Journal of Volcanology and Geothermal Research最新文献

{"title":"Investigating the connection between superhydrous melts, magma reservoir nucleation and the scarcity of mafic eruptions in post-collisional settings","authors":"Alissa Näpflin ,&nbsp;Răzvan-Gabriel Popa ,&nbsp;Ioan Seghedi ,&nbsp;Olivier Bachmann","doi":"10.1016/j.jvolgeores.2026.108542","DOIUrl":"10.1016/j.jvolgeores.2026.108542","url":null,"abstract":"<div><div>Magma reservoir emplacement in the brittle upper-crust typically requires prolonged heating to modify host-rock rheology, allowing magma to accumulate rather than erupt. In thermally immature crust, early eruptions are expected to be mafic, yet many volcanic provinces, particularly those with water-rich melts, lack significant initial mafic volcanism, suggesting an alternative trapping mechanism. We investigate this using Caraci volcano (Romania's Apuseni Mountains), a water-rich system that started with relatively differentiated, andesitic eruptions. The first eruptions at Caraci extruded water-rich (5–6 ± 0.35 wt% dissolved H₂O) amphibole-plagioclase andesites (890–920 ± 22 °C) stored at water-saturated conditions in the upper-crust (∼2 ± 0.5 kbar). These magmas were associated with superhydrous primitive melts (&gt;6 wt% H₂O), which evolved in a polybaric system (crystallization pressure varying from 2 to 8 ± 0.5 kbar), evidenced by high-Mg amphibole and delayed plagioclase crystallization. These deeper storage melts likely reached water saturation during ascent towards the upper crust, inducing degassing and crystallization, which increased viscosity and enabled stalling in the cold crust, explaining the lack of initial mafic eruptions and providing the efficient trapping mechanism in a thermally immature crust. Progressive drying of the source and generation of less hydrous magmas initiated the eruptions and construction of the stratovolcano, and ultimately terminated the system. As a result, the final eruption extruded somewhat drier (4–4.5 ± 0.35 wt% H₂O), hotter (930–960 ± 45 °C) pyroxene-bearing andesites erupted from water-undersaturated storage. This trapping mechanism of water-rich magmas may explain the typical scarcity of mafic volcanism in arc and post-collisional settings.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108542"},"PeriodicalIF":2.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelled versus tracked ballistic trajectories of volcanic bombs at Stromboli (Italy)","authors":"A. Sork ,&nbsp;L. Watson ,&nbsp;B. Kennedy ,&nbsp;R.H. Fitzgerald ,&nbsp;J. Taddeucci ,&nbsp;M. Sellier ,&nbsp;P. Scarlato ,&nbsp;E. Del Bello ,&nbsp;T. Ricci","doi":"10.1016/j.jvolgeores.2026.108543","DOIUrl":"10.1016/j.jvolgeores.2026.108543","url":null,"abstract":"<div><div>Validation for computational modelling of volcanic ballistic projectiles (VBPs) has often been accomplished by replication of field-surveyed VBP distributions. However, a range of ejection parameters can result in the same impact location, with differing impact energies and therefore hazard implications. Ballistic hazard models must accurately represent the whole trajectory to better estimate ballistic energy and interpret eruption dynamics.</div><div>We examine model performance by directly measuring Strombolian VBP ejection parameters and trajectories from high-speed video and comparing with modelled trajectories using the same parameters. We illustrate the effects of velocity and size on drag. We synthesize and investigate different methods by which the Reynolds number (<em>Re</em>) - drag coefficient (C_D) relationship is incorporated into models and how this affects modelling results. Our computational model allows for application of different existing <em>Re</em>-C_D methods and direct comparison to tracked trajectories on the metrics of impact distance and peak height.</div><div>Even with validated ejection parameters and appropriate <em>Re</em>-C_D relationships, the model rarely accurately reproduces both height and distance within a 5% threshold. The most common scenario is model overestimation of both metrics. The gas jet is the largest factor contributing to this discrepancy. Significant slowing of VBPs in excess of gravity is observed while bombs are rising (and within the gas jet radius) but not while falling. Slowing in the gas jet is potentially caused by friction with ash and lapilli, surface temperature effects, or other fluid dynamics effects.