zone (CVZ). Its activity culminated in the last major explosive eruption in April 1993. Lascar andesites which erupted in April 1993 have a phase assemblage composed of plagioclase, clinopyroxene, orthopyroxene, Fe–Ti oxides, and rhyolitic glass. To better constrain storage conditions and mechanisms of magmatic differentiation for andesitic magmas in a thick continental crust, crystallization experiments were performed in internally heated pressure vessels at 300 and 500 MPa, in the temperature (T) range of 900–1050 °C, at various water activities (a H 2 O) and oxygen fugacities (log f O 2 between QFM + 1.5 and QFM + 3.3 at a H 2 O =1 ; QFM is quartz–fayalite–magnetite oxygen buffer). The comparison of experimental products with natural phase assemblages, phase compositions, and whole-rock compositions was used to estimate magma storage conditions and to reconstruct the magma plumbing system. We estimate that Lascar two-pyroxene andesitic magmas were stored at 975±25 °C, 300±50 MPa, and log f O 2 of QFM +1.5±0.5 , under H 2 O-undersaturated conditions with 2.5 wt % to 4.5 wt % H 2 O in the melt. The geochemical characteristics of the entire suite of Lascar volcanics indicates that a fractionating magmatic system located at a depth of 10–13 km is periodically replenished with less evolved magma. Some eruptive stages were dominated by volcanic products resulting most probably from the mixing of a mafic andesitic magma with a felsic component, whereas compositional variations in other eruptive stages are better explained by crystal fractionation processes. The relative importance of these two mechanisms (mixing vs. crystal fractionation) may be related to the amount and frequency of magma recharge in the reservoir. [ABSTRACT FROM AUTHOR]

We report a tephra deposit in the southern Lake Titicaca Basin, Bolivia, which was deposited by a major, previously unrecognized eruption sometime between AD 400 and 720. Archaeological data suggest these centuries were characterized by a substantial community migration to Tiwanaku, where social interaction networks gave birth to one of the Andes' first large complex societies. Here we provide an initial characterization of this tephra, based on samples from the archaeological site Khonkho Wankane. The same tephra is present at two other archaeological sites in the region. Given the great distance to the nearest active volcano, this tephra layer likely derives from a large-magnitude, Late-Holocene explosive eruption of a Central Andean volcano. We suggest that this major event be included in the human history of the region, given its inferred magnitude and wide dispersal area. Future research could confirm the Khonkho tephra at other sites, identify the source volcano, estimate its volume, and more precisely date the eruption. [ABSTRACT FROM AUTHOR]

Multidisciplinary studies of volcanic processes and their timescales are vital for the assessment and mitigation of the risk of future volcanic disasters. Paleomagnetic and rock magnetic approaches have long been applied in diverse volcanological studies worldwide. In this review, we provide conceptual and methodological explorations of a representative suite of paleomagnetic and rock magnetic applications, and discuss their future perspectives in Korean volcanological research. These paleomagnetic and rock magnetic applications will contribute to a better understanding of volcanic and associated processes during the pre-, syn-, and post-eruption periods, and their timing and duration, and also contribute to the improvement of spatiotemporal correlations of volcanic and associated units in Korea. Thus it will be connected to meaningfully lead future volcanic hazard analyses. [ABSTRACT FROM AUTHOR]

The evolution of volcanic plumbing systems, which controls the style and size of eruptions, is largely determined by processes at depths that are not observable. Scientists use numerical models to simulate these processes and compare the outputs with data on erupted products to understand the plumbing system and eruption processes. However, our ability to explore the parameter space in order to match petrological and geophysical observations is limited by the computational cost required for such simulations. As an alternative, we present a statistical emulator that can reproduce the numerical results as a function of a set of input parameters. This approach can be used to invert the observed distribution of whole rock chemistry to determine the duration of interaction between magmas preceding an eruption and identify the best matching input parameters. This method intrinsically includes error propagation, thus providing reliable confidence intervals for the relevant parameters of the numerical simulations.

We present DiadFit—an open-source Python3 tool for efficient processing of Raman spectroscopy data collected from fluid inclusions, melt inclusions and silicate melts. DiadFit is optimized to fit the characteristic peaks from CO2 fluids (Fermi diads, hot bands, 13C), gas species such as SO2, N2, solid precipitates (e.g. carbonates), and Ne emission lines with easily tweakable background positions and peak shapes. DiadFit's peak fitting functions are used as part of a number of workflows optimized for quantification of CO2 in melt inclusion vapour bubbles and fluid inclusions. DiadFit can also convert between temperature, pressure and density using various CO2 and CO2-H2O equations of state (EOS), allowing calculation of fluid inclusion pressures (and depths in the crust), conversion of homogenization temperatures from microthermometry to CO2 density, and propagation of uncertainties associated with EOS calculations using Monte Carlo methods. There are also functions to quantify the area ratio of the silicate vs. H2O region of spectra collected on silicate glasses to determine H2O contents in glasses and melt inclusions. Documentation and worked examples are available (https://bit.ly/DiadFitRTD, https://bit.ly/DiadFitYouTube).

