The essence of mineral prospectivity prediction lies in the quantitative extraction and integration of multi-source geoscience information, with current research frontiers focusing on the intelligent extraction of ore-controlling factors and their nonlinear modeling. With the rapid development of data science and artificial intelligence, the integration of mathematical models and machine learning algorithms for multi-source mineral exploration data mining has emerged as a key research frontier in mineral prospectivity modeling (MPM). In this study, the box-counting method and the spectrum–area (S–A) fractal model were used in combination to quantitatively analyze structural features, remote-sensing-derived alteration information, and geochemical anomalies. The study revealed that high fractal dimension zones of remote-sensing-derived alterations are spatially consistent with alteration anomalies, while structural patterns identified through fractal analysis showed strong spatial agreement with known ore-controlling structures, offering robust alteration and structure related predictor variables for MPM. For geochemical information extraction, compositional data analysis was applied to construct principal component (PC1 and PC2) score maps, which were further combined with the S–A fractal model to identify corresponding geochemical anomaly fields. This integrated approach systematically revealed the spatial distribution patterns of principal components and the underlying geochemical anomaly structures, thereby providing essential geochemical predictors for model development. By integrating multi-source prospecting predictors, including metallogenic geological background, structural and remote sensing alteration fractal modeling results, and geochemical characteristics, three predictive models were developed: a convolutional block attention module-based convolutional neural network (CBAM-CNN), a simulated annealing-based random forest (SA-RF), and an improved particle swarm optimization-based support vector machine (IPSO-SVM). Following a comparative evaluation of model performance, the Shapley additive explanations (SHAP) method rooted in cooperative game theory was utilized to perform global interpretability analysis of the best-performing model, enabling a quantitative assessment of both the magnitude and direction of each mineral prospectivity predictor’s contribution to the model output. The results indicated that major ore-controlling structures, alteration-related fractal dimensions, and geochemical principal components were assigned higher explanatory weights in the model, effectively uncovering the dominant controlling factors and their coupling relationships in regional mineralization. These findings underscore the theoretical significance and practical utility of the SHAP method in data-driven geoscientific modeling.

In northeastern China, Mesozoic porphyry Mo-dominated deposits are abundant but porphyry Cu deposits are rare. Investigating the mechanisms controlling the formation of the limited number of the porphyry Cu deposits is critical in understanding the regional Cu metallogeny. Here, we present geochronological and geochemical data for the Cu-mineralized and barren intrusions in the newly discovered Baoquan porphyry deposit in the northern Great Xing'an Range. Zircon U-Pb dating indicates that the mineralized quartz diorite porphyry and barren syenogranite were emplaced at similar to 115 Ma and similar to 312 Ma, respectively. The quartz diorite porphyry (SiO2 = 62.7-63.9 wt%) has high alkaline contents (Na2O + K2O = 6.82-8.28 wt%), is enriched in LILEs (K, Rb, Ba, and Sr) and depleted in HFSEs (Th, Nb, Ta, Zr and Ti), and exhibits low initial Sr-87/Sr-86 ratios (0.7049-0.7067) and positive epsilon(Nd)(t) values (+1.9 to +2.0), as well as positive zircon epsilon(Hf)(t) values (+4.9 to +13.6), indicating that the parental magma was predominantly derived from the mantle, likely metasomatized by fluids derived from the subducted Paleo-Pacific slab. In contrast, the barren syenogranite (SiO2 = 76.4-78.0 wt%) is depleted in Sr (40.6-82.4 ppm) and Ba (348-498 ppm), with high Zr + Y + Ce + Nb values (206-277 ppm), showing A-type granite affinities. The Baoquan ore-related porphyry is oxidized (Delta FMQ = +1.2 in average) as calculated using magmatic oxybarometer using trace elements in zircon, in contrast with that of the barren syenogranite with lower magmatic Delta FMQ values (+0.6 in average). The porphyry also has low Zr contents (average 151 ppm) and Sr/Zr ratios (average 7.96), consistent well with other Cu-fertile magmas. Additionally, it also displays adakitic signatures with relatively high Sr/Y ratios (78-130), low Dy/Yb ratios (1.86-2.03) and negligible Eu anomalies (Eu/Eu* = 0.79-0.96). These findings suggest that zircon and hornblende fractionation, rather than plagioclase separation, has dominated magma crystallization, further indicating a high magmatic water content. Together with previously published data for the other Cu-mineralized intrusions in NE China, it is proposed that the magmas with high oxygen fugacities and H2O contents that have experienced high-pressure fractionation are favorable for Cu mineralization. Notably, the intrusions with such characteristics are mainly distributed in the northern Great Xing'an Range characterized by thickened Mesozoic crust, where should be prioritized for future Cu exploration.

