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2025, Volume 32 Issue 6
25 November 2025 Previous Issue    Next Issue

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On the academic accomplishments and contribution of Professor Deng Jinfu MO Xuanxue, LUO Zhaohua, LIU Cui 2025, 32(6): 1-8.  DOI: 10.13745/j.esf.sf.2025.7.13 Abstract ( 67 )   HTML ( 19 )   PDF (1603KB) ( 71 )   Professor Deng Jinfu was an outstanding petrologist and tectono-petrologist,who made significant contributions to petrogenesis, petro-tectonics, crust-mantle deep processes, and ore mineralization,and cultivating high-level scientific and technological talents in geoscience of China. His achievements include: combining petrology with fundamental disciplines, especially advancing the formation and development of Petrophysicochemistry, which propelled petrology from descriptive science to theoretical frameworks; accurately determining relationships between petrotectonic assemblages and tectonic environments, and, on this basis, analyzing China’s tectonics and their temporal evolution, thereby advancing tectono-petrology; leadingthe compilation of China’s first 1∶2500000 tectonic map of intrusive rocks and contributing substantially to national mineral resource potential assessments; revealing crust-mantle structures and deep processes through petrological probing, with pioneering work on Mesozoic-Neogene lithosphere thinning in eastern China; proposing theories and methodologies for continental dynamics studies, including a new model for Chinese lithospheric evolution: continental roots-plume tectonics; establishing China’s first lithosphere-scale tectonic domain division and proposing a three-tiered crust-mantle dynamic system for the mainland; and demonstrating that upheaval in the lithosphere-asthenosphere system drives mineralization “explosions”, while three-dimensional discontinuous reactivation at the lithospheric scale creates optimal ore-hosting spaces within continental-scale metallogenic belts. References | Related Articles | Metrics

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Tracing the deep geological processes of the Mesozoic-Cenozoic oceanic plate on the continental margin of the East Asian continent in China XIAO Qinghui, LIU Yong, LI Tingdong, PAN Guitang, LU Songnian, DING Xiaozhong, ZHANG Kexin, PANG Jianfeng, QIU Ruizhao, ZHAO Guochun, ZHANG Heng, CHENG Yang, FAN Yuxu, FU Li 2025, 32(6): 9-28.  DOI: 10.13745/j.esf.sf.2025.8.62 Abstract ( 38 )   HTML ( 12 )   PDF (10030KB) ( 79 )   There remains no unified understanding regarding the causes of Mesozoic-Cenozoic continental margin tectonics in the East Asian continent of China, with significant differences persisting. Based on the geological framework of oceanic plates, this paper re-examines these causes. Our findings reveal that: (1) Subduction of oceanic plates along the Mesozoic-Cenozoic continental margin of East Asia was not only widespread but also continuously extended into the mantle transition zone (400-660 km depth), where they accumulated. This formed a novel thermodynamical system with crust formation and continent building functions, termed ‘second continental dynamics’ or the ‘second continent’. This system controlled the formation and evolution of the Mesozoic-Cenozoic continent in China. (2) Numerous oceanic islands, seamounts, and oceanic plateaus have been identified within subduction-accretionary complex zones in the Chinese mainland. Their coexistence with the opposing tectonic regime of oceanic plate subduction within the same subduction zone indicates that the formation and evolution of the Chinese mainland were fundamentally constrained by the subduction of five ancient oceanic plates (Paleo-Asian Ocean, Tethys Ocean, Paleo-Pacific Ocean, Okhotsk Ocean, and South China Ocean). (3) Within the Xar Moron subduction-accretionary complex zone in Inner Mongolia, three genetically distinct regimes of oceanic islands and seamounts have been discovered: ‘mantle plume’ type, mid-ocean ridge type, and island arc type. This demonstrates that the tectonic backgrounds during the evolution of these ancient oceans were diverse and complex, forming in environments including island arcs, hotspots, mantle plumes, back-arc basins, and mid-ocean ridges. The island arc environment is clearly linked to plate subduction, while hotspots and seamounts are associated with mantle plumes. This indicates that two opposing tectonic regimes- intra-oceanic subduction and intra-plate asthenospheric mantle upwelling - coexisted during ancient ocean evolution. Based on these findings, we propose that the Mesozoic-Cenozoic orogenic belts in East Asia formed through the composite evolution of an intra-oceanic subduction + intra-plate asthenospheric mantle upwelling system. This system was triggered by the mantle transition zone (the ‘second continent’) beneath these belts, rather than solely by mantle plumes. Consequently, the discovery of island arc-type oceanic islands and seamounts provides crucial scientific evidence for establishing the theoretical model of coexisting intra-oceanic subduction and intra-plate asthenospheric mantle upwelling within the Mesozoic-Cenozoic orogenic belts of East Asia, within the context of oceanic plate geology in China. It is therefore essential to re-evaluate the influence of the mantle transition zone (the ‘second continent’) beneath these orogenic belts on the formation and evolution of the Chinese mainland, its metallogenic potential, and its implications for strategic ore-prospecting predictions. Figures and Tables | References | Related Articles | Metrics

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Overview of magmatic arc system $\boxed{\hbox{DENG Jinfu}}$ 2025, 32(6): 29-60.  DOI: 10.13745/j.esf.sf.2025.7.80 Abstract ( 78 )   HTML ( 22 )   PDF (10146KB) ( 144 )   Classical plate tectonics theory posits that no magmatic activity occurs between the trench and the volcanic arc, with magma primarily originating from the mantle wedge above the subducting oceanic slab. The discovery of adakites in the last century demonstrated that subducting oceanic crust itself can undergo partial melting. Recent studies have further revealed that various parts of oceanic plates, such as oceanic plateaus (aseismic ridges) and active mid-ocean ridges, can also subduct and generate partial melting, forming magmatic arcs. This paper analyzes global examples of magmatic arcs formed by the subduction of different oceanic plate components. We propose six distinct types of magmatic arc systems (MAS): (1) MAS formed by subduction of aged oceanic crust; (2) MAS formed by subduction of oceanic plateaus; (3) MAS formed by subduction of active mid-ocean ridges; (4) MAS formed by subduction of young oceanic crust; (5) MAS formed by subduction of the youngest oceanic crust; and (6) MAS formed by subduction of normal oceanic crust. For each type, we discuss and summarize the formation mechanisms, the petrotectonic assemblages of igneous rocks, and their spatiotemporal evolutionary characteristics. This study serves as a framework for further research on magmatic arc systems preserved within the continental block of China. It provides novel perspectives for constraining the nature of subducted oceanic slabs and reconstructing the composition of vanished ancient oceanic plates, offering new insights for the study of oceanic plate geology. Figures and Tables | References | Related Articles | Metrics