Understanding the longevity of Mars's dynamo is key to interpreting the planet's atmospheric loss history and the properties of its deep interior. Satellite data showing magnetic lows above many large impact basins formed 4.1-3.7 billion years ago (Ga) have been interpreted as evidence that Mars's dynamo terminated before 4.1 Ga—at least 0.4 Gy before intense late Noachian/early Hesperian hydrological activity. However, evidence for a longer-lived, reversing dynamo from young volcanics and the Martian meteorite ALH 84001 supports an alternative interpretation of Mars's apparently demagnetized basins. To understand how a reversing dynamo would affect basin fields, here we model the cooling and magnetization of 200-2200 km diameter impact basins under a range of Earth-like reversal frequencies. We find that magnetic reversals efficiently reduce field strengths above large basins. In particular, if the magnetic properties of the Martian mantle are similar to most Martian meteorites and late remagnetization of the near surface is widespread, >90% of large (> 800 km diameter) basins would appear demagnetized at spacecraft altitudes. This ultimately implies that Mars's apparently demagnetized basins do not require an early dynamo cessation. A long-lived and reversing dynamo, unlike alternative scenarios, satisfies all available constraints on Mars's magnetic history. Weak magnetic fields above Mars's large impact basins are often interpreted as a signature of the dynamo's early cessation. Here, the authors demonstrate that these weakly magnetic basins may instead have formed in a long-lived but reversing dynamo. [ABSTRACT FROM AUTHOR]

This article examines the distribution of minor and trace elements in colorless beryl from the Pashki deposit in Afghanistan. The study found that the lithium content in the beryl from this deposit is higher than in other pegmatites, making it a useful indicator for prospecting lithium-rich pegmatites in the region. The article also discusses the distribution of other elements in the crystal growth zones of beryl, suggesting the presence of sector zoning. This sector zoning may indicate differences in the growth mechanisms of different crystal faces. [Extracted from the article]

Gosong Beach in Bengkayang, West Kalimantan, is selected as a potential Nuclear Power Plant (NPP) site candidate. Volcanic and intrusive rocks are found in the radius of 150 km from it. Based on IAEA (International Atomic Energy Agency) standard, the main assessment target is volcanic rock that is younger than 10 Ma. However, there are Tertiary volcanic and intrusive rocks next to and cover a wide area around the NPP site that show volcanic activities over the Tertiary period. Therefore, it is necessary to investigate this group of rocks to understand its characteristics. This study aims to characterize the geochemistry and petrology of the Tertiary volcanic and intrusive rocks found in northwestern Kalimantan. The fieldwork was conducted to observe and to take Serantak volcanic rocks, Bawang dacite, Niut volcanics, and Sintang intrusion samples. The XRF and micro-XRF analyses were conducted to characterize the geochemical aspect, while petrography and AMICS analyses were conducted to characterize the mineralogical aspect. The result shows that Serantak volcanic rocks, Bawang dacite, Niut volcanics, and Sintang intrusion are derived from tholeiitic to calc-alkaline as a product of mantel partial melting in the subduction zone which go through fractional crystallization. The volcanic activity was initiated by the rise of primitive parental magma from partial melting in the shallow-depth subducted crust as indicated by the garnet-free HREE pattern, the enrichment of LILE and LREE, and the depleted HREE. The Tertiary magmatism in northwestern Kalimantan was found in a small activity with a small impact on the NPP candidate site at Gosong Beach, Bangkayang. [ABSTRACT FROM AUTHOR]

The Manyovu redbeds are an up to 600 m succession of fine-grained, siliciclastic strata in northwestern Tanzania and are part of the Neoproterozoic Bukoban Supergroup. Previous authors estimated the age of the Manyovu redbeds to be Neoproterozoic or older based on the K-Ar dates of underlying volcanic rocks (ca. 800 Ma). However, no other age constraints exist for these Neoproterozoic units. U-Pb detrital zircon results from six stratigraphic intervals of the Manyovu units, including both sandstone and siltstone samples, indicate maximum depositional ages as young as 614 ± 6 Ma, almost 200 m.y. younger than the underlying volcanics, with primary detrital contributions from Pan-African orogens, which indicates that these units are syn-tectonic accumulations associated with the assembly of Greater Gondwana/Pannotia. Detrital zircon spectra and modal compositions reveal that the sediment that formed these strata was sourced from a range of terranes, including continental blocks (i.e., Tanzania Craton), magmatic arcs (i.e., Mozambique Belt and Arabian-Nubian Shield), and recycled orogens (e.g., Ubendian-Usagaran belts). Together, these data indicate that the Manyovu redbeds accumulated following the Marinoan Snowball Earth event (ca. 635 Ma) and record the initiation of collision along the Mozambique Belt during Pan-African orogenesis and the formation of greater Gondwana. [ABSTRACT FROM AUTHOR]

