The chemical composition of biotite can reflect the physical and chemical conditions and evolution process of magma. This study collected the EPMA data of 1455 biotite samples derived from I-type,S-type,and A-type granites to explore their differences and intrinsic association with granite type. The results show that the biotites from I-type granite are relatively rich in SiO₂,TiO₂,MgO,and MnO,while the biotites from S-type granite are relatively rich in Al₂O₃ and Na₂O,and the biotites from A-type granite are relatively rich in FeO^T. Based on the chemistry of biotites from I-type,S-type,and A-type granites,The I-type granite forms in a relatively high temperature,low pressure,and high oxygen fugacity environment. In contrast,the S-type granite usually forms in a relatively high-pressure environment,and the oxygen fugacity and temperature are lower than those of the I-type granite. The F and Cl contents and enrichment extent of biotite from different granite types are also significantly different,with relatively highest F and Cl contents in the biotites from A-type granites. Previous studies have shown that biotite composition has excellent potential to distinguish the genetic types of granites,but the existing classification models based on biotite composition still have significant uncertainty. PCA,t-SNE,UMAP dimensionality reduction methods and decision tree-based random forest (RF),extreme random tree (ERT),gradient boosting decision tree (GBDT),extreme gradient boosting (XGBoost),lightweight gradient boosting (LightGBM)and CatBoost machine learning model algorithms were applied to identify I-type,S-type and A-type granites based on calculated molar proportions of cation assignment in the biotite formula. The results show that PCA,t-SNE,and UMAP dimensionality reduction methods are not ineffective in distinguishing different granite types. In contrast,machine learning models based on decision trees can effectively identify granite types with more than 94.5% accuracy. In the biotite formula,T.Al,T.Fe³⁺,M.Al,M.Mg,and M.Mn are the five key cation assignments that affect the classification of machine-learning models.

Over the years, quantitative indicators in the upstream (exploration) to downstream (mining, beneficiation, and smelting) phases of the industrial chain have primarily relied on valuable elements. However, due to the diversity of minerals hosting these elements (where a single element can be present in multiple mineral phases), relying solely on elemental quantification often leads to significant discrepancies between resource reserve assessments in the early stages and resource recovery evaluations later on. Evidently, as the beneficiation process aims to recover target minerals containing recoverable elements, it is more reasonable to use the content of target minerals, rather than target elements, as the quantitative indicator. Consequently, for recoverable target minerals, the application of artificial intelligence image recognition technology for rapid and accurate quantification merits further investigation. The Huangtun copper-gold deposit in Anhui, a hydrothermal deposit, has copper (Cu) as one of its primary recoverable resources, with chalcopyrite being the primary mineral phase hosting Cu. Through the use of deep learning methods for microscopic image analysis, chalcopyrite was identified and quantified in 114 samples from 13 boreholes across five exploration lines in the mining area. The results demonstrate that AI image recognition technology based on deep learning can accurately identify and quantify chalcopyrite, providing a more comprehensive understanding of the spatial variation and distribution of copper resources compared to elemental quantification. This has significant implications for guiding exploration, mining, beneficiation, and separation of deep copper deposits or related minerals (such as gold), ultimately enhancing the comprehensive utilization efficiency of resources.

Minerals are important recorders of Earth’s evolution over billions of years. Data-driven research in mineralogy makes it easier to understand the underlying laws and driving mechanisms of the evolutionary processes of Earth. Iron plays a critical role in the matter and energy cycles, evolution of life, and environmental remediation, and is also recognized as a vitally important ‘oxygen fugacity buffer’ during the evolution of Earth surficial system. A total amount of 949 iron minerals are collected in this study. And by exploring their evolutionary patterns and distributional characteristics, a preliminary framework is constructed to tap into the intrinsic links between the evolution of deep-time iron minerals, evolution of Earth’s environment and evolution of life. The results reveal that the diversity of iron minerals has expanded episodically throughout geological history, and the peak of the growth stage coincides with the period of supercontinent collisions. The processes of plate motion, atmospheric oxygenation, and life’s metabolic activities have combined to promote the evolution of iron minerals in a more complex and diverse direction. Furthermore, back propagation neural network (BPNN), random forest (RF) and support vector regression (SVR), are used to establish and predict the evolution model of iron minerals since 4.0 Ga. The results show that RF is more appropriate to predict the evolution trend more accurately with stronger generalization ability than BPNN and SVR.