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The prospect of ocean plate geology: Focusing on the geological reconstruction of the oceanic subduction zone in China and neighboring areas PAN Guitang, REN Fei, ZHANG Kexin, XIAO Qinghui, LU Songnian, REN Guangming, PANG Weihua, CUI Xiaozhuang, PENG Zhimin, ZHANG Xiangfei 2025, 32(6): 61-88.  DOI: 10.13745/j.esf.sf.2025.7.7 Abstract ( 35 )   HTML ( 7 )   PDF (14390KB) ( 75 )   Since the theory of plate tectonics was put forward, nearly 60 years of geological practice, aiming at the root of the problem of “plate tectonics landing” and the limitations of “OPS”, Academician Li Tingdong’s team proposed the concept of oceanic plate geology (OPG). Using the principles and methods of plate tectonics, it studies the plate geological remains of the oceanic lithosphere in the extinct ocean and the back-arc ocean basin in the continent. It is mainly to study the petrotectonic assemblages and temporal-spatial structure of the subduction-accretionary complex belt of the oceanic crust, and reconstruct the evolution history of the oceanic crust from spreading to subduction, and the evolution relationship and dynamic process of the adjacent crustal tectonic units. It provides a breakthrough point for the innovative construction of the irreversible evolution theory of both supercontinent convergence-breakup and ocean-continental tectonic regime transformation, which has great scientific significance. Based on the National mineral resources potential evaluation—Metallogenic Geological BackgroundProject and its geotectonic series mapping and integrated research in China, as well as the recent geo-geotectonic mapping and integrated research in the Tethys tectonic domain and adjacent areas, this paper focuses on the geological reconstruction of five identified oceanic subduction-convergent consumption zones in China and adjacent areas: ①Jaisang-lrtys-Nanmongbiji-Solunshan-Xilamulun-Changchun-Kaishantun convergent belt; ②Ural-Turkestan-South Tianshan-Niujuanzi-Xichangjin-Engelwusu convergent belt; ③Bangong Lake- Shuanghu-Nu River-Changning-Menglian-Chiang Mai-Raumo-Wendong convergent belt; ④Kuanping-Foziling convergent belt; ⑤Pingxiang-Yingyangguan-Pingxiang-Jiangshao convergent belt. Identifying the geological remains of the extinct ocean (convergent belt) in the continent should be the frontier and hot spot of regional, national and even global tectonic research. Figures and Tables | References | Related Articles | Metrics

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Deep earth material exploration and mineralization prediction: Methods, applications, and future prospects WANG Tao, HOU Zengqian, HUANG He, YANG Liqiang, ZHENG Yuanchuan, SUN Jian, BAO Xuewei, HOU Tong, FAN Runlong, XU Bo, ZHANG Jianjun, ZHU Xiaosan, YIN Jiyuan, SU Yuping 2025, 32(6): 89-130.  DOI: 10.13745/j.esf.sf.2025.8.61 Abstract ( 39 )   HTML ( 8 )   PDF (23153KB) ( 96 )   Deep material exploration remains a major challenge in deep Earth science, primarily due to the scarcity of effective and reliable methods. This limitation constrains our understanding of the material composition, evolution, and geodynamics of the Earth’s interior. This paper synthesizes recent progress in theoretical frameworks, methodologies, and applications for deciphering deep lithospheric architecture. The methodological system mainly encompasses: (1) petrogenetic and mineralogical studies of magmatic rocks to identify lithotypes of deep-sourcess; (2) xenolith (including xenocryst) studies to directly constrain the composition of the deep lithosphere; (3) elemental geochemical tracing and mapping to link magmatic petrogenesis with deep-source characteristics; (4) radiogenic isotope systems (e.g., Nd, Hf) to determine temporal attributes (juvenile vs. ancient) of deep materials; (5) stable isotopes (e.g., O, Mg, Ca) to trace deep-to-shallow cycling processes that influence the composition of deep materials; (6) xenocrystic/inherited zircon analysis to resolve the temporal and compositional evolution of deep materials; (7) geophysical investigations to derive physical parameters and infer rock types/compositions of the deep lithosphere; (8) petrological experiments and modeling to bridge compositions constrained by geochemical signatures (isotopes/elements) with physical properties detected through geophysical methods; (9) multidisciplinary data integration and synthesis. Applying these approaches has yielded significant breakthroughs, including delineation of orogen-craton boundaries, reconstruction of 3D/4D architectures of representative tectonic units, characterization of basement attributes beneath sedimentary basins, and elucidation of lithospheric controls on regional metallogenesis. Finally, challenges in isotopic mapping are discussed, along with critical research priorities and perspectives on future directions that could lead to transformative discoveries in deep Earth exploration. Figures and Tables | References | Related Articles | Metrics

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The distribution and evolution of Ocean Plate Stratigraphy in the Central Orogenic System of China ZHANG Kexin, LUO Mansheng, KOU Xiaohu, HE Weihong, XU Yadong, SONG Bowen, WANG Lijun, WANG Jiaxuan, WANG Shendong, CHEN Fenning, CHEN Ruiming, LI Chengdong 2025, 32(6): 131-155.  DOI: 10.13745/j.esf.sf.2025.4.91 Abstract ( 32 )   HTML ( 7 )   PDF (13482KB) ( 87 )   The Central Orogenic System spans the central part of China, comprising six NW-SE trending orogenic belts: the Qilian, Altun, North Qaidam, West Kunlun, East Kunlun, and Qinling. Tectonically located in the northern part of the Tethyan domain of China, it has undergone the evolution of the Proto- and Paleo-Tethyan archipelagic ocean systems since the breakup of the Rodinia supercontinent. This paper systematically compiles and integrates the geological records of ophiolitic mélanges and other oceanic crust remnants from over 185 outcrops of various ages in the Central Orogenic System (including 393 isotopic dating data). Based on tectonic settings and evolution with age constrained, seven OPS (Ocean Plate Stratigraphy) tectonic-stratigraphic provinces are delineated and further divided into 15 sub-provinces. The study introduces the lithological assemblages of OPS and their spatiotemporal distributions in each province and sub-province. Based on the division and correlation of OPS chronological sequences, the Phanerozoic OPS framework and its spatiotemporal evolution model of the Central Orogenic Belt is established for the first time and the evolution of Tethyan domain related to the Central Orogenic System is discussed. Figures and Tables | References | Related Articles | Metrics

