Volcanic Activity Research Articles

Magma recharge in persistently active basaltic–andesite systems and its geohazards implications: the case of Villarrica volcano, Chile

We report whole-rock chemistry, mineral chemistry, and volatile content from Villarrica volcano’s major recent paroxysms and background activity. Composition of the volcanic products are basalt to basaltic andesite with whole-rock SiO2 content between 50 and 56 wt%, and a mineralogy dominated by olivine (Fo71-80), clinopyroxene (Mg# ~ 50) and plagioclase (An60–80). Volatile contents in melt inclusions are up to 1.5 wt% H2O, 500 ppm CO2, 1230 ppm sulfur and 580 ppm chlorine. Regardless of the type of activity, there are no substantial variations in whole-rock composition or the volatile content when the activity switches from background activity to a major paroxysm, strongly suggesting that this shift does not just depend on the arrival of new magma in the shallow magmatic system. Geothermobarometry constrains crystallization of the major mineral phases at various depths between 3 and 12.7 km, suggesting that degassing of a volatile-rich recharge magma occurs deeper than 12 km, producing efficient mixing throughout the whole system, and sustaining the lava lake activity in Villarrica’s summit crater. The occurrence of a permanent lava lake also suggests that the magma recharge must be close to continuous and therefore sudden changes between background and paroxysmal volcanic activity are likely controlled by relatively small changes in the rate of recharge and/or the volatile release rate in the magmatic system. This has important implications for the understanding of eruption triggers and the forecasting of volcanic eruptions.Graphical abstract

Mineral chemistry and P-T conditions of the Karakaya volcanites at Kırka-Afyon-Isparta volcanic province, Afyon, Turkey

The Kırka-Afyon-Isparta Volcanic Province (KAIVP) is one of the best known regions in Turkey for the origin and petrological evolution of the high potassium volcanic activity. The temporal and spatial variability of volcanic rocks in the region exerts significant control over their geochemical diversity. Alkaline and ultrapotassic volcanic rocks of the Afyon volcanism are the first products of asthenospheric origin after the orogenesis in western Anatolia. We have determined the mineralogical and petrographic properties of the Karakaya volcanites surrounding Afyon with the help of microprobe analyses. Estimated thermobarometers are calculated. The Karakaya volcanites have been grouped into four different units according to their their mineralogical, petrographic and geochemical characteristics: Seydiler ignimbirite, basaltic trachyandesite, trachyandesite, trachyte and lamproite. Most samples display hypocrystalline porphyritic texture, whereas samples of lamproite unit have a holocrystalline texture. Generally, volcanic units also exhibit some textural evidence of disequilibrium crystallisation, such as sieve texture and corrosion in plagioclase phenocrysts, zoning and inclusions in clinopyroxene phenocrysts. Mineral thermobarometric estimations in all suites were tested on clinopyroxene and feldspar compositions, considering different authors’ approaches. Values of temperatures and pressure range from 1105 to 1273ºC and 5.6 to 12.2kbar, respectively. The temperature and pressure values calculated from the mineral-melt associations in the volcanics suggest that the Afyon Volcanites were affected by magma mixing processes and crystallised at different depths during the transport of magma.

High-frequency climate forcing causes prolonged cold periods in the Holocene

Understanding climate variability across interannual to centennial timescales is critical, as it encompasses the natural range of climate fluctuations that early human agricultural societies had to adapt to. Deviations from the long-term mean climate are often associated with both societal collapse and periods of prosperity and expansion. Here, we show that contrary to what global paleoproxy reconstructions suggest, the mid to late-Holocene was not a period of climate stability. We use mid- to late-Holocene Earth System Model simulations, forced by state-of-the-art reconstructions of external climate forcing to show that eleven long-lasting cold periods occurred in the Northern Hemisphere during the past 8000 years. These periods correlate with enhanced volcanic activity, where the clustering of volcanic eruptions induced a prolonged cooling effect through gradual ocean-sea ice feedback. These findings challenge the prevailing notion of the Holocene as a period characterized by climate stability, as portrayed in multi-proxy climate reconstructions. Instead, our simulations provide an improved representation of amplitude and timing of temperature variations on sub-centennial timescales.

