Determining the temperature of crustal anatexis associated with granitic magmatism is vital for understanding the petrogenesis of granites and the processes underlying crustal anatexis. During the partial melting of meta-sedimentary rocks, the breakdown of biotite at elevated temperatures can lead to the formation of peritectic garnet, which is typically rare or absent at lower temperatures when melting is predominantly driven by muscovite breakdown. This distinction makes magnesium (Mg) isotopes a valuable tool for tracing relative variations in crustal melting temperatures, as garnet exhibits the lowest delta 26Mg values compared to other Mg-bearing phases under equilibrium fractionation. However, the extent to which temperature variations influence melt Mg isotope compositions remains inadequately understood. In this study, we present Mg and oxygen isotope data for high-and low-temperature leucogranites from the Himalayan orogen, alongside whole-rock major and trace element data, and zircon Ti content from previous studies. Low-temperature leucogranites, with maximum Ti-in-zircon temperatures ranging from 739 to 801 degrees C, display negative delta 26Mg values between-0.70 and-0.14 %o, aligning with most global S-type granites. Conversely, high-temperature leucogranites, exhibiting maximum Ti-in-zircon temperatures of 800 to 855 degrees C, possess positive delta 26Mg values ranging from 0.46 to 0.53 %o, significantly exceeding those of Himalayan metasedimentary rocks and most global S-type granites. The high-temperature leucogranites also demonstrate relatively elevated Nb/Ta and Eu/Eu* ratios, while their whole-rock delta 18O and CIA values are comparable to those of low-temperature leucogranites. These findings suggest that fluid alteration, fractional crystallization, and crustal assimilation have a minimal impact on the Mg isotope discrepancies between the two granite groups. We propose that the positive delta 26Mg values of the high-temperature leucogranites result from a greater fraction of peritectic garnet in the melting residue, attributable to higher anatectic temperatures. Phase equilibrium modeling indicates that the peritectic reaction involving muscovite breakdown is swiftly replaced by biotite breakdown as temperatures rise, leading to a steady increase in the corresponding fraction of garnet. Equilibrium fractionation calculations further corroborate that melt delta 26Mg values rise with an increasing fraction of peritectic garnet, with values at high temperatures significantly surpassing those at lower temperatures. Consequently, this study elucidates a causal relationship between Mg isotope composition and anatectic temperature, highlighting that whole-rock Mg isotopes can serve as a reliable indicator for distinguishing between high-and low-temperature S-type granites.

Lake eutrophication is a global environmental issue influenced not only by surface pollution but also by subsurface hydrological connectivity. This study investigates Dongping Lake, a typical lake system, by integrating Piper diagrams, hydrochemical analysis, the Gibbs model, Euclidean distance, and hydrogeological profiling to elucidate the distinct roles of natural processes and human activities in shaping water chemistry and hydrological connections. Results indicate that natural weathering processes, particularly carbonate dissolution, dominate the ion composition of karst and bedrock fissure water. In contrast, human activities, such as agricultural fertilization and domestic wastewater discharge, drive significant evolution in pore water toward SO4 2- and Cl-Na types, with high ion variability (CV > 30%). Hydrologically, Dongping Lake exhibits close connectivity with adjacent karst water and the Daqing River, while interaction with the Yellow River is limited. A closed-loop water cycle is identified, wherein the Yellow River laterally recharges Quaternary pore water, which then vertically exchanges with karst water before discharging into Dongping Lake. This study underscores the coupled impacts of natural geochemical processes and anthropogenic inputs on lake systems, providing a scientific basis for integrated water resource management in similar watersheds.

The subduction polarity of the Mongol-Okhotsk Ocean (MOO) during the Mesozoic remains contentious, with competing models advocating for southward, northward, or bidirectional subduction. The Xifengshan area in the northern Great Xing'an Range, located south of the Mongol-Okhotsk suture, preserves Early-Middle Jurassic calc-alkaline intrusions, which provides important constraints on this debate. We present zircon U-Pb ages, whole-rock geochemistry, and Lu-Hf isotopes for diorite, granodiorite, and monzogranite from this area. Zircon U-Pb dating yields ages of 178-173 Ma, defining a short-lived magmatic pulse. The suite is calc-alkaline, enriched in LILE and depleted in Nb-Ta-Ti, typical of arc magmas. The diorite represents the most mantle-proximal preserved end-member of the system and records substantial mantle input from a slab-modified mantle wedge. Geochemical trends (increasing Rb/Th, decreasing Sr with differentiation) reflect plagioclase-dominated fractional crystallization with minor AFC. Local adakitic-like signatures are better interpreted as differentiation-related effects than as direct evidence for slab melting. Zircon epsilon Hf(t) values (+1.62 to +11.55) and TDM1 ages (363-772 Ma) are greater than the crystallization ages, indicating substantial juvenile input together with the variable involvement of previously accreted crustal components. We suggest that mantle wedge-derived magmas modified by slab-related components triggered the partial melting of the arc crust, whereas subsequent intracrustal differentiation produced the observed intrusive sequence. The continental arc system provides robust evidence for the southeastward subduction of the MOO during the Early-Middle Jurassic, resolving the long-standing polarity controversy.