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108543"},"PeriodicalIF":2.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrous upper mantle facilitated alkali basalt genesis in the Southeastern Carpathians, Romania","authors":"Levente Patkó ,&nbsp;Ákos Kővágó ,&nbsp;Thomas Pieter Lange ,&nbsp;Alexandru Szakács ,&nbsp;Monika Huraiová ,&nbsp;Márta Berkesi ,&nbsp;László Előd Aradi ,&nbsp;Szilveszter Gergely ,&nbsp;Ábel Szabó ,&nbsp;Károly Németh ,&nbsp;Csaba Szabó ,&nbsp;István János Kovács","doi":"10.1016/j.jvolgeores.2026.108540","DOIUrl":"10.1016/j.jvolgeores.2026.108540","url":null,"abstract":"<div><div>This study investigates the structural hydroxyl content in clinopyroxenes from five cumulate xenoliths hosted by alkali basaltic pyroclastic rocks collected from the Perşani Mountains Volcanic Field (southeastern Transylvania, Romania), revealing structural hydroxyl concentrations ranging from 261 to 436 ppm wt. From these measurements, the ‘water’ content of the equilibrium parental alkali basaltic melt was estimated at 1.2 to 2.5 wt%, consistent with global values for alkali basalts. The mantle source ‘water’ content was also determined and resulted to be a ‘water’-rich mantle volume, ranging from 400 to 840 ppm wt. under batch melting and 310 to 660 ppm wt. for fractional melting models. The hydrous signature appears to be linked to the influence of an earlier subduction event, sustained by continued fluid release from remnants of the sinking slab at asthenospheric depths. The findings highlight the crucial influence of ‘water’ in upwelling mantle material, especially in regions affected by slab rollback and detachment, as is the case in the study area of the East Carpathian bend zone, where ‘water’ governs the extent of partial melting and enhances melt generation.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108540"},"PeriodicalIF":2.3,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the seismic structure of shallow magmatic conduits: Insights from the Salina Island (southern Italy)","authors":"I. Granados-Chavarría ,&nbsp;F. Di Luccio ,&nbsp;M. Calò ,&nbsp;D. Famiani ,&nbsp;M. Lupi ,&nbsp;M. Palano ,&nbsp;G. Ventura","doi":"10.1016/j.jvolgeores.2026.108536","DOIUrl":"10.1016/j.jvolgeores.2026.108536","url":null,"abstract":"<div><div>The plumbing systems of closely spaced individual volcanoes and volcanic fields may be very complex due to the interaction (or not) of different magma storage zones and magma pathways at variable depths. Ambient noise tomography unveils the shallow seismic structure of Salina Island (Southern Italy), which is characterized by 6 proximal and partly overlapping volcanoes developed between 244 and 15.6 ka. We use two months of continuous data from 40 nodal stations deployed in 2023 at uneven interstation distances. This seismic array yields tomographic maps down to 1.5 km depth in which the geometry of the volcano flank collapses and shallower plumbing systems of eruptive fissures are clearly imaged. Shear wave velocity maps reveal the main structures and deposits of the ‘twin’ stratovolcanoes of Monte dei Porri, to the west, and Monte Fossa delle Felci, to the east. High velocity anomalies beneath these volcanoes become less pronounced at ∼200 m b.s.l. revealing the transition from submarine to subaerial lava flows. 3D images of the eastward dipping subcircular conduits below the main volcanoes suggest that the deep feeding system is located offshore to the east.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108536"},"PeriodicalIF":2.3,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An analog experiment showing varying shapes of pyroclasts by including crystals and bubbles","authors":"Sayaka Oda,&nbsp;Atsuko Namiki","doi":"10.1016/j.jvolgeores.2026.108534","DOIUrl":"10.1016/j.jvolgeores.2026.108534","url":null,"abstract":"<div><div>Low-viscosity basaltic and basaltic andesitic magmas form pyroclastic materials with various shapes, such as scoria, volcanic ash, and Pele’s hair, through fracturing. Brittle fracture of low-viscosity magma is unlikely. Instead, fluid dynamical deformation during the eruption may cause the magma to tear off. The various morphologies of pyroclast shapes should be determined by their deformation