Evidence of a Low‐Velocity Zone in the Upper Mantle Beneath Cumbre Vieja Volcano (Canary Islands) Through Receiver Functions Analysis

AbstractOceanic volcanic islands have a complex internal structure due to their geological evolution. La Palma is the second youngest in the Canary Islands. Historical eruptions occurred in the Cumbre Vieja (CV) volcanic system, including the last 2021 Tajogaite eruption. The seismicity before, during, and after the Tajogaite eruption provides valuable information for a better understanding of deep volcanic processes. We applied the receiver function technique to image the crustal and upper mantle structures beneath the CV volcanic complex. We investigated the first 50 km of the lithosphere, identifying various seismic discontinuities. After a thin layer of recent volcanic rocks, we found a layer corresponding to the old oceanic crust. Beneath the Moho, we found a significant decrease in the seismic velocities until about 37 km of depth. This low‐velocity layer corresponds to a zone of partial melting with interconnected magmatic chambers that feed the volcanic activity in CV.

Late-Pleistocene rejuvenated volcanism and flank collapse deposits on a Cretaceous seamount near El Hierro, Canary Archipelago

Henry Seamount is a Cretaceous submarine volcano located 40 km southeast of El Hierro, the youngest of the Canary Islands, at 3700 m water depth. On the seamount's summit region, a widespread layer of heterolithologic volcaniclastic ash and lapilli beneath centimeters to decimeters of pelagic sediment was discovered and sampled during R/V Meteor cruise 146. The dominant lithology is a glassy basaltic ash that is depleted in highly incompatible elements and enriched in sulfur (S/K2O ratios of 0.10–0.20) compared to El Hierro lavas, suggesting an origin by a deep-sea volcanic eruption on Henry Seamount. Uranium-series disequilibria constrain the age of this ash to <350 ka, which implies rejuvenated volcanic activity of the seamount after up to 126 Ma of dormancy. This rejuvenated activity is possibly related to the Canary hotspot, where heating of lithosphere that had become amphibole-metasomatized during the formation of Henry Seamount led to renewed melt production. In contrast to the dominant ash type, most other volcaniclastic samples are geochemically indistinguishable from El Hierro lavas. The variety of lithologies, the angular to edge-rounded shapes of many fragments, and intimate mixture with the predominant ash suggest that this group of volcaniclastics was transported from El Hierro to Henry Seamount by a submarine debris avalanche and associated turbidity current. This implies a runup of up to 700 m even for centimeter-sized basaltic clasts after up to 40 km of lateral transport. ArAr age constraints for two samples are ∼190–200 ka, which is consistent with the southeast-directed giant Las Playas II landslide from El Hierro as the most likely source. Henry Seamount thus provides a rare example where collapse-induced deposits from another volcanic edifice are found on top of a seamount and are mingled with ash to lapilli from previous rejuvenated volcanism. Mingling and reworking of the tephra may explain the lack of a discernible eruption center on top of the seamount.

Regional noise source location based on the time delays between station pairs from ambient noise interferometry

Identifying the location of a potential noise source assists in understanding the characteristics of the seismic or volcanic activity and provides valuable information for hazard assessment. Unlike the conventional waveform-based techniques that rebuild the source energy into the possible source region, we apply a simplified method to determine the absolute location of the noise source based on the station-pair time-delays from ambient noise interferometry. Synthetic tests demonstrate the robustness of the method and the locating precision is mainly influenced by the signal-to-noise ratio of the synthetic waveforms, and the higher frequency bandwidth source signals are more likely to result in accurate detection of the source. An application at the Central Tien Shan indicates that our method is capable of locating the known virtual source from the empirical Green’s functions. Furthermore, assuming a surface wave velocity, the depth of the source can be generally recovered from ambient noise interferometry in a simplified 3-D homogeneous model. The new method sheds light on applications of ambient noise interferometry for locating potential sources, making it suitable for detecting time-dependent behavior.