Deciphering the magmatic evolution of S-type granites through zircon petrochronology presents significant challenges due to the textural complexities observed in this mineral, particularly so for the Himalayan leucogranites in which zircon is characterized by large relict cores but narrow overgrowth rims. Conventional whole-rock geochemical approaches often fail to adequately resolve dynamically varied magmatic sources and processes. In this study, we utilize integrated in-situ monazite U-Th-Pb geochronology, and trace element and Nd isotope geochemistry of the Cuonadong granitic suite, which includes two-mica granite, muscovite granite, and pegmatite, located in the eastern Tethyan Himalaya, to constrain the timing, duration and evolution process during magma crystallization. Our monazite data collectively reveal a crystallization history lasting ca. 5.2 Myr and three distinct magmatic pulses occurring at ca. 20, 18, and 16 Ma, respectively, characterized by progressively decreasing epsilon(Nd)(t) values (from -8.7 to -15.4) and varying rare earth element (REE) compositions, collectively documenting evolving melt sources and discrete or cogenetic crystallization processes. The earliest phase (similar to 19-20 Ma), consisting of all three lithologies, have epsilon(Nd)(t) values ranging from -12.5 to -8.7, featuring pegmatites with the most depleted epsilon(Nd)(t) values and the earliest crystallization initiation relative to two-mica and muscovite granites. This challenges the general fractionation crystallization model, but suggests that the pegmatitic melts originate from volatile-rich sources within Higher Himalayan Crystalline Sequence (HHCS) metapelites under extensional decompression of South Tibet Detachment System (STDS). Subsequent pulse (similar to 17-18 Ma) also includes the three lithologies and displays comparable Nd isotope compositions (epsilon(Nd)(t) = -13.5 to -9.4) alongside systematic REE variations that reflect concomitant fractional crystallization of monazite and feldspar. In the latest pulse, the muscovite granites crystallized earlier (16.8-16.3 Ma) than the two-mica granites (16.2-15.6 Ma) and have higher epsilon(Nd)(t) values than the latter (-13.8 to -12.3 vs -15.4 to -13.3). Therefore, the apparently systematic variations in REE compositions do not testify fractional crystallization-controlled process but only illustrate respective crystallization processes of two melt batches. Importantly, the progressively lowering epsilon(Nd)(t) values with crystallization ages suggest an increasing incorporation of ancient Lesser Himalayan Sequence (LHS) material since 20 Ma, probably driven by the movement along the Main Central Thrust (MCT). These findings fundamentally challenge the recently proposed fractionation crystallization model regarding the relationship between the three lithologies of interest, rejecting the simplistic differentiation trends from two-mica granite through muscovite granite to pegmatite. Instead, we propose a dual-control mechanism (crustal anatexis and fractional crystallization) involving decompression melting of HHCS metapelites associated with STDS extension, combined with increasing LHS involvement over time, facilitated by MCT activity. By elucidating the potential for combining isotope and trace element information retained in monazite, our results demonstrate the unique capability of monazite to resolve melt source evolution during orogenic process. This research establishes a novel framework for investigating S-type granite petrogenesis in collisional orogens through integrated in-situ petrochronology and isotope tracer.