The paper presents a study of typomorphic characteristics of placer gold from tributaries of the Kengeveem River, Magadan oblast. The placer gold was studied by optical and scanning electron microscopy at the Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences. As a result, the first information on the morphology, internal structure, and chemical composition of placer gold from the southeastern Taigonos Peninsula was obtained. Three mineral types of the gold were determined. The first type is dominant. Its grains are characterized by subore morphology, with weak and medium roundness. Only Au and Ag are present in the composition of native gold, other macrocomponents were not found. The gold fineness is 750‒950‰. Some gold grains bear signs of supergene transformation, which is expressed in the development of high-fineness gold rims and intergranular veins. The second type of the gold is represented by well-rounded plates with a fineness of 980‒990‰. The third type is loose aggregates of secondary high-grade mustard gold. The obtained data allowed us to determine the different transport distances of native gold and to consider the low-sulfide epithermal Au‒Ag mineralization and presumably distal gabbroids as the primary sources of gold. [ABSTRACT FROM AUTHOR]

The mineral chemistry, whole-rock geochemistry, 40Ar / 39Ar dating and Sr-Nd-Pb-Hf isotopes of the Eocene Narman (Erzurum) Volcanic rocks in the southeast of the Eastern Pontides Orogenic Belt (EPOB, NE Türkiye) were investigated. The Narman Volcanites consist of basaltic dyke, basaltic lava, and basaltic volcanic breccia facies. Volcanites contain plagioclase (An34-80), clinopyroxene (Wo38-47En41-50Fs5-18), and olivine (Fo68-90) as phenocrystals with magnetite/titanomagnetite microphenocrysts. New 40Ar-39Ar ages suggest that these volcanic rocks erupted between 44.5 ± 0.1 and 43.4 ± 0.1 Ma, within the Middle Eocene (Lutetian). Narman Volcanites have calcalkaline character, with medium-high K content. Volcanites are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE), while they are depleted in terms of high field strength elements (HFSE). Chondrite-normalized rare earth element distributions have concave shape with moderate enrichment (LaN/LuN = 2.78–7.99), leading to consideration that the magmas forming the volcanics derived from similar sources. Isotopically, the rocks in the Narman Volcanites have low-medium initial 87Sr/86Sr values (0.70405–0.70485), initial 143Nd/144Nd values (0.512606–0.512848) and positive Ndi (+0.5 – +5.2). Depleted mantle Nd model ages were TDM1 = 0.29–0.62 Ga and TDM2 =0.43–0.83 Ga. (206Pb/204Pb)i, (207Pb/204Pb)i, and (208Pb/204Pb)i values vary in the ranges of 18.246–18.709, 15.578–15.616, and 38.225–38.791, respectively. The initial (176Hf/177Hf)i ratios for the volcanites are between 0.282770 and 0.283013, while the εHf values range from +7.6 to +9. All the evidence supports the conclusion that the parental magma for the rocks probably derived from an enriched lithospheric mantle, previously metasomatized by fluids derived from subducted slab during asthenospheric upwelling, due to fragmented asymmetric delamination in a postcollisional extensional tectonic environment. [ABSTRACT FROM AUTHOR]

Diffusion chronometry is a technique gaining interest in the scientific community related to volcanology and petrology; however, modelling can be challenging for non-expert users. Here, we present DiffSim, a user-friendly standalone freeware that allows users to calculate magmatic timescales simulating 1D diffusion of major elements in olivine, orthopyroxene, titanomagnetite, and melt (inclusions). The freeware works solving the Fick's second law equation (for both Cartesian and spherical polar coordinates, depending on the phase) using finite differences through the Crank-Nicolson method. Users must specify the initial composition vs. distance profile, the time resolution, and the intensive conditions (such as temperature, pressure, and oxygen fugacity). For orthorhombic phases, such as olivine and orthopyroxene, users must also specify the plunge and the trend of the (001)-axis and the angle traverse of the 2D section being studied. The best-fitting profile, comparing the natural (measured) and the modelled (calculated) profiles, is obtained using the least-squares fitting method in accordance with the total time specified by the user for performing the diffusion modelling. To determine the uncertainties of the timescale calculation, DiffSim propagates errors based on the uncertainties associated with each intensive condition and the experimental diffusivity measurements. DiffSim is available as executable freeware, allowing researchers and students to use diffusion chronometry to elucidate information about crustal processes with ease and precision. [ABSTRACT FROM AUTHOR]