The Bangpu deposit, located in the eastern Gangdese metallogenic belt of Tibet, SW China, is a large-scale porphyry deposit characterized by Mo-rich and Cu-poor mineralization. Systematically deciphering the spatial coupling between alteration and mineralization and establishing effective alteration exploration indicators are essential for objectively evaluating its metallogenic potential and guiding exploration. This study employs short-wave infrared (SWIR) spectroscopy to investigate alteration-mineralization relationships. Results demonstrate that the deposit exhibits typical porphyry-type alteration zonation, comprising three distinct zones from the center outward: phyllic -> argillic -> propylitic. The phyllic zone shows a strong spatial correlation with high-grade Mo-Cu mineralization. SWIR spectral parameters-illite crystallinity index (IC), Al-OH absorption depth (Dep2200), and Al-OH absorption peak position (Pos2200) reveal systematic variations: (1) IC and Dep2200 exhibit a significant positive correlation (R = 0.80), with anomalously high values (IC > 2.5, Dep2200 > 0.20) delineating ore zones; (2) Pos2200 values show a progressive increase from the mineralization center toward peripheral zones. These variations establish robust exploration indicators: IC > 2.5, Dep2200 > 0.20, and Pos2200 < 2206 nm. Integrated analysis of alteration zonation and spectral parameters identifies the contact zones between ore-forming intrusions and country rocks in the northeastern sector and deeper part as high-priority adjacent diorite porphyry zones.

The Da'anhe skarn Au deposit is located in the Lesser Xing'an-Zhangguangcai Range, northeastern China. The timing of the skarn mineralization and the causative intrusion is still unclear, and the magmatic physicochemical properties responsible for the gold mineralization need further investigation. In this study, U-Pb ages of the magmatic zircon and hydrothermal garnet, as well as whole rock and zircon geochemistry, have been determined to address the issues. The garnet U-Pb ages of two skarn samples from Da'anhe are 181.9 +/- 7.1 Ma and 181.0 +/- 9.0 Ma, respectively, which are consistent with the zircon U-Pb ages of the two gabbrodiorite samples (184.1 +/- 0.6 Ma and 184.3 +/- 1.3 Ma, respectively). The results indicate a genetic relationship between the gabbrodiorite and skarn mineralization. The gabbrodiorite in Da'anhe belongs to the high-K calc-alkaline to calc-alkaline series and is similar to typical arc magmas, which is characterized with enrichment of LILEs and depletion of HFSEs. The relatively low whole-rock Fe2O3/(FeO + Fe2O3) ratios (<0.4) and estimated magmatic oxygen fugacities (Delta FMQ = -1.29 to +1.45 with an average of -0.43) from zircon trace elements, which are significantly lower than those oxidized porphyry Cu/Mo systems in the region, suggest that the ore-forming magmas are highly reduced. Moreover, the absence of whole-rock Eu anomalies and the relatively high zircon 10000 x (Eu/Eu*)/YbN ratios (3.50-10.03, average 5.53) from the less evolved gabbrodiorite sample indicate a high-water parental magma, a favorable condition for hydrothermal mineralization. The present study suggests that Au-only skarn deposits like Da'anhe could be generated from a reduced, high-H2O magmatic system.