Sandstone-hosted rhenium (Re) deposits are rare, and their mineralization mechanisms remain poorly constrained. The Re deposits in the Muchuan area of the southwestern Sichuan Basin provide an excellent natural laboratory for investigating Re enrichment in sandstone-hosted systems. In these deposits, chlorite is widespread and closely associated with mineralization, indicating its potential as an indicator mineral for tracing oreforming processes. Here, EPMA, LA-ICP-MS, and TEM analyses were conducted to characterize the morphology and composition of ore-related chlorite, aiming to elucidate the genesis of chlorite and assess its significance in recording ore-forming processes. Two chlorite types were recognized. Altered chlorite formed through hydrothermal replacement of biotite at 89-290 degrees C and evolved from Fe-rich to Mg-rich compositions during cooling, recording a fluid evolution from reducing, weakly acidic conditions to relatively oxidizing and more alkaline conditions. Authigenic chlorite occurred as grain-coating, pore-lining, and pore-filling cement and was characterized by Al-rich, Fe-poor compositions, high Re contents (average 32.70 & times; 10-6), and formation temperatures of 37-153 degrees C. Chlorite was identified as a host for Re. Part of the Re was incorporated into chloriteassociated jordisite through isomorphous substitution, whereas the remainder was concentrated by adsorption onto chlorite and chlorite-hosted organic matter. Hydrocarbon-bearing hydrothermal fluids derived from the Upper Triassic Xujiahe Formation migrated into oxidized Jurassic sandstones, where fluid-rock interaction induced chloritization and Re precipitation. These results establish a genetic link among hydrocarbon-related fluids, chloritization, and Re enrichment, and identify chlorite as a key indicator mineral for sandstone-hosted Re mineralization.

The Sijiaying iron deposit in eastern Hebei Province is one of the largest banded iron formation (BIF)-hosted iron deposits in China and contains significant high-grade iron ore resources. However, the genesis of these high-grade ores and the mechanisms responsible for iron enrichment remain controversial. In this study, representative normal-grade and high-grade ores were investigated through detailed petrographic observations, in situ trace element analyses of magnetite and pyrite by LA-ICP-MS, and sulfur isotope analyses of pyrite by LA-MC-ICP-MS. Petrographic observations indicate that two types of high-grade iron ore occur in the deposit: primary sedimentary high-grade ore and hydrothermally altered high-grade ore. Magnetite from primary sedimentary high-grade ore exhibits geochemical characteristics similar to those of normal-grade BIF ores, including comparable trace-element compositions and pronounced positive Eu anomalies, suggesting derivation from submarine hydrothermal-sedimentary processes. In contrast, magnetite from hydrothermally altered high-grade ore is characterized by lower rare earth element abundances, enrichment in selected transition metals, and weaker Eu anomalies, indicating modification by later hydrothermal activity. Pyrite associated with hydrothermally altered ores exhibits trace-element characteristics and sulfur isotope compositions suggestive of a magmatic-hydrothermal contribution to fluid evolution. Integrated petrographic and geochemical evidence indicates that the studied hydrothermally altered high-grade ores were mainly formed by carbonate-rich hydrothermal alteration of pre-existing BIF. Quartz dissolution textures, carbonate alteration, and pyrite mineralization suggest that hydrothermal silica leaching, accompanied by relative Fe enrichment, was a major upgrading process. Although limited Fe remobilization cannot be excluded, no direct petrographic or geochemical evidence for large-scale external Fe addition was observed in the studied samples. Pyrite trace-element and sulfur isotope compositions, together with the spatial association between altered ores and migmatitic granite, are consistent with a contribution from migmatization-related magmatic–hydrothermal fluids. These results provide new constraints on the formation of high-grade ores in BIF-hosted iron systems in the North China Craton.

The northeastern Qinghai-Tibet Plateau (NQTP) is a region highly sensitive to climate fluctuations. However, detailed evidence regarding the timing and processes of its Quaternary glaciations remains limited in many subregions. Here, we systematically identify, quantify, and date glacial landforms in the Chaka North Mountains using an integrated approach that combines high-resolution remote sensing, digital elevation model (DEM) morphometric analysis, and optically stimulated luminescence (OSL) dating, supplemented by field mapping. Our morphometric results demonstrate that cirques, U-shaped valleys, and distinctive moraine ridges are widely distributed throughout the region, providing evidence of significant Quaternary glacial activity. OSL dating of sediments mantling frontal moraines provides minimum stabilization ages of 111.5 f 9.3 ka and 110.7 f 11.2 ka, indicating a major glaciation during the penultimate glacial period (Marine Isotope Stage 6, MIS 6). Additional OSL ages of 112.7 f 23.6 ka and 74.9 f 11.5 ka from glacial lacustrine sediments indicate two distinct phases of lacustrine sedimentation: one during MIS 6 and the other during late MIS 5a. These findings suggest that the Chaka North Mountains experienced more extensive glaciation during MIS 6 than during the Last Glacial Maximum (LGM), as reflected by a significantly lower equilibrium line altitude (ELA). Our study provides a foundational chronostratigraphic framework for a key transitional region, offering critical constraints on the spatiotemporal evolution of the Quaternary cryosphere and the drivers of glacial asynchrony in the NQTP.