Long-lasting farside volcanism in the Apollo basin: Chang'e-6 landing site

A major lunar scientific question is the cause of the paucity of farside mare basalts. The South Pole-Aitken Basin (SPA) is the largest (2400×2050 km) and most ancient lunar impact basin. The Apollo peak-ring basin, the largest impact feature within the SPA, is located on its northeast edge in a transitional zone of crustal thickness and compositions. The Chang'e-6 (CE-6) mission, the first sample-return mission to the lunar farside, is targeted to land in the southern Apollo basin, sampling farside mare basalts with critical insights into early lunar evolution. In preparation for the CE-6 sample return, we conducted a comprehensive study of Apollo basin volcanism. We found that volcanic activity began in the Nectarian Period (∼4.05 Ga) (cryptomaria) and continued into the Eratosthenian Period (∼1.79 Ga). At least two Imbrian-aged episodes of eruptions occurred in the southern part of the Apollo basin where CE-6 is targeted to land. At ∼3.35 Ga, low-Ti (∼3.2 wt %) volcanism was active, and its products covered the entire low topographic region of the southern Apollo basin, between the inner and outer rings. Closely following its eruption at ∼3.07 Ga, high-Ti basalts (∼6.2 wt %) erupted close to the Chaffee S crater and flowed east with decreasing thickness until encountering proto-wrinkle ridges. In addition, volcanic activity in the region is significantly correlated with low crustal thickness, primarily thinned by the SPA and Apollo impact events. For regions of intermediate-thick crust (Oppenheimer crater), dikes stalled under the crater floor, spreading to form sills and a floor-fractured crater. For thin crust regions (Apollo basin interior), dikes erupted directly, forming extensive lava flows. In areas of thick highland crust, we see no evidence of extrusive activity or floor-fractured craters, suggesting that dikes there do not reach the surface and are intrusive. CE-6 samples returned from the unique geological setting will provide significant petrogenetic information to address further the paucity of farside mare basalts and the lunar nearside-farside dichotomy. To solve those scientific questions, the high-Ti mare region in south Apollo basin is recommended as the priority landing site.

Last 150 kyr volcanic activity on Mauritius island (Indian ocean) revealed by new Cassignol-Gillot unspiked K–Ar ages

We present new K–Ar ages extending the volcanic history of Mauritius Island towards the Holocene. Mauritius volcanism is associated with the activity of the Réunion hotspot, the magmatism of which produced the Deccan Traps across the Cretaceous-Tertiary (KT) boundary and continues up to present on Réunion Island. After shield building from before 8.9 Ma to 4.7 Ma, Mauritius Island underwent an unusual volcanic evolution involving two rejuvenation stages (3.5–1.9 Ma and <0.7 Ma) separated by a 1.2 Myr hiatus. The lower bound of the second rejuvenation stage being poorly constrained, it is not clear whether volcanism in this island has come to a rest. Given the occurrence of uneroded, and yet undated strombolian cones in Mauritius, it is important to better constrain the latest activity of this island in order to assess its volcanic hazard. The importance of dating the end of this stage is also enhanced by the fact that most of the surface of Mauritius is covered by the lavas of the rejuvenation stages, hence indicating a recent volcanic activity that needs to be better characterized for risk assessment.We focus here on the last 150 ka interval which lacked precise age controls with only a few whole-rock and groundmass 40Ar/39Ar plateau ages available (Moore et al., 2011), ranging from 138 ± 29 to 40 ± 48 ka (uncertainties are 1 σ). Our six new Cassignol-Gillot unspiked K–Ar ages obtained on plagioclase or groundmass range from 113 ± 7 to 14 ± 3 ka, with much lower uncertainties than previous ages available. Our major and trace element analyses of the dated samples highlight the compositional homogeneity of the lavas erupted in the last rejuvenation stage, showing no geochemical evolution.Our results, with ages as young as 14 ± 3 ka, demonstrate that near-Holocene volcanism is present in Mauritius Island, with no evidence of fading magmatism in the last 150 ka. Our second youngest age at 44 ± 5 ka implies that the latest activity occurred after a ∼30 kyr repose interval, with the consequence that Mauritius volcanism may resume at any time.