The spatial distribution of geological hazards exhibits significant heterogeneity and scale dependence. Therefore, a key challenge in susceptibility assessment is to effectively characterize spatial heterogeneity and accurately identify the main controlling factors. To address this, this study introduces a comprehensive framework. Qingyuan County, Liaoning Province, was selected as the study area. Hazard point clustering and Thiessen polygons were used to construct a six-level zoning system. The Fick’s law _ K Nearest Neighbor (FLA_KNN) algorithm was applied to screen optimal feature subsets for each zone, and susceptibility predictions were generated using a Particle Swarm Optimization _ Random Forest (PSO_RF) model. Model performance was evaluated by AUC, Accuracy, Precision, Recall, and MSE. Results show that: (1) Spatial heterogeneity zoning improved accuracy by about 5%, with prediction accuracy following a nonlinear trend across scales. The 4-level scheme achieved the best performance (AUC = 0.923); (2) Feature optimization further enhanced performance, stabilizing at eight features, with profile curvature and rainfall being most important; (3) High-risk areas were concentrated along the southwestern fault zone and central valleys, jointly influenced by slope (5°–20°), tectonic activity (fault density 0–0.1), and human activities (distance to roads 0–500 m). This framework provides a novel approach for susceptibility assessment and supports disaster prevention planning.

Geophysical exploration techniques play a pivotal role in enhancing the accuracy of mineral prospecting predictions. However, relying solely on individual methods often introduces uncertainties. This study presents a case study from the Yongxin gold deposit, where we integrated audio-frequency magnetotelluric (AMT) methods with gravimetric surveying and high-resolution magnetic profiling to overcome this challenge. Advanced three-dimensional modeling techniques were utilized to precisely delineate lithological variations and deep-seated mineralization features inherent to the area. The inversion and interpretation of cross-sectional AMT data provided insights into the subsurface structure down to a depth of 1.5 km. This enhanced data reliability was achieved through an integrated interpretation constrained by multiple datasets, enabling a more accurate inference of the deeper geological framework. Furthermore, by amalgamating various datasets, we uncovered characteristics of deep mineralization, the three-dimensional configuration of mineralization-related rock masses, and the spatial orientation of known ore deposits. This holistic approach facilitated a comprehensive understanding of the deeper geological formations. A detailed analysis of ore-controlling structures and exploration markers led to the development of a tailored geological-geophysical model for mineral exploration within the study area, serving as a valuable reference for future deep exploration efforts.

The identification of the genetic type of a mineral deposit, based on the compositional characteristics of specific minerals, has long been a focus of interest for economic geologists and mining companies. Traditional binary plots, due to the limitation of their dimensions, fail to encompass the whole element information, potentially introducing bias to the discrimination results. This is particularly the case in classifying Zn-Pb deposits. The current study employs four widely used machine learning algorithms (random forest, extreme gradient boosting, support vector machine, and multi-layer perceptron) to train 4908 sets of element data for sphalerite compiled from five distinct Zn-Pb deposit types (VMS, SEDEX, MVT, skarn, and epithermal). The data are then visualized and interpreted through principal component analysis and t-distributed stochastic neighbor embedding, which indicate that reducing sphalerite element data to a two-dimensional projection leads to the loss of significant feature information, hindering the ability to effectively distinguish the genesis of the deposit. The machine learning results show that all four models have macro F1-scores above 0.95 on the test set, demonstrating robustness and excellent generalization ability, which reflects the reliability of using sphalerite geochemistry to distinguish Zn-Pb mineralization types. The SHAP value analysis highlights the key role of Mn, Fe, Ge, Cd, and Co concentrations in facilitating the differentiation of deposit types through machine learning algorithms. Our models show an accuracy rate of 83% in predicting the combined results on an external, independent data set. The models have also been applied to classify three Zn-Pb deposits of unknown types, and the results are consistent with geological observations. The models' parameters have been further exported and programmed into an Excel macro program and a user-friendly software application, which can be accessed via https://sdeakii.github.io/machine-learning.