Thermoelectric typomorphism of pyrite has been widely used in prospecting and prediction of gold deposits. However, the thermoelectric characteristics of magnetite and its application in prospecting are rarely reported. Taking the main mining area of Bayan Obo Iron deposit as the research object, the thermoelectric coefficient measuring instrument BHTE-08 has been used to test and study the pyroelectric property of magnetite. The results show a significant thermoelectric anomaly in the eastern part of the main mining area, which is closely related to the occurrence of metal sulfides (especially pyrite and pyrrhotite) through microscopic observation. In particular, the proportion of magmatic magnetite in this anomaly area is high, so it is speculated that magmatism leads to a large amount of magnetite and sulfide accumulation in this area, which may be a channel for deep magma ascent. This understanding is important and significant for deep prospecting in Bayan Obo’s main-east mining area. In addition, the thermoelectric properties of magnetite and pyrite mixed samples in different proportions under artificial conditions are tested, and it is considered that the pyroelectric characteristics of magnetite have broad application prospects and practical significance in evaluating the quality of iron ore.

Magnetite and pyrite are typical minerals that exist widely in metal deposits, and their resistance properties, especially at constant activation temperature, are rarely studied in ore prospecting. The resistivity of magnetite and pyrite in Bayan Obo iron mining area of Inner Mongolia and Huangtun copper-gold mining area of Anhui was measured by BHMR-08 variable temperature thermal resistance meter. The results show that there is a low resistivity area of magnetite related to metal sulfides in the eastern depth of Bayan Obo iron mine area. The resistivity of magnetite in this area is mostly less than 9×10^-4 Ω·m, and it is mainly magmatic origin magnetite. Combined with previous studies, it is believed that there may be a magmatic channel in this area, which is a magmatic magnetite rich area and has great prospecting potential in the deep. The resistivity difference between the pyrite in the breccia pipe and the pyrite outside the breccia pipe is obvious in Huangtun copper-gold deposit area of Anhui Province. Among them, the resistivity value of pyrite in the breccia pipe is relatively large and the distribution range is wide, and the highest value can reach 20-40 Ω·m. The resistivity of pyrite outside the breccia tube is relatively small and the distribution range is narrow, mostly less than 10 Ω·m. Therefore, the resistivity value of pyrite is an important physical typomorphic characteristic to distinguish pyrite inside and outside breccia pipe effectively, which plays a certain role in the search for gold deposits.

This study investigates Carboniferous volcanic rocks (basalt, basaltic andesite, and andesite) from the Hara Arat Mountain (Hashan) area on the northwestern margin of the Junggar Basin to elucidate their petrogenesis and tectonic setting. Results indicate that these three rock types exhibit moderate MgO content (3.21%-6.82%), moderate to high Al₂O₃ content (11.30%-17.78%), and elevated total alkali content (K₂O+Na₂O=4.24%-7.24%). Basalt samples show relatively low K₂O content, reflecting Na-enrichment relative to K, and are classified as low-K tholeiitic basalts. In contrast, basaltic andesites and andesites display high calc-alkaline element contents, consistent with island arc volcanic rock characteristics. Isotopic analyses reveal medium-low ⁸⁷Sr/⁸⁶Sr ratios (0.702877-0.706620) and high ε_Nd(t) values (+4.59 to+9.85), indicating magma interaction between crustal and mantle components in a deep magma chamber. Compared to basalts, basaltic andesites and andesites show enrichment in large ion lithophile elements (e.g., Ba), relative enrichment in high field strength elements (e.g., U, Pb), and depletion in Nb, typical of subduction-related island arc magmatism. Trace element and rare earth element patterns suggest that basalts originated from depleted mantle melts under a convergent tectonic regime, while intermediate volcanic rocks record the subduction of oceanic plates beneath continental plates. This process involved the replacement of the depleted mantle wedge by sediments or melts derived from the dehydrating subducting slab, followed by partial melting to form basaltic andesites and andesites. Combined with regional geological data, the subduction of the oceanic plate persisted until the late Carboniferous.