history. High crystallinity in magma increases its effective viscosity, potentially enabling brittle-like fracture. To understand how the shape of pyroclastic material produced by low-viscosity magma is determined, we conducted uniaxial extension experiments using a magma analog mixture of liquid, solid, and gas phases. Our experiments demonstrate that fluids with a high solid particle fraction (<span><math><mo>&gt;</mo></math></span>0.3) tend to tear off at a small strain, thereby generating a rough fracture surface. The solid particles were undeformable, and a high particle fraction reduced the thickness of the deformable liquid region. Thin liquid films are easily disrupted, and thus a small strain can break the entire fluid. In contrast, a particle-free bubbly fluid generates thin threads. Bubbles can coalesce to create a large bubble and deform. Vertically elongated bubbles split the fluid in the longitudinal direction, forming threads. The former mechanism may generate the irregularly shaped scoriae, and the latter forms Pele’s hair. Our experimental results indicate that suspended crystals and bubbles in magma affect not only the physical properties of magma but also the fracture manner, thereby determining the shapes of pyroclasts.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108534"},"PeriodicalIF":2.3,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperspectral imaging, mineralogy, and degassing: Exploring the volcanic hydrothermal system of Red Crater, Tongariro, Aotearoa New Zealand","authors":"Daniel Sturgess ,&nbsp;Gabor Kereszturi ,&nbsp;Agnes Mazot ,&nbsp;Rachelle Sanchez ,&nbsp;Antonio M. Álvarez-Valero ,&nbsp;Vladyslav Zakharovskyi","doi":"10.1016/j.jvolgeores.2026.108535","DOIUrl":"10.1016/j.jvolgeores.2026.108535","url":null,"abstract":"<div><div>Hydrothermal alteration on volcanoes can compromise the strength and permeability of the host rock, contributing to flank collapses (e.g., Te Maari, 2012) and phreatic eruptions (e.g., Whakaari, 2019). Alteration processes occur at volcanoes hosting hydrothermal systems, where hot, acidic fluid flow is driven by a supply of magmatic heat and gas inputs, resulting in the dissolution of primary minerals and the deposition of secondary assemblages. We investigated hydrothermal alteration at Red Crater, Tongariro, Aotearoa New Zealand, using a combination of laboratory and airborne hyperspectral imaging, mineralogical, and geochemical techniques. Two distinct alteration styles were identified: (1) advanced argillic alteration, characterised by amorphous silica, kaolinite, and alunite, primarily focused at the Red Crater scoria cone, and (2) silicification at Oturere and the Emerald Lakes. The distribution of these units was mapped using supervised image classification of airborne hyperspectral data. Textural and isotopic analyses suggest acid-sulphate alteration is primarily driven by the oxidation of rising H₂S in a steam-heated environment. Red Crater hosts four main regions of heightened degassing, coinciding with geothermal surface features and hydrothermal alteration deposits, with 26.2 <span><math><mo>±</mo></math></span>1.5 t/d of CO₂ emissions and an H₂S flux of 131.1 g/m²/d. This study presents a conceptual model of hydrothermal alteration processes at Red Crater. Our mapping of alteration and degassing can indicate areas of potential future hazards, and may support simulations assessing flank instability, improving hazard assessment at this active vent.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108535"},"PeriodicalIF":2.3,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Granophyric crystallization within the Gomez Tuff, the world's largest pantelleritic ignimbrite, Davis Mountains, Trans-Pecos Texas","authors":"Don F. Parker ,&nbsp;John C. White ,&nbsp;Kevin Urbanczyk","doi":"10.1016/j.jvolgeores.2025.108527","DOIUrl":"10.1016/j.jvolgeores.2025.108527","url":null,"abstract":"<div><div>The Gomez Tuff was erupted ∼37 Ma as an explosive component of widespread silicic lava (“flood rhyolite”). The Gomez eruption covered an area &gt; 4000 km², with an estimated dense rock equivalent volume of ∼220 km³, making it the largest known pantelleritic ignimbrite. The eruption formed a ∼18 × 24 km-diameter caldera, within which the ignimbrite ponded to thicknesses approaching 500 m. Estimated water content (∼1.9 wt%) of the erupting magma was relatively low, favoring eruption of dense pyroclastic flows over pyroclastic falls. Within thicker sections of the tuff, rheomorphic flow created flow banding, large folds and ramp structures. Granophyric crystallization (af, cpx, aenig, amph, qz) destroyed the fragmental nature of the tuff, except for abundant lithic inclusions.