Satellite-derived seasonal fluctuations in surface displacement and soil moisture: Implications for landslide activity

Context While human activities are the primary source of elevated soil metal concentration, natural geological processes can also contribute significantly. Aims This study investigated the influence of parent rock lithology on the concentration of arsenic, chromium, copper, nickel, lead, and zinc in soils of the O’Higgins Region, central Chile. Methods The soils developed on five distinct lithologies: andesites (intermediate volcanic rocks), felsic volcaniclastics, mixed (intermediate and felsic) volcanics, plutonic rocks, and metamorphic rocks. A total of 38 topsoil samples (0–10 cm) and their corresponding 22 parent rock samples were collected from watersheds selected to represent background conditions. Selective dissolution using citrate–bicarbonate–dithionite and hydroxylamine hydrochloride was employed to quantify trace element association with iron oxides (FeOx) and manganese oxides (MnOx). Key results Adsorption onto FeOx was the primary control on trace element retention across all soils. Notably, FeOx retained over 50% of total soil arsenic, reflecting the strong affinity between arsenate and FeOx surfaces, likely driven by binuclear inner-sphere complexation, whereby an arsenate ion replaces two hydroxyl ions on the FeOx surface. Conclusions This study demonstrates that the influence of parent rock lithology on soil trace element content is not a direct relationship, but is instead mediated by the complex interplay between FeOx and MnOx. Implications The novelty of this work lies in highlighting the differential influence of these oxide phases on the retention of As relative to divalent metals.

Since the Cenozoic, the peripheral orogenic belts around the Junggar Basin have undergone substantia uplift in response to far-field deformation associated with the India-Asia collision. However, conventional geochronological methods commonly provide only indirect or insufficiently resolved constraints on the timing and geomorphic expression of late Cenozoic uplift and exhumation. Combustion metamorphic (CM) rocks, generated when coal seams are brought into shallow, oxygen-rich conditions during tectonic uplift and denudation and subsequently ignite spontaneously, offer a potential near-surface chronometer for these processes. In this study, we characterized coal maceral composition, rank, and spontaneous combustion tendency; documented the distribution, petrography, and mineral assemblages of CM rocks through field investigations, thin-section observation, and X-ray diffraction; and applied zircon (U-Th)/He dating to constrain the timing of CM rock formation. Three zircon grains define a tightly clustered Middle Pleistocene population with a weighted mean age of 0.63 ± 0.19 Ma, which we interpret as the principal timing of coal seam combustion and CM rock formation. Two older single-grain ages (8.7 ± 0.5 Ma and 87.7 ± 5.4 Ma) are treated cautiously as incompletely reset or inherited pre-combustion thermochronologic components rather than as independent combustion events. The spatial distribution and ages of CM rocks show a clear correspondence with late Cenozoic uplift and exhumation of the orogenic belt. These results demonstrate that zircon (U-Th)/He thermochronology of CM rocks can provide a useful chronological marker for near-surface tectonic processes and offers an additional approach for reconstructing late Cenozoic tectonic evolution in intracontinental orogenic settings.

Research subject. The transverse (sub-latitudinal) structures of the sub-meridional Ural fold belt. Aim . To clarify the nature and age of the transverse structures and their metallogenic significance. Methods and materials . The analysis of geological, tectonic, and structural data on the sub-latitudinal structures throughout the Urals was performed. Results . The current knowledge of the transverse structures of the Urals has been reviewed and generalized. In the West Mugodzhar volcanic zone and the Irgiz synclinorium of the Mugodzhars, geological complexes corresponding to the deeper levels of the Magnitogorsk megasynclinoorium were brought to the Earth’s surface. Such exposure could only have resulted from a vertical uplift of approximately 5–8 km followed by erosion of Paleozoic rocks in the Mugodzhars. In the western sector of the Urals, the structural pattern differs markedly from that in the eastern sector. Here, beginning in the south – where the influence of the Caspian Depression is already pronounced – a gradual northward uplift is observed. This is accompanied by the progressive exposure, at the present-day erosion level, of increasingly ancient complexes, transitioning from sedimentary rocks in the south to metamorphic rocks in the northern part of the Southern Urals. The amplitude of uplift in these metamorphic complexes reaches at least 12 km. Thus, the vertical movements that caused the observed sublatitudinal zonation of the Urals in the south occurred in different directions in its western and eastern sectors. Conclusions . The observed lateral zonation of the Urals is primarily controlled by variations in the present-day depth of erosion across different regions. These variations, in turn, reflect differences in the rates and magnitudes of post-Paleozoic uplift, most notably during the Middle and Late Triassic. Consequently, lateral zonation is only indirectly related to the formation of pre-Mesozoic mineral resources in the region. Nevertheless, understanding the depth of erosion in different parts of the Urals is essential for metallogenic assessments. For younger mineral resources, such as hydrocarbons (oil and gas) and placer deposits, sub-latitudinal zonation plays a decisive role.