The Lhasa‐Qiangtang collision closed the Meso‐Tethys Ocean, but the exact timing of this event remains hotly debated. Here, we present geochronological and paleomagnetic analyses conducted on Cretaceous volcanics from western Qiangtang to constrain the Lhasa‐Qiangtang collision in western Tibet. Our investigations yield a paleolatitude of ∼30.5 ± 5.0°N for western Qiangtang during ca. 110–100 Ma. A reanalysis of previously acquired Mesozoic‐Cenozoic paleomagnetic data from western Qiangtang suggests a stationary position during ca. 136–34 Ma. Examination of paleomagnetic data from western Lhasa reveals a significant reduction in northward paleolatitudinal motion during the Early Cretaceous, dropping from ∼12.3 cm/yr to nearly zero. Integration of our paleomagnetic findings with available geological records has led to conclude that the Lhasa‐Qiangtang collision in western Tibet occurred at ca. 132 Ma. Additionally, we infer that crustal shortening on the order of ∼1,000 km happened between Lhasa and Qiangtang during the Early Cenozoic. Plain Language Summary: The Tibetan Plateau comprises multiple different blocks, which originated from the Gondwana in the southern hemisphere. Their convergence histories toward Euraisa have changed the global land‐sea distributions since the Late Paleozoic. The time at which the Lhasa block, one of the Tibetan blocks, accreted to the Qiangtang block to the north remains poorly constrained. In this work, we provide robust data suggesting a latitude of ∼30.5 ± 5.0°N for western Qiangtang during the Early Cretaceous (ca. 110–100 Ma). We also compiled the available latitudinal data from western Tibet in combination with geological observations. We suggest Lhasa collided with Qiangtang during 132 million years ago in western Tibet. Significant shortening of the continental crust by ∼1,000 km between the Lhasa and Qiangtang blocks occurred after their collision. Key Points: Western Qiangtang had a paleolatitude of ∼30.5 ± 5.0°N at ca. 110–100 MaA substantial decrease in the paleolatitudinal motion of western Lhasa occurred in the Early CretaceousThe Lhasa‐Qiangtang collision in western Tibet occurred at ca. 132 Ma [ABSTRACT FROM AUTHOR]

Over the last 7 years, geodetic data have detected periods of uplift and subsidence of the active volcano Ol Doinyo Lengai in Tanzania. Although numerous eruptions of the volcano have occurred historically, a systematic investigation of transient deformation using continuous Global Navigation Satellite System (GNSS) data has not been undertaken. We use the Targeted Projection Operator (TPO) to assess 7 years of continuous GNSS data from the TZVOLCANO network for transient signals and find rapid uplift spanning March 2022–December 2022 and then steady‐state uplift through August 2023. We conduct a nonlinear inversion of the GNSS velocities associated with the transient signal using dMODELS and find consistency with an inflating spheroidal source located 2.3 ± 0.6 km beneath the crater. Prior to March 2022, geodetic data indicated quiescence just below Ol Doinyo Lengai, thus detecting transient deformation with TPO allows for tracking changes in the magmatic system over time in the Natron Rift. Plain Language Summary: Ol Doinyo Lengai is an active stratovolcano in the youthful Natron Rift characterized by alternating periods of calm lava flows and explosive eruptions. Volcanic hazards and risk are major issues in the Natron Rift largely because of nearby communities, tourism, and air traffic. Volcanic eruptions are often preceded by magma intruding into a shallow reservoir that causes observable surface uplift. The uplift phase normally occurs before an eruption and is regarded as a key precursor for eruptive processes. These precursory uplift signals can be quite small. In this study we use high precision terrestrial data to monitor surface motions and use numerical approaches to detect potential volcanic signals due to magma reservoir changes. We detect rapid uplift from March 2022 to December 2022 and continued steady uplift through August 2023. Modeling suggests the uplift is from an active shallow magmatic source. This work demonstrates the ability to detect temporal changes in surface uplift at an active volcano. Key Points: Continuous Global Navigation Satellite System (GNSS) data systematically detect transient deformation for the first time at Ol Doinyo LengaiNo transient motion is detected before March 2022, then a period of rapid uplift until December 2022, and afterward steady‐state upliftTransient signal detection with the Targeted Projection Operator (TPO) allows for tracking temporal changes in the magmatic system [ABSTRACT FROM AUTHOR]

Among Líĺwat people of the Interior Plateau of British Columbia, an oral tradition relays how early ancestors used to ascend Qẃelqẃelústen, or Mount Meager. The account maintains that those climbers could see the ocean, which is not the case today, because the mountain is surrounded by many other high peaks, and the Strait of Georgia is several mountain ridges to the west. However, the mountain is an active and volatile volcano, which last erupted circa 2360 cal BP. It is also the site of the largest landslide in Canadian history, which occurred in 2010. Given that it had been a high, glacier-capped mountain throughout the Holocene, much like other volcanoes along the coastal range, we surmise that a climber may have reasonably been afforded a view of the ocean from its prior heights. We conducted viewshed analyses of the potential mountain height prior to its eruption and determined that one could indeed view the ocean if the mountain were at least 950 m higher than it is today. This aligns with the oral tradition, indicating that it may be over 2,400 years old, and plausibly in the range of 4,000 to 9,000 years old when the mountain may have been at such a height. [ABSTRACT FROM AUTHOR]

The Don terrane, which is extensively reworked by metamorphism and granitoid intrusions, is part of the Volga–Don orogen stretching along the eastern margin of the Sarmatian segment of the East European Craton. The terrane consists of gneiss-granites of the Pavlovsk complex, metavolcanic rocks, ranging from basaltic andesites to dacites (amphibolites and gneisses), and metasedimentary rocks (marbles and calc-silicate rocks) of the Don Group. The volcanic rocks are typically enriched in LILE and LREE and show negative HFSE anomalies, indicating fluid-assisted melting of the mantle wedge in a subduction zone. The Nd isotopic composition (εNd2200 = –1.2 to +3.4, model age 2180–2550 Ma) and Hf isotopic composition (εHf = –4.3 to +3.3, model age 2290–2640 Ma) indicate an enriched mantle or a mixed crustal–mantle source of the parental melts of the volcanics and a juvenile source for sediments of the Don Group. The U–Pb zircon metamorphic age of the gneisses and amphibolites is 2047 ± 7 Ma, and that of the thermal effect of the granitoid batholith on the host rocks is 2060 ± 4 Ma. According to isotope geochemical and geochronological data, the Don Group is underlain by Archean rocks, contains Archean detrital zircons, but the age of this group is no older than 2300 Ma. A facies and age analogue of the Don Group is the Temryuk Formation of the Central Azov Group of the Ukrainian shield. In the Paleoproterozoic, the eastern margin of Sarmatia was likely a continental arc, which was nearly coeval with the island arc–backarc basin system of the Losevo Group. [ABSTRACT FROM AUTHOR]