After the India-Asia collision at ca. 55 ± 10 Ma, widespread magmatic activity was developed after 45 Ma across the entire Tibetan Plateau and the Himalayan orogen. The origin and genesis of these igneous rocks are crucial to decipher the geodynamic processes in the post-collisional stage. However, previous studies mainly focus on igneous rocks from individual orogens or terranes, with rare attempts integrating them together to build a holistic model. This study concentrates on the post-collisional intrusive rocks from both sides of the Indus-Yarlung Tsangpo suture zone (the Himalayan orogen and the Lhasa terrane). By summarizing published geochronological and geochemical data, we aim to construct the spatiotemporal distribution of these rocks, characterize their geochemical compositions, and discuss their petrogenesis. The results enable us to place constraints on the bulk geodynamic evolution across the Indus-Yarlung Tsangpo suture zone between the two tectonic zones.Based on formation ages and distributions, the target intrusive rocks can be categorized into five groups: (I) ca. 45 Ma intrusive rocks from Himalaya, including both mafic and felsic rocks; (II) 45–25 Ma felsic intrusive rocks from Himalaya; (III) 25–8 Ma mafic, adakitic and non-adakitic felsic intrusive rocks from Himalaya; (IV) 45–25 Ma adakitic rocks from Lhasa; and (V) 25–8 Ma adakitic rocks from Lhasa. Both the 25–8 Ma rocks from Himalaya and Lhasa are the main magmatic record of these two zones. In addition to minor ca. 45 Ma and 25–8 Ma mafic rocks from Himalaya, other Himalayan intrusive rocks have higher SiO2 contents than the Lhasa adakitic rocks (55.9–86.0 wt%, 94 % >70 wt% for Himalaya vs 54.4–78.8 wt%, 57 % in the range of 65–70 wt% for Lhasa). The Himalayan intrusive rocks are mainly subalkaline, and the felsic ones are predominately peraluminous, characterized by a wide range of Rb/Sr ratios (e.g., 0.12 to 405, median = 4.48 for 25–8 Ma rocks) which are overall higher than those of the Lhasa adakitic rocks and significant negative Eu anomalies (mean = 0.69). The Lhasa adakitic rocks are mainly subalkaline, potassic granodiorites and granites, consisting of both metaluminous and peraluminous rocks. Their Eu/Eu* ratios concentrate around the unity (80 % at 0.73 to 1.03) and Rb/Sr ratios are overall low (0.13–4.57, median = 0.18) and have limited variations (90 % at 0.06 to 0.94). In addition, the Lhasa rocks generally have typical adakitic characteristics, including high Sr/Y and La/Yb ratios and low Y and Yb concentrations, but only a small part of the ca. 45 Ma and 25–8 Ma felsic rocks from Himalaya display such features. Combining whole-rock SrNd isotope characteristics, it is noteworthy that partial melting in the Himalaya mainly involves the metasedimentary rocks in the ancient upper-middle crust, while that in Lhasa involves the metamafic rocks in the juvenile lower crust. Furthermore, the Lhasa adakitic rocks align well with the potassic-ultrapotassic volcanic rocks from the Tibet Plateau in the isotope-element plots, demonstrating the addition of the potassic-ultrapotassic magmas to the formation of the adakitic rocks. In addition, the minor occurrences of mafic rocks and adakitic rocks in Himalaya indicate the occasional melting of mantle and mafic rocks, respectively, in the post-collisional stage.Consequently, we propose a lithospheric mantle foundering model for the petrogenesis of post-collisional intrusive rocks from both sides of the Indus-Yarlung Tsangpo suture zone, with three-stage processes for the geodynamic evolution of the Himalaya-Lhasa tectonic collage. Stage I at ca. 45 Ma: breakoff of the subducting Neo-Tethyan oceanic slab, inducing upwelling of the asthenospheric mantle and heating the overlying lithosphere to cause partial melting of the lithospheric mantle and crust to produce mafic and felsic rocks, respectively. Stage II at 45–25 Ma: sporadic foundering of the lithospheric mantle across the Indus-Yarlung Tsangpo suture zone, inducing upwelling of the asthenospheric mantle and providing heat for partial melting of the Himalayan felsic crust and the Lhasa mafic lower crust to form sporadic leucogranites and adakitic rocks, respectively. Stage III at 25–8 Ma: continuous and significant foundering of the Himalaya and Lhasa lithospheric mantle, inducing voluminous upwelling of the asthenospheric mantle and leading to extensive partial melting of the Himalayan felsic crust and the Lhasa mafic crust to produce the synchronous magmatic burst in the both sides of the Indus-Yarlung Tsangpo suture zone.