Based on two major rainfall events that triggered clustered landslides in Changning, Baoshan, southwestern Yunnan Province, China, this study integrates multi-scale spatial analysis, systematic field investigations, and geomechanical characterization to examine the distribution patterns and rainfall-triggering mechanisms of clustered landslides. A total of 255 landslides were identified, exhibiting a belt-like distribution along the main river valleys with pronounced clustering at mid-to-high elevations and moderate slopes. High-incidence zones are concentrated at elevations of 1860 ~ 1900 m, slopes of 20° ~ 40°, and outcrops of gray-black thin-layered microcrystalline schist and gray-white quartz schist, with a strong orientation preference toward south- to southeast-facing slopes. Notably, landslide density on natural slopes located more than 500 m from roads is higher than in adjacent areas, indicating that the spatial pattern is primarily controlled by topography-lithology combinations rather than anthropogenic engineering disturbances. Microstructural analysis reveals pervasive schistosity, cleavage fractures, and clay-rich weathering bands, with weathering driving the evolution from dense to porous, loose structures, forming highly permeable, low-strength weak zones. Direct shear tests further show significantly reduced shear strength in shallow layers and weakened zones, which are highly sensitive to water content and external disturbances. Intense rainfall rapidly infiltrates, increases pore water pressure, and softens shallow layers, activating schistosity planes and inducing displacement, thereby promoting clustered and concentrated landslides. This study clarifies the spatial controls and coupled internal-external mechanisms of rainfall-induced landslides in metamorphic rock regions, providing essential scientific guidance for landslide hazard assessment and disaster mitigation planning in Yunnan's mountainous watersheds.

The exposed basement of the Variscan Iberian Massif includes various remains of the accretionary Cadomian orogen that fringed the northwestern margin of Gondwana in the late Neoproterozoic–Terreneuvian. Subduction of the Mirovoi Ocean beneath Gondwana was responsible for the formation of an arc system that was finally accreted to the continental margin. In the Iberian Massif, a complex Cryogenian–Fortunian arc/backarc system is preserved in the Ossa-Morena Zone, whereas a thick Ediacaran–Fortunian infill of a vast retroarc basin, developed as a result of arc accretion, is exposed in the Central Iberian, West-Asturian-Leonese and Cantabrian zones, defining a proximal (hinterland) to distal (foreland) transect. Wedge-top, foredeep and forebulge basin domains may be recognised in the foreland basin, but the basement of these Ediacaran–Fortunian successions is nowhere exposed. The Cadomian suture zone is currently exposed along the Variscan-age Badajoz-Córdoba shear zone that separates the Ossa-Morena Zone from the Central Iberian Zone. The suture is defined by an ‘accretionary unit’ consisting of high pressure metamorphic rocks and dismembered ophiolites, which is sandwiched between an underlying Gondwana margin Parautochthon (lower plate) and an overlying Ossa-Morena-like arc/backarc unit (upper plate). This geometric superposition implies southward polarity of the subduction responsible for the accretion, i.e. antithetic to the main subduction beneath Gondwana responsible for the development of the Cadomian arc. This double subduction system requires the existence and closure of a backarc basin, which is documented by the development of a secondary arc in the northern half of the Ossa-Morena Zone.