The crystal-chemical variations of spinels grown as a function of cooling rate (ΔT/Δt) were analyzed via X-ray electron-microprobe (EPMA) maps. Maps were collected serially by using a fixed distance. Spinels solidified from a tholeiitic MOR basaltic liquid (B100) cooled at cooling rates (ΔT/Δt) of 1, 7, 60, and 180 °C/h, between 1300 and 800 °C and at ambient P and fO2. As ΔT/Δt increases, the amount of spinel is invariably <5 area% and its size decreases. Compared to the previous data set collected by common single and selected EPMA analytical points (112 analyses), the kinetic effects induced by ΔT/Δt are here quantitatively captured by a large number of analyses (2052). The TiO2, Al2O3, MgO, and FeOtot show large compositional variations at low cooling rates (from 1 to 60 °C/h), and only the average TiO2 concentration shows a well-defined trend as a function of ΔT/Δt. However, calculated average cation amounts (apfu) unveil quantitative kinetic effects. When ΔT/Δt increases (from 1 to 180 °C/h), only Ti4+ shows a linear decreasing trend, whereas the other major Al3+, Fe3+, Fe2+, and Mg2+ cations alone are scattered. Conversely, the sums of trivalent (Al3++Fe3+) and divalent (Mg2++Fe2+) cations quantitatively capture the effect of the ΔT/Δt. These new outcomes could be the base of novel geospeedometers with significant implications in volcanology, geophysics, and material sciences in regard to silicate melt rheology on Earth. They should be extended to high-pressure, hydrated, and low oxygen fugacity conditions. Furthermore, the analytical approach used here to capture kinetic effects on spinel growth and compositions can be also applied to other crystalline phases grown from silicate liquids. [ABSTRACT FROM AUTHOR]

The Pleiades Volcanic Field is made up of some 20 monogenetic, partly overlapping scoria and spatter cones, erupted in the last 900 ka, cropping out from the ice close to the head of the Mariner Glacier in northern Victoria Land, Antarctica. Erupted products vary from hawaiite to trachyte, defining a complete mild Na‐alkaline differentiation trend. Mafic samples are characterized by multi‐elemental patterns typical of OIB magmas, moderately low 87Sr/86Sr (0.7037) and high 143Nd/144Nd (0.51284), with a clear within‐plate affinity, indicating a subcontinental lithospheric source. With increasing SiO2, 87Sr/86Sr ratios increase up to 0.7052 and 143Nd/144Nd decrease to 0.51277, supporting the hypothesis of open‐system evolution, with significant crustal assimilation during fractional crystallization. The erupted volume of most evolved products (∼7 km3), according to fractionation models, suggests that primitive magmas should have been more than 10 times larger, indicating the occurrence of a large magma plumbing system, unexpected for a volcanic field of monogenetic scoria cones. The occurrence of a complete fractionation trend with large magma chambers and large assimilation rate is unusual, if not unique, among the alkali basaltic volcanic fields and it is matched by a climax of activity during the last glacial maximum (30 ka), as indicated by new 40Ar‐39Ar ages (30 ± 3 ka and 25 ± 2 ka) for samples from the two most prominent edifices. Therefore, we hypothesize a role of a thick ice cap in suppressing eruptions and ultimately leading to prolonged magma residence time in the subsurface, favoring significant fractionation coupled with unusual high rates of crustal assimilation. Plain Language Summary: The Pleiades volcanic field is made up of some 20 monogenetic scoria and spatter cones, which erupted in the last 900 ka close to the head of the Mariner Glacier in northern Victoria Land, Antarctica. The erupted products are very unusual for alkali basaltic volcanism: indeed, whereas few samples show clear within‐plate subcontinental lithospheric characteristics and were directly derived from the mantle source, most of the products formed after extensive fractional crystallization matched by significant crustal assimilation, implying that primitive magma volumes are 10 times larger than outcropping products in an unusually large magma plumbing system. These peculiar features coincided with a climax of activity during the last glacial maximum (30–25 ka). Therefore, we speculate that a thick ice cap favored high rates of crystal fractionation coupled with crustal assimilation and was responsible for increasing magma residence times in chambers at crustal depths and suppressing the eruptive potential of magmas. Key Points: The Pleiades complex (NVL, Antarctica) is made up of some 20 monogenetic cones aged 900–0 ka, defining a complete Na‐alkaline trendFractionation models show much larger volumes of primitive magmas, indicating the occurrence of an unusually large magma plumbing systemA climax of activity occurred during the last glacial maximum (30 ka). Thickness variation of the ice cap may have influenced volcanic activity [ABSTRACT FROM AUTHOR]

