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Mesozoic intraplate metallogenesis in South China HU Ruizhong, GAO Wei, FU Shanling, SU Wenchao, PENG Jiantang, BI Xianwu Earth Science Frontiers    2024, 31 (1): 226-238.   DOI: 10.13745/j.esf.sf.2024.1.9 Abstract （1610）   HTML （22）    PDF（pc） （6348KB）（399）       Knowledge map    Save Intraplate metallogenesis is a significant global scientific issue. The South China block is renowned for its large-scale mineralization occurring far away from active continental margins during the Mesozoic. It formed a low-temperature metallogenic province of gold, antimony, lead, and zinc deposits in the west (Yangtze block) and a high-temperature metallogenic province of tungsten-tin polymetallic deposits in the east (Cathaysia block), making it an ideal natural laboratory for intraplate metallogenesis studies. The two metallogenic provinces of South China have long been considered distinct systems due to their spatial separation. However, our research revealed that the low-temperature mineralization in the west (230-200 Ma and 160-130 Ma) occurred simultaneously with the high-temperature mineralization in the east, and has similar geochemical fingerprints to the latter. Both types of mineralization were probably driven by the Indosinian intracontinental orogeny and Yanshanian asthenosphere upwelling beneath South China. Therefore, there is a genetic linkage between the two metallogenic provinces, and together they constitute a giant polymetallic domain spreading planarly under intraplate setting. The current distribution status of the low- and high-temperature mineralization types in the west and east is controlled by the eastward increase of denudation degree in South China after ore formation. It is predicted that there may exist high-temperature W-Sn polymetallic deposits beneath the eastern region of the low-temperature metallogenic province. A new intraplate metallogenesis model for South China was established. The significant features of the new model include metallogenesis occurring within preexisting weakness zones of lithosphere, continental crust serving as sources for metallogenic elements, and coexistence of high- and low-temperature mineralization exhibiting a distinct planar distribution. The model differs from the metallogenic mechanism in continental plate margins. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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International Continental Scientific Drilling Project of the Songliao Basin: Terrestrial Geological Records of the Cretaceous Dinosaur Age Earth Science Frontiers    2024, 31 (1): 511-534.   DOI: 10.13745/j.esf.sf.2024.1.4-en Abstract （1344）   HTML    PDF（pc） （5783KB）（133）       Knowledge map    Save Over the past century global temperatures continue to rise, and the Earth may enter a greenhouse period in the future with no ice at the poles. The Cretaceous was a typical greenhouse period in deep time, and thus understanding the Cretaceous climate is significant for interpreting past climate changes and predicting future trends. The International Continental Scientific Drilling Project of the Songliao Basin is the world's first continental scientific drilling project to penetrate the Cretaceous continental strata within the framework of the ICDP. This project is aimed to investigate Cretaceous terrestrial climate and environmental changes, and to explore the mechanisms of massive terrestrial organic matter accumulation and enrichment. Spanning 16 years, this project achieves a continuous and complete 8187-meter core with a recovery rate exceeding 97%, establishes a high-precision chronostratigraphic framework for the Cretaceous continental strata in the Songliao Basin, reconstructs multi-temporal-scale terrestrial climate cycles and climate events during the Cretaceous period, reveals the mechanisms of Cretaceous sea-level fluctuations, and confirms marine incursion events in the Songliao Basin. The International Continental Scientific Drilling Project of the Songliao Basin has promoted global collaboration among geologists to study Cretaceous greenhouse climates, leading to a series of high-impact research achievements. It has provided crucial scientific support for the sustainable development of oil and gas exploration in the Songliao Basin, and has generated significant social benefits and substantial international and domestic influence. The International Continental Scientific Drilling Project of the Songliao Basin represents a milestone stage in exploring deep-time Earth, and it is foreseeable that in the future, humans will continue enhancing the understanding of deep-time climate and environmental evolution with the aid of scientific drilling. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Developing structural control models for hydrothermal metallogenic systems: Theoretical and methodological principles and applications YANG Liqiang, YANG Wei, ZHANG Liang, GAO Xue, SHEN Shilong, WANG Sirui, XU Hantao, JIA Xiaochen, DENG Jun Earth Science Frontiers    2024, 31 (1): 239-266.   