The southwestern region of China is tectonically situated within the Tethyan tectonic domain, with the eastern part comprising the Upper Yangtze Block, while the western orogenic belt forms the main part of the Tibetan Plateau. This belt was formed by the subduction of the Paleo-Tethys Ocean and subsequent arc-continent collision, and was later further modified by the India-Asia collision, resulting in complex geological structures such as the Hengduan Mountains. The lithostratigraphy in this region can be divided into six independent units. In terms of mineralization, the area encompasses two first-order metallogenic domains: the Tethyan-Himalayan and the Circum-Pacific. This study synthesizes extensive previous research to systematically investigate representative rare earth element (REE) deposits (e.g., Muchuan and Maoniuping in Sichuan; the Xinhua deposit in Guizhou; the Lincang deposit in Yunnan). Through comparative analysis of regional tectonic-metallogenic settings, we demonstrate that REE distribution in Southwest China is fundamentally controlled by Tethyan tectonic evolution: sedimentary-weathered types dominate in the east, while orogenic magmatism-related types prevail in the west. These findings reveal critical metallogenic patterns, establishing a foundation for cross-regional resource assessment and exploration targeting. The region hosts 32 identified REE occurrences, predominantly light REE (LREE)-enriched, genetically classified as endogenic, exogenic, and metamorphic deposit types. Metallogenic epochs include Precambrian, Paleozoic, and Mesozoic-Cenozoic periods, with the latter being most REE-relevant. Six prospective exploration areas are delineated: Mianning-Dechang, Weining-Zhijin, Long’an, Simao Adebo, Shuiqiao, and the eastern Yunnan-western Guizhou sedimentary-type district. Notably, the discovery of paleo-weathering crust-sedimentary-clay type REE deposits in eastern Yunnan-western Guizhou significantly expands regional exploration potential, opening new avenues for future resource development.

The tectonic background and sedimentary environment during the transition period from the Ordovician to Silurian have been widely studied by many scholars. This study focuses on the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation in the Bajiaokou profile at the southern margin of the Qinling Orogenic Belt in southern China. In order to study the aggregation mechanism of organic matter, geochemical proxies were proposed, including redox proxies (V, V/Al, U, U/Al, Mo, and Mo/Al), paleoproductivity proxies (P, P/Ti, Ba, Ba/Al, and Si-XS), paleoclimate proxies (CIA), and terrigenous flux proxies (Al, Zr, and Zr/Al). In addition, Al-Co[EF] x Mn[EF] is used to provide information on paleoenvironmental parameters such as watermass restriction conditions. The redox proxies show that the Wufeng-Longmaxi shale is mainly accumulated under oxic-dysoxic conditions. During the shale deposition period of Wufeng-Longmaxi formations, the marine surface primary productivity in the southern Qinling area is generally low to moderate. The paleoclimate proxies show that from the Late Ordovician to the Early Silurian the southern Qinling area generally had a warm and humid climate. The upwelling current is widely developed in the northern margin of the Sichuan Basin and the southern margin of the Qinling area. Although the upwelling current was highly developed during the deposition of the Wufeng Formation in the Bajiaokou profile, the concentrated accumulation of a large amount of volcanic ash resulted in the low primary productivity of the ocean. During the sedimentary period of the Longmaxi Formation in the Bajiaokou profile, the development of seasonal upwelling currents and a small amount of volcanic ash supply increased the primary productivity to moderate, which provided a good material basis for the enrichment of organic matter, but the high detritus flux and the water body condition of oxic-dysoxic resulted in the slight enrichment of organic matter.

The Lesser Xing'an-Zhangguangcai Range of northeast China is located in the eastern segment of the Central Asian Orogenic Belt (CAOB), which records intense magmatism during the Mesozoic. The petrogenesis and geodynamic setting of the Early Jurassic intrusive rocks in this region are unclear. In this paper, we present new zircon U-Pb age and whole-rock geochemical data for these intrusive rocks to investigate their origins and tectonic setting. Zircon U-Pb dating suggests these intrusive rocks were emplaced during the Early Jurassic (197-187 Ma). The granites are enriched in silica and alkali, and depleted in MgO and CaO. They are metaluminous to weakly peraluminous, and have high A/CNK values and low zircon saturation temperatures (TZr ~ 779°C), suggesting they are highly fractionated I-type granites derived by partial melting of lower crustal materials. The granites exhibit negative Nb, Ta, P, Eu, and Ti anomalies due to fractional crystallization. The diorites and gabbros have low SiO2 contents and high Mg# values, and are enriched in light rare earth and large-ion lithophile (Ba, K, and Sr) elements, and depleted in heavy rare earth and high field strength (Nb, Ta, and Ti) elements. The geochemical characteristics show that the mafic magmas were derived by partial melting of mantle that had been metasomatized by subduction-related fluids. Based on the geochemical characteristics of coeval intrusive rocks and the regional geological setting, we suggest the Early Jurassic intrusive rocks in the Lesser Xing'an-Zhangguangcai Range were formed along an active continental margin, possibly as a result of bidirectional subduction of the Mudanjiang Oceanic plate between the Jiamusi and Songnen-Zhangguangcai Range massifs.