The evolution of multifractal structures in various physical processes, such as climatology, seismology, or volcanology, serves as a crucial tool for detecting changes in corresponding phenomena. In this study, we explore the evolution of the multifractal structure of volcanic emissions with varying energy levels (observed at Colima, Mexico, during the years 2013–2015) to identify clear indicators of imminent high-energy emissions nearing 8.0×108 J. These indicators manifest through the evolution of six multifractal parameters: the central Hölder exponent (α0); the maximum and minimum Hölder exponents (αmax , αmin); the multifractal amplitude (W=αmax-αmin); the multifractal asymmetry (γ=[αmax-α0]/[α0-αmin]); and the complexity index (CI), calculated as the sum of the normalized values of α0 , W , and γ. Additionally, the results obtained from adapting the Gutenberg–Richter seismic law to volcanic energy emissions, along with the corresponding skewness and standard deviation of the volcanic emission data, further support the findings obtained through multifractal analysis. These results, derived from multifractal structure analysis, adaptation of the Gutenberg–Richter law to volcanic emissions, and basic statistical parameters, hold significant relevance in anticipating potential volcanic episodes of high energy. Such anticipation can be further quantified using an appropriate forecasting algorithm. [ABSTRACT FROM AUTHOR]

Stratovolcanoes are common globally, with high‐altitude summit regions that are often glacier‐clad and intersect the seasonal and perennial snow line. During an eruption, interaction between snow/ice and hot, pyroclastic deposits will potentially lead to extensive melt and steam production. This is particularly pertinent when pyroclastic density currents (PDCs) are emplaced onto and propagate over glacierised substrates. Generated melt and steam are incorporated into the flow, which can cause a transformation from a hot, dry granular flow, to a water‐saturated, sediment‐laden flow, termed a lahar. Both PDCs and ice‐melt lahars are highly hazardous due to their high energy during flow and long runout distances. Knowledge of the physics that underpin these interactions and the transformation to ice‐melt lahar is extremely limited, preventing accurate descriptions within hazard models. To physically constrain the thermal interactions we conduct static melting experiments, where a hot granular layer was emplaced onto an ice substrate. The rate of heat transfer through the particle layer, melt and steam generation were quantified. Experiments revealed systematic increases in melt and steam with increasing particle layer thicknesses and temperatures. We also present a one‐dimensional numerical model for heat transfer, calibrated against experimental data, capable of accurately predicting temperature and associated melting. Furthermore, similarity solutions are presented for early‐time melting which are used to benchmark our numerical scheme, and to provide rapid estimates for meltwater flux hydrographs. These data are vital for predicting melt volume and incorporation into PDCs required to facilitate the transformation to and evolution of ice‐melt lahars. Plain Language Summary: When volcanoes explosively erupt they may produce avalanches of hot, dry volcanic ash. When these volcanic avalanches occur on snow and glacier‐covered volcanoes, they produce steam and melt, that can mix with the volcanic avalanche, transforming it to a cool, wet volcanic mudflow. Both volcanic avalanches and mudflows are extremely destructive and dangerous due to their high speeds and long flow paths. Historically, these flows have resulted in many fatalities and extensive building and infrastructure damage. We investigate the conditions under which transformation from volcanic avalanches to mudflows can occur. We use small‐scale laboratory experiments to measure the transfer of heat, steam, and melt generation when a hot ash layer is emplaced onto an ice layer. A numerical model is presented to describe this heat transfer at large scales, like in natural volcanic settings. This can be used to estimate the amount of melt required to cause this transformation from volcanic avalanche to mudflow. This can help us predict the destructiveness of these interactive events, and help us convey the hazard to stakeholders, and populations living in regions affected by volcano‐ice interactions. Key Points: Pyroclast‐ice interactions are investigated using laboratory experiments and numerical modelingThe parameter space that governs melting and steam generation is estimatedMeltwater source flux hydrographs show similarities with rainfall‐driven lahar source hydrographs [ABSTRACT FROM AUTHOR]

Seamounts and basaltic basement can influence deformation and mass fluxes within subduction zones. We examined seamounts and volcanic units across the western Hikurangi Plateau, near the Hikurangi subduction margin, New Zealand, with seismic reflection images. Volcanism at the Hikurangi Plateau occurred in at least three phases that we attribute to (1) Early Cretaceous large igneous province formation, the top of which is marked by laterally continuous and dipping wedges of reflections that we interpret as lava flows; (2) Late Cretaceous seamounts and volcaniclastics that erupted onto the crust of the Hikurangi Plateau and make up the majority of seamount volume and basement relief; and (3) late-stage, Pliocene volcanics that erupted through and adjacent to Cretaceous seamounts and younger sediments of the northcentral Hikurangi Plateau. The Pliocene volcanoes do not appear to be strongly welded to the plateau basement and may be petit spot volcanoes that are related to the displacement and accumulation of hydrous transition zone melts. Large seamounts and volcaniclastic units are evenly distributed across most of the Hikurangi Plateau near the Hikurangi margin but are absent from the Pegasus Basin. Although faults are imaged throughout the basement of the Pegasus Basin, contemporary normal faulting of the Hikurangi Plateau is uncommon, except for a zone of Quaternary normal faults near the Pliocene volcanics. These trends indicate that the Hikurangi megathrust may be more influenced by volcanic structures in the north and central Hikurangi margin, where plateau rifting and voluminous seamount eruptions have more substantially overprinted the original Early Cretaceous basement. [ABSTRACT FROM AUTHOR]