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Why should we drill through intact ocean crust? NIU Yaoling 2025, 32(6): 156-178.  DOI: 10.13745/j.esf.sf.2025.8.63 Abstract ( 32 )   HTML ( 2 )   PDF (19588KB) ( 72 )   The current view on the formation and architecture of ocean crust is a cornerstone of the plate tectonics theory, yet this theory remains incomplete because several fundamental questions remain unresolved: What rocks actually constitute the oceanic crust? To what extent does its thickness vary? And what is the petrological nature of the crust-mantle boundary, i.e., the Mohorovičić discontinuity (Moho)? Much of our present understanding relies on assumptions that have never been rigorously tested, and some widely held misconceptions stem from selective interpretations of convenient hypotheses. One of the most pervasive is that the crust inferred from seismic velocities above the Moho is entirely of magmatic origin. Testing this idea was the primary motivation for “Project Mohole” (1957-1966), which aimed to drill through the entire ocean crust, penetrate the Moho, and sample the mantle. Although the project was terminated due to escalating technical challenges and rising costs, it laid the technological foundation for subsequent international ocean drilling programs. The central hypothesis, that the ocean crust above the Moho is entirely magmatic, remains untested. Because the global Moho lies at a nearly uniform depth of (6.0±1.0) km, Earth scientists have long assumed that this “seismic crust” corresponds to a magmatic crust of globally uniform thickness, independent of spreading rate. However, at slow- and ultraslow-spreading ridges, serpentinized mantle peridotites are exposed on the seafloor and in places dominate the crustal rock association, contradicting this view. To critically and objectively evaluate prevailing models of ocean ridge magmatism, it is therefore essential to drill through intact oceanic crust into the mantle. Since only fast-spreading ridges are likely to generate a complete magmatic crust, drilling should target geologically simple areas of the Pacific seafloor. With the decommission of the U.S. drillship JOIDES Resolution in late 2024, China’s D/V Meng Xiang has become the world’s only vessel currently capable of drilling through the ocean crust; its advanced technology and lower operational costs now make the longstanding goal of penetrating intact ocean crust a realistic prospect. Highlights: • Drilling through intact ocean crust is essential to resolve fundamental scientific questions and complete plate tectonics theory. • The assumption that “seismic crust” equals “magmatic crust” has misled Earth science for decades and must be corrected. • At slow- and ultraslow-spreading ridges, “seismic crust” is not purely magmatic but a chaotic mixture of magmatic rocks and serpentinized mantle peridotite. • Only direct drilling through intact crust in the Pacific can reveal the true petrological nature of the Moho. • China’s D/V Meng Xiang is now the world’s only drillship capable of penetrating the intact ocean crust, making this longstanding scientific dream achievable. Figures and Tables | References | Related Articles | Metrics

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Metallogenesis in collisional orogens: New insights and advances HOU Zengqian, YANG Zhiming, ZHANG Hongrui, WANG Rui, SONG Yucai, LIU Yan, ZHENG Yuanchuan, XU Bo, WANG Qingfei, LIU Yingchao 2025, 32(6): 179-209.  DOI: 10.13745/j.esf.sf.2025.4.49 Abstract ( 51 )   HTML ( 5 )   PDF (14781KB) ( 129 )   The theoretical framework for metallogenesis in collisional orogen belts is established, yet aspects like lithospheric architecture, deep mineralization processes, thermal regimes and ore genesis mechanisms require refinement. Interdisciplinary research and experimental simulations have greatly improved our understanding of collision-related metallogenesis in orogenic systems. Our research demonstrates that collision zones can be divided into two fundamental types: cold- and hot-collisions. The former includes the Pyrenean, Alpine, and Caledonian orogenic belts, while the latter includes the Zagros, Himalayan, and Variscan orogenic belts. The distinction between these regimes is primarily controlled by lithospheric thermal states and geodynamics. Pre-collision oceanic subduction modifies overlying lithosphere via mantle refertilization, juvenile lower crust formation, and crustal reworking, controlling Cu-Au-REE magmatism during subsequent collision. Asthenospheric upwelling drives crust-mantle exchange, providing deep metallogenic drivers. Mineral deposits within collisional orogen belts include porphyry Cu-Au deposits, Mississippi Valley-type (MVT) Pb-Zn deposits, carbonatite-associated REE deposits, orogenic Au deposits, and rare metal deposits related to leucogranites. The key factors for the formation of collisional giant porphyry Cu deposits include: moderately dipping continental subduction, vertical slab tearing, juvenile lower crust anatexis, and sulfides remobilization. The major factors for the formation of MVT Pb-Zn deposits include: fold-thrust belt, transpression or extension environments, basinal brine migration along detachments, and structural traps. The formation of carbonatite-associated REE deposits is related to the recycling of REE-enriched sediments via subduction, partial melting of carbonate-rich mantle sources, crustal magma evolution, and wall-rock metasomatism by saline melts. The main factors for the formation of orogenic Au deposits include: trans-lithospheric architecture and crust-mantle decoupling, accumulation and devolatilization of volatile-rich, mantle-derived ultrapotassic magma, and fluid flux along crustal-scale faults. Leucogranite-related rare metal deposits form through anatexis of fertile crust and magma differentiation facilitated via heat advenction along detachments. Metallogenic models for these deposit types are refined through comparative analysis. Figures and Tables | References | Related Articles | Metrics

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Fluid overpressure and its relationship with the genesis of metal deposits SU Shangguo, ZHANG Yanan, CHEN Xuegen, WANG Wenbo, LU Xin, LIU Cui, WANG Peng, WANG Yue, HAO Jinhua, YANG Zongfeng, XUE Song, CHEN Zhen, ZHANG Xinyan, LIU Yingtian, LI Mengtong, WANG Chengrui, CUI Xiaoliang, JIANG Xiao, ZHANG Bo, CUI Ying, LI Xiaowei, ZHAO Zhidan 2025, 32(6): 210-223.  DOI: 10.13745/j.esf.sf.2025.7.26 Abstract ( 29 )   HTML ( 2 )   PDF (21889KB) ( 72 )   Fluid overpressure plays a key role in the formation of metal deposits. This paper presents the first systematic summary of the definitions and types of fluid overpressure, reporting three representative deposits closely associated with this mechanism: the Oulbulage porphyry Cu-Au deposit (Inner Mongolia), the Jinchuan magmatic Cu-Ni-(Pt) sulfide deposit (Gansu Province), and the Wuan Nanminghe iron deposit (Hebei Province). In the Oulbulage deposit, key evidence includes shock-induced textures in anisotropic garnet and phengite paragenetic with sulfides, which formed at 14.5 kbar. For the Jinchuan deposit, evidence includes dense radial fractures within early-formed sulfides and olivine. In the Wuan deposit, evidence comprises radial fractures in early-stage magnetite and plagioclase porphyry with multiple feldspar phenocrysts. Notably, cryptoexplosive breccias are widespread in all three deposits. Finally, the authors propose a fluid-overpressure-based mineralization prediction model that could significantly reduce exploration costs, and discuss key scientific challenges and future research directions. Figures and Tables | References | Related Articles | Metrics