Mafic-ultramafic dykes often have a close genetic relation with Au deposit.Properly understanding this relationship can provide a centain degree of guidance for mineral-prospecting.The concealed hornblende gabbro of Zhengguang is located within the Zhengguang gold mining area, situated on the eastern slope of the Greater Khingan Mountains in the Duobaoshan ore concentration district.Through conducting zircon U-Pb dating and Hf isotope composition analysis, the age of the hornblende gabbro zircon was determined to be (117.3±2.4) Ma. Additionally, two groups of captured magmatic zircon ages were identified, ranging from (468-484) Ma and (489-550) Ma, indicating that the dike was formed during the Early Cretaceous period.The zircon Hf isotopes exhibit ε_Hf(t) values ranging from -2.33 to 12.78. The sample data points fall within the range of the Early Cretaceous volcanic rock belt of the Greater Khingan Mountains. The Hf isotope values show significant variation, predominantly positive, which is associated with contamination from mantle-derived magma mixed with crustal materials. The fLu/Hf ratios range from -0.96 to -0.90, and the two-stage model ages are concentrated between 533 and 1316 Ma.The light and heavy rare earth elements show significant fractionation, with the curve leaning to the right. There is depletion in Nb, Sr, and Zr, while Th, Ta, and Nd are enriched. The contents of Zr (26.6×10^-6-35.8×10^-6), Hf (1.39×10^-6-2.08×10^-6), and Cr (102×10^-6-360×10^-6) vary, and the ratios of La/Nb (142.5-214.8) and Zr/Ba (0.16-0.19) reflect characteristics of mantle-derived magma, indicating formation in an extensional tectonic setting. The hornblende gabbro and the gold mineralization in the Nenjiang-Heihe metallogenic belt, such as that in the Sandaowanzi area, as well as the dioritic dikes associated with mineralization, were formed during the same period (110-125 Ma) and under similar extensional tectonic settings. This suggests that these dikes may serve as indicators for the Early Cretaceous gold mineralization in the Zhengguang mining area.

The Weishan rare earth element (REE) deposit in Shandong is located in the Laiwu-Zibo-Weishan REE belt in the eastern part of the North China Craton and is one of the three major light REE deposits in China. To better investigate the migration and enrichment processes of REEs, this study conducted detailed mineralogical research on the Weishan deposit. Based on the mineral paragenesis and cross-cutting relationships between veins, the hydrothermal mineralization of the Weishan rare earth deposit was divided into four stages: (Ⅰ) K-feldspar+quartz+calcite, (Ⅱ) sulfate+quartz+calcite, (Ⅲ) REE minerals+quartz+calcite+sulfate+fluorite, and (Ⅳ) calcite+quartz+fluorite+sulfides. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and electron probe microanalysis (EPMA) of each mineralization stage revealed that the main REE minerals are bastnäsite, parisite, strontianite-(Ce), and minor monazite, (Ce) apatite, and thorite. Additionally, these REE minerals are closely associated with fluorite, calcite, and sulfate minerals, indicating that the ore-forming fluid was likely a H₂O-CO₂-NaCl-F-REE- \mathrm{S} {\mathrm{O}}_4^{2-} hydrothermal system. During the mineralization process, ions such as F^-, Cl^-, \mathrm{C} {\mathrm{O}}_3^{2-}, and {\mathrm{S}\mathrm{O}}_4^{2-} contributed to varying degrees to the migration and enrichment of key ore-forming elements. Considering the regional tectonic background, this paper proposes that the Weishan REE deposit formed under the tectonic regime of the rollback of the subducting Paleo-Pacific Plate, with the complex late-stage differentiation of crust-mantle mixed magma and associated ore-forming fluids playing a key role in the mineralization process.

Nano materials inevitably enter the soil and water environment in the process of usage and treatment, and then affect the composition, physicochemical properties, and the relative content of minerals in the near surface environment. However, the mechanism and process of mineral phase transformation in soil and soil by nanomaterial are still unclear. In this work, carbon nanotube (CNT), a typical nano material, was used to explore its effect on the phase transformation of ferrihydrite (Fh), a widely distributed nano mineral, by means of X-ray diffraction, scanning electron microscope, zeta potential, Fourier transform infrared spectroscopy and ammonium oxalate extraction experiment. The obtained results show that the main transformed product of Fh is hematite. The oppositely charged CNT interacts with Fh through electrostatic attraction and the formation of Fe-O-C bonds, which inhibit the transformation process of Fh without changing the type of the product. In addition, the coexisting CNT reduces the average particle size of hematite in the product. This work provides an example to understand the mechanism of mineral phase transformation in soil and explore the impact of artificial substances on soil.

The transformation of ferrihydrite affects the mineral composition and element fate of near-surface iron oxides, which has important geochemical significance and has been widely concerned. With the deepening of research, research methods have been constantly innovated. This study summarizes the commonly used research methods on ferrihydrite transformation, including spectroscopy (X-ray diffraction, infrared spectroscopy, Raman spectroscopy, Mössbauer spectroscopy, X-ray absorption fine structure spectroscopy, etc.), morphology (scanning electron microscopy and transmission electron microscopy), element analysis, magnetic analysis, etc. We explore the application of these common methods(qualitative and quantitative) in the process of ferrihydrite phase transformation, and propose the advantages and limitations of different research methods. Finally, the application of in-situ testing method in the future research of ferrihydrite is prospected. This study provides basic information for exploring the transformation process of iron oxide minerals in the near surface environment.