DOI: 10.13745/j.esf.sf.2024.1.40 Abstract （1315）   HTML （25）    PDF（pc） （5137KB）（722）       Knowledge map    Save A defining feature of a hydrothermal metallogenic system (HMS) is strong structural control on ore mineralization. A systematic analysis of the geometry, kinematics, thermodynamics, and rheology of multiscale ore control structures is crucial for understanding the genesis of HMSs and for ore prospecting. The main challenges include: transitioning from static to multiscale spatiotemporal analysis of the 4D dynamical system involving ore-control structural frameworks, permeability structures, ore-forming fluid pathways, and mineralization deformation networks; identifying key influencing factors of fluid pathways that control ore deposition; and unraveling the mechanism of structure-fluid coupling control of ore formation and localization. This study presents the theoretical and methodological principles and application for developing structural control models for HMSs in the following aspects. (1) The theoretical core. It states that fluid, not structure, is at the core of a structural control model. Fluid flow and ore formation within a hydrothermal system are influenced by the fault zone architecture and permeability structure, where permeability, in linking fluid flow and fluid pressure variation, is key to understanding ore control structures. (2) Stress and pressure dynamics. It considers that differential stress and fluid pressure difference result in diverse combinations of ore control structures, while differences in regional stress field and host rock strength result in variations in mineralization type. (3) Growth of fluid pathways. It considers that fluid pathways initiate from isolated microfractures within the upstream host rocks of overpressured fluid reservoirs which evolve along the direction of the steepest pressure gradient to form new extended fractures through growth and interconnection. These extended fractures eventually interconnect to form fluid pathways. As ore deposition takes place during brief periods of high fluid flux when repeated fault sliding induces rapid changes in fluid pressure, flow velocity, and stress, rapid pressure release—caused by a disruption of dynamic equilibrium in the fluid system due to fluid pathways growth—is a key factor driving metal precipitation. (4) Integrated research. Methodology involves integrating macro and microscopic examination of ore control structures, integrating geological history and stress analysis, combining local and regional analyses, adopting shallow and deep perspectives, and employing a multidisciplinary, multiscale approach to study various ore-controlling factors. (5) Geological mapping. Methodology involves using structure-alteration-mineralization network mapping to characterize alteration-mineralization rock blocks in terms of geometric parameters for ore control structures (such as type, shape, size, occurrence, spacing), and performing quantitative analyses (such as topological analysis of hydrothermal vein-fracture systems, 3D geometric analysis of ore bodies) to determine ore-control structural frameworks and permeability structures and reveal the connectivity of mineralization deformation networks and their ore-forming potential. (6) Numerical modeling. Methodology involves developing geological models, selecting appropriate thermodynamic parameters and dynamic boundary conditions, and utilizing methods such as HCh and COMSOL to perform quantitative simulation of spatiotemporal variations in fluid flow, heat-mass transfer, stress deformation, and chemical reactions during ore formation. This is an effective approach to unveil the mechanism of ore formation controlled by structure-fluid coupling and ore localization pattern, predict ore-forming centers, and identify mineral exploration targets. Based on the above principles, this paper proposes a research methodology for model building, focusing on deriving metallogenic models and ore deposition patterns based on structure-fluid coupling control. Briefly, hydrothermal veins-fracture systems and structure-alteration-mineralization networks are selected as primary research subjects. Research methods include geometric description, kinematic assessment, rheological/dynamic analyses, and thermodynamic synthesis, seeking to delineate ore-control structural frameworks, identify mineralization centers, trace the developments of ore-forming fluid pathways and various mineralization styles, and reveal the spatiotemporal evolution patterns of permeability structures. Additionally, the causal relationship between tectonic reactivation and ore localization is explored. Finally, a metallogenic model based on structure-fluid coupling is constructed to support strategic mineral exploration. This research methodology was applied for mineral prediction in the Jiaojia gold field, Jiaodong Peninsula; its validity and effectiveness were tested and approved. