The Zavkhan Terrane, one of the largest Precambrian microcontinents in the Central Asian Orogenic Belt, hosts a unique combination of magmatic complexes, carbonate sediments, and eclogite facies rocks. These features provide critical insights into the Rodinia supercontinent evolution, the global carbon cycle, and high-field-strength element mobilization during deep subduction. While the magmatic and sedimentary history of the terrane has been relatively well studied, the discovery of high-pressure metamorphic rocks raises new questions about its tectonic evolution. This study presents integrated petrological, geochemical, and geochronological data from metamorphic rocks (felsic schist, pelitic schist, and amphibolite) associated with the Urgamal eclogite in the Zavkhan-Khungui zone and the Khungui eclogite in the Mélange zone, both within the Zavkhan Terrane. Metasedimentary rocks associated with both eclogites were deposited at both active and passive continental margins and recorded a clockwise metamorphic P–T path. Amphibolites exhibit MORB-like geochemistry and underwent amphibolite-facies metamorphism (0.7–0.9 GPa, 395–449 °C). Zircon U–Pb ages constrain the protoliths of the Urgamal (<811 Ma) and Khungui (1.89 Ga) eclogites to mafic magmatism linked to crustal extension. The near-peak zircon U–Pb age of the Urgamal eclogite (522 Ma) and the Khugnui eclogite Sm–Nd age (526 Ma) confirm that both eclogites experienced eclogite facies metamorphism during the Early Cambrian. These data suggest that the Mélange Zone extends from the Khungui eclogite to the Urgamal eclogite over a northwest-trending distance of approximately 200 km, herein referred to as the HP Hutul Mélange Zone. The HP Hutul Mélange Zone formed consequent to a subduction-induced collision between the southern and northern domains of the Zavkhan Terrane during the Early Cambrian. During the collision, predominantly Tonian-aged magmatic and sedimentary rocks underwent metamorphism in the northwestern part of the Hutul Mélange Zone, whereas rocks older than 1.89 Ga metamorphosed in the southeastern part.

Intra-crustal magma mixing in the formation of potassic mafic rocks

Geological structures and thermal regime along volcanoes and basement rocks of Tangyin rift geothermal field from resistivity survey and Radon detection

ABSTRACT Intense debate has surrounded the tectonic placement of microcontinents in the eastern Central Asian Orogenic Belt of NE China, with particular focus on the Jiamusi Block. The oldest basement rocks within the Jiamusi Block belong to the Mashan Complex, which preserves evidence of the Late Pan-African granulite-facies metamorphic overprinting. Characterizing this complex is therefore essential for elucidating the tectonic affinity of the Jiamusi Block. Here, we present zircon–monazite U–Pb geochronology, zircon trace-element compositions, and zircon Hf–O isotopic data for paragneisses from the Mashan Complex. Detrital/Inherited zircon ages from five paragneiss samples indicate that the Mashan Complex comprises two distinct supracrustal sequences, whose protoliths were deposited at approximately 1027–895 Ma and 777–757 Ma. Metamorphic zircons recovered from the paragneisses yield a range of concordant ages from 567 to 458 Ma. The few younger analyses down to 458 Ma may represent isolated or mixed ages and are not used to define the principal retrograde interval. The U–Pb ages of metamorphic zircons and monazites, together with zircon Hf–O isotopic compositions, indicate that the paragneisses reached peak granulite-facies metamorphism at 567–563 Ma, followed by retrograde metamorphism between 553 and 476 Ma. CDF and 2D-MDS analyses of detrital zircons support a tectonic affinity of the Jiamusi Block with Northeast India. Based on this and previous studies, it is suggested that the Jiamusi Block underwent a complete Neoproterozoic–Early Palaeozoic tectonothermal evolution corresponding to the Rodinia–Gondwana cycle, including 935–891 Ma arc magmatism and Rodinia peripheral accretion, 825–750 Ma rifting and lithospheric thinning during the break-up of Rodinia, and 567–470 Ma high-grade metamorphism followed by post-orogenic extension associated with the Kuunga–Pinjarra Orogeny.