For the purposes of extracting genesis and prospecting information of the Erdaokan Ag-Pb-Zn deposit, a detailed investigation on chemical compositions,trace elements, rare earth element, as well as S-Pb isotopes of the pyrite related to mineralization.Genetic typomorphic characteristics of the pyrite, such as S/Fe, Au/Ag, Co/Ni, Fe/(S+As), Fe/(S+As), Co-Ni-As, etc., suggest that this deposit belongs to the intermediate to epithermal volcanic hydrothermal deposit, with the pyrite from the middle-superficial part of the prospecting orebody. The LREE are relatively more enrichment than The HREE. Eu negative anomalies are weak but Ce anomalies are not significant. Relative enrichment high field strength element(HFSE)such as Th,U,P,Hf and Yb. Loss large ion lithophile element(LILE) such as Rb, K and Sr.Ratios of Y/Ho reveal that the pyrite in the oreforming fluid closely related to the crust and mantle. The Zr/Hf and Nb/Ta values indicate that the ore-forming fluid is in a stable environment. However, there may be foreign hydrothermal substances mixed in the ore-forming process. Sulfur isotope values are concentrated in +2.3‰ to +8.6‰, it indicates that the source of ore-forming material is deep. Ratios of ²⁰⁶Pb/²⁰⁴Pb (18.007-18.034), ²⁰⁷Pb/²⁰⁴Pb (15.501-15.522), and ²⁰⁸Pb/²⁰⁴Pb (37.704-37.755), for the pyrites suggest that the ore-forming materials were sourced mainly from the mantle materials mixing with minor crustal materials.Based on the geochemical characteristics and typical deposit characteristics of this area, the Erdaokan Ag-Pb-Zn deposit is considered to be an epithermal hydrothermal silver deposit,which has been denuded to the middle and shallow part at present, and still has certain prospecting potential in the deep part.

Pyrite is the most prevalent metal sulfide in the Earth’s crust, widely distributed in various types of metal deposits and serving as a crucial gold-bearing mineral in gold deposits. This study focuses on pyrite from typical gold deposits in the Muping-Rushan metallogenic belt. Through integrated polarized microscopy and electron probe microanalysis, we systematically investigated the typomorphic composition of pyrite in different stages of four metallogenic stages of gold deposits in the study area. Polarizing microscope analysis and electron microprobe elemental mapping showed that there are obvious differences in crystal form and grain size of pyrite in different mineralization stages. Stage Ⅰ pyrite (Py1) is coarse-grained panidiomorphic-hypidiomorphic cubic pyrite. Stage Ⅱ pyrite (Py2) is fine-grained hypidiomorphic-allomorphic pentagonal-dodecahedral crystal. Stage Ⅳ pyrite (Py3) is fine-grained panidiomorphic-hypidiomorphic cubic pyrite. The arsenic contents are higher at the rims and in cracks of stage I cube pyrite (Py1) and around stage Ⅱ fine-grained pentagonal dodecahedral pyrite (Py2). Native gold and silver occur mainly as thin veins in cracks in stage Ⅰ pyrite (Py1) or around stage Ⅱ pyrite (Py2). Electron microprobe analysis of major and trace elements also shows significant differences. The content of Fe and S in stage Ⅰ pyrite is the closest to the theoretical value, while stage Ⅱ pyrite has an obvious sulfur deficit, and stage Ⅳ pyrite has a ferrum deficit. In addition, the study of gold occurrence state indicates that the invisible gold in the gold deposits from the Muping-Rushan gold belt is Au⁰ nanoparticle gold. From the early to late mineralization stages, pyrite exhibits a crystal morphology transition from cubic → fine-grained pentagonal dodecahedral → fine-grained cubic forms, indicating a progressive cooling trend of ore-forming fluids. The main mineralization stage is characterized by moderate-low temperatures with elevated sulfur fugacity.