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Interactions between clay minerals and microbes: Mechanisms and applications in environmental remediation DONG Hailiang, ZENG Qiang, LIU Deng, SHENG Yizhi, LIU Xiaolei, LIU Yuan, HU Jinglong, LI Yang, XIA Qingyin, LI Runjie, HU Dafu, ZHANG Donglei, ZHANG Wenhui, GUO Dongyi, ZHANG Xiaowen Earth Science Frontiers    2024, 31 (1): 467-485.   DOI: 10.13745/j.esf.sf.2024.1.19 Abstract （1273）   HTML （19）    PDF（pc） （3834KB）（321）       Knowledge map    Save Clay minerals and microbes co-exist in natural environments, and their interaction can influence energy flow and element cycling. Clay minerals provide microbes with physical/chemical protection against environmental stress, as well as nutrients boosting their metabolism. Structural iron in clay mineral is an important electron acceptor/donor for iron-reducing/oxidizing microbes, where in redox environment many iron-reducing/oxidizing bacteria can reduce/oxidize structural Fe(III)/Fe(II) in clay minerals as they gain energy from the redox process. During such process redox microbes can alter the atomic structure of clay minerals through dissolution, transformation and precipitation where secondary minerals are also produced. Clay mineral-microbe interaction plays important role in geochemical cycling of carbon, nitrogen, silicon and phosphorus. Clay mineral can reduce organic carbon bioavailability and mineralization rate through adsorption; whereas under fluctuating redox conditions it can activate molecular oxygen to produce reactive oxygen species to degrade organic matters thus increasing their bioavailability. Through adsorption clay mineral can also reduce extracellular enzyme activity in organic matter degradation. Microbes can affect nitrogen cycling in clays by coupling iron oxidation (reduction) with nitrate reduction (ammonia oxidation) in clay. Phosphorus adsorption on clays and silicon release during weathering can affect the metabolic activity of microbes. Clay mineral-microbe interaction can find a wide range of application in heavy metal stabilization, organic pollutant degradation and sterilization. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Long-range effects of mid-ocean ridge dynamics on earthquakes, magmatic activities, and mineralization events in plate subduction zones CHENG Qiuming Earth Science Frontiers    2024, 31 (1): 1-14.   DOI: 10.13745/j.esf.sf.2024.1.23 Abstract （1253）   HTML （60）    PDF（pc） （6135KB）（534）       Knowledge map    Save The deep processes of plate subduction zones are closely related to extreme geological events that occur in continental magmatic arcs. The processes of plate subduction and mountain building can lead to events such as earthquakes, magmatic activity, and mineralization. The occurrence of these extreme events is closely related to factors such as crust-mantle interaction, mantle wedge formation, partial melting of the lithosphere, and tectonic magmatism during subduction. However, little is known about the long-term and long-range effects of heterogeneities or innate defects in the newly formed crust at mid-ocean ridges on the extreme events described above. During the formation of new crust at mid-ocean ridges, due to factors such as plate expansion, pressure reduction, and asthenospheric material upwelling, the temperature of the new crust increases, pores and cracks develop, the density decreases, and the structure is complex. Therefore, the newly formed crust has heterogeneities in density, strength, temperature, thickness, etc. These crustal differences will influence and decide the behavior of plates during expansion and subduction, with long-term effects on events such as earthquakes, volcanoes, and mineralization caused by subduction. Analyses of the Pacific subduction and the Andes orogen have revealed that sudden changes in plate movement speed, plate subduction angle, plate slab tearing, lithospheric thickness, Moho depth, etc., have long-range effects on the spatiotemporal distribution of earthquakes, volcanoes, and porphyry copper deposits. These understandings are of great significance for predicting the spatiotemporal distribution of extreme geological events in plate subduction and collision zones. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Geothermal resources exploration and development technology: Current status and development directions SUN Huanquan, MAO Xiang, WU Chenbingjie, GUO Dianbin, WANG Haitao, SUN Shaochuan, ZHANG Ying, LUO Lu Earth Science Frontiers    2024, 31 (1): 400-411.   