Hydrothermal systems related to antimony (Sb) and gold (Au) ores form under low- to medium-temperature conditions (150−350 °C) and are often associated with major ore deposit belts. Ongoing debate surrounds the characteristics of ore-forming fluids, which are influenced by fluid sources, fluid-rock reactions, and evolutionary processes. Trace elements in quartz are critical for understanding fluid evolution in magmatic-hydrothermal systems (e.g., porphyry-epithermal deposits). This study analyzed trace elements in quartz from 43 Sb and Au deposits worldwide, focusing on low- to medium-temperature conditions. The deposits included Mesozoic Sb belts, Carlin-type and intrusion-related Au provinces in China, and late Paleozoic Sb-Au deposits in Europe. The findings reveal that Ti-Al geochemical diagrams indicate distinct affinities for the host rocks. Specifically, systems hosted by igneous rocks display elevated Ti/Al ratios (>0.005), whereas those hosted by sedimentary rocks exhibit lower ratios (<0.005). Metamorphic rock−hosted systems are best characterized by Sb-As plots and a ternary diagram involving (Ge + As)−Ti × 5−Sb. The observed relationships between Sb and As suggest that trends in Sb mineralization are more closely aligned with metamorphic rock−hosted systems, whereas trends in Au mineralization are associated with igneous rock−hosted systems in the current dataset. Sedimentary rock−hosted systems show quartz trace-element trends indicative of both Sb and Au mineralization. The Li-Al trends further highlight the distinct fluid evolution associated with Sb and Au mineralization, particularly in vein-type Sb, intrusion-related Au, and Carlin-type Au deposits. Variations in trace elements within quartz are attributed to compositional changes induced by cooling. Our results demonstrate that the trace-element signatures identified in quartz provide new insights into the evolution of fluids in low- to medium-temperature hydrothermal Sb and Au systems.

Kepahiang Regency, Bengkulu Province has significant geothermal potential due to its location on the subduction line and the Sumatra Musi segment fault. This research aims to identify the subsurface lithology of the geothermal zone using the Magnetotelluric method. This method measures the response of natural electric and magnetic fields to determine subsurface resistivity values. Inversion of 1D Magnetotelluric data at six pointsv (MT5, MT6, A6, A5, A1, A4) showed three classes of resistivity values of low (0.21-4.0 Ωm), medium (31-80 Ωm), and high (≥200 Ωm). Low resistivity zones are found at MT6 and A6, indicating the presence of geothermal reservoirs in the form of sandstone, limestone, and igneous rocks. Medium resistivity at MT5 and A5 indicates a clay layer as caprock, while high resistivity at A1 and A4 indicates hot rocks in the form of granite and metamorphic rocks. These results provide a preliminary picture of geological conditions for geothermal exploration in the area.

Rock identification plays a fundamental role in geological work, particularly in resource reservoir characterization, stratigraphic division, engineering stability assessment, and hazard prevention. However, traditional manual identification approaches exhibit low efficiency and limited ability to capture dynamic and fine-grained features. To address these challenges, this study employs image recognition and object detection techniques to classify igneous, sedimentary, and metamorphic rocks. We propose an improved You Only Look Once version 11 (YOLO11)-based model by integrating the Efficient Visual State Space (EVSS) module, which enhances the extraction of key rock characteristics-such as texture and fractures-by modeling long-range spatial dependencies and overcoming the locality limitations of conventional convolutional networks. The proposed method is evaluated against three mainstream deep learning models. Experimental results show that the EVSS-enhanced YOLO11 achieves the highest classification accuracy of 92%, outperforming the Vision Transformer (ViT, 85%), ResNet (74%), and the standard YOLO11 (87%). In object detection tasks, the EVSS-integrated YOLO11 also demonstrates superior performance, achieving a mean average precision at 50% intersection-over-union (mAP50) of 91.8% compared to 87.7% for the original YOLO11. By combining efficient visual feature modeling with multi-scale detection capability, this study confirms the effectiveness and robustness of the EVSS-YOLO11 framework for rock image identification, providing strong technical support for intelligent geological analysis.