Sea surface acidification events in the Andaman Sea associated with the last Toba volcanic activity

To date, little is known about the impact of super-eruptions on ocean biogeochemistry. Using boron isotopes ratios measured on planktonic foraminifera in the marine sediment core BAR94–25, we provide a high-resolution pH record in the Andaman Sea (North of Sumatra), spanning Marine Isotopic Stage 5 to 3. This transition encompasses the super-eruption of the Toba volcano, 74,000 years ago, making it possible to decipher the potential impact of the super-eruption emissions on the ocean pH for the first time. Our results show that inferred foraminiferal pH values generally follow those predicted by glacial-interglacial CO2 variations. However, several abrupt pH drops coincide with Toba ash deposition. This suggests the occurrence of acidification events possibly related to Toba volcanic sulphur emission episodes. These pH drops are followed by anomalous pH increases, possibly relating to localised increases in seawater alkalinity following the alteration of large ash deposits on land.

The most common habitable planets III – modelling temperature forcing and surface conditions on rocky exoplanets and exomoons

ABSTRACT Small rocky planets, as well as larger planets that suffered extensive volatile loss, tend to be drier and have thinner atmospheres as compared to Earth. Such planets probably outnumber worlds better endowed with volatiles, being the most common habitable planets. For the subgroup of fast rotators following eccentric orbits, atmospheres suffer radiative forcing and their heat capacity provides a method for gauging atmospheric thickness and surface conditions. We further explore the model presented in a previous paper and apply it to real and hypothetical exoplanets in the habitable zone of various classes of stars, simulating atmospheric and orbital characteristics. For planetary eccentricities e ∼ 0.3, the forcing-induced hypothetical temperature variation would reach ∼80 K for airless planets and ∼10 K for planets with substantial atmospheres. For Kepler-186 f and Kepler-442 b, assuming e ∼ 0.1, temperature variations can reach ∼24 K. We also consider habitable exomoons in circular orbits around gas giants within the habitable zone, which suffer radiative forcing due to their epicyclic motion. We study several combinations of parameters for the characterization of planets (mass, eccentricity, and semimajor axis) and exomoons (mass, orbital radius, albedo, and atmospheric characteristics) for different stellar types. For e ∼ 0.3, exomoon temperature varies up to ∼90 K, while for ∼0.6 variations can reach ∼200 K. Such exomoons may plausibly retain their volatiles by continued volcanic activity fuelled by tidal dissipation. Although currently undetectable, such effects might be within reach of future Extremely Large Telescope-class telescopes and space missions with mid-infrared and coronagraphic capabilities.

Characteristics of inclusions in chang 7 member and shale oil accumulation stages in Zhijing-Ansai area, Ordos Basin.

In order to further clarify the shale oil accumulation period of the Chang 7 member of the Mesozoic Triassic Yanchang Formation in the Zhijing-Ansai area of the central Ordos Basin, Using fluid inclusion petrography analysis, microscopic temperature measurement, salinity analysis and fluorescence spectrum analysis methods, combined with the burial history-thermal history recovery in the area, the oil and gas accumulation period of the Chang 7 member of the Yanchang Formation in the Zhijing-Ansai area was comprehensively analyzed. Sixteen shale oil reservoir samples of the Mesozoic Triassic Yanchang Formation in seven typical wells in the study area were selected.The results show that the fluid inclusions in the Chang 7 member of Yanchang Formation can be divided into two stages. The first stage inclusions mainly develop liquid hydrocarbon inclusions and a large number of associated brine inclusions, which are mainly beaded in fracture-filled quartz and fracture-filled calcite. The fluorescence color is blue and blue-green, and the homogenization temperature of the associated brine inclusions is between 90-110°C. The second stage inclusions are mainly gas-liquid two-phase hydrocarbon inclusions, gas inclusions and asphalt inclusions. Most of them are distributed in the fracture-filled quartz, and the temperature of the associated brine inclusions is between 120-130°C. Fluid inclusions in Chang 7 member of the Yanchang Formation can be divided into two stages. The CO2 inclusions and high temperature inclusions in the Chang 7 member of the Yanchang Formation are mainly derived from deep volcanic activity in the crust.