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Types, genesis, and implications of phlogopite in the Jinchuan Cu-Ni (Pt) sulfide deposit, Gansu Province, China YU Xianghui, LIU Cui, SU Shangguo, LIU Jixu, WANG Miao, GUO Xu, ZHOU Chenghao, GAO Yalin 2025, 32(6): 224-244.  DOI: 10.13745/j.esf.sf.2025.7.12 Abstract ( 13 )   HTML ( 1 )   PDF (40404KB) ( 39 )   The Jinchuan Cu-Ni-(PGE) sulfide deposit in China ranks as the world’s third largest and Asia’s largest deposit of its type, constituting a vital strategic resource reservoir. Significant debate persists regarding the genesis and metallogenic mechanisms of this deposit. Phlogopite is a common hydrous mineral within the rocks and ores of Jinchuan, and its relationships with rock-forming and metallic minerals can elucidate the interconnections between magmatism, mineralization, and fluid activity. Based on systematic microscopic observations of phlogopite coupled with elemental geochemical characteristics, this study identifies two distinct types within the Jinchuan deposit: Type A and Type B phlogopite. Type A phlogopite typically exhibits subhedral to euhedral habits with prominent deep yellowish-brown to colorless pleochroism. It predominantly occurs in barren to low-grade rocks, displaying symplectite/symplectic intergrowth with grains of olivine and pyroxene, indicating crystallization contemporaneously with these minerals from the mantle-derived ultramafic magma. Elemental analysis reveals its similarity to phlogopite found in kimberlites and lamprophyres from regions like the USA and South Africa. It was classified as ‘re-equilibrated’ phlogopite rather than primary magmatic phlogopite, signifying slight modification by mantle-derived melt-fluid flux. Type B phlogopite also commonly exhibits subhedral to euhedral habits but lacks pleochroism. It occurs in relatively higher-grade ores and more intensely altered rocks, developing between rock-forming minerals, sometimes in symplectite/symplectic intergrowth, and is often associated with metallic minerals or crosscut/replaced by them. It similarly displays symplectite/symplectic intergrowth with surrounding olivine and pyroxene grains, which are typically serpentinized or chloritized. Type B phlogopite was presumably also generated from magmatic crystallization. Elemental analysis indicates its resemblance to phlogopite in certain South African peridotites, classifying it as ‘neocrystallized’ phlogopite, which experienced stronger modification by mantle-derived melt-fluid flux and is associated with the main mineralization stage. Type A phlogopite formed under relatively high-temperature, high-Ti, and high-oxygen fugacity conditions characterized by low Si, Mg, and Na, but enrichment in Fe and Al, favoring the enrichment of metallic elements like Fe. Type B phlogopite formed through the modification of Type A phlogopite. Consistent with this, its elemental signature suggested that the modifying agent was a mantle-derived, Mg-, Si-, and Na-enriched, but Ti-, Fe-, and Al-depleted melt-fluid flux rich in volatile components such as Cl. During this process, rock-forming minerals absorbed Mg while releasing Fe, contributing to ore formation. The crystallization temperatures of phlogopite were calculated using Ti geothermometry. The continuous vertical variation in these crystallization temperatures likely represents prolonged, sustained melt-fluid flux, indicating that the Jinchuan ultramafic intrusion functioned primarily as a long-term conduit for melt-fluid flux. This persistent flux may be the key factor enabling the progressive enrichment of metallic elements and the formation of the deposit. Figures and Tables | References | Related Articles | Metrics

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Dicussion on geomorphic characteristics and formative causes of the Chinese mainland LI Tingdong, LIU Yong, WANG Miao, LIU Caiyun 2025, 32(6): 245-255.  DOI: 10.13745/j.esf.sf.2025.9.32 Abstract ( 42 )   HTML ( 13 )   PDF (8256KB) ( 82 )   China possesses the world’s most complex and distinctive topography, characterized by crisscrossing mountains and rivers, scattered lakes, swamps, and wetlands. Its landscape encompasses a complete range of natural elements: mountains, water bodies, forests, farmland, lakes, grasslands, deserts, and glaciers. Globally rare geomorphological spectacles include: the stepped terrain distribution, the towering Tibetan Plateau, the basin-and-range topography of the northwest, the vast deserts and the Gobi, the Loess Plateau of the north, the high mountain gorges of the Hengduan Mountains, and the diverse karst landscapes of Yunnan, Guizhou, Guangxi, and Sichuan. In this paper, we examine the distribution characteristics of China’s four topographic tiers and their relationship with the thickness of the Earth’s crust and lithosphere. Based on the coupling of geological genesis and physical geography, China’s mountain ranges are classified into six groups. The types, distribution, and characteristics of mountain ranges, rivers, lakes, and wetlands in China are analyzed. Furthermore, the paper discusses the geological background of the Chinese mainland and its role in shaping the natural geographical pattern, geomorphological landscapes, and ecosystems. Figures and Tables | References | Related Articles | Metrics

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Crustal structure and chemical composition of the Yingpan-Jinding-Beiya-Panlong transect in southeastern Tibetan Plateau ZHAO Zhidan, LEI Hangshan, BAI Zhiming, LIU Dong, WANG Zhenzhen, XU Bo, MIAO Zhuang, HOU Zengqian, MO Xuanxue 2025, 32(6): 256-275.  DOI: 10.13745/j.esf.sf.2025.10.50 Abstract ( 35 )   HTML ( 10 )   PDF (10284KB) ( 52 )   The structure, composition, and evolution of the continental crust represent one of the unique and defining characteristics of Earth, distinguishing it from other planets, and constitute one of the most significant scientific questions in modern Earth sciences. The continental crust plays an indispensable role in various spheres of the Earth system. It serves as a link that facilitates interactions between the lithosphere and surficial layers, and it represents a key site for studying geological processes such as crust-mantle material and energy exchange, magmatism, and mineralization. Research methods for investigating crustal structure, composition, and evolution primarily include probing the physical properties of deep crustal layers, studying deep-seated xenoliths brought to the surface by magmatic activities, analyzing ancient metamorphic basement rocks, and reconstructing magmatic processes. This study focuses on geological transect along a northwest-southeast trending crustal profile, extending from Yingpan in Lanping County, Yunnan Province, through Jinding in Lanping County and Beiya in Heqing County, to Panlong in Kunming, crossing the southeastern margin of the Tibetan Plateau and the western margin of the Yangtze Craton (referred to as the Yingpan-Panlong transect). Comprehensive research on the crustal structure and chemical composition has been conducted along a 50 km-wide transect and its adjacent areas. Structurally, the profile traverses the Lanping-Simao Block, passes through the Jinding and Beiya ore deposits, and extends eastward to the western margin of the Yangtze Craton. Using an existing geophysical depth profile, combined with geochemical and geochronological data from ancient metamorphic complexes, magmatic rocks, deep crustal xenoliths, and sedimentary cover rocks, this paper integrates data from geophysics, experimental petrology, and rock geochemistry. A crustal rock composition model for the geological units within the Yingpan-Panlong transect is proposed. The elemental and isotopic compositions of the upper, middle, and lower crust are estimated, with further discusses on the processes, crustal evolution, tectonic-magmatic activities, and mineralization in the Yingpan-Panlong transect and adjacent regions. Figures and Tables | References | Related Articles | Metrics

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Seismic shock induced formation of garnet coronas in eclogites: A perspective YANG Jianjun 2025, 32(6): 276-285.  DOI: 10.13745/j.esf.sf.2025.8.64 Abstract ( 25 )   HTML ( 4 )   PDF (6490KB) ( 32 )   High-pressure metamorphic rocks are distributed along fossil seismic faults in orogenic belts. It is generally believed that high-pressure metamorphism occurs due to fluid infiltration into deep faults within subducted slabs. However, studies of garnet coronas in eclogites show that these textures are characteristic of mineral growth through fluid-absent metamorphic reactions, reflecting disequilibrium during the formation of the eclogite assemblages. Phase diagram modeling of plagioclase pseudomorphs from various localities indicates that the high-pressure assemblages are H2O-undersaturated. On the other hand, the corona textures, like the stellate and micropoikilitic textures, suggest crystallization in rapid processes. The rapid growth of high-pressure minerals under H2O-undersaturated conditions requires unusually high diffusion and reaction rates, which can be explained by the effect of seismic shock waves. This is supported by accumulating evidence, here particularly referenced to data at Yangkou in the Chinese Su-Lu high-pressure metamorphic belt. Figures and Tables | References | Related Articles | Metrics