The Central Asian Orogenic Belt (CAOB), one of the world’s largest orogens, extending from the Ural Mountains in the west to the Russian and the Chinese Far East, is the result of long-lived multi-stage tectonic evolution, including Proterozoic to Paleozoic accretion and collision, Mesozoic intracontinental modification, and Cenozoic rapid deformation and uplift [...]

The focus of exploration geochemistry is an accurate interpretation of geochemical data and the precise extraction of anomaly information related to mineralization from complex geological information. However, geochemical data are component data and exhibit a closure effect. Thus, traditional statistical methods cannot adequately reveal and identify the distribution of deep-seated anomaly information. This paper focuses on the Sidaowanzi area in Inner Mongolia and uses multivariate component data analysis methods to process 1:50 000 soil geochemical data. Using the Exploratory Data Analysis (EDA) method, the spatial distribution and internal structure characteristics of raw, logarithmic, and isometric logarithmic ratio (ILR) transformed data were compared and, coupled with robust principal component analysis (RPCA) and elemental component biplots, the association between element combinations and mineralization indicated by these three types of data was revealed. The S-A method was used to decompose composite anomalies of the ILR transformed RPCA score data to extract the characteristics of elemental combination anomalies and background distribution, and the Fry analysis method was utilized to analyze the dominant mineralization direction within the area. The results show that (1) data transformed using the ILR eliminated the influence of the closure effect, making the data more uniform on a spatial scale and exhibiting characteristics of an approximately normal distribution. (2) The S-A method was further used to decompose the composite anomaly of the PC1 and PC2 principal component combinations. The screened-out anomaly and background fields can essentially reflect the ore-causing anomalies dominated by Au and Cu-Mo mineralization. Moreover, the extracted anomalies and background information closely align with known mineral deposits (prospects) and can effectively identify weakly retarded geochemical anomaly information. (3) Fry analysis based on geochemical anomalies indicates that the dominant mineralization directions, by an assemblage dominated by Au and Cu-Mo, predominantly occur in the NE, NW, and proximate EW orientations. The combined application of the aforementioned three methods for the quantitative analysis of geochemical data aims to explore a transferable methodological system, providing new insights and approaches for further prediction of mineralization potential.

The extraction and integrated analysis of multi-source geological data are key steps in the prediction of mineralization. Current studies are focusing on the extraction and integration of the deep-level mineralization information. In the era of big data, mathematical models and computer algorithms for data mining of multi-source prospecting information have emerged as a leading research area in mineral prediction. In this study, we quantitatively analyzed the structure and remote sensing alteration information using the concentration–area (C–A) fractal model and the box-counting method for the Duobaoshan mineralization area, Heilongjiang Province, China. Results indicate that areas of high fractal dimension of remote sensing alteration correspond to abundant alteration anomalies. Fractal characterization of geological structures is consistent with the spatial distribution. Therefore, fractal characterization provides predictive factors of structure and remote sensing alteration in the development of a predictive model of mineralization. Soil geochemical data were analyzed using the component data analysis (CDA) method and the spectrum–area (S–A) fractal model. The analyses identified anomalous and background signals represented by the PC1 and PC2 principal component combinations. These combinations show a strong correlation between geochemical anomaly data and known deposits in the study area, suggesting that the S–A model effectively identifies geochemical anomalies that can be used as a predictive factor of a mineralization prediction model. The mineralization prediction model was developed using random forest (RF) and support vector machine (SVM) algorithms. The model incorporates predictive factors from multiple sources, including the ore-forming geological background, fractal-characterized geological structure, fractal-characterized remote sensing alteration, and geochemical characteristics. The models incorporated the C–A fractal model to evaluate the probability of mineral prediction. By integrating the characteristics of multi-source mineral prospecting information with the predictive results of machine-learning models, we delineated eight prospective mineralization areas. This approach validates the effectiveness of a combined method involving fractal theory and machine-learning in mineral exploration, offering new insights and theoretical guidance for further mineral prospecting in the study area