The Dongwujiiazi deposit is a structurally controlled orogenic gold deposit situated in the eastern part of the Chifeng–Chaoyang gold belt along the northern boundary of the North China Craton. This study establishes a comprehensive metallogenic model for the Dongwujiiazi gold deposit by integrating whole-rock geochemistry (major and trace elements), in situ trace elements and REEs in zircon, multi-isotope systems (H, O, S, Pb), and precise zircon U–Pb geochronology. Five types of intrusive and associated rocks are identified within the main biotite-pyroxene gneiss host of the Dongwujiiazi gold deposit: mylonitized granitic pegmatite, mylonitized porphyritic monzogranite, propylitized fine-grained quartz monzodiorite, quartz monzonite, and porphyritic dolerite. The gold-bearing polymetallic sulfide ores are composed of pyrite, chalcopyrite, sphalerite, galena, digenite, and native gold. Zircon grains in the Dongwujiiazi gold ore (2502 ± 15 to 2539 ± 18 Ma) are inherited from surrounding Neoarchean gneiss, recording older crustal sources rather than forming contemporaneously with the gold mineralization. H–O isotopes indicate that the ore-forming fluids were mixed in origin, involving both magmatic and metamorphic components. S and Pb isotopes suggest that the mineralizing sulfur was mainly derived from a magmatic source, while lead originated predominantly from lower crustal materials associated with the surrounding high-grade metamorphic rocks. In this study, we present a new metallogenic model for the Dongwujiiazi gold deposit, in which slab-derived and lower-crustal metamorphic fluids interacted with ascending magmas, resulting in fluid mixing and gold precipitation within structurally controlled zones of gneissic host rocks. Combined geochemical and isotopic evidence (H–O, S, Pb) indicates contributions from both magmatic and metamorphic sources, supporting formation as an intracontinental orogenic gold system in an active continental margin.

The Ruby metamorphic core complex domain encompasses an ∼10,000 km2 area that includes the Ruby Mountains, East Humboldt Range, Wood Hills, Windermere Hills, and Pequop Mountains in northeast Nevada, USA. The domain contains metamorphic and mylonitized mid-crustal rocks that were exhumed by an intricate array of poorly understood Late Cretaceous−Cenozoic normal faults. This study establishes the first holistic structural architecture and sequence of normal faulting in the Ruby metamorphic core complex domain. The architecture and sequence of faulting are established by synthesizing new and published geologic mapping, and geochronology and sedimentology of synextensional basin fill. Our synthesis shows that after Mesozoic thrust faulting via the Windermere-Angel Lake and Independence thrusts, including a period of Barrovian metamorphism, the core complex sustained four phases of exhumation accommodated by normal faulting. The first phase of normal faulting produced the top-to-the-west to -northwest Pequop fault and was active at some time between 84 Ma and 41 Ma. The second phase began between 38 Ma and 35 Ma and was accommodated by the newly recognized, top-to-the-northwest Ruby-East Humboldt (REH)-Holborn fault. The REH-Holborn fault was a rolling-hinge-style, ductile-to-brittle normal fault that created a synextensional basin filled with sediment of the Clover Creek formation from at least 35−17 Ma. Basin filling was followed by the extinction of the fault between 17 Ma and 15 Ma. The third phase of exhumation was accomplished by N-striking horst-and-graben−style normal faults of the 16 Ma to >3 Ma east-dipping Thousand Springs and west-dipping Knoll-Ruby fault systems, whose synextensional basins filled with sediment of the Humboldt Formation. The modern range-bounding normal faults are accomplishing the fourth and ongoing phase of exhumation. This study has implications for previous work that attributes high pressures recorded by metamorphic rocks to tectonic overpressure in that it shows that significant thrust faulting was a prominent contributor to the development of high pressures. Moreover, this study shows that significant Eocene−Oligocene exhumation of mid-crustal rocks−−previously attributed to diapirism in the absence of regional extension−−occurred during extension and was accommodated by the REH-Holborn normal fault. This indicates that diapirism was not the primary mode of exhumation.