</div><div>Gomez phenocryst assemblages include alkali feldspar (Or₃₆_–₃₉) and quartz ± fayalite, with minor hedenbergite, ilmenite and apatite. Magmatic conditions previously deduced from these assemblages assuming <em>P</em> = 2 kbar, a magmatic temperature of ∼750 °C from phase equilibria and not using fayalite in the calculations indicated a temperature range of ∼870 to 750 °C, with oxygen fugacity (ΔFMQ ∼ −1.92) below the NNO buffer (<span><span>Parker and White, 2008</span></span>). Alternative calculations suggest ranges of 855 to 766 °C, assuming fayalite stable in all samples, and 900 to 700 °C, assuming aenigmatite was stable in lieu of fayalite. The calculations assuming neither fayalite nor aenigmatite was stable as a phenocryst are preferred, as fayalite was only observed in two samples and aenigmatite was not observed as a phenocryst in any sample.</div><div>The original Peralkalinity Index (P·I.) was likely ∼1.3. During granophyric crystallization (at ∼687 °C) in thick sections of the tuff, groundmass feldspar increased its iron content and became more potassic, driving glass and calculated groundmass compositions to ∼1.48. In the final stages of crystallization, groundmass pyroxene approached stoichiometric aegirine and arfvedsonite became less magnesian and more sodic, suggesting that the P·I. of the final crystallizing glass neared 1.8, judging from comparison to the Type 1 Green Tuff of Pantelleria.</div><div>We model the Gomez magma chamber as an extensive sill, in which pantelleritic magma accumulated above a reservoir of trachytic magma. Eruption of the ignimbrite efficiently drained the evolved magma, allowing the eruption of trachyte lava, which subsequently filled the caldera.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108527"},"PeriodicalIF":2.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-volcanic hazards assessment at Karangetang Volcano, Indonesia due to the reactivation of two craters","authors":"Herlan Darmawan ,&nbsp;Bondan Galih Dewanto ,&nbsp;Argo Galih Suhadha ,&nbsp;Imam Santoso ,&nbsp;Farikhotul Chusnayah ,&nbsp;Amalia Nurwijayanti ,&nbsp;Afif Ari Wibowo ,&nbsp;Atrida Hadianti ,&nbsp;Nurkhalis Rahili","doi":"10.1016/j.jvolgeores.2026.108533","DOIUrl":"10.1016/j.jvolgeores.2026.108533","url":null,"abstract":"<div><div>Increased volcanic activity on inhabited volcanic islands requires a rapid volcanic-hazards assessment to reduce potential casualties and losses. Karangetang Volcano (2.78°N, 125.406 E), located on Siau Island, poses significant threats to approximately 70,000 residents due to its increased activity over the last decade. In this study, we assessed volcanic hazards of Karangetang Volcano by integrating satellite imageries from Landsat 8 and 9, Sentinel-1 SLC, Sentinel-2, and Sentinel-5 TROPOMI. These satellites have been used to analyse land surface temperature (LST), thermal areas, volcano deformation, and SO₂ over the last decade. The results highlighted reactivation of two craters (southern and northern) that influenced the directions of both lava and pyroclastic flows from the north, west, southwest, to the south flank area during the 2015, 2019, and 2023 eruption crises. The highest thermal anomalies were recorded in August 2015, November 2019, March 2023, and August 2023, with a maximum land surface temperature of ∼103.29 °C. Furthermore, cumulative displacement indicated that Karangetang experienced long-term deflation, possibly caused by the cooling of lava and the solidification of pyroclastic deposits on the western part of the Karangetang summit. Observations of SO₂ emissions indicated that Karangetang experienced low degassing, with a maximum SO₂ mass of 1.832 kt. Based on multi-parameter satellite observations, Karangetang has been highly active over the last decade, and mitigation preparedness should be conducted in the north, west, southwest, and south flank areas.