To explore the sedimentary environment and the background of the source area of organic-rich shales in the Wufeng-Longmaxi Formations in the northern Sichuan Basin, samples from Well XX1 in the area were subjected to geochemical testing and analysis of organic carbon content, trace elements, and rare earth elements (REEs). The results show that the total content of REE (Sigma REE) of the shale in the Wufeng-Longmaxi Formations varied from 183.08 to 234.66 mu g/g with an average of 212.59 mu g/g, which is significantly higher than the content of the North American shale composite. The fluctuations in the total amount of REEs in the shale of the Wufeng-Longmaxi Formations reflect certain differences in the geochemical conditions of the Upper Ordovician-Lower Silurian shale. The ratios of LREE/HREE, La-N/Yb-N, La-N/Sm-N, and Gd-N/Yb-N and the distribution of normalized REE patterns indicate that the source supply or sedimentary structural background may have changed during the shale deposition period of the Wufeng Formation, while the shale deposition period of the Longmaxi Formation may be in a relatively stable source supply and sedimentary structural background. There is no significant correlation between delta Ce and Sigma REE, and the obviously negative Eu abnormity and the weak Ce abnormity indicated that the diagenesis had a limited impact on REEs. Geochemical parameters such as values of & sum;REE, delta Eu, delta Ce, Ce-anom, and La-N/Yb-N indicate that the climate during the Wufeng-Longmaxi Formation shale deposition period was warm and humid, and the shale was deposited mainly in the suboxic-anoxic water environment. The deposition rate was stable and slow, providing good conditions for the production and preservation of organic matter. At the same time, this shows that the water environment of Wufeng Formation is more anoxic and reductive than that of Longmaxi Formation, which is more conducive to the preservation of organic matter. The correlation between Sigma REE and the content of Sc, Ti, Cr, Co, Zr, Nb, Th, Hf, Ta, and other elements indicates that the sources of REEs in the shale of Wufeng and Longmaxi Formations in the study area are similar, mainly terrestrial clasts, and some may come from the sea. The REE distribution pattern shows that the shale provenance of the Wufeng-Longmaxi Formations mainly comes from the upper crust. The La/Yb-& sum;REE diagram shows that the sediment-parent rocks are mainly early sedimentary rocks and these sediment-parent rocks have granite provenance characteristics. Compared to La/Yb, LREE/HREE, La-N/Yb-N, and other REE characteristic parameters, it is inferred that the tectonic background of the study area is dominated by passive continental margin.

Apatite is widely used as an indicator mineral to reflect the characteristics and petrogenesis of host magma. In this study, we present apatite geochemical and in-situ Sr-Nd isotopic data of monzogranite, granodiorite and dioritic enclave in the eastern Songnen-Zhangguangcai Range Massif, aiming to fingerprinting their petrogenesis and magmatic evolution processes. Based on apatite textures and geochemistry characteristics, the apatites were categorized into two distinct groups. Group 1 apatites have subhedral-anhedral textures and high Sr content (> 500 ppm). The majority of their epsilon Nd(t) values are relatively consistent with those of host monzogranites, indicating that they crystallized from crustal-derived material. Conversely, Group 2 magmatic apatites have euhedral-subhedral and core-rim textures, as well as low Sr content (< 500 ppm). This group can further be divided into two subgroups of Group 2A and 2B based on zoned textures and compositions. Group 2A zoned apatites exhibit high Sr/Nd and Sr/Y ratios at the rim and have discontinuous Ba contents, suggesting that they were derived from magma mixing and the granodiorite may be the felsic end-member. The Group 2B apatites are characterized by high Ce and Eu contents with low Y contents and Sm/Nd ratios, indicating that they originated from metaluminous I-type granitoids. The apatites also record the magmatic evolution processes, including fractional crystallization of plagioclase and titanite, as well as fluid exsolution. Combining apatite and whole rock geochemistry, it is shown that the parental magma was related to subduction of Mudanjiang Oceanic crust.