The northeastern Jiaolai Basin of China hosts significant gold resources (223 t contained Au) and has substantial exploration potential for the identification of new gold mineralization. However, the mineralization in this area differs from most deposits elsewhere in the Jiaodong gold province in terms of mineral assemblages and host rocks, meaning that the genetic processes that formed the Jiaolai Basin mineralization remain controversial. Here, we integrate field observations, petrography, in situ monazite U-Pb and sericite Rb-Sr dating, mineral chemistry, sulfur isotope analysis, and thermodynamic modeling of the Tudui, Longkou, and Houkuang deposits to develop a genetic model for the gold mineralization located within the Jiaolai Basin. The deposits in this area are hosted within Paleoproterozoic metamorphic rocks and granites and are dominated by disseminated sulfide-hosted Au mineralization controlled by NE-SW−striking faults. Monazite U-Pb and sericite Rb-Sr dating constrain the timing of mineralization to the Early Cretaceous (ca. 120 Ma), synchronous with regional gold mineralization elsewhere within the Jiaodong gold province. The mineralization contains two generations of pyrite: Pyrite-I is medium- to coarse-grained, euhedral to subhedral, and is present as large individual crystals that are commonly replaced by magnetite. Pyrite-II is anhedral to subhedral and coexists with pyrrhotite, chalcopyrite, magnetite, and gold. In situ sulfur isotope analysis indicates that δ34S values decrease from Py-I to Py-II (Longkou: 10.6‰ to 8.4‰; Houkuang: 9.5‰ to 6.3‰; Tudui: 7.4‰ to 6.3‰), indicating an increase in oxygen fugacity (fO2) of the ore-forming fluid. Thermodynamic modeling indicates that this increase in fO2, along with the formation of alteration minerals, reduced the solubility of Au(HS)2− complexes within the ore-forming hydrothermal fluid by ∼75%, leading to efficient gold precipitation. The overall heavy sulfur isotope values (6‰−12‰) combined with previously published lead isotope data that yielded values similar to those obtained for gold deposits elsewhere within the Jiaodong region suggest that the mineralization in the study area involved metals and sulfur derived from a subduction-modified region of the lithospheric mantle. These data demonstrate that gold mineralization in the northeastern Jiaolai Basin was contemporaneous with regional ore-forming events and that all of the deposits in this area derived metals and sulfur from similar sources and record identical metal precipitation processes. All of this indicates that the gold mineralization in the northeastern Jiaolai Basin is genetically linked to the regional-scale Early Cretaceous ore-forming system in the wider Jiaodong region.

The discovery of altered rock−type gold orebodies in southeastern Guizhou (southwestern Jiangnan orogen) highlights the region’s significance as a major gold province. However, the timing and the ore-forming processes remain poorly constrained, hindering a comprehensive understanding of gold metallogenic patterns. The Kengtou gold deposit (>15 tons Au) comprises both quartz vein−type and altered rock−type orebodies. Two types of hydrothermal monazite (Mnz1, Mnz2) were identified in this study. Mnz1, associated with pre-ore ankerite (Ank1) and rutile, occurs within unmineralized metamorphic rocks. In contrast, Mnz2 is spatially associated with auriferous sulfides within gold orebodies. Trace-element analyses show that Mnz1 has significantly higher total rare earth element (ΣREE) concentrations (430,658−583,738 ppm, mean = 565,224 ppm) than Mnz2 (67,779−172,804 ppm, mean = 137,558 ppm), although both exhibit similar hydrothermal-type chondrite-normalized REE distribution patterns. Laser ablation−inductively coupled plasma−mass spectrometry (LA-ICP-MS) U-Pb dating yielded lower-intercept ages of 443 ± 16 Ma (Mnz1) and 410 ± 13 Ma (Mnz2). These ages constrain two distinct hydrothermal episodes: The earlier episode (ca. 443 Ma) represents a pre-ore stage related to Caledonian regional greenschist-facies metamorphism that triggered widespread sericitization, while the later episode (ca. 410 Ma) marks the main gold mineralization stage during late Caledonian extension, where fluid-rock interaction led to the precipitation of gold-bearing pyrite. Overall, we propose that the recognition of two episodes of Caledonian hydrothermal activity has implications for district-scale gold exploration in the southwestern margin of the Jiangnan orogen.

This study presents an integrated petrographic and geochemical investigation of granitoid and metamorphic ‎rocks from the Pamsi locality in the North Cameroon Domain of the Pan-African Fold Belt. Field observations, ‎microscopic analysis, and whole-rock geochemistry reveal five main lithological units: amphibole-biotite ‎granite, leucogranite, granodiorite, orthogneiss, and amphibolite. These rocks form a calc-alkaline suite ranging ‎from syeno-diorite to granite, classified as I-type, sub-alkaline, potassic to hyperpotassic, and predominantly ‎peraluminous to metaluminous. Geochemical signatures include strong LREE enrichment, negative Eu ‎anomalies in most samples, and multi-element patterns showing negative Ta-Nb, Sr, and Ti anomalies with ‎positive Th, Zr, and U anomalies, characteristic of differentiated magmas from mixed crustal-mantle sources. ‎Tectonic discrimination diagrams indicate volcanic arc to syn-collisional settings consistent with Pan-African ‎orogenesis. Pathfinder element analyses reveal preliminary indications of lithium exploration potential, with ‎samples N11 and N51 showing notable cesium enrichment (8.80–11.30 ppm) and elevated Cs/Rb ratios. Based ‎on established geochemical correlations—and pending direct lithium measurements—estimated lithium ‎contents of 200–800 ppm are proposed as preliminary targets for further investigation. These results highlight ‎the Pamsi area as a promising prospect for lithium mineralization associated with evolved pegmatitic systems, ‎warranting systematic follow-up studies‎.