DOI: 10.13745/j.esf.sf.2023.9.25 Abstract （1246）   HTML （24）    PDF（pc） （4567KB）（352）       Knowledge map    Save Geothermal energy is an important non-carbon-based renewable energy with several advantages such as local availability, deployment stability/reliability, and low carbon emissions. It represents an unique resource for ensuring energy security and promoting green, low-carbon transition. Since the beginning of the 21st century China's geothermal industry has experienced rapid development, making it a world leader in direct geothermal use, particularly in direct utilization of medium and deep geothermal resources for heating. However, as the majority of China's land regions are within tectonic plates and the country lacks medium-high temperature geothermal resources in the energy-intensive regions in the east, the development of geothermal power generation in China has been slow. In this study, the main distribution characteristics and development status of geothermal resources in China are discussed, and the current geothermal exploration, development, and utilization technologies are summarize, which involve exploration techniques based on geothermal genesis models, site selection evaluation techniques, thermal storage description technologies, sustainable development techniques, and key engineering technologies related to “heat extraction without water consumption.” In order to increase the geothermal energy market size amid energy transition, it is necessary to tap into deep geothermal resources with higher quality and broader applications in the future. Recommendations from this study include continuing strengthening basic theoretical research and technical innovation, inventorying China's deep geothermal resources as early as possible, addressing key technology challenges (e.g., high-temperature drilling/completion, complex-structure well, deep thermal storage retrofitting, underground heat exchange, EGS), and promoting synergistic development of “geothermal plus” multisource energy. Efforts should also be made to increase construction of demonstration projects and foster application market development. At the same time, it is essential to establish a sound policy and regulatory system, increase policy support, strengthen management and supervision, and create a favorable environment for the healthy, standardized, and sustainable development of the geothermal industry. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Biogeochemical cycles in the Anthropocene and its significance LIU Congqiang, LI Siliang, LIU Xueyan, WANG Baoli, LANG Yunchao, DING Hu, HAO Liping, ZHANG Qiongyu Earth Science Frontiers    2024, 31 (1): 455-466.   DOI: 10.13745/j.esf.sf.2024.1.26 Abstract （1237）   HTML （18）    PDF（pc） （1322KB）（261）       Knowledge map    Save The Earth has entered a new geological epoch - the “Anthropocene”, wherein humanity has become the principal driving force behind global changes. These activities, through their transformative effect on biogeochemical processes and the cycles of essential biogenic elements, are exerting a direct and indirect impact on the Earth's ecosystem's vital functions, thereby posing numerous challenges to human well-being and the sustainability of our development. Drawing from the latest advancements in Earth System Science, this paper offers an exhaustive review of the Anthropocene's global change dynamics, the pivotal role and evolving patterns of biogeochemical cycles across various Earth spheres, and their transformation. It specifically delves into the repercussions of human actions, including the exploitation of natural resources and shifts in production and consumption paradigms, on these biogeochemical cycles and their consequent climatic, ecological, and environmental effects. This study underscores the necessity of a holistic grasp of the complex, multi-scaled biogeochemical cycle processes propelled by human activities and their ecological and environmental ramifications. It advocates for an integrated approach in research, amalgamating natural and social sciences, anchored in the principles and methodologies of Earth System Science, aimed at deciphering the intricacies of the Anthropocene's social-ecological systems. Conclusively, the paper delineates strategic research areas and trajectories for investigating the Anthropocene's biogeochemical cycles, emphasizing the critical need to resolve the intricate scientific challenges posed by these cycles in an epoch deeply influenced by human endeavors and climatic change. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Evolutionary geodynamics and remote effects of the uplift of the Qinghai-Tibet Plateau LIU Demin, WANG Jie, JIANG Huai, ZHAO Yue, GUO Tieying, YANG Weiran Earth Science Frontiers    2024, 31 (1): 154-169.   