Medium-entropy perovskites containing Sn, Zr, Hf, and Te were synthesized via hydrothermal methods. Solid-state NMR confirms a uniform elemental distribution. In these vacancy-ordered double perovskites, the electronic behavior is shaped by more than just entropy. The intrinsic electronic properties of the constituent elements, such as the p-type nature of Sn, Zr, and Hf and the n-type nature of Te, create complex interactions. The simultaneous presence of both carrier types (p- and n-type) leads to emergent behaviors including the formation of spontaneous p-n junctions and localized electric fields. The creation of heterojunctions can lead to complex effects on a material's photoluminescence quantum yield (PLQY). While low concentrations of heterojunctions can boost PLQY, others may introduce new issues that can reduce it. These findings underscore the inadequacy of traditional crystallographic metrics in capturing the complex structure-property relationships that govern the behavior of high-entropy alloys. Effective rational design requires acknowledging that the incorporation of electronically dissimilar B-site cations frequently gives rise to spatially heterogeneous charge transport driven by local domain formation.

Based on the geological information collected from 861 dispersed metals occurrences in China (most of which include several deposits), the dispersed metal deposits in China are divided into 11 main deposit types, including meso-epithermal type, chemical deposition type, biochemical deposition type, skarn type, magmatic-hydrothermal type, weathered type, porphyry type, magmatic type, submarine volcanic rock-hosted type, subaerial volcanic rock-hosted type, and porphyry-skarn composite type. The mineralization periods of dispersed metal deposits in China are mainly concentrated in the Late Paleozoic and Mesozoic, with the Yanshannian and Variscan being the most important mineralization periods; In space, 42 dispersed metal metallogenic belts can be divided. Among them, the mid-eastern region of the Upper Yangtze Block metallogenic belt, the southern margin of the North China Craton metallogenic belt, the Middle-Lower Yangtze River metallogenic belt, Shanxi (fault uplift) metallogenic belt, Nanling metallogenic belt, west Guangxi-southwest Guizhou-northeast Yunnan metallogenic belt, and the coastal areas of Zhejiang-Fujian-Guangdong are important metallogenic belts of dispersed metal deposits in China, as well as important regions with prospecting potential; Lead-zinc deposit, bauxite deposit, coal deposit, copper-molybdenum deposit, copper-nickel deposit, copper polymetallic deposit and iron polymetallic deposit are important deposits for searching for dispersed metals. Strengthening the comprehensive evaluation of associated resources in the mining process and improving the comprehensive recovery of dispersed metals in mining mines are also important ways to increase dispersed metals resources.