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Genesis of picrites in Sichuan Kuangshanliangzi: Constraints from olivine composition profile LUO Zhaohua 2025, 32(6): 286-302.  DOI: 10.13745/j.esf.sf.2025.7.27 Abstract ( 23 )   HTML ( 1 )   PDF (18800KB) ( 34 )   Picrite, as one of the evident manifestations of mantle plume activity, has garnered significant attention from researchers. However, many picrites contain olivine crystals exhibiting diverse crystallization habits, indicating the incorporation of xenocrystic olivine. Thus, characterizing the properties of olivine crystals is crucial for understanding the petrogenesis of picrites and their geological implications. This study presents compositional profile analyses of representative olivine grains from picrite sills in the Kuangshanliangzi Fe deposit, western Sichuan Province. We identify four distinct populations of olivine crystals: coarse-grained olivine, aggregate olivine, inclusion olivine, and spinifex olivine. Statistical analyses reveal that coarse-grained olivine exhibits a major peak at ~Fo84 and a minor peak at ~Fo77. Aggregate olivine shows a major peak at ~Fo92 and a minor peak at ~Fo77. Inclusion olivine (~Fo82) and spinifex olivine (~Fo77) each display a single peak, with the former being compositionally uniform and the latter exhibiting a steep compositional gradient. By combining compositionally similar coarse-grained and inclusion olivines, three distinct olivine populations are recognized in the Kuangshanliangzi picrites. These three types are also identified in Emeishan basalt and Dabanshan gabbro, suggesting that magma mixing is a ubiquitous process within the magmatic system of the Emeishan Large Igneous Province. Thermodynamic and fluid dynamic analyses indicate that aggregate olivine crystallized at ~4 GPa and ~1600 ℃, coarse-grained olivine (and inclusion olivine) mainly formed at ~2-2.5 GPa and ~1450-1550 ℃, and spinifex olivine crystallized at ~0.1 GPa and ~1200 ℃. Accordingly, spinifex olivine is interpreted to have crystallized from the carrier magma, whereas the other two types represent antecrysts transported from deeper magma chambers by the ascending melt. The NiO content of olivine generally increases with Fo content but exhibits four distinct secondary trends. These trends are characterized by modest increases in Fo accompanied by sharp rises in NiO, implying that the magma was a volatile-fluid-supersaturated system. Furthermore, the volumetric proportion of olivine varies markedly with elevation, and the occurrence of aggregate olivine suggests rapid magma ascent. Based on these findings, we propose that the Kuangshanliangzi magmatic system comprised at least three deep-seated magma chambers, and that the picrites represent mixtures of melt, crystals, and fluids rather than products of direct consolidation from a primitive picritic magma. Figures and Tables | References | Related Articles | Metrics

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The petrogenesi and deep dynamic implications of Middel-Late Neoproterozoic intermediate-mafic rocks on southwestern margin of Yangtze Block JIANG Xiuwei, LAI Shaocong, ZHU Yu, QIN Jiangfeng, ZHU Renzhi, LIU Min, YANG Hang, YANG Zhen, XUE Wenbin 2025, 32(6): 303-322.  DOI: 10.13745/j.esf.sf.2025.8.99 Abstract ( 23 )   HTML ( 1 )   PDF (18492KB) ( 31 )   The early-middle Neoproterozoic (ca.937-820 Ma) intermediate-mafic rocks in the western and southwestern margins of the Yangtze Block are generally considered to have formed in the metasomatized mantle source of subduction zone, but the middle-late Neoproterozoic (ca.820-710 Ma) intermediate-mafic rocks had remained controversial. Based on this, this paper presents systematic geochronology and geochemistry studies for the newly identified Taiyangzhai metamafic rocks and Liujiazhai amphibole gabbro on the southwest margin of the Yangtze Block to investigate their petrogenesis, mantle metasomatism and deep dynamic setting. Zircon U-Pb results show that the Taiyangzhai metamafic rocks and Liujiazhai amphibole gabbro were formed at (713 ± 6.3) Ma, and (712 ± 3.6) Ma, respectively. The Taiyangzhai metamafic dike has varying MgO (3.3%-7.2%), total Fe2O3 (8.3%-15.5%), CaO (11.3%-12.7%), high TiO2 (1.2%-2.6%) and low K2O (0.26%-0.33%), belonging to the tholeiite series. These rocks are slightly enriched in LREEs and depleted in HREEs, enriched in LILEs (Ba, Pb, Sr) and Ti, but depleted in HFSEs (Nb, Ta, Zr, Hf). They also have varied zircon εHf(t) (-1.9~+1.4) and positive whole-rock εNd(t) (+1.5~+3.9), showing decoupling characteristics. Combined with the high TiO2, Nb contents, Nb/Y (0.40-0.77) and Nb/Zr (0.13-0.18) ratios, the Taiyangzhai metamafic rocks originated from the mantle source modified by slab melts. Liujiazhai amphibole gabbro has high MgO (5.4%-7.2%), total Fe2O3 (14.5%-16.2%) and TiO2 (2.8%-3.4%), low Mg# values (40.0-49.6) and varying K2O (0.5%-2.3%). These amphibole gabbros are enriched in LREEs, depleted in HREEs, enriched in LILEs (Rb, Pb, Sr) and Ti, but depleted in HFSEs (Nb, Ta, Zr, Hf). These samples have varied zircon εHf(t) (-0.7~+5.9) and negative whole rock εNd(t) (-1.8~-1.3). Combined with high K2O, Nb ((3.4-6.2)×10-6) and Th ((0.4-1.2)×10-6) contents, as well as high Nb/Y (0.23-0.33) and Nb/Zr (0.08-0.11) ratios, suggest that they were derived from a mantle source modified by slab melt and sediment melt. These intermediate-mafic rocks formed in an extended back-arc setting. We propose that the western and southwestern margins of the Yangtze Block underwent a tectonic transition from subduction to back-arc extension from the early-middle to middle-late Neoproterozoic. Figures and Tables | References | Related Articles | Metrics