Selection of hard rock TBM cutterhead design and operating parameters for a range of metamorphic rock suits in a tunnelling project using laboratory scale linear cutting tests—some investigations

This study combines structural mapping, petrographic analysis, and U-Pb zircon geochronology of low-grade metamorphic rocks from the Iberian Pyrite Belt (IPB), located in the westernmost domains of the South Portuguese Zone (SPZ). At Ilha do Pessegueiro beach, the Cercal volcanic-sedimentary complex (VSC) rocks, assigned to the Late Devonian in previous studies, exhibit a dominant S 1 slaty cleavage overprinted by S 2 crenulation cleavage. This ductile deformation has been attributed to contractional tectonics. However, new structural data indicate that older ductile structures formed in relation to a low-grade extensional shear zone (D 1 -E) and were tectonically transported to the east-southeast. The new age of the Cercal VSC felsic metatuffs (ca. 364-363 Ma) is consistent with VSC ages from other areas of the IPB, enabling us to bracket the D 1 -E deformation event between the Tournaisian and the Bashkirian. After the D 1 syn-convergent extension, a subsequent contractional deformation event (D 2 -C), resulting from the latest events of the Gondwana-Laurussia oblique convergence, caused inversion of the Carboniferous synorogenic basins and the formation of a thrust-and-fold belt. Recent data for the late Devonian-early Carboniferous geology of the IPB appear to support a correlation between the SPZ and the Meguma terrane.

Defining the geotectonic setting of crystallization for the igneous protoliths of high- and ultrahigh-grade metamorphic rocks must acknowledge that the high mobility of many elements commonly used in widely accepted tectonic discrimination diagrams makes them unreliable in such cases. Unlike igneous rocks, there are no unequivocal formulas for assigning geotectonic settings to high- or ultrahigh-grade metamorphic rocks, and each occurrence must be evaluated on a case-by-case basis, integrating whole-rock rare earth and trace element distributions, with the support of isotopic data (e.g. U–Pb, Sm/Nd and Lu–Hf). In this study, the main Precambrian occurrences of high-grade and ultrahigh-pressure (UHP) metabasites from the Ceará Central Domain (CCD, Borborema Province, NE Brazil) are shown to have formed during extensional events, rather than from collisional magmatism. Protoliths of the two recognized UHP-type metabasites from the CCD, namely the coesite-bearing retrograde eclogites of Forquilha and Jerimum, are indicated to have crystallized during the Rhyacian and Calymmian extensional events, respectively. Other high-grade occurrences relate mainly to the Calymmian extensional event and show geochemical similarities to mid-ocean ridge basalt. Tonian metabasites are recognized as registering events that led directly to the Neoproterozoic amalgamation of the West Gondwana supercontinent and are represented by metabsites hosted by the metasedimentary Independência Group and by the Lagoa Caiçara Unit anatexites. The first set of rocks also present a geochemical signature that suggests crystallization in an oceanic basin, while the second metabasites have an evident crustal component in their geochemistry (crustal contamination). Although the superposition fabrics of these three extensional events in the CCD rocks are recognizable, their exact duration and development within the context of Wilson Cycles are not fully constrained, with exception of the last event (Tonian).