Sedimentary Paleoenvironment and Organic Matter Enrichment Characteristics of Lacustrine Shahezi Shale in Songliao Basin: Insights from the Continental Scientific Drilling.

The lacustrine shale of the Shahezi Formation in the Songliao Basin has obvious organic matter enrichment characteristics and great potential for oil and gas resources. At present, the understanding of the sedimentary paleoenvironment and organic matter enrichment characteristics of the lacustrine shale of the Shahezi Formation is relatively weak. Therefore, taking the international continental scientific drilling Program (ICDP) borehole Songke-2 (SK-2) with continuous and whole Shahezi cores as the research object, combined with organic geochemistry, elemental geochemistry, and logging data, the sedimentary paleoenvironment and organic matter enrichment mechanism were studied. The results show that the organic matter of Shahezi shale is generally in the high to over mature stage. The kerogen type of organic matter is mainly II2-III. The organic matter is mainly derived from the lake basin's own algae and terrestrial higher plants. The total organic carbon (TOC) content of Shahezi shale is relatively high, and the TOC is mainly distributed between 1% and 2%. The Shahezi Formation is dominated by clay shale and siliceous shale, and experienced moderate chemical weathering during deposition. According to the analysis of organic geochemistry and elemental geochemistry data, the paleoenvironment of organic matter deposition in Shahezi shale was dominated by warm and humid climate in the early stage, and then experienced multiple cooling and arid periods. The climate type turned to semihumid-semiarid, with stable terrigenous debris input, low deposition rate, brackish water salinity and oxygen-rich-oxygen-poor water environment. The sedimentary period of Shahezi Formation is in the Cretaceous oceanic anoxic Aptian-Albian stage. During the oceanic anoxic event, the anoxic sedimentary environment and the frequent volcanic activity have an important impact on the organic matter enrichment. The oceanic anoxic event and volcanic activity are the main causes of water body hypoxia in the lake basin. The nutrients brought by volcanic activity are also one of the reasons for promoting the growth of lake basin organisms, creating good conditions for organic matter enrichment. The enrichment of organic matter in Shahezi Formation is the result of the interaction and coupling of various factors such as paleoclimate, paleoenvironment, paleoproductivity, water environment, terrestrial input, and major geological events. And, the organic matter enrichment model of Shahezi Formation shale is established.

Early arc crust formation preserved in the Grenadines archipelago, southern Lesser Antilles arc.

Intra-arc diversity in volcanic activity and composition is ubiquitous, but its underlying causes remain largely unresolved in many settings. In this work, we examine such variability in the Grenadines archipelago, southern Lesser Antilles arc. Here, juxtaposed volcanic centres exhibit eruptive longevities and chemistries distinct from northern counterparts in the same arc. Our goal is to explain this deviation by investigating variations in magmatic processes using petrological data from erupted crustal xenoliths and lavas, and interpreting these findings within the context of the archipelago's tectonic history and geophysical structure. Textural analyses of xenoliths reveal crystallization over a wide range of pressure-temperature-melt composition conditions in the crust. Mineral phases display discrete compositional trends pointing towards significant inter-island variability in underlying plumbing systems. The geochemical variety of erupted magmas is reminiscent of the entire arc. We speculate that the Grenadines represents the early onset of subduction forming the modern-day Lesser Antilles arc. Extrusive volcanism initiated as submarine activity. Subsequent uplift eroded the original topography of these volcanic centres following the eventual cessation of volcanism in the Neogene. The positioning of the Grenadines on an elevated platform provides rare modern insight into early arc crust formation not commonly preserved in established active arcs.