The age and petrogenesis of volcanic-subvolcanic rocks associated with Au mineralization of the recently discovered Yidonglinchang Au deposit in the Lesser Xing'an Range provide insights into late Mesozoic Au metallogenesis in NE China. In this paper, we report zircon U-Pb chronological and Hf isotopic, whole-rock geochemical, and Sr-Nd isotopic data of the andesite porphyry and quartz diorite porphyry from the Yidonglinchang Au deposit. Zircon U-Pb dating shows that the andesite porphyry and quartz diorite porphyry associated with Au mineralization were formed at 101 and 99-97 Ma, respectively, suggestive of an early Late Cretaceous Au mineralization event in the Lesser Xing'an Range. Whole-rock geochemical data reveal that they have low SiO2 contents (59.87-61.48 % and 55.91-63.22 %, respectively) and high Mg# values (41.5-55.4 and 43.2-61.3, respectively). In addition, these rocks are enriched in large-ion lithophile elements (e.g., K, Rb, and Ba) and depleted in high-field-strength elements (e.g., Nb, Ta, P, Ti, Zr, and Hf). The rocks have slightly negative to positive zircon epsilon Hf(t) values (-2.3 to 5.7) and negative whole-rock epsilon Nd(t) values (-3.3 to -2.9), indicating a metasomatized mantle source with some contamination by crustal materials. Combined with regional magmatic and metallogenic characteristics, we conclude that the Au mineralization at Yidonglinchang formed as a result of early Late Cretaceous magmatic-hydrothermal activities. Previously obtained data show that the orogenic Au deposits in the northern NE China formed mainly during the Early Cretaceous, earlier than the late Early Cretaceous to Late Cretaceous epithermal Au deposits in the eastern NE China. The formation of the late Mesozoic Au mineralization in the northern and eastern NE China was likely controlled by distinct tectonic settings. During the late Early to early Late Cretaceous, the rollback of Paleo-Pacific oceanic slab beneath eastern NE China generated an extensional setting that led to large-scale magmatism and associated Au mineralization.

Regional tectonics can provide excellent transport channels and precipitation sites for mineralized hydrothermal fluid. Studying the spatial relationship and distribution trends of regional tectonics and metal mineralization has theoretical and practical significance for revealing regional mineralization regularities and guiding mineral exploration. This study considers the Nenjiang-Heihe metallogenic belt, through the fractal box dimension method and Fry analysis, to explore the spatial distribution characteristics and patterns of tectonics. The results were as follows. (1) NE and NW directions are the main tectonic directions in the study area, with high-density areas concentrated in the central-eastern and central-western regions, demonstrating an overall ring-like distribution pattern. (2) Fractal dimensions of the linear structures of the NE and NW directions and the entire study area are 1.543, 1.493, and 1.622, respectively, with a strong coupling relationship between the lineament fractal high-value area and rhombic-grid spatial distribution of known deposits. (3) Gold mineralization shows the NEE and NWW directions as two main mineralization trends; the intersection area is the gold-potential area. The main trend direction of the Cu-Mo metallogenic trend belt is the NNW direction; the intersection area with the NEE direction gold metallogenic trend belt is the Au-Cu-Mo potential mineralization area.

为了实现下嘎来奥伊河铅锌多金属矿床深部找矿预测,根据矿区地质和矿床地质资料,采用Micromine三维建模软件对深部地层、矿体等进行了三维地质建模,实现了深部地质体的三维可视化、透明化,运用"立方体预测模型"和找矿信息量法对矿区多源地质数据进行统计分析.最终在矿区内圈定了铅锌矿找矿靶区3 处、磁铁矿找矿靶区4 处,为下一步找矿工作提供了参考和依据.