Crystallisation kinetics play a fundamental role in controlling conduit dynamics and eruptive style. The degree of superheating is critical in controlling crystallisation kinetics; however, its effect is still debated and has an unclear impact on eruption dynamics. Here, we investigate how superheating influences clinopyroxene nucleation in tephritic magmas from the 2021 Tajogaite eruption (La Palma, Spain) through both in situ and ex situ view experiments. Our findings show that superheating delays nucleation by dissolving pre-existing nuclei, thereby inhibiting crystallisation upon return to subliquidus conditions. Using a numerical model, we investigate how different nucleation delays resulting from different degrees of superheating affect magma ascent dynamics. Depending on the initial thermodynamic conditions and on the pre-eruptive history of magma, an increased nucleation delay can significantly reduce crystal content during ascent, lowering magma viscosity and affecting eruptive style. These findings highlight the critical role of pre-eruptive thermal histories in controlling eruptive style, and provide constraints for refining experimental protocols and numerical models, with direct implications for improving volcanic hazard assessment and eruption forecasting.

Unraveling the role of mantle and crustal processes in Mo–Cu enrichment: Insights from the large Tongchanggou deposit, eastern Tibet

We investigate the magma plumbing system of the 2.8-ka Saruana Lava at Chokai volcano, northern Honshu, based on mineral chemistry and textures. The Saruana Lava is a 0.6 km 3 basaltic andesite containing mafic enclaves with porphyritic and equigranular textures. Whole-rock compositions define linear trends on Harker diagrams, with Ni decreasing to near-zero concentrations at ~60 wt% SiO₂. Phenocrysts include olivine, plagioclase, augite, orthopyroxene, titanomagnetite, and rare amphibole. Olivine shows only normal zoning, whereas plagioclase and pyroxenes exhibit both normal and reverse zoning. Crystals are classified into felsic antecrysts, mafic antecrysts, and autocrysts based on zoning patterns, mineral chemistry, and inclusion assemblages. Felsic antecrysts, forming the cores of reversely zoned crystals, originated from an andesitic crystal mush stored in the mid-crust. Thermobarometric estimates indicate crystallization at approximately ~850 °C and mid-crustal pressures, consistent with a partially molten mush reservoir. Mafic antecrysts include Fo85–88 olivine with spinel derived from primitive basalt magma. Equigranular mafic enclaves represent crystal accumulation in basalt magma at deeper crustal levels prior to interaction with the felsic system, consistent with amphibole-based pressure estimates. Reverse zoning records partial dissolution of mush-derived crystal cores followed by overgrowth in basalt magma. These textures indicate rapid thermal interaction between hot basalt and a cooler felsic crystal mush, resulting in simultaneous partial melting of mush minerals and crystallization in the mafic magma. Diffusion profiles in olivine constrain the recharge-to-eruption timescale to weeks to months. The Saruana Lava preserves a crystal-scale record of basalt recharge into a felsic crystal mush and the development of a chemically and texturally heterogeneous magma prior to lava emplacement. • Phenocrysts were classified to reconstruct stages of basalt recharge and crystal mush interaction. • Thermal diffusion promoted resorption of mush-derived crystals and overgrowth in basalt magma. • Equigranular enclaves record deep crystal accumulation in basalt magma (~900 MPa). • Diffusion profiles constrain the recharge-to-eruption timescale to weeks to months. • Zoning patterns and glass compositions document the development of a chemically heterogeneous magma.

Forensic analysis of Cheakamus basalt lavas (BC, Canada): Magnitude, intensity and hazard implications for effusive eruptions in complex mountainous drainage systems

The Milin ultramafic–mafic intrusive rocks, exposed in the southeastern segment of the Gangdese batholith within the southern Lhasa subterrane, provide critical insights into the Late Cretaceous tectonic-magmatic evolution of southern Tibet. New zircon U Pb geochronology yields a crystallization age of ca. 85 Ma, indicating that the mantle-derived magmatism was synchronous with the peak of the regional magmatic flare-up. Petrological and geochemical evidence reveals that these rocks are hydrous cumulates that were primarily formed via fractional crystallization and accumulation of olivine and clinopyroxene. They are characterized by high MgO contents and Mg# values, light rare earth element (LREE) enrichment, heavy rare earth element (HREE) depletion, pronounced negative Nb anomalies, and positive Ta anomalies. Further, their highly positive zircon ε Hf (t) values (+10.5 to +14.4) and specific trace element signatures (e.g., low Nb/U and Ce/Pb ratios) indicate that the magmas were derived from depleted asthenospheric mantle metasomatized by subduction-related fluids. Based on all of the data, we attribute the formation of the Milin intrusions to the roll-back of the subducted Neo-Tethyan oceanic slab. This geodynamic process triggered asthenospheric upwelling and decompression melting of the fluid-modified mantle reservoir, producing hydrous high-Mg parental magmas that drove Late Cretaceous crustal growth in the southern Lhasa subterrane. • Milin ultramafic–mafic magmatism persisted until ca. 85 Ma, coeval with the regional flare-up. • These rocks are hydrous cumulates derived from a fluid-metasomatized depleted asthenospheric mantle. • Neo-Tethyan slab roll-back induced asthenospheric upwelling and triggered this magmatism.