Extensive igneous intrusions in the northern Datong Coalfield have significantly altered coal seams. The Chaigou coalmine is an area in the Datong Coalfield that has been severely affected by igneous intrusions, yet it has remained a research gap to date. To more intuitively visualize the three-dimensional morphology of igneous rocks, investigate the differentiation laws of magma intrusion in multi-seam systems, and explore the thermal evolution characteristics of coal macerals, this study investigated diabase characteristics using borehole data, laboratory tests, and three-dimensional modeling. The samples were subjected to vitrinite reflectance measurements, proximate analysis, and ultimate analysis, as well as systematic observations of macroscopic coal petrological characteristics and microscopic maceral characteristics. The differences in coal petrological parameters between normal coal and contact-metamorphosed coal were identified and statistically analyzed. On the basis of summarizing and classifying the maceral types, the evolution and identification of macerals in the contact-metamorphosed coal were discussed. Results indicate diabase was primarily intruded as multilayer sills along coal roofs and weak planes. The intrusion covers over 95% of the area. Magma preferentially invaded the Upper Carboniferous–Lower Permian Taiyuan Formation #5(3+5) coal seam, causing maximum impact with a cumulative thickness of 8.31 m. Intense contact metamorphism increased vitrinite reflectance (Ro,max) to 3.05%–3.85%. The coal exhibits high ash and low volatile matter. Microscopic observations reveal significant thermal evolution in macerals. Vitrinite transforms into anisotropic structures, while liptinite vanishes completely. Neo-formed high-temperature components are generated, including mesophase spheres, mosaic structures, and pyrolytic carbon. This study provides an important reference for three-dimensional geological modeling, differentiation laws of magma intrusion in multi-seam systems, and coal mine safety production in coalfields affected by igneous intrusions under similar geological conditions.

For the first time, this study explores the valorization of graphite schist (GS), a metamorphic rock, as a novel supplementary cementitious material (SCM) in concrete. Portland cement (PC) was partially replaced with GS at 0, 10, and 15% by mass to prepare CC (control), GC10, and GC15 mixes, respectively. Physical, mechanical, hydration, microstructural, and radiation shielding properties were investigated. GS showed superior particle fineness, higher surface area, notable antifungal activity, and remarkable thermal stability up to 800°C, outperforming PC in several aspects. Unlike GC15, GC10 achieved sustained compressive strength, closely related to that of CC. Microstructural analysis revealed that GS functioned mainly as a filler with limited pozzolanic reactivity, contributing moderately to particle packing. However, unhydrated cement particles and weakened interfacial transition zones were more prevalent at 15% GS. The improved performance of GC10 over curing periods reflected the more favorable influence of 10% GS on hydration and microstructure. Moreover, GS incorporation slightly improved fast neutron attenuation but reduced gamma-ray shielding due to increased porosity and reduced density. Overall, GS can be a promising multifunctional SCM, offering antifungal potential, acceptable neutron shielding, balanced strength, and reduced PC usage at 10% replacement.

• Ap2 U–Pb ages (∼150 Ma) date Jurassic gold at Wangmushan. • Fluid mixing and water–rock interaction controlled Au mineralization. • Wangmushan differs from Cretaceous deposits, guiding exploration. The Wangmushan gold deposit, located in the Zhenghe region of the Southeast China Volcanic Belt (SCVB), is hosted by Proterozoic metamorphic rocks and Jurassic volcanic-subvolcanic rocks. Mineralization at Wangmushan occurred in two stages, each associated with distinct apatite generations: early-ore stage Ap1 (Ap1M in metamorphic rocks, Ap1V in volcanic rocks) and late-ore stage Ap2 (Ap2M, Ap2V). In situ U–Pb dating of Ap2M and Ap2V yields consistent ages of ∼150 Ma, indicating that metamorphic- and volcanic-hosted ores formed synchronously under a single Jurassic magmatic-hydrothermal system. Petrographic observations and trace element analyses of apatite and auriferous pyrite reveal that early-stage mineralization was dominated by magmatic-hydrothermal fluids, whereas late-stage mineralization experienced increasing influence from oxidizing meteoric water, accompanied by enhanced water–rock interaction. Fluid mixing and water–rock interaction are interpreted as key controls on gold precipitation. Compared to younger Cretaceous deposits in the SCVB, Wangmushan is temporally and genetically distinct, exhibiting unique orebody morphology, mineral assemblages, and alteration patterns. These findings not only highlight the complexity of Jurassic magmatic-hydrothermal evolution in southeastern China but also suggest that similar volcanic settings may host previously unrecognized gold deposits, providing important implications for regional exploration.