The Pulang copper deposit is located in the eastern part of Diqing Tibetan Autonomous Prefecture in northwest Yunnan. It occurs in the Late Triassic quartz diorite porphyry quartz diorite porphyry granite diorite porphyry complex. Due to the extremely weak research on the ore-bearing fluids in the northern mining section of the first mining area of the Pulang porphyry copper deposit, the understanding of the ore-forming system has been restricted.This article conducts petrographic observations, uniform temperature tests, and laser Raman probe composition analysis on fluid inclusions of ore bearing quartz fluids in the northern part(line 20-44) of the first mining area of the mining area. The results show that the ore bearing quartz veins in the northern part of the first mining area of the Pulang copper deposit are widely developed with gas-liquid two-phase inclusions and three-phase inclusions containing daughter crystals. The types of daughter crystals mainly include rock salt, potassium salt, calcite, chalcopyrite, etc. Fluid inclusions have two types: high salinity and medium low salinity. The uniform temperature range of high salinity fluid inclusions is 243-418 ℃, with an average of 338 ℃, a uniform pressure range of 1008-1552 MPa, and an average of 1178 MPa; The salinity is 30.1%-49.7%, with an average of 36.6%; The density ranges is 0.89-1.16 g/cm³, with an average of 1.02 g/cm³; The uniform temperature range of medium low salinity is 317-438 ℃, with an average of 392 ℃; The uniform pressure range is 370-559 MPa, with an average of 464 MPa. The salinity is 5.7%-13.0%, with an average of 9.3%; The density ranges is 0.55-0.77 g/cm³, with an average of 0.66 g/cm³. Based on analysis, it is believed that the ore-forming fluid in the northern part of the first mining area of the Pulang Copper Mine did not experience significant boiling, indicating that the area is not the ore-forming center. The laser Raman spectroscopy show that the gas phase composition of the inclusion contains CH₄, H₂O, and SO₂, indicating that the early ore-forming fluids may have been in a reducing environment. The decrease in temperature and pressure of high salinity medium density fluids, as well as the mixing effect of magmatic fluids, jointly led to the formation of vein like and disseminated mineralization in the northern area of the first mining area of the Pulang copper mine.

Epidote group minerals are common hydrous nesosilicate. The unique crystal structure of epidote allows them to be significantly enriched in various trace elements, especially divalent large ionic lithophilic elements (Sr and Pb), rare earth elements (REE), and transition group metallic elements (TME). Under certain temperature and pressure conditions, these ions will be substituted with Ca, Fe, and Al ions in cordite in a homogeneous manner. This paper summarizes the microstructural changes brought about by the substitution of elements such as Fe, Mn, Sr, Pb, Cr, V, and REE in the crystals of epidote, and aid in understandingthe important applications of such microstructural properties in tracing the fluid source region, in indicating the changes in fluid composition and processes, and in geochronology.

Allanite is a common accessory phase in granite, skarn and granite pegmatite. As the major carrier of light rare earth elements (LREE) and trace elements such as Th, U and Sr, allanite can control LREE content well within the critical temperature range of the subduction zone. The effect of changes that its composition to structure have directive influence to the research of earth science. This paper summarise the characteristics of the cell parameters of the three epidote group minerals contain allanite, epidote and zoisite through a series systematic structural and chemical compositional analyses. Such as single-crystal X-ray diffraction (XRD), powder X-ray diffraction, and LA-ICP-MS. We discuss the effects of composition on the structure in the epidote group minerals on the basis of the series of analyses. According to experimental data comparisons, as REE³⁺ substitutes for Ca²⁺ and occupies the A2 site, the unit cell parameters a, b, c and V of the epidote-group minerals exhibit corresponding increases. The change in unit cell volume is particularly significant, expanding from 457.92 ų to 479.93 ų, representing a volume increase of approximately 4.8%. Additionally, the (110), ($31\overline{1}$311¯), (222+123+114), (322+$42\overline{4}$424¯), and (307) lattice planes of allanite can indirectly reflect the content and occupancy of REEs within the mineral structure.This study investigates the crystal structure and chemical composition of allanite, revealing the regulatory mechanism of rare earth elements (REEs) substituting for Ca²⁺ and its geochemical significance.

Background collection

In western Hainan Island, pegmatites were widely distributed in the Baoban Complex. The geochemical research of pegmatites has not been carried out, and the types, genesis and rare metal metallogenic potential are still unclear. Based on field geological characteristics and microscopic observations, major elements, trace elements and rare earth elements of whole rock and single minerals (mica,feldspar) and feldspar X-ray powder diffraction were carried out on pegmatites in the Baoban complex. The type of pegmatites is classified, the metallogenic potential of pegmatites is analyzed, and its genetic relationship between pegmatites and adjacent granites are discussed. The pegmatites belong to the muscovite albite pegmatite, which have high silicon and aluminum content, low calcium and magnesium content and peraluminous. Trace elements are generally enriched in large ion lithophile elements, and depleted in high field strength elements. Light rare earth elements are relatively enriched, while heavy rare earth elements are relatively depleted. Electron Probe Micro-Analysis shows that the mica in the pegmatites is mainly muscovite, and the feldspar is mainly albite, the second oligoclase and microcline. The pegmatites have a low degree of evolution. The pegmatites are classified as the allanite-monazite type of muscovite-rare-element-REE(REL-REE)subclass. The content of rare metals in pegmatites is low, and the cell volume of microcline is smaller than that of rubidium-rich pegmatite. The pegmatites do not have rare metal mineralization potential.