A Quantitative Provenance Analysis (QPA) Approach to Quantify Controls on Sediment Generation and Sediment Flux in the Upper Reaches of the Magdalena River (Colombia): 1. Natural and Anthropic Controls on the Sand Fraction

AbstractThis study investigates the upper Magdalena river basin (Colombia), which is characterized by tectonic activity, tropical climate, heterogeneous lithological assemblages, and anthropic influence. It aims to comprehend factors controlling sediment generation, flux, and composition by incorporating petrographic data from 27 recent fluvial samples along with geochemistry, geomorphological parameters, historical precipitation, land cover, landsliding and suspended sediment load data. The analysis shows mismatches between sand composition and drainage lithology distribution. A new set of endmember mixing models is presented, quantifying the impacts of erodibility, sand generation potential (related to lithology), and sediment connectivity between hillslopes and river outlets (related to geomorphology). Results show enhanced sediment generation from sedimentary rocks (up to 40%) due to high erodibility, and decreased sediment flux from low‐ to medium‐grade metamorphic rocks (up to 60%) due to controlling morphometric parameters. Overrepresentation of plutonic and high‐grade metamorphic rocks and underrepresentation of volcanic rocks (up to 100%) are controlled by mineralogical and textural parameters. Enhanced landsliding activity in areas with volcanic activity occasionally overshadows basin‐wide compositional trends driven by morphological and lithological characteristics, as it controls rare overrepresentation of volcanic and low‐grade metamorphic detritus in the sand fraction. Sediment retention by hydroelectric dams significantly decreases suspended sediment flux by 30%, while deforestation plays a minor role in sediment flux. This study underscores the importance of coupling sediment generation, geomorphology and the distribution of stochastic events related to seismic activity in any sediment production‐focused study and for developing numerical models in Quantitative Provenance Analysis (QPA).

Sedimentation tempo in an Early Jurassic erg system: Refined chronostratigraphy and provenance of the Clarens Formation of southern Africa

AbstractThe Clarens Formation is a widespread aeolianite deposited over southern Gondwana and represents the final phase of erg evolution in the main Karoo Basin during the Early Jurassic. Previous age assessments of the formation hinge on limited detrital zircon data, supplemented by relative ages from the biostratigraphy and geochronology of the adjacent Karoo units. This study refines the depositional history of the Clarens Formation, including its sediment source dynamics as well as basin‐wide geochronological framework, based on U–Pb dating of detrital zircon grains, together with petrographic and sedimentological characterization. The abundant presence of heavy minerals like zircon, tourmaline and rutile suggests large‐scale detritus recycling, while the uniform sandstone composition on a regional scale is an indication of sediment homogenisation across the basin. Based on the prominent detrital zircon age fractions, the sediments are interpreted as having been reworked from pre‐existing rocks of the Karoo Supergroup (Permian), the Damara and Saldania Orogenic belts (650–490 Ma), whereas minor sources can be assigned to the Namaqua‐Natal Mobile Belt (1.35–1.1 Ga) and the western Sierras Pampeanas (1.30–1.33 Ga). Unstable minerals (hornblende, garnet, titanite, feldspar) provide evidence for a nearby granitic source east and southeast of the basin, related to likely Grenvillian rocks (1.0–1.3 Ga). An Early Jurassic zircon age fraction is linked to volcanic activity in the Chon Aike Magmatic Province that, at the time, was situated south and southwest of the study area. Maximum depositional ages derived from these detrital zircon dates suggest that the sedimentation of the Clarens Formation spanned an interval of ~10 Ma during the Pliensbachian and early Toarcian. More specifically, the lower part of the formation is of early Pliensbachian age or younger (~191–192), while the upper part is of early Toarcian age or younger (~181–183 Ma). These age patterns are particularly prominent in the south of the basin that was situated closer to the volcanic source.