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The impact of volcanic eruptions on aviation safety MA Lin, YUAN Jieyan, GUO Zhengfu 2025, 32(6): 323-337.  DOI: 10.13745/j.esf.sf.2025.7.8 Abstract ( 16 )   HTML ( 1 )   PDF (4153KB) ( 9 )   Volcanic eruptions not only play a significant role in the Earth’s historical climate changes but also pose a serious threat to modern aviation safety. Explosive eruptions can eject volcanic ash into the atmosphere, where it is dispersed into the stratosphere by atmospheric circulation, directly endangering the safety of aircraft operations. With the successful delivery of China’s domestically produced large aircraft and potential exports to volcanically active Southeast Asia, research on the impact of volcanic ash on aviation safety holds critical practical significance for enhancing the global competitiveness of China’s aircraft and ensuring international flight safety. To address these challenges, this study aims to: (1) systematically summarize the physicochemical properties of volcanic ash; (2) comprehensively assess its interaction mechanisms with aircraft engines based on previous literatures; (3) conduct a case study using Indonesian volcanoes (Volcanic Explosivity Index VEI≥3, during 2010-2018) to evaluate the potential impact of volcanic hazards on the regional flight safety. Key findings include: (1) To prevent volcanic ash from entering aircraft engines, the monitoring and prediction of volcanic ash clouds are critical for flight route planning and selection. The accuracy of remote sensing monitoring is influenced by the composition, density, shape, and optical properties of volcanic ash. (2) Once volcanic ash is ingested by the engine, the deposition behavior of the particles influences the extent of damage to the engine. This process is affected by factors such as particle composition, density, shape, glass transition temperature, and viscosity. (3) The corrosive effect of deposited volcanic ash on thermal barrier coatings (TBCs) within aircraft engines is a critical factor affecting their service life. The associated degradation mechanism can be summarized as the infiltration of molten ash into the TBCs, followed by chemical reactions and the precipitation of new crystalline phases. Current protection strategies mainly include physical isolation to prevent infiltration, chemical sacrificial layer protection, melt crystallization protection, and the construction of special micro-nano surface structures. (4) Spatially, the viscosity of volcanic ash from VEI ≥ 3 eruptions in Indonesia between 2010 and 2018, calculated at 1200 ℃ under volatile-free conditions, are relatively similar (within 1-2 orders of magnitude), suggesting comparable spreading potential. Temporally, volcanic activity in this region during the same period posed a consistent threat to aviation safety, despite only minor fluctuations in intensity. Future efforts should focus on the following key points: (1) enhancing real-time volcanic ash monitoring technologies; (2) improving the algorithms and accuracy of dispersion models; (3) developing property-dependent deposition models for volcanic ash; (4) optimizing protective strategies for TBCs; and (5) advancing the construction of integrated experimental platforms for studying volcanic ash and aviation safety. These actions will safeguard China’s aircraft operations in volcanic zones and bolster its global market competitiveness. Figures and Tables | References | Related Articles | Metrics

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The tectonic setting of Jurassic-Cretaceous intrusive arcs and mineralization in Northeast China FENG Yanfang, LI Jize, JIN Xiao, $\boxed{\hbox{DENG Jinfu}}$, XIE Yalin, NIU Lu, XIONG Yinhong 2025, 32(6): 338-349.  DOI: 10.13745/j.esf.sf.2025.9.1 Abstract ( 22 )   HTML ( 2 )   PDF (7283KB) ( 44 )   During the Jurassic to Cretaceous period, the composite intrusive arcs in Northeast China can be divided into two intrusive arcs in the north and south. The north is the Great Xing’an Range-Lesser Xing’an Range intrusive arc and the south is the Zhangguangcai Range-Yanliao intrusive arc. The petrotectonic assemblage and ore deposits within the intrusive arcs of Northeast China show close spatial and temporal relations. In the northern side, the Great Xing’an Range-Lesser Xing’an Range intrusive arc shows obvious NE-trending horseshoe shapes, divided into three rings from the outside to the inside. Its rock assemblage in the order of Xidaweng-Daguokuidingzi intrusive arc (TTG suite) → Manzhouli-Lesser Xing’an Range intrusive arc (GG suite) → Yakeshi intrusive arc (G suite). In addition, the Zhangguangcai Range-Yanliao intrusive arc in the southern side consists of the Linjiang-Fusong-Suifenhe intrusive arc (TTG suite) → Ulanhot-Linxi-Chifeng-Chengde-Xianghuangqi intrusive arc (GG suite) → West Ujimqin Banner-Duolun intrusive arc (G suite). The corresponding tectonic settings are, in order, outer oceanic subduction zone → main oceanic subduction zone → inner oceanic subduction zone, and the ore mineralization is Au-Cu → Au and Cu-Mo → Mo. As the intrusive arcs mature, the corresponding ore minerals also differ, revealing the intense relationship between the compositional polarity of the intrusive arc and ore mineralization. The complex oceanic-oceanic plate convergence formed by the subduction of the western Mongolian-Okhotsk Ocean and the eastern Raohe-Hamatong Ocean, Izanagi Ocean, as well as the reactivation of the southern lithospheric discontinuous tectonic zone, promoted the Yanshanian metallogenic explosion in northeast China. Based on the exploration and research of the geological background of mineralization, it is predicted that Northeast China may become a large-scale base for gold, molybdenum, and copper mineral resources in the future. Figures and Tables | References | Related Articles | Metrics

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Spatio-temporal fractal structures in sedimentary sequences and their geological significance RUAN Zhuang, WANG Yueyun, CHANG Qiuhong, YU Bingsong 2025, 32(6): 350-366.  DOI: 10.13745/j.esf.sf.2025.8.67 Abstract ( 19 )   HTML ( 2 )   PDF (7552KB) ( 24 )   The formation of sedimentary sequences is controlled by tectonic activity, sea (lake)-level change, and climate evolution, resulting in complex multiscale spatiotemporal structures. While traditional methods struggle to reveal their intrinsic patterns, fractal theory offers a novel approach. Using the Shahejie Formation in the Jiyang Depression as a case study, this research systematically analyzes the spatiotemporal fractal structures of sedimentary sequences and their geological implications. First, the Hurst index quantifies temporal fractal characteristics to interpret sedimentary environment evolution. Second, power spectral density analysis reveals self-organized criticality (SOC) of the sedimentary system, and a filter-based technique for extracting long-range spatiotemporal correlations is proposed. Finally, fractal dimensions of pore structures are characterized to quantitatively evaluate their impact on reservoir permeability. Results demonstrate that: (1) The Hurst index quantifies long-term sedimentary trends; (2) SOC optimizes reservoir parameter analysis; (3) Fractal theory critically supports pore-throat structure evaluation. This study advances understanding of sedimentary complexity and provides new theoretical/methodological foundations for hydrocarbon exploration and reservoir assessment. Figures and Tables | References | Related Articles | Metrics

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The mineralogical footprint of carbon cycles during geopolymer construction materials development: Case study on Xiong’an green new materials DONG Guochen, WANG Hui, ZHANG Yihe, ZHANG Na, LIU Yanbin, XIE Bingjing, JING Yi, MO Jun 2025, 32(6): 367-376.  DOI: 10.13745/j.esf.sf.2025.8.68 Abstract ( 15 )   HTML ( 5 )   PDF (7863KB) ( 7 )   Carbon cycle and emissions have been receiving widespread attention recently in daily human activity. This study, focusing on the new material production process in Xiong’an New District, has conducted field investigations and laboratory measurements on the carbon composition, content, and forms in mine tailings, construction waste, and products at 3-day, 7-day, and 28-day curing periods. The variation in carbon content and its transformation across different stages of the product lifecycle were studied, and the quantities of carbon emission and absorption were estimated. It is found that the treatment process of mine tailings and construction waste releases only CO2 gas, with no variation in solid and liquid forms of carbon. Conversely, the solidification process of the new material slurry sequesters CO2. Overall, the whole production process absorbs more CO2 than it releases, acting as a carbon sink process. Preliminary estimates indicate that 1 m3 of the new construction material absorbs 21.87 kg (approximately 11.05 m3) of CO2 gas during production. As truly green materials, their application will demonstrate significant economic potential and create a wide range of social benefits. Figures and Tables | References | Related Articles | Metrics