The tectonic evolution history of Xing-Meng Orogenic Belt (XMOB) during the Paleozoic has been highly argued, one of the most controversial issues is the accretionary orogenic mechanism and the tectonic evolution of the Paleo Asian Ocean (PAO), whether the tectonic regimes were operated by continuous subduction-arc systems or extension after the orogenic process? The Daxing'an Mountains area, located in the eastern part of the XMOB, is an important window to study the tectonic evolution of the PAO. Previous studies on the tectonic evolution of the PAO in the Daxing'an Mountains is limited to the geological evolution evidence of the Late Paleozoic ophiolites and various magmatic rocks widely distributed in the region, but the evolution evidence of the Early Paleozoic geological bodies is often ignored. This paper studies in detail a set of metamorphic complex rock series developed in Zhalantun area in the northern Daxing'an Mountains, and predecessors have divided it into "Zhalantun Massif", approach the Xinghuadukou Group and Jiagada Formation; the study shows that there is no ancient crystalline basement in this area, and the original Xinghuadukou Group and Jiagada Formation are disintegrated into Zhalantun island arc, it also puts forward a new understanding of the structure and evolution of Zhalantun island arc. It is considered that the tectonic evolution of Zhalantun island arc during Paleozoic can be divided into three stages: The first stage is the lateral accretion orogenic mechanism of two arcs-one belt- one basin during Cambrian, and divided into Daheishan arc volcanic rock belt (514 similar to 505Ma), Dongjiagou arc volcanic rock belt (505 similar to 492Ma), Wuxingchun-Dayishan tectonic complex zones (rock: 524 similar to 509a; stroma: 504 similar to 502Ma) and Yongli inter arc basin (495Ma +/-), overall slightly be younger trend from north to south; the contents of total alkali and potassium decreased gradually, and large ion lithophile elements show an increasing trend, Fe and K/Rb decreased gradually, show a good geochemical polarity. The second stage is the vertical superposition and residual sea basin sedimentation stage of Ordovician-Silurian (465 similar to 425Ma), the Middle Ordovician C-type adakitic tonalite and Middle Silurian island arc hornblende gabbro; and Tongshan and Huanghuagou formations of forearc basins in Late Ordovician-Middle Silurian were deposited. The third stage is the vertical superposition stage of Carboniferous magma arc (405 similar to 350Ma), the whole Zhalantun area is in the overall Andes arc evolution stage, and a large number of calc alkaline arc volcanic rocks and intrusive rocks are formed, accompanied by strong compressive deformation at the same time, the Cambrian arc volcanic rock is also involved in the structural belt. Through the geological structure and the geochemical polarity of magmatic rocks, the island arc was accretionary geological body of subducted and retreated by ancient ocean plate from south to north, and it is the product of northward subduction of the northern branch of the PAO. The determination of the Zhalantun island arc accretion model and the research results of island arc igneous rock chronology and geochemistry, further evidence confirms the existence of sustained oceanic subduction during the Paleozoic era in the eastern part of the XMOB, this provides new information for the study of the mechanism of accretionary orogeny in the XMOB and the tectonic evolution of the PAO. At the same time, Early Paleozoic islandarc andesite superimposed Late Triassic intrusive magmatism in Zhalantun area, and it is the similar metallogenic setting in north side Super large Duobaoshan copper deposit, Zhalantun island arc belongs to the southwest extension of Duobaoshan island arc, its formation and evolution are of important indication significance to the search for China Duobaoshan style Medium and super large Cu-Au polymetallic deposits.

The Dabaoshan porphyry Cu deposit(420 kilotons（kt） of Cu @ 0.36%) is located in South China. The newly discovered Cu orebodies are hosted in the dacite porphyry adjacent to a granodiorite porphyry. The alteration and mineralization timing and stages of the porphyry Cu deposit were not well-constrained. In this study, we combine field mapping, petrography, whole-rock geochemistry, hydrothermal rutile U-Pb dating and Cu isotopes to synthesize an ore model at Dabaoshan. In situ hydrothermal rutile U-Pb dating yields an age of 159 ± 13 Ma, which brackets the timing of porphyry Cu mineralization. From top to bottom, the alteration zones in Dabaoshan are divided into quartz-sericite, biotite, chlorite-epidote, and chlorite-sericite subzones. Veins are classified into four stages（Stage 1 to 4） with Stage 4 quartz-sericite-chalcopyrite veins being the main Cu ore-bearing veins. The mineralized dacite porphyry has high SiO 2 , but low MgO, CaO, and Na 2 O contents. The chalcopyrite hosted in veins exhibits δ 65 Cu = values ranging from -1.29‰ to 0.51‰. Such copper isotope fractionation is attributed to vapor-brine phase separation, and mixing of fluids from different geochemical reservoirs. The timing of Cu mineralization and hydrothermal alteration support that the Jurassic granodiorite porphyry is an ore-forming intrusion at Dabaoshan.

Multiple sets of source rocks are developed in the Baijiahai Uplift of the Junggar Basin. The gas genetic types and sources of deep coalbed methane (CBM) in the Jurassic period of the Baijiahai Uplift are inconclusive. Based on the analysis of geochemical characteristics, maturity, natural gas composition, and carbon isotope of source rocks, combined with plate verification and seismic interpretation, the genetic types of deep CBM in Jurassic were identified, and the gas source and migration path of deep CBM in Jurassic were revealed. The results show that the three sets of source rocks of Carboniferous, Permian, and Jurassic in Baijiahai Uplift have good hydrocarbon potential. The organic matter types of Jurassic source rocks are mainly II2 and III, and the evolution of organic matter is in the low-maturity stage. The deep CBM in Jurassic atoms is a mixed gas containing exogenous input gas. The coal-type gas is derived from the Carboniferous, Permian, and Jurassic humic kerogens, with an average proportion of 54.47%. The oil-type gas is derived from the Permian sapropelic kerogens, with an average proportion of 45.43%. In the plane, the closer to the fault, the greater the proportion of oil-type gas. The genetic types and gas sources of Jurassic deep CBM in the Baijiahai Uplift are clarified in this study area. The research results are helpful to deepen the understanding of the enrichment law of deep CBM and provide references for the optimization of favorable exploration areas.