Tropical mafic rock weathering, riverine lithium isotopes, and the evolution of Cenozoic seawater chemistry

A synthetic geochronological and geochemical dataset of mafic rocks in the northwestern North China Craton and its tectonic and mineralization implications

Recent studies have shown the interest of automating the classification of rock images using deep learning architectures. The biggest issue for practitioners when applying these methods to real-world data sets generated during mineral exploration is the long time required to create and label a data set. This study proposes a complete workflow to label and classify drill core photographs with minimal time required for labeling through five successive steps: i) using exploration drill core photographs, rock cores are separated from wooden trays using morphological operators; ii) feature descriptors are then extracted from rock images using color histograms for colorimetric information and Gabor filters for texture information; iii) features extractors then serve as input data for self-organizing maps (SOM) for generating clusters that can be partially labeled by geologists for generating a labeled data set with limited efforts, generating a data set made of labeled and unlabeled images; iv) the partially labeled data set can then be used to train either fully supervised or semi-supervised deep learning architectures for generating classifications; v) the classification model obtained can then be re-used on unseen data to automate logging process. This study presents this workflow separately for two different geological domains, namely a data set of sedimentary rocks classified according to the intensity of bleaching features and a data set of crystalline basement rocks classified by lithological domains. Software code and data set are made publicly available. • Development of a complete workflow to transform drill-core photographs datasets (directly obtained from mineral exploration) into a labeled dataset usable for deep-learning tasks. • Evaluation of the possibility of inferring lithological (for the basement subset) and alteration (for the basin subset) classes based on a self-labeling strategy. • Evaluation of the potential to improve classification accuracy by using unlabeled samples in a semi-supervised way.

This paper focuses on developing a sustainable, high-temperature-resistant geopolymer mortar by selecting the most optimal fine aggregate type for high-temperature conditions. The developed building material has superior properties to conventional concrete and could possibly be significant in the context of fire-safety building materials. Ceramic brick waste (CBW) from open landfills and metakaolin waste (MKW) from an expanded glass production company (Lithuania) were used as precursor materials in a geopolymer system. The precursors were systematically substituted from 0 to 100% weight in five distinct compositions (F1-F5). The alkaline activator was a blend of 8M sodium hydroxide and sodium silicate (Na2SiO3/NaOH = 1.5). Five types of fine aggregates were examined: ordinary river sand (OSA), granite (GRA), basalt (BAS), ceramic waste (CBW), and corundum (COR), with a fraction size from 0 to 3mm and the constant fine aggregate to precursor (FA/P) ratio of 1.5. Geopolymer mortar specimens were prepared to assess their compressive strength and density before and after exposure to high temperatures ranging from 200 to 800°C. A two-way analysis of variance (ANOVA) was conducted to evaluate the reliability of the residual compressive strength outcomes. The study showed that properly selected fine aggregates in an appropriate binder system improves high-temperature resistance. After 800°C exposure, mortars with 75% CBW and 25% MKW precursors containing CBW and COR aggregates exhibited minimal microcracking and residual strengths of 34.7MPa (78.7%) and 53.0MPa (108.6%), respectively. This performance is attributed to partial reactivity, low thermal expansion, and inherent thermal stability.