Accurately constraining the basement formation and metamorphic deformation age of the North China Craton is the key to understanding the early tectonic evolution of the North China Craton. The Jiandeng intrusion is located in the Zanhuang complex in the southeast member of the central orogenic belt of the North China Craton, which is ~2.5 Ga granite and has undergone multi-stage metamorphism and deformation. A detailed multidisciplinary study on Jiandeng intrusion and associated undeformed pegmatites, coarse-grained deformed granite, fine-grained deformed granite,and granitic stock within Jiandeng intrusion includes field investigation, petrography, petrogeochemistry, and zircon U-Pb chronology. The results show that the main lithologies are gneiss syenogranite and monzogranite pegmatite for undeformed pegmatites. The lithologies of the other three intrusions are syenogranite. The geochemical characteristics of jiandeng intrusion and veins show high Si, rich in K and alkali elements contents, low Ti, Fe, Mg and Ca content, and rich in large ion lithophilic element Rb but deficient in high field strength element Ti. The Rb/Sr ratio ranges from 0.75 to 1.56, indicating crustal source characteristics. High Al and low Ti, and high Pb and low Th in magmatic zircon, further indicate that the Jiandeng intrusion belong to peraluminous S-type granite. LA-ICP-MS dating of zircon shows that there are ~2.5 Ga and ~2.3 Ga granite magmatic events. Veins magmatic activity can be divided into three stages, with the first three stages formed at ~2.5 Ga, ~2.3 Ga, and ~2.1 Ga, respectively. The fine-grained deformed granite records a metamorphic event at 1897±17 Ma. The tectonic evolution of the North China Craton is driven by a combination of multi-stage magmatic intrusions and metamorphic events. The formation of the Jiandeng intrusion at ~2.5 Ga marks the formation of a unified basement, indicating an early tectonic stabilization process. The Paleoproterozoic granite intrusions (2.3 Ga and 2.1 Ga) revealed a cracking-extensional event within the craton, and the metamorphic event of ~1.85 Ga represented a subduction collision process between the eastern and western land masses.

The Hanxing region of the southern Taihang Mountains, located in the central North China Craton, hosts numerous Mesozoic intermediate-mafic intrusive rocks. Among them, the Hongshan alkaline complex exhibits a distinctive lithological composition and serves as a key to understanding the tectonic evolution of the craton during the Early Cretaceous. This study conducted whole rock geochemistry and zircon U-Pb chronology analysis on typical lithology in the Hongshan intrusion and related volcanic rocks, and compared which with the published geochemical data, zircon U-Pb ages, and Lu-Hf isotopes of various intrusions in the Handan-Xingtai region. The genesis and evolution of the Hongshan complex were analyzed. This study shows that the Hongshan alkaline volcanic-intrusive complex consists of high-silica, Al-rich, and high-alkali rocks belonging to the shoshonite series. The La and La/Sm ratios exhibit a positive correlation. Hf isotopic compositions of zircons vary between enriched mantle and ancient lower crust (ε_Hf(t)= —17-—10, T_DM2=1800-2200 Ma), indicative that it is of crust-mantle mixed origin. The zircon U-Pb ages of quartz syenite, quartz syenite porphyry, pyroxene syenite, and trachytic tuff are 129.6±2.9 Ma, 128.6±3.0 Ma, 126.5±0.47 Ma, and 130.6±3.0 Ma, respectively, which are consistent with the magmatic timeframe of other intrusions in the Handan-Xingtai region. Comprehensive research suggests that the Hongshan alkaline complex was formed through the mixing of shoshonitic magma with both crustal- and mantle-derived magmas. The shoshonitic magma originated from the partial melting of pyroxenite residues formed during the early evolution of the craton and retained in the mantle. The mafic magma, on the other hand, was generated by partial melting of an enriched mantle source. This magmatic evolution and rock formation reflect a process of lithospheric thinning and asthenospheric upwelling, which was likely triggered by the rollback of the Paleo-Pacific Plate during the Early Cretaceous, leading to the development of a back-arc extensional setting in regions including Hanxing.

Different stress regimes and strain rates in nature can influence the transition temperature of rocks from brittleness to ductility, estimating the deformation and metamorphism temperatures of mylonite in ductile shear zones is crucial for interpreting thermochronological results. To assess the applicability of geothermometers(biotite/muscovite Ti geothermometers) in ductile shear zones, our study employed mineral dynamic recrystallization of mylonite and plastic deformation features, such as EBSD quartz <c>-axis fabrics, to estimate the deformation and metamorphism temperatures of Ziyuan ductile shear zones in Northeastern Guangxi, ranging from 400 to 550 ℃. Through the utilization of electron probe analysis techniques, chemical composition analyses were conducted on newly formed fine-grained biotite and muscovite resulting from dynamic recrystallization during ductile shearing. By employing biotite/muscovite Ti thermometers, the metamorphic deformation temperature of mylonite in the Ziyuan ductile shear zone were estimated to be between 409-528 ℃ and 458-605 ℃, respectively. Through comparative analysis, the temperatures obtained using geothermometers were essentially consistent within the allowable error range with those estimated using plastic deformation features, providing a basis for the application of biotite/muscovite Ti thermometers in extensional ductile shear zones.