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Geochemistry and petrogenesis of Miocene dikes in the Shigatse area, southern Tibet LI Lichan, ZHAO Zhidan, TANG Yan, LIU Dong, WANG Zhenzhen, WANG Qing, ZHU Dicheng, MO Xuanxue 2025, 32(6): 377-395.  DOI: 10.13745/j.esf.sf.2025.10.57 Abstract ( 20 )   HTML ( 2 )   PDF (16118KB) ( 27 )   Dikes are small-scale intrusions with mineral compositions similar to those of contemporaneous magmatic rocks. The Miocene dikes in the southern Gangdese exhibit diverse modes and ages, recording information pertaining to both magmatism and tectonics. This study focuses on dikes in Xaitongmoin County, Shigatse, combining geochemistry, geochronology, and Lu-Hf isotopes to elucidate their petrogenesis, structural characteristics, source properties, and geodynamic implications. Zircon U-Pb dating indicates that the dikes were emplaced between 15.2 and 14.5 Ma, identifying them as post-collisional Miocene intrusions. Geochemically, these dikes exhibit high MgO, high Mg#, and elevated concentrations of incompatible elements. They also show adakitic characteristics, including high Sr, low Y and Yb, high Sr/Y ratios, enrichment in light rare earth elements (LREE) and large ion lithophile elements (LILE), and depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE). Based on integrated geochemical and structural features, we propose a genetic model: delamination of the lower crust triggered gravitational collapse of the southern Lhasa terrane, leading to superimposed N-S and E-W extensional structures. The delaminated lower crust underwent partial melting upon reaching the asthenosphere and incorporated mantle components. The resulting melts ascended along the normal faults and rifts formed by extension, ultimately forming the Shigatse diorite porphyry dikes with two spatial orientations emplaced in close temporal proximity. Figures and Tables | References | Related Articles | Metrics

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Earth Science in the Era of Foundation Models: How AlphaEarth is Reshaping Quantitative Geoscience CHENG Qiuming, YANG Yilin, ZHOU Yuanzhi, ZHANG Yuanzhi 2025, 32(6): 396-410.  DOI: 10.13745/j.esf.sf.2025.9.68-en Abstract ( 24 )   HTML ( 2 )   PDF (7751KB) ( 20 )   Since the beginning of the 21st century, advances in big data and artificial intelligence have driven a paradigm shift in the geosciences, moving the field from qualitative descriptions toward quantitative analysis, from observing phenomena to uncovering underlying mechanisms, from regional-scale investigations to global perspectives, and from experience-based inference toward data- and model-enabled intelligent prediction. AlphaEarth Foundations (AEF) is a next-generation geospatial intelligence platform that addresses these changes by introducing a unified 64-dimensional shared embedding space, enabling—for the first time—standardized representation and seamless integration of 12 distinct types of Earth observation data, including optical, radar, and lidar. This framework significantly improves data assimilation efficiency and resolves the persistent problem of “data silos” in geoscience research. AEF is helping redefine research methodologies and fostering breakthroughs, particularly in quantitative Earth system science. This paper systematically examines how AEF’s innovative architecture—featuring multi-source data fusion, high-dimensional feature representation learning, and a scalable computational framework—facilitates intelligent, precise, and real-time data-driven geoscientific research. Using case studies from resource and environmental applications, we demonstrate AEF’s broad potential and identify emerging innovation needs. Our findings show that AEF not only enhances the efficiency of solving traditional geoscientific problems but also stimulates novel research directions and methodological approaches. Figures and Tables | References | Related Articles | Metrics

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A preliminary discussion on the mineral exploration system theory: Control-mapping exploration system architecture for hydrothermal deposits HAN Runsheng, ZHANG Yan 2025, 32(6): 411-437.  DOI: 10.13745/j.esf.sf.2025.4.6 Abstract ( 30 )   HTML ( 4 )   PDF (18669KB) ( 67 )   Under the growing global demand for mineral resources, the efficient exploration has become a critical pathway to ensuring resource security. With the sharp rise in mineral consumption, the deep-earth exploration and geophysical-geochemical methods, along with transformative innovations in AI and information technology, are crucial for establishing a theoretical framework for rapid and precise mineral exploration systems. This framework especially targets extensively distributed hydrothermal deposits. Hydrothermal deposits exhibit several key characteristics, including (1) pronounced structural controls, (2) polygenetic fluid sources, (3) multistage metallogenic processes, (4) heterogeneous orebody geometries, (5) diversified mineral assemblages, (6) intensive hydrothermal alteration halos, (7) exceptional economic significance, and (8) formidable exploration challenges. The hydrothermal deposits are genetically linked to tectonic dynamics, magmatic-hydrothermal activities or geothermal systems. Thus, these deposits are often governed by tectonic setting, fluid properties, and ore-forming physicochemical conditions. Fundamentally, the ore-forming process is driven by the dynamic mechanisms of hydrothermal fluid migration and mineral precipitation. The ore deposits result from tectonically driven metal activation, fluid migration, and the coupling between tectonic terminals (pathways) and fluid terminals (traps) during mineralization. For decades, deposit models have played a critical role in mineral exploration practices. However, the theory and technology of mineral exploration based on these models still face significant challenges in meeting the demands of deep-seated ore prospecting. To address these challenges, this study synthesizes both domestic and international research findings in mineral exploration,combined with extensive field experience from our research team. Building on the conceptual framework of mineral exploration systems, our team applies the “Mapping” concept to elucidate the control-response relationships among three interrelated system: the Metallogenic Tectonic System (MTS), the Hydrothermal Metallogenic System (HMS), and the Exploration Information System (EIS). Then, leads to the development of a preliminary architecture for the Control-Mapping Exploration System Theory of Hydrothermal Deposits (HD-CMSA) is established, emphasizing the tripartite synergy among the MTS, HMS, and EIS. When building on this architecture and working from the four dimensions of time, space, material, and energy, this study identifies and addresses key scientific and technological challenges in the Theoretical Framework of Control-Mapping Systems (TFCMS) and the Methodological Framework of Control-Mapping Systems (MFCMS). Finally, this study elucidates the multiscale control of the MTS over ore districts, ore fields, and deposits, as well as the multiscale mapping relationships between the geophysical-geochemical anomaly information system and both the MTS and the HMS. Moreover, the effectiveness of the “Exploration Trilogy” technical workflow, applied at multiple scales (ore district to ore field to deposit), is validated through case studies. This research presents a novel theoretical paradigm for predicting deep-seated concealed deposits or orebodies and advancing mineral exploration. The research can significantly enhance the efficiency of mineral resource exploration and evaluation, thereby facilitating the New Round of Strategic Action for Mineral Exploration breakthroughs. Figures and Tables | References | Related Articles | Metrics