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108533"},"PeriodicalIF":2.3,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An integrated approach for finding hidden alignments of point-like volcanic elements that occur in volcanic fields","authors":"E. Pardo-Igúzquiza ,&nbsp;P.A. Dowd","doi":"10.1016/j.jvolgeores.2026.108532","DOIUrl":"10.1016/j.jvolgeores.2026.108532","url":null,"abstract":"<div><div>In this paper a new approach is proposed for uncovering alignments in a point field of volcanic elements. Volcanoes, scoria (cinder) cones, maars, eruption points, submarine seamounts, fissures, vents, calderas, craters, dykes, fault ridges, fumaroles, pit craters, among others, can be considered as volcanic elements in so far as each individual element is treated as a point, for example by considering the centroid of the feature. This novel approach uses both a statistical method and an exact method to find alignments of points hidden in a point field. The statistical method uses both the global and the local approach, and an intermediate alternative is introduced between the global (all neighbours) and the local approach (nearest neighbour) by using the k-nearest neighbours. This new approach was found to be optimal for a value of k in the range of 5 to 20. In all cases, of both statistical and exact methods, the uncertainty of the estimates is evaluated by using confidence limits so as to minimize the acceptance of spurious alignments of volcanic features. The proposed procedures also avoid any bias introduced by the geometry of the study area. In addition, the spatial distribution of the volcanic points can be homogeneous or heterogeneous. The proposed methodology is illustrated with a point field of volcanic cones on La Palma island in the Canary archipelago. The alignments of volcanic features have applications in volcano-tectonics, volcanic geomorphology and the assessment of volcanic hazards.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108532"},"PeriodicalIF":2.3,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of the eruptive processes and new 40Ar/39Ar dating of Plio-Pleistocene monogenetic volcanism in the Folded Middle Atlas (Northern Morocco). Implications of eruption style variation with climate changes","authors":"Said Haidatte ,&nbsp;Károly Németh ,&nbsp;Abdelilah Fekkak ,&nbsp;Hind El Hachimi ,&nbsp;El Houcine El Haous ,&nbsp;Omar Outaaoui ,&nbsp;Michele Lustrino","doi":"10.1016/j.jvolgeores.2026.108530","DOIUrl":"10.1016/j.jvolgeores.2026.108530","url":null,"abstract":"<div><div>During the Plio-Pleistocene, several individual monogenetic volcanoes were emplaced in the Folded Middle Atlas region in Central Morocco. These eruptions are primarily concentrated on anticlinal ridges and are structured by a network of NNE-SSW-oriented faults, inherited from Alpine or older tectonic phases. This study investigates three Pleistocene (2.5-0.8 Ma) small scoria cones and one partially preserved maar, here dated with ⁴⁰Ar/³⁹Ar geochronology to 0.281 Ma, indicating the youngest hydrovolcanic eruption of this area.</div><div>The temporal distribution and morphological diversity of volcanic edifices in northern Africa during the Plio-Pleistocene are inferred to be closely associated with paleoclimatic fluctuations, which alternated between arid and humid phases. Strombolian explosive eruptions created scoria cones primarily during arid periods, facilitating magmatic outgassing with minimal interaction between magma and the water table. In contrast, hydrovolcanic eruptions were promoted by wetter climatic conditions, which were susceptible to interaction between upwelling magma and surface water or shallow aquifers.</div><div>Scoria cones consist of pyroclastic deposits of varying grain sizes, including scoriaceous pyroclasts such as small portions of coarse ash lapilli and volcanic bombs with different morphologies. Their last eruptive activity phases are typically represented by thin lava flows, indicating a gradual shift to Hawaiian-type mild explosive dynamics. Conversely, maar formations are characterized by ejecta deposits from phreatomagmatic explosions, indicating rapid interaction between magma and varying volumes of external water, likely occurring during a single eruptive event.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108530"},"PeriodicalIF":2.3,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}