Electronic distance measurements (EDM) represent one of the first methods to detect ground deformation on volcanoes. Used since 1964, they enable acquiring precise distance measurements, whose time repetition may highlight changes related to volcanic activity. This technique was widely used on volcanoes from the 1970s to the early 2000s and has been used many times to model position, geometry, and volumes of magmatic and hydrothermal sources. This paper reports the EDM experiences, results and data acquired on Sicilian volcanoes (Etna, Vulcano, Stromboli and Pantelleria) from the early 1970s, which have played a major role in the birth of the volcano-geodesy for volcanic process knowledge, making the Sicilian volcanoes among those with the longest geodetic record in the world. [ABSTRACT FROM AUTHOR]

The paper presents data on the miaskite syenites of the Lovozero massif, pulaskites of the Khibiny massif, rocks of the larvikite–lardalite series of the Kurga massif, and subalkaline volcanics, which are preserved as remnants in the roof of the massifs. The studied rocks are characterized by a low agpaitic coefficient of <1, the absence of minerals typical of peralkaline rocks (eudialyte, aenigmatite, etc.), and the presence of zircon. The morphological features and chemical composition of zircon from miaskite of the Lovozero massif syenite indicate that the mineral is of magmatic nature. The crystallization age of the miaskites was dated on zircon at 373 ± 5 Мa. The isotope-geochemical characteristics of rocks of the subalkaline series indicate that the miaskites of the Lovozero massif are of mantle origin, show no indications of their crustal contamination, and were produced during the evolution of ankaramite melt. The pulaskites of the Khibiny massif were formed according to an analogous scenario, except their assimilation with crustal material, whose proportion did not exceed, according to model calculations, 10%. [ABSTRACT FROM AUTHOR]

We analyzed published datasets relating to the composition of glasses from melt inclusions in minerals of volcanics from the Eastern Volcanic Belt and Sredinny Range of Kamchatka. A significant difference was found between the distribution of silica concentration in the rocks and melts: intermediate and basic compositions are most common among the rocks, whereas the glasses in melt inclusions are predominantly acidic. The distribution of major and trace elements was analyzed. It was shown that the contents of some elements are environment-specific (e.g., Nb and light REEs). We identified trace element ratios in melts that most strongly correlate with the geodynamic setting. [ABSTRACT FROM AUTHOR]

Previous geophysical investigations of the western continental margin of India (WCMI) confirm the two-phase breakup history of the margin with the first breakup taking place between India and Madagascar that created the Mascarene Basin in the Late Cretaceous and the second breakup event in Early Paleocene with Seychelles separating from India. Despite numerous geoscientific studies along the WCMI, the opening of the Laccadive basin, situated along the southern part of the margin, remains poorly constrained. In this study, we evaluate the multi-channel seismic reflection and gravity anomalies at the margin to identify the early rift signatures in conjunction with the magnetic anomaly identifications in the Mascarene Basin. The analysis led to the identification of two trends of extensional structures, a NNW–SSE-oriented structure over the Laccadive Ridge north of Tellicherry Arch, interpreted to result from ENE–WSW extension, and a SSW–NNE-oriented structure in the Laccadive basin region towards the south, interpreted to result from NW–SE extension. Previous plate reconstruction models of the Mascarene Basin using marine magnetic lineations suggest that the ENE–WSW extension observed over the Laccadive Ridge could be related to the India–Madagascar separation. We associate the pattern of sediment deposition and the presence of a Paleocene trap volcanics, linked with the NW–SE grabens observed in the Laccadive basin region, to the extension between the Laccadive Ridge and the western coast of India after the separation of Madagascar from India. We further propose that the anticlockwise rotation of India and the passage of the Réunion plume have facilitated the opening of the Laccadive basin. [ABSTRACT FROM AUTHOR]

The only occurrence of Lower Triassic silicic volcanic rocks within the South China Block is in the Qinzhou Bay area of Guangxi Province. LA‐ICP‐MS zircon U‐Pb dating reveals that volcanic rocks of the Beisi and Banba formations formed between 248.8 ± 1.6 and 246.5 ± 1.3 Ma, coeval with peraluminous granites of the Qinzhou Bay Granitic Complex. The studied rhyolites and dacites are characterized by high SiO2, K2O, and Al2O3, and low MgO, CaO, and P2O5 contents and are classified as high‐K calc‐alkaline S‐type rocks, with A/CNK = 0.98–1.19. The volcanic rocks are depleted in high field strength elements, e.g., Nb, Ta, Ti, and P, and enriched in large ion lithophile elements, e.g., Rb, K, Sr, and Ba. Although the analyzed volcanic rocks have extremely enriched zircon Hf isotopic compositions (εHf(t) = –29.1 to –6.9), source discrimination indicators and high calculated Ti‐in‐zircon temperatures (798–835°C) reveal that magma derived from enriched lithospheric mantle not only provided a heat source for anatectic melting of the metasedimentary protoliths but was also an endmember component of the S‐type silicic magma. The studied early Triassic volcanics are inferred to have formed immediately before closure of the Paleo‐Tethys Ocean in this region, as the associated subduction would have generated an extensional setting in which the mantle‐derived upwelling and volcanic activity occurred. [ABSTRACT FROM AUTHOR]