Granites containing abundant dioritic enclaves are widespread in the Songnen-Zhangguangcai Range Massif (SZRM). However, the role of mantle- and crust-derived magmas in the petrogenesis of the dioritic enclaves is debated. We present new zircon U-Pb-Hf-O isotopic compositions, whole-rock geochemistry, mineral geochemistry, and Sr-Nd isotopic compositions of hornblendites and dioritic enclaves and their host granites to elucidate their origins and investigate crust-mantle hybridization. Zircon U-Pb dating suggests that these intrusive rocks were emplaced during the Early Jurassic (197-186 Ma). The geochemical characteristics of hornblendites are similar to those of the Early Jurassic mafic-ultramafic rocks in the Lesser Xing'an-Zhangguangcai Range. They yield low (87Sr/86Sr)i ratios (0.704266-0.704324), high eNd(t) values (3.87-3.91), and are enriched in Ba, Sr, and K and depleted in Nb, Ta, and Ti, suggesting that they were derived from the partial melting of mantle wedge metasomatized by sediment melt. The host granites have high SiO2 (>65.12 wt%) and low MgO (<1.92 wt%) and Al2O3 (<16.23 wt%) contents and are to metaluminous-peraluminous high-K calc-alkaline rocks. In addition, they yield positive zircon eHf(t) values (3.42-7.58), zircon d18O values (4.87%.-5.85%.) and whole-rock eNd(t) values (0.10-0.44), suggesting that the granitic magma originated from the partial melting of continental crust with the involvement of mantle-derived melts. The field and petrographic observations and geochemical analyses indicate that the enclaves were derived from magma mixing and mingling. The dioritic enclaves contain K-feldspar megacrysts and back-veins, and plagioclase crystals within them are reversely zoned and have ocellar textures. The weighted mean ages of the host granites (186 +/- 3 and 188 +/- 2.3 Ma) are similar to those of the dioritic enclaves (186 +/- 1.8 and 188 +/- 1.1 Ma). The major element contents of the intrusive rock are linearly correlated with the SiO2 contents, and the whole-rock geochemical and isotopic characteristics of the hornblendites and host granites show that they are the mafic and felsic end-members, respectively, involved in the magma mixing. Therefore, we propose that underplating by mantle-derived magma likely triggered partial melting of the continental crust to produce felsic magma, and the dioritic enclaves were formed by the mixing and mingling of mantle- and crust-derived magma alongside melting, assimilation, storage, and homogenization. This suggest that the Mudanjiang Oceanic crust was subducted westward beneath the SZRM during the Early Jurassic.(c) 2023 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Breakthroughs in shale gas exploration in the Upper Ordovician-Lower Silurian strata of the Upper Yangtze Platform have attracted interest in its sedimentary-tectonic evolution, but the tectonic background of the northern margin of the Upper Yangtze Platform remains unclear. In this paper, the Wufeng-Longmaxi formations on the northern margin of the Upper Yangtze Platform were investigated. Based on geochemical and mineral-ogical analyses of the tuffs/K-bentonites of the Wufeng Formation and the barite in the Longmaxi Formation, as well as previous research results, it was concluded that the northern margin of the Upper Yangtze Platform was in an extensional tectonic background during the Late Ordovician-Early Silurian. Detailed analysis revealed that, (1) the U-Pb zircon age of the tuff in the Bajiaokou section in South Qinling is 443.91 +/- 0.92 Ma. The Zr/ TiO2-Nb/Y diagram of the tuffs/K-bentonites indicates that their protoliths were alkaline-subalkaline basalt and andesite series rock. Based on the Th-Hf/3-Ta, Th-Tb*3-Ta*2, and TiO2-Nb/3-Th diagrams, there are undis-covered intraplate tension calc-alkaline basalts in the northern Yangtze Platform or the southern Qinling region, which provided volcanic clastic materials to the Ziyang, Lan'gao, Chengkou, Yichang and other regions. (2) Scanning electron microscopy revealed that the barite crystals in the Longmaxi Formation exhibit dissolution features and have a large particle size. Energy spectrum analysis of these barite crystals revealed that they have C, O, S, and Ba contents of 8.48 wt%, 22.98 wt%, 13.09 wt% and 55.44 wt%, so they are speculated to have been formed via cold methane seep genesis in a weak extensional tectonic setting. The 87Sr/86Sr ratios of the barite revealed that different types of barite were simultaneously formed in this area under the influences of hydro-thermal and cold methane seeps. (3) The analysis of the heavy minerals in the Lower Silurian strata in the Bajiaokou section revealed that the provenance in the South Qinling area changed significantly during the late Early Silurian. Based on the above analyses, the northern margin of the Upper Yangtze Platform was in an extensional tectonic setting during the Late Ordovician-Early Silurian. The distribution of the total organic carbon content indicated that the extensional tectonic background provided good conditions for the enrichment and preservation of organic matter. The results of this study provide an understanding of the regional sedimentary-tectonic pattern and evolution of the Yangtze Platform during this period, as well as a reference for future shale gas exploration in this region.