ABSTRACT Fish taphonomy can be used as a high-resolution indicator of lacustrine environmental conditions, which are highly sensitive to environmental fluctuations. Here, we reconstruct the palaeoenvironmental conditions of an overfilled lake system (Agua de la Zorra Formation, Triassic) and the impacts of volcanic activity in the sedimentary record. A total of 189 mudstone and sandstone samples were analysed using semi-quantitative taphonomic attributes, and fish assemblages were analysed taxonomically. Four taphonomic modes were identified (Mode A: isolated/dispersed, Mode B: associated/dispersed, Mode C: disarticulated/associated, Mode D: articulated), indicating thermal fluctuations during the accumulation of the specimens. Accordingly, two thermal scenarios were identified. The lower section, disrupted by basaltic lava flows interbedded with distal lake deposits, shows marked water-temperature fluctuations (cold to warm temperatures), presenting all taphonomic modes and the highest fish diversity. The upper section exhibits more stable conditions (gradual transition towards warmer temperatures). Taphonomical comparison from the Agua de la Zorra succession with other regional Triassic lacustrine systems reveals resemblance with successions interpreted as balanced-fill lake systems, supporting a transitional scenario from overfilled to balanced-fill conditions for the Agua de la Zorra succession. Thus, fish taphonomy serves as an independent proxy refining lake basin models and environmental interpretations.

Abstract This study investigates the geological architecture and tectonic evolution of the Queih shear belt, located in the Central Eastern Desert of Egypt, within the Egyptian Nubian Shield. An integrated approach combining multi-sensor satellite remote sensing (Landsat-8, ASTER, Sentinel-1 A), aeromagnetic data analysis, and systematic field investigations was employed to delineate lithological units, structural features, and deformation phases. Advanced image processing and Enhanced Horizontal Gradient Amplitude (EHGA) techniques enabled precise mapping of lithological contacts, faults, folds, and shear zones. The results reveal that the Queih shear belt is a complex horst structure of Precambrian basement rocks, bounded by major normal faults and affected by a polyphase tectonic history. Four principal ductile deformation episodes (D1–D4), followed by Phanerozoic extensional tectonics (D5), are documented, involving NNW–SSE and ENE–WSW compression, transpressional shearing, and alternating dextral and sinistral strike-slip faulting related to the Najd Fault System. The spatial and temporal relationship between molasse sedimentation and phases of wrench faulting is highlighted, providing new insights into the interplay between sedimentation and tectonic reactivation during the late Neoproterozoic. This work refines geological maps of the region and advances understanding of crustal processes the Egyptian Nubian Shield.

Abstract The Precambrian basement of Madagascar hosts numerous yet poorly studied chromitite occurrences. The Ranomena deposit, a representative example in the North Toamasina chromite district, is hosted within lenticular mafic-ultramafic bodies of the Betsimisaraka/Anaboriana-Manampotsy domain. The chromitites exhibit disseminated to massive textures with cumulus chromite and orthopyroxene as the primary intercumulus silicate. Chromite compositions are high-Cr (Cr# mostly > 60) with elevated TiO2 (0.18–0.78 wt.%) and trace-element signatures (enrichments in Ti, Zn, Co, Mn, V, Sc; depletions in Ga, Ni) resembling those of stratiform chromitites. Whole-rock PGE patterns show relative enrichment in Os, Ir, Ru, and Rh over Pt and Pd, akin to the Lower Group chromitites of the Bushveld Complex. Zircons have been both identified in situ in thin sections and separated from mineral concentrates. Zircons from chromitite samples yield concordia U–Pb ages of 530.4 ± 2.2 Ma and 525.3 ± 2.3 Ma, respectively. Their δ18O values (4.7–6.1‰) and εHf(t) values (−5.4 to + 6.8) indicate variable degrees of crustal contamination. A binary mixing model suggests that the parental magmas formed from mantle-derived melts variably hybridized with crustal material (∼15–20% in the slightly earlier pulse). The Ranomena chromitites are coeval with post-collisional granitic magmatism in the central East African Orogen. We propose that they crystallized from mafic magmas generated during lithospheric delamination and asthenospheric upwelling in a post-collisional extensional setting, which may represent a previously unrecognized type of chromitite formation setting in orogenic belts.