Abstract A major challenge in mantle geochemistry is determining the source composition and melt fraction involved in melting. We provide a new Rare‐Earth Element (REE) inverse model that provides source concentration, source and melt mineral modes, and melt fraction based on the difference between separate determinations of bulk distribution coefficients and constrained by boundary conditions. An analytical inverse of the batch melting equation provides expressions for source, Coi, and bulk distribution coefficient of the mantle, Doi, with two unknowns, the initial concentration of La in the mantle, CoLa, and Pi, the bulk distribution coefficient of the melt. We traverse through a range of CoLa steps and examine thousands of melt modes, Pi, at each step. Thousands of trial melt modes fail by generating Doi that are inconsistent with partition coefficients. Many surviving trials cannot be inverted to estimate a mantle mode. Other boundary conditions eliminate even more trials. Surviving trials are ordered by the difference between Doi calculated from the REE data of a lava suite and Dci calculated from partition coefficients and mantle mode. We select the solution with the closest fit that passes all the boundary conditions. We tested our new model with lava suites from Hawaii where different lines of evidence suggest that they melted from different mantle sources, Mauna Kea representing shield‐stage lava and submarine Kiekie representing rejuvenated stage lava. Our inverse determination of mantle composition and melting parameters was consistent with earlier models based on assumptions of HREE composition.

The Eastern Kunlun Orogenic Belt (EKOB), located north of the Qinghai-Tibetan Plateau, recorded voluminous late Palaeozoic – early Mesozoic intermediate-acid volcanic rocks. The tectonic evolution of the Palaeo-Tethys Ocean from initial subduction and final closure and post-collision extension has been hotly debated. This study examines the petrogenesis of Palaeozoic to Early Mesozoic volcanic rocks at six locations: Xiahe, Elashankou, Jirimai, Harizha, Nagengkangqieer, and Yazigounan. The investigation involves detailed field observations, petrology, zircon U-Pb geochronology, Lu-Hf isotopes, and whole-rock geochemical analysis. The rocks analysed represent three episodic volcanic events. The ca. 257–245 Ma volcanic rocks were derived from magma mixing response to the subduction. The ca. 227–220 Ma highly fractionated I-type volcanics were derived from partial melting of the ancient lower crust, with varying contribution proportions of mantle materials. The ca. 216 Ma A-type volcanic rocks derived from partial melting of the juvenile crust. In this study, using existing regional geological data and spatiotemporal distribution of the magmatic region, combined with our new data, we attempt to propose more rational models to reveal the tectonic evolution of the Palaeo-Tethys Ocean, and we recognize three significant time nodes: (1) Ca. 240 Ma marks the final closure time of the Palaeo-Tethys Ocean. (2) Ca. 230 Ma indicates the vital tectonic regime transition from compression to extension response to slab break-off and continued lithospheric delamination. (3) Ca. 216 Ma mark the beginning of the final stage of orogeny in the EKOB, and mild magmatism lasts to ca. 200 Ma in response to the mountain collapse. [ABSTRACT FROM AUTHOR]

This article reports on the state-of-the-art and future perspectives of machine learning (ML) in petrology. To achieve this goal, it first introduces the basics of ML, including definitions, core concepts, and applications. Then, it starts reviewing the state-of-the-art of ML in petrology. Established applications mainly concern the so-called data-driven discovery and involve specific tasks like clustering, dimensionality reduction, classification, and regression. Among them, clustering and dimensionality reduction have been demonstrated to be valuable for decoding the chemical record stored in igneous and metamorphic phases and to enhance data visualization, respectively. Classification and regression tasks find applications, for example, in petrotectonic discrimination and geo-thermobarometry, respectively. The main core of the manuscript consists of depicting emerging trends and the future directions of ML in petrological investigations. I propose a future scenario where ML methods will progressively integrate and support established petrological methods in automating time-consuming and repetitive tasks, improving current models, and boosting discovery. In this framework, promising applications include (1) the acquisition of new multimodal petrologic data; (2) the development of data fusion techniques, physics-informed ML models, and ML-supported numerical simulations; and (3) the continuous exploration of the ML potential in petrology. To boost the contribution of ML in petrology, our main challenges are: (1) to improve the ability of ML models to capture the complexity of petrologic processes, (2) progressively link ML algorithms with the physical and thermodynamic nature of the investigated problems, and (3) to start a collaborative effort among researchers coming from different disciplines, both in research and teaching. [ABSTRACT FROM AUTHOR]