Fine quartz particles released by coal mining and combustion can be detrimental to human health, potentially causing permanent lung damage and even death. Therefore, research on the particle size distribution, modes of occurrence, and formation mechanisms of quartz in coal is essential for guiding safe and efficient coal mining as well as the safe utilization of coal resources. In this study, multiple analytical methods, including X-ray fluorescence, inductively-coupled-plasma-mass spectrometry, quantitative X-ray diffraction, optical microscopy, and scanning electron microscopy, were employed to determine the geochemical and mineralogical features of coal from the Haiwan mine located in the Ordos Basin, China. The Haiwan coal is a bituminous coal with low ash, low sulfur, and high volatile content. The inorganic constituents in the coals were derived from intermediate and felsic rocks of the Yinshan Orogenic Belt, as well as from multiple stages of authigenesis and fluid injections. Notably, quartz constitutes a high proportion of the low-temperature ashes of the coal, with an average proportion of 42.8 %. Authigenic quartz primarily occurs in the form of aggregates of sub-micron to micron-sized particles, typically closely coexisting with kaolinite and boehmite. This mineral assemblage resulted from precipitation of Si-rich solutions leached from the lithologies of the provenance area, along with the dissolution of terrigenous detrital feldspars and desiliconization of kaolinite. Most of the authigenic quartz particles (<10 m) with sharp edges in the coals, which are small enough to easily enter the respiratory tract, might do harm to lung tissue. Therefore, although the contents of SiO2 (4.5 %) and quartz (5.41 %) are low on a whole coal basis, prolonged inhalation of these quartz particles may still pose health risks to humans, especially from the combustion products (i.e., coal ash) which contain much higher proportions of quartz.

Drawing upon an understanding of the distribution characteristics of groundwater in the Taoshan rock mass within the Yushan Uplift region of southern Jiangxi, this study utilizes mathematical statistics, ion ratio coefficients, factor analysis, and mineral dissolution equilibrium methods to characterize in detail the hydrochemical features of groundwater in humid mountainous areas. Furthermore, the study delves into the lithological source control and the primary natural mechanisms that underlie these characteristics. The results indicate that the average pH of groundwater in the study area is 7.13, classifying it as weakly alkaline. The dominant cations are Ca2+ and Na+, accounting for 61% and 26% of the total cations, respectively, while the dominant anion is HCO3−, constituting 91% of the total anions. The total dissolved solids (TDS) range from 37.93 mg/L to 228.16 mg/L, indicating low mineralization. The groundwater types are primarily HCO3-Ca·Na and secondarily HCO3-Ca. The groundwater type is mainly controlled by rock weathering, with the primary ion sources influenced by the weathering and dissolution of silicate rocks, supplemented by contributions from carbonate rock dissolution. Ion ratio analysis further confirms that the major ions in groundwater predominantly originate from the weathering of silicate minerals, with minimal influence from human activities. Na+, K+, and H2SiO3 are primarily derived from the weathering and dissolution of silicate rocks, while the weathering and dissolution of carbonate rocks (e.g., calcite) significantly contribute to Ca2+ and Mg2+. TDS shows significant positive correlations with Mg2+, SO42−, HCO3−, Na+, and Ca2+, with the most pronounced correlations observed between TDS and Ca2+ and HCO3−, exhibiting a correlation coefficient of 0.89. Factor analysis reveals that the first principal component has relatively high loadings for TDS, Ca2+, HCO3−, Mg2+, and SO42−. Additionally, among 45 natural spring water samples, 36 exhibit metasilicic acid (H2SiO3) concentrations exceeding 30 mg/L, meeting the standards for metasilicic acid mineral water and demonstrating significant potential for development and utilization.