The nature and timing of Mid-Devonian–Visean plutonic activity in the Variscan Bohemian Massif (BM) and the Central Western Carpathians (CWC) differed profoundly. In the BM, most of this period was marked by vigorous arc-related magmatism that ceased only at ~340 Ma by the collision and the ensuing slab break-off. The oceanic subduction passed to deep continental underthrusting, and relamination of felsic metaigneous material of Saxothuringian origin, soon thereafter transformed into (U)HP–HT granulites. The Visean activity in the BM was characterized by an emplacement of voluminous (ultra-)potassic plutons and countless dykes of matching chemistry, but practically no syn- to early post-collisional S-type granitoids. In the BM, the bulk of S-type magmas was produced in Serpukhovian or younger. In the CWC, the evolution started later but was considerably faster; the classic magmatic arc seems not to be preserved here. Subduction, evidenced by Frasnian back-arc mafic magmatism and anatexis, was terminated by collision and early (Late Devonian) slab break-off. The attendant heat pulse produced dioritic rocks, and then a Tournaisian late-collisional flare-up of the I- and immature (biotite-bearing) S-type granitoids. The mature (muscovite-bearing) Visean S-type granites were already post-collisional. In the CWC, the (ultra-)potassic magmatic rocks are conspicuously missing, as are the (U)HP–HT granulites. This reflects a too early slab break-off and/or inappropriate composition of the downgoing continental slab. The contrasting Mid-Devonian to Visean magmatic histories clearly reflect distinct paleogeographic positions of the BM vs. CWC crustal segments, probably along the two unconnected sutures in the widely separated branches of the Variscan orogenic collage.

Abstract The 31 August 2025 Mw 5.9 Asadabad earthquake in eastern Afghanistan caused severe damage despite its moderate magnitude, raising questions about rupture processes and seismic hazard in the southern Hindu Kush. Using Sentinel‐1 InSAR and teleseismic waveform modeling, we reveal a complex, multi‐stage shallow (4–5 km) rupture involving the mainshock and three M > 5.0 aftershocks. Surface deformation ranges from ∼10 to 35 cm, and fault planes exhibit moderate to steep dip angles, with secondary rupture approaching the surface. Time‐series InSAR shows ∼2 mm/yr localized interseismic uplift near the epicenter, consistent with localized shallow deformation prior to the earthquake. Occurring within exposed crystalline basement rocks without mapped Quaternary faults, the earthquake ruptured a previously unknown immature, distributed fault system. These findings help explain the high damage relative to magnitude and highlight significant seismic hazard in orogenic interiors from moderate‐magnitude, shallow ruptures on unmapped faults.

The source-to-surface journey of volatile-flooded magmas: The archetypal case of the Campi Flegrei unrest Caldera

• A late Paleozoic exhumation phase is detected in the Victoria Land, Antarctica. • An intra-foreland topographic high developed in the Transantarctic basin. • AFT and ZHe data constrain the exhumation-burial history of the Prince Albert Mts. The late Paleozoic-Mesozoic geological record of Antarctica is preserved in sedimentary successions deposited in the Gondwanide retroarc foreland basin. This basin developed as a direct response to convergence and crustal thickening along the southern margin of Gondwana during subduction of the paleo-Pacific plate. This protracted convergent tectonic setting drove the evolution of the Transantarctic Basin, which persisted from the Devonian through the Jurassic. The Transantarctic Basin is primary filled up by continental deposits, now exposed along the Transantarctic Mountains from the Weddell Sea to the northern Victoria Land. These Devonian-Jurassic sedimentary successions exhibit variations in thickness, provenance, and sedimentary facies, reflecting the long-term evolution of the paleo-Pacific convergent margin. This study investigated the late Paleozoic-Mesozoic paleo-topographic evolution of the central Prince Albert Mountains, where a thin Gondwanan stratigraphic succession is exposed. We integrate low-temperature thermochronological data (apatite fission-track and zircon (U-Th)/He) with stratigraphic evidence. Modeled thermal histories reveal an exhumation episode during the late Carboniferous to Permian, associated with the growth and subsequent erosion of a previously undescribed topographic high, referred to as Prince Albert High. The Prince Albert High formed between northern and southern Victoria Land and evolved synchronously with the Devonian-Triassic deposition of the Beacon Supergroup. We interpret its formation as a response to far-field stresses transmitted from the paleo-Pacific convergent margin, providing new insights into the geodynamic history of the Transantarctic Basin. Subsequently, this topographic high was buried beneath a Mesozoic overburden. This burial left evidence of a medium-temperature (150–180 °C) reheating process recorded in the basement and cover rocks.