Archean basement rock in Jiyang Depression has gradually become one of the focuses of hydrocarbon exploration. At present, the research on the characteristics of basement rock reservoir and the conditions of hydrocarbon accumulation in this area is not mature. On the basis of core observation, thin section identification, macroelement analysis, XRD, scanning electron microscopy, nuclear magnetic resonance and well seismic data analysis, the development characteristics of Archean basement rock reservoir and favorable geological conditions for hydrocarbon accumulation in Jiyang Depression are studied. The results show that the rock types of Archean basement rock reservoir in Jiyang Depression are mainly granites, gabbro, felsic gneiss, plagioclase amphibolite and cataclastic rock. Developed weathered crust type and inside type reservoir; The physical properties of the weathered crust are best in the semi-weathered zone, and the reservoir space is the solution pore, solution fracture, structural fracture and solution expansion fracture. The porosity of the reservoir is concentrated in 2.2%~3.8%, the average permeability is 2.79×10^-3 μm², and the average density of imaging logging fractures is 1.4 bars/m. The weathering crust is dominated by Class Ⅱ reservoirs, followed by class Ⅰ reservoirs. The inside type reservoir space is dominated by structural fractures, followed by a small number of dissolution fractures, with porosity ranging from 1.1% to 1.9%, average permeability of 1.69×10^-3 μm², and average density of imaging logging fractures of 0.6/m, which is dominated by Class Ⅲ reservoirs, followed by class Ⅱ reservoirs. The basement rock reservoir in Chengbei area is adjacent to the hydrocarbon-generating depression of the Yellow River Estuary, and hydrocarbon migrated along the top unconformity and tectonic fault of the Archean basement rock buried hill, overlying the lower Paleozoic Cambrian-Ordovician carbonate rocks, and the mudstones of the Paleogene Sha3 and Sha4 provide effective sealing. Finally, hydrocarbon accumulated in weathering crust and inside fractures at the top of basement rock during the Ming Huazhen period (3.0~1.5 Ma) of Neogene Pliocene. The research results are of great significance to the hydrocarbon exploration of basement rock in Jiyang Depression.

The individual hydrocarbon sulfur isotopes in crude oil provides key geochemical information for determining oil maturity and depositional environment. The crude oils from the Liaohe Western Depression were analyzed using gas chromatography with multicollector inductively coupled plasma mass spectrometry (GC-MC-ICP MS), in conjunction with gas chromatography/mass spectrometry (GC-MS) technology. The δ³⁴S values of individual hydrocarbon in three genetically different crude oils show significant differences. The δ³⁴S value of freshwater mature oil from the Jinzhou oilfield (20.57‰) is the highest, and the individual hydrocarbon sulfur isotopes exhibit an initial increase followed by a decrease with increasing methylation degree. The δ³⁴S value of low mature oil from the Shuguang-Gaosheng oilfield in a saline environment (19.23‰) is slightly lower than the former, and the monomeric hydrocarbon sulfur isotopes increase with the degree of methylation. The δ³⁴S value of low mature oil from the Niuxintuo oilfield in a semi-saline environment (14.47‰) is the lowest. An increasing trend in δ³⁴S values with maturity is observed, and there is a good negative correlation between Δδ³⁴S_{1-mDBT-4-mDBT} and the maturity parameter C₂₉sterane ααα20S/(S+R), indicating the controlling role of maturity, which may be the primary factor affecting δ³⁴S values. The δ³⁴S values of crude oils with similar maturities show a good positive correlation with gamacerane/C₃₀ hopane and an inverse correlation with C₁₉/C₂₃ tricyclic terpane, indicating that a reducing saline environment promotes the sulfurization of organic matter, resulting in heavier δ³⁴S values. The mild biodegradation has a small impact on δ³⁴S values and does not cause obvious isotopic fractionation. Individual hydrocarbon sulfur isotopes serves as a reliable indicator for assessing crude oil maturity and depositional environments, offering a scientific foundation for hydrocarbon exploration and development.