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Formation environment and hydrocarbon-generating potential of Carboniferous source rocks in the Gucheng Sag, Junggar Basin GONG Deyu, HAN Yan, YANG Bin, ZHANG Hua, ZHOU Chuanmin, WANG Shaoqing, WANG Ruiju, MIAO Yihao 2025, 32(6): 438-456.  DOI: 10.13745/j.esf.sf.2025.7.5 Abstract ( 17 )   HTML ( 1 )   PDF (17091KB) ( 9 )   The Carboniferous petroleum system is one of the most significant gas exploration domains in the Junggar Basin. In recent years, substantial source rocks and natural gas have been discovered in the Upper Carboniferous Bashan Formation in the eastern Fukang Sag of the southeastern Junggar Basin. The Gucheng Sag, also located in the southeastern Junggar Basin, shares a similar Carboniferous tectonic and paleogeographic background with the eastern Fukang Sag. However, the Carboniferous source rocks in the Gucheng Sag are poorly understood. Based on stratigraphic chronology, sedimentary petrology, organic geochemistry, and basin simulation, we determined the age of the Carboniferous source rocks in the Gucheng Sag. We analyzed their sedimentary environment and hydrocarbon generation potential, and delineated the distribution of large-scale effective source rocks. The results indicate that the Carboniferous source rocks in both the Gucheng Sag and eastern Fukang Sag were deposited during the early Late Carboniferous (Moscovian-Bashkirian Stage), corresponding to the Bashan Formation. The Bashan Formation in both sags is characterized by a fan delta succession. However, the Gucheng Sag exhibits steep gradients and narrowly spaced sedimentary sub-environments, with swamps rarely developed on the delta plain and sedimentary gravity flow deposits commonly occurring at the delta front. The Bashan source rocks in the Gucheng Sag are dominated by Type III kerogen with medium organic matter abundance. They reached the hydrocarbon generation threshold in the late Late Permian, and the area currently within the main oil-generating window covers 727 km2. In contrast, the Bashan source rocks in the eastern Fukang Sag show significant variations in organic type, abundance, and maturity. Those in the Gucheng Sag were deposited in a reducing brackish environment with organic matter input dominated by bacterial and algal sources, whereas the eastern Fukang Sag samples display greater variations in redox conditions, salinity, and biogenesis, dominated by terrestrial organic sources. The Bashan source rocks in the Gucheng Sag generally exceed 50 m in thickness, with thickness centers (>100 m) in the north and south. Their hydrocarbon generation intensity typically exceeds 2.0 million tons/km2, covering an area of 890 km2. These results enhance the understanding of the Carboniferous petroleum system in the Junggar Basin and provide a foundation for accelerating petroleum exploration in the study area. Figures and Tables | References | Related Articles | Metrics

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Genesis mechanisms and enrichment factors of crust-mantle mixed source helium: Taking helium in deep natural gas in the Songliao Basin as an example CHEN Yue, TAO Shizhen, YANG Yiqing, LIU Xiangbai, LUO Xia, WANG Ying, LIU Guodong, CHEN Yanyan, GAO Jianrong, LI Chunbai, FU Li, WANG Lei 2025, 32(6): 457-472.  DOI: 10.13745/j.esf.sf.2024.5.28 Abstract ( 12 )   HTML ( 4 )   PDF (7191KB) ( 27 )   This study investigates the origin and enrichment of crust-mantle mixed helium in natural gas of organic-inorganic hybrid origin within the Songliao Basin, eastern China. The research is framed within the tectonic dynamics of eastern China and an analysis of the basin’s unique geological conditions for basin formation, hydrocarbon generation, accumulation, and associated resource formation. Focusing on natural gas from the deep Xujiaweizi and Changling faults, we examine large intracontinental rift basins developed on a Paleozoic fold basement during Mesozoic and Cenozoic subduction of the Pacific Plate. These basins feature deep-seated faults and magmatic activities connecting to the mantle, with medium-acidic, U-Th-rich magmatic rocks present in both the basement and sedimentary cover. The origin and distribution of deep natural gas and associated helium are highly complex. Natural gas exhibits varying degrees of organic-inorganic hybrid genetic characteristics, with occurrences of inorganic hydrocarbon gases and CO2 gas reservoirs (or shows in individual wells). Based on comprehensive analysis of previous data, new measurements of natural gas components and noble gas isotopes presented here, and analysis of helium genesis mechanisms and enrichment factors from individual well data, this study demonstrates that the deep gas fields (reservoirs/wells) in the Songliao Basin exhibit the following characteristics: (1) Noble gas isotope geochemistry (3He/4He) reveals characteristics of crust-mantle mixed helium, with CO2 content showing a positive correlation with the proportion of mantle-derived helium, indicating that CO2 acts as the carrier gas for the secondary migration of mantle-derived helium; (2) The volcanic rocks and granites developed in the deep Lower Cretaceous Yingcheng Formation and Huoshiling Formation are potential sources for helium, and helium mainly occurs in the Lower Cretaceous Denglouku Formation and Yingcheng Formation; (3) Natural gas wells proximal to the main faults within the fault depressions exhibit higher helium content than those located distally; (4) The high-quality regional seals of the First and Second Members of the Quantou Formation, as well as the seals of the Second Member of the Denglouku Formation, the Fourth Member of the Yingcheng Formation, and the First and Second Members of the Shahezi Formation, provide favorable seals for helium preservation. This study elucidates the enrichment factors and distribution patterns of crust-mantle mixed helium within natural gas of organic-inorganic hybrid origin in the Songliao Basin, providing theoretical support for the exploration and discovery of helium-enriched areas. Figures and Tables | References | Related Articles | Metrics

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The characteristics of global podiform chromites and prospecting potential in China YUAN Jianguo, ZHANG Wanyi, PANG Zhenshan, LI Guangxu, CHEN Gang, GUO Lingjun, ZHAI Qingguo, TENG Xuejian, WAN Yu, SHI Chunyuan 2025, 32(6): 473-496.  DOI: 10.13745/j.esf.sf.2025.5.32 Abstract ( 36 )   HTML ( 3 )   PDF (12581KB) ( 50 )   Chromite is an important strategic metal mineral, which has two genetic types: stratiform and podiform. The results show that the podiform chromite is mainly distributed in the Tethys, PaleoAsian Ocean, Pacific Rim and Gondwana metallogenic regions, especially the Tethys and PaleoAsian Ocean metallogenic regions. In these two metallogenic regions, many large to super-large podiform chromite deposits have been found abroad, while in the same tectonic belt within China, the chromite deposits found are small and scattered. The comparative analysis shows that the potential of chromite resources in China has not been fully tapped, and the chromite prospecting confidence should be enhanced, focusing on the areas such as Sartokay in Xinjiang, Yarlung Zangbo River and Bangong Lake-Nujiang River in Tibet, Erlian-Hegenshan in Inner Mongolia and Dadaoerji in Gansu Province, so as to improve prospecting ideas, optimize prospecting technology and methods, and speed up drilling verification. End the long-term situation of totally relying on import from abroad as soon as possible. Figures and Tables | References | Related Articles | Metrics