Factor analysis and countermeasures for global warming based on data science methods

In recent years, the frequent and intensifying occurrence of extreme weather events such as heatwaves, floods, and storms worldwide has led scientists and policymakers to be increasingly concerned about the phenomenon of global warming. The global average temperature has steadily risen over the past few decades, and 2015-2022 has been identified as the warmest years on record. Taking global warming as the research object, the main problem is to find out the factors affecting climate change. The article predicts the global average temperature of the future and builds a model to analyse the relationship between global average temperature, time, location and the factors affecting climate change. The prediction models of ARMIA and EEMD-LSTM were built, and the model with the best fit was obtained after several iterations of tuning and trial optimization. The results showed that Flood, Storm, and Extreme temperature, had a high correlation with the global average temperature. The data of greenhouse gas indicators such as CO2, NO, and CH4, and catastrophes such as earthquakes, Volcanic activity, and wildfires have objective effects on global warming. Random forest regression model pairs were developed, and analysis of the importance of each component to the model showed that CO2 concentration and CH4 concentration had significant effects on global average temperature. Propose measures that can curb or slow down global warming.

Heat transport process associated with the 2021 eruption of Aso volcano revealed by thermal and gas monitoring

The thermal activity of a magmatic–hydrothermal system commonly changes at various stages of volcanic activity. Few studies have provided an entire picture of the thermal activity of such a system over an eruptive cycle, which is essential for understanding the subsurface heat transport process that culminates in an eruption. This study quantitatively evaluated a sequence of thermal activity associated with two phreatic eruptions in 2021 at Aso volcano. We estimated plume-laden heat discharge rates and corresponding H2O flux during 2020–2022 by using two simple methods. We then validated the estimated H2O flux by comparison with volcanic gas monitoring results. Our results showed that the heat discharge rate varied substantially throughout the eruptive cycle. During the pre-eruptive quiescent period (June 2020–May 2021), anomalously large heat discharge (300–800 MW) were observed that were likely due to enhanced magma convection degassing. During the run-up period (June–October 2021), there was no evident change in heat discharge (300–500 MW), but this was accompanied by simultaneous pressurization and heating of an underlying hydrothermal system. These signals imply progress of partial sealing of the hydrothermal system. In the co-eruptive period, the subsequent heat supply from a magmatic region resulted in additional pressurization, which led to the first eruption (October 14, 2021). The heat discharge rates peaked (2000–4000 MW) the day before the second eruption (October 19, 2021), which was accompanied by sustained pressurization of the magma chamber that eventually resulted in a more explosive eruption. In the post-eruptive period, enhanced heat discharge (~ 1000 MW) continued for four months, and finally returned to the background level of the quiescent period (< 300 MW) in early March 2022. Despite using simple models, we quantitatively tracked transient thermal activity and revealed the underlying heat transport processes throughout the Aso 2021 eruptive activity.Graphical abstract

Trace Element and Isotope Geochemistry of Tschicoma Formation Intermediate Composition Dome Complexes, Jemez Mountains Volcanic Field, New Mexico, USA

Abstract Repeated intrusions of mafic magma have long been known to be a driver of long-lived magmatic systems. Although the importance of mafic recharge of silicic magma systems is well-documented in igneous petrology, the origin of this recharge magma is sometimes obscure. By examining the pre-caldera intermediate dome complexes of the Tschicoma Formation and their relationship to a dacitic recharge event into the Tshirege Member of the Bandelier Tuff, we aim to better understand the origin of mafic recharge events into the Bandelier magma chamber of Valles caldera, and the relationship between different stages of volcanic activity within the broader Jemez Mountains volcanic field (JMVF). Based on major, trace element and radiogenic isotopic data, we divide the Tschicoma Formation into three geochemical groups with similar petrologic evolutionary paths. The Cerro Grande, Cerro Rubio and Pajarito Mountain volcanic dome complexes form group A and have assimilated various amounts of a granitoid crustal component with low εNd, εHf and radiogenic Pb. Group B consists of the Sawyer Dome, Rendija Canyon and Caballo Mountain dome complexes, which have principally evolved through different degrees of fractional crystallization of the same parent magma, itself a result of complex interactions of a mafic mantle-derived magma with the crust. The dacite domes and flows around Tschicoma Peak and the newly described Cañada Bonita dacite form group C and are the result of mixing of Rendija Canyon magma with mafic recharge magma which is preserved as distinct mafic enclaves. At a later stage of the JMVF, during the eruption of the Tshirege Member, distinctive hornblende–dacite pumices formed as a result of the influx of more mafic recharge magma into the system, which mobilized a pre-existing dacite intrusion and injected it into the Tshirege rhyolite ( Stimac, 1996; Boroet al.,2020). Based on trace element and isotopic compositions, we propose that dacite which was injected into the Tshirege magma chamber was related to the earlier-erupted Tschicoma Formation and itself represents a mixing product of Tshirege rhyolite and a precursor to the Tschicoma dacites. This implies that the Tschicoma magmatic system was long-lived yet dormant during the eruption of the Otowi Member of the Bandelier Tuff, then was reactivated shortly before the Tshirege eruption, temporarily co-existing and interacting with the Bandelier system as it erupted.