Water plays a critical role in the formation of granitic magmas and continental crust, but distinguishing water-present and water-absent anatectic scenarios using the geochemistry of granites is controversial. In this study we use an integrated approach that combines whole-rock major and trace element geochemistry, Ti-in-zircon thermometry, phase equilibrium modeling and trace element modeling to study the water regime that produced the Miocene granites from the Malashan-Gyirong area in central Himalaya to solve this controversy. The Gyirong granites have relatively low CaO, Sr and Ba and high Rb and (Sr-87/Sr-86)(i) and the Malashan granites have relatively high CaO, Sr and Ba and low Rb and (Sr-87/Sr-86)(i), and were classified as group A and group B granites, respectively. Following previous interpretation, group A and group B granites are consistent with the products of water-absent and water-present melting of metasedimentary rocks, respectively. Ti-in-zircon thermometry yielded maximum values of 761-796 degrees C for the Gyirong granites and 730-764 degrees C for the Malashan granites. Distinct variation trends in zircon trace element compositions indicate that these two groups of granites were not linked by crystallization differentiation. Using average compositions of Proterozoic pelite as starting materials, phase equilibrium modeling was carried out at a variety of P-T-H2O conditions typical of the Himalayan orogen, P = 5, 10 and 15 kbar, T = 600-800 degrees C, H2O = 0-10 wt%. Pelite can produce melts with coupled CaO-Na2O contents for both groups at 10 kbar. Specifically, constraints from compositions and temperatures require that the bulk H2O content is ca. 1-2 wt% for group A granites and > ca. 4 wt% for group B granites. Compared with the maximum structural water content of the pelite at 10 kbar (1.77 wt%), this study testifies that group A granites formed under water-absent conditions and group B granites under water-present melting conditions. Modeling shows that water-present melting can produce melts with high Sr-Ba and low Rb contents resembling group B granites, while water-absent melting can produce melts with low Sr-Ba and high Rb contents resembling group A granites. This study highlights that water can indeed cause differences in granite geochemistry but a comprehensive investigation is required to better determine the role of water during crustal anatexis.

Petrological, geochronological, and geochemical analyses of mafic rocks in northern Liaoning were conducted to constrain the formation age of the Proterozoic strata, and to further study the source characteristics, genesis, and tectonic setting. The mafic rocks in northern Liaoning primarily consist of basalt, diabase, gabbro, and amphibolite. Results of zircon U-Pb chronology reveal four stages of mafic magma activities in northern Liaoning: the first stage of basalt (2209 ± 12 Ma), the second stage of diabase (2154 ± 15 Ma), the third stage of gabbro (2063 ± 7 Ma), and the fourth stage of magmatic protolith of amphibolite (2018 ± 13 Ma). Combined with the unconformity overlying Neoproterozoic granite, the formation age of the Proterozoic strata in northern Liaoning was found to be Paleoproterozoic rather than Middle Neoproterozoic by the geochronology of these mafic rocks. A chronological framework of mafic magmatic activities in the eastern segment of the North China Craton (NCC) is proposed. The mafic rocks in northern Liaoning exhibit compositional ranges of 46.39–50.33 wt% for SiO2, 2.95–5.08 wt% for total alkalis (K2O + Na2O), 6.17–7.50 wt% for MgO, and 43.32–52.02 for the Mg number. TiO2 contents lie between 1.61 and 2.39 wt%, and those of MnO between 0.17 and 0.21 wt%. The first basalt and the fourth amphibolite show low total rare earth element contents. Normalized against primitive mantle, they are enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Ti), and exhibit negative anomalies in Sr and P, as well as slight positive anomalies in Zr and Hf. The second diabase and the third gabbro have similar average total rare earth element contents. The diabase shows slight negative Eu anomalies (Eu/Eu* = 0.72–0.88), enrichment in large ion lithophile elements (Ba), depletion in Rb, and slight positive anomalies in high field strength elements (Th, U, Nb, Ta, Zr, Hf, Ti), with negative anomalies in K, Sr, and P. The gabbro is enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Hf), and exhibits positive anomalies in Eu (Eu/Eu* = 1.31–1.37). The contents of Cr, Co, and Ni of these four stages of mafic rocks are higher than those of N-MORB. The characteristics of trace element ratios indicate that the mafic rocks belong to the calc-alkaline series and originate from the transitional mantle. During the process of magma ascent and emplacement, it is contaminated by continental crustal materials. There are residual hornblende and spinel in the magma source of the first basalt. The other three magma sources contain residual garnet and spinel. The third gabbro was formed in an island arc environment, and the other three stages of mafic rocks originated from the Dupal OIB and were formed in an oceanic island environment. The discovery of mafic rocks in northern Liaoning suggests that the Longgang Block underwent oceanic subduction and extinction in both the north and south in the Paleoproterozoic, indicating the possibility of being in two different tectonic domains.