In this study, the crude oil samples of Jurassic Sangonghe Formation in Moxizhuang area were selected and analyzed by geochemical experiments. The geochemical characteristics of aromatic compounds in crude oil samples of Sangonghe Formation in Moxizhuang area were analyzed by gas chromatography-mass spectrometry. Combined with carbon and hydrogen isotopes of n-alkanes, the source, maturity and sedimentary environment of organic matter were determined. The results show that the crude oil of Jurassic Sangonghe Formation in Moxizhuang area is dominated by phenanthrene series compounds, and the contents of pyrene, benzopyrene compounds are relatively abundant. The contents of 1,2,5-trimethylnaphthalene, biphenyl, anthracene and perylene derived from higher plants are less. Combined with the characteristics of hydrogen isotope composition of monomer hydrocarbons, it indicates that the organic matter is mainly derived from lower aquatic organisms, with a little contribution from higher plants. The dominant fluorene in the three fluorene series compounds reflects that the sedimentary environment of the crude oil in the Sangonghe Formation is dominated by freshwater deposition, and the reducibility is weak. The maturity parameters such as MPI-1, F₁ and F₂ all show that the thermal evolution degree of crude oil in Sangonghe Formation is high and it is in the high maturity stage. By using cluster analysis method, combined with the comparison results of monomer hydrocarbon carbon isotope and some aromatic hydrocarbon parameters, it is indicated that the crude oil of Sangonghe Formation has a good genetic relationship with the source rock of Permian Lower Wuerhe Formation. The results can provide reference for the exploration and development of oil and gas resources in Moxizhuang area.

The paleo-marine environment and paleo-sedimentary environment information preserved by the Neoproterozoic clastic and carbonate mixed sedimentary rocks can respond to the Neoproterozoic oxidation events. In this paper, via a combination of sedimentological and geochemical methods, the Hejiazhai Formation in western Henan Province was taken as a case study to discuss the sedimentary characteristics and its depositional environment, to reconstruct the pale-oceanic conditions and finally to provide some basis for the paleoenvironmental reconstruction of the Neoproterozoic southern margin of the North China Craton. The Hejiazhai Formation is composed of marlstone, limestone and quartz-bearing clastic limestone, and some molar-tooth structures and stromatolites can be seen, which are the characteristics of marine carbonate tidal flat deposits. The ratios of V/Cr、 Ni/Co and Sr/Ba indicate that there is a good correlation between the paleo-water depth and the redox condition of the paleo-ocean in the Hejiazhai Formation. It has experienced three cycles of water deepening and shallowing, and the oxygen content of the paleo-ocean decreases and then increases. By comparing with the paleoenvironment of the strata in the same period, the marine environment around the early Neoproterozoic plate has shown an oxidation state. We can use the conclusion of sedimentary environment analysis of Hejiazhai Formation to analyze the sedimentary environment and paleogeographic conditions of carbonate rocks in the southern margin of North China. The results of the analysis can provide evidence support for the Neoproterozoic oxidation events.Keywords: Neoproterozoic; Hejiazhai Formation; diamictite; stromatolite; Western Henan

The construction of coal macromolecular model is of fundamental significance for studying the physical and chemical properties and efficient utilization of coal. However, there is still a lack of construction and comparison of macromolecular models reflecting the properties of different rank coals. Therefore, this study used industrial analysis and elemental analysis, as well as nuclear magnetic resonance carbon spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy and other test methods, combined with previous data, constructed and collected Hequ coal, Xiaoyi coal, Dianping coal, Gaoyang coal, Yangquan coal, Zhaozhuang coal and other 13 different coal rank coal macromolecular model sequences across lignite to anthracite (R_o=0.46%-3.21%). The macromolecular structure parameters of coal show that the aromatic carbon rate in aromatic structure increases in three stages with the increase of coal rank. The bridged aromatic carbon and bridged aromatic carbon increase linearly, and the side-branched aromatic carbon and oxygenated aromatic carbon decrease rapidly before the first jump point of coal metamorphism. The lipid carbon ratio in the fat structure is opposite to the aromatic carbon ratio, showing a three-stage decreasing trend. The methyl carbon increases before the first jump point and finally decreases; The fluctuation of methylene carbon corresponds to the three coalification jumps; the change rule of oxygenated fat carbon is not obvious. The content of oxygen-containing functional groups decreases with the increase of coal rank. The decrease of van der Waals energy and bond stretching energy plays a leading role in molecular stability, and hydrogen bond energy only plays a role in low rank(lignite) and medium coal(long flame coal, gas coal) and between molecules. The total energy of multi-molecules in low and medium rank coal(lignite to lean coal) is lower than that of equivalent single molecules, while the energy of multi-molecules in high-rank coal(lean coal and anthracite) is higher than that of equivalent single molecules due to π-π interaction. In general, the macromolecular model sequence established in this paper reflects the law of coal metamorphism and reveals the energy composition of coal molecules. The research results are expected to provide basic coal molecular configuration for further coal macromolecular simulation work.