Role of volcanism and impact heating in mass extinction climate shifts

This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts. Our research reveals that low-temperature heating of sulfide leads to global cooling through the release of sulfur dioxide (SO2), while intermediate-temperature heating of hydrocarbons and carbonates releases substantial carbon dioxide (CO2), contributing to global warming. High-temperature heating additionally generates SO2 from sulfate, further contributing to global cooling. Different degrees of contact heating of the host rock can lead to different dominant volatile gas emissions, crucially driving either warming or cooling. Moreover, medium to high-temperature shock-heating resulting from asteroid impacts produces soot from hydrocarbons, also contributing to global cooling. Large-scale volcanic activity and asteroid impacts are both events that heat rocks, emitting the same gases and particles, causing climate changes. The findings elucidate the critical role of heating temperature and heating time in understanding major climate changes during mass extinctions.

Detrital signatures of the Ghomaride Culm cycle (Rif Cordillera, N Morocco): New constraints for the northern Gondwana plate tectonics

The Carboniferous detrital suites of the Ghomaride Subdomain (Rif Cordillera, N Morocco) has been undertaken in order to obtain paleogeographic and paleotectonic constraints. Microconglomerate and sandstone samples from eight sections belonging to four sectors were petrographically studied. This northern Gondwana domain was part of the Paleo-Mesomediterranean Plate, located between the Iberian-French Plates and the African Paleo-Atlas-Saharian Domain, which outlines a gap of knowledge since these domains are now part of the Alpine peri-Mediterranean chains. Part of this data-lacking is related to the sandstone detrital modes that have never studied in this area, allowing to obtain information about provenance derived from growing orogens, as well as orogenic processes, and tectonic, climatic and/or erosional events. The study has revealed that the sandstones are litharenites to feldsphatic litharenites, evolving upward to lithic arkoses, and has evidenced a quartzolithic petrofacies with a transitional recycled orogen provenance. The metamorphiclastic detritus displays a low to middle-upper metamorphic rank upwardly referred to a subducted terrane. Serpentinite-like detritus indicates a metamorphosed oceanic crust being dismantled. A supply from the Rheic Ocean seems improbable since it was very far and beyond the Iberian Plate. Therefore, closer oceanic sutures should be proposed, probably separating the Paleo-Mesomediterranean Plate from the Iberian-French Plate and from the Paleo-Atlas-Saharian Domain. The sin-sedimentary volcanic activity (felsic to mafic) reinforces the idea of subductions. A correlation with other Culm successions of the western Paleotethys has allowed the performing of a paleogeographic-paleotectonic model during the Paleotethysian tectonic phase, in which the studied sandstones were deposited in a foredeep connected northward with limestone platforms and with a crystalline emerged domain (hinterland-orogenic front: Iberia-French Plate and part of the Paleo-Mesomediterranean Plate) and transitioning southward to an oceanic branch of the western Paleotethys, and finally with the Paleo-Atlas-Saharian band acting as passive margin in the foreland.