DOI: 10.13745/j.esf.sf.2024.1.146 Abstract （1212）   HTML （25）    PDF（pc） （5959KB）（464）       Knowledge map    Save The formation of the Qinghai-Tibet Plateau as Earth's “third pole” is the most distinguishing and significant result of neotectonic movements under Earth's rhythmic tectonic events since the Cenozoic era. The characteristics and importance of tectonic landforms in the region, the tectonic regime of the plateau, the evolutionary dynamics and the impact and long-range effects of the plateau uplift on peripheral basins and even the entire Chinese subcontinent have been the focus of academic attention to this day. This article redefines the range of tectonic landforms of the Qinghai-Tibet Plateau, and establishes the importance of the plateau uplift to global tectonics. According to the results, the remote effects of the Qinghai-Tibet Plateau and its south/north extension spans across Asian along 105°E longitude, in general, reaching the Arctic Ocean in the north and reaching the Pacific Ocean in the south. Hence, this article uses the large circle of 105°E longitude as the dividing line between the Eastern (to the east of the line) and Western Hemispheres. The Qinghai-Tibet Plateau is location at the intersection of the world's largest and most important north-south and east-west structures, and the Pamir Plateau is the backbone of regional structures. The Qinghai-Tibet Plateau originates from the Pamir Plateau, a thermal dome during the Indosinian period, which later transformed into an abnormal gravity column with a diameter of 200 km and sank 600 km vertically to form a vertical open-close structure to be completed in the Cretaceous period. From the Pamir Plateau at the center there are three horizontal compressional-extensional tectonics expanding to the east, and one to the west. During the Xishan period, the Pamir Plateau also experienced igneous intrusion, while its Cretaceous structure remained largely undeformed. In the Paleogene, the India-Asia collision formed the magnificent Himalayan orogenic belt that was first compressed and then uplifted. Expanding northward from the Himalayas three mantle branches rose during the Quaternary, causing the entire Qinghai-Tibet Plateau to rise. According to the deep dynamics model established in this article, the early stage of the plateau uplift is manly manifested by centrifugal movement of geological bodies in vertical direction and extensional movement in horizontal direction, and the later stage of mainly compression, is manifested by centripetal vertical movement and horizontal compression movement of geological bodies. In terms of driving force, thermal energy is the main driving force in the early stage and gravity potential energy in the later stage. The uplift of the Qinghai-Tibet Plateau is the most remarkable geological event of the Cenozoic era within the Eurasian continent. It has direct impacts on the shallow lithosphere and the crust's surface layer through short- and long-range effects, affecting topography, energy and natural resources, ecology, environment, and geohazards closely related to human survival and development. Under the remote effects of the Qinghai-Tibet Plateau uplift the Baikal Lake Rift, the Fenwei Rift, and the East Africa Great Rift Valley are formed. Finally, five issues are briefly discussed: the naming and timing of the Indosinian movement; the timing of start/termination and types of the Indosinian movement; the Qinghai-Tibet Plateau being the best place to study various types of orogenic belts; the determination of the eastern and western tectonic structures of the Himalayan orogenic belt; and the exploration of the four-dimensional dynamics model of the Pamir Plateau. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Two modes of deep carbon cycling in a big mantle wedge: Differences and effects on Earth's habitability LI Shuguang, WANG Yang, LIU Sheng’ao Earth Science Frontiers    2024, 31 (1): 15-27.   DOI: 10.13745/j.esf.sf.2023.10.7 Abstract （1206）   HTML （29）    PDF（pc） （7453KB）（398）       Knowledge map    Save In this paper we summarize the evidence for the deep carbon cycling in a big mantle wedge composed of the deeply subducted Western Pacific Plate in the mantle transition zone and the exposed Late Cretaceous and Cenozoic intraplate basalts. We explore the differences in the carbon cycle between the big mantle wedge and island arc systems regarding metasomatic agents, carbonate species, redox reactions and mechanisms of partial melting of carbonated mantle, as well as their effects on maintaining a stable oxygen level in the Phanerozoic atmosphere and on the periodic changes in the greenhouse effect. We point out that quantitative estimate of the proportion of carbon left in the mantle transition zone through reduction of deep subducted carbonates into diamond, and carbon returned to the atmosphere through intraplate basaltic volcanoes, is an important topic for future study. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Integrated chronostratigraphic framework for Cretaceous strata in the Songliao Basin WU Huaichun, LI Shan, WANG Chengshan, CHU Runjian, WANG Pujun, GAO Yuan, WAN Xiaoqiao, HE Huaiyu, DENG Chenglong, YANG Guang, HUANG Yongjian, GAO Youfeng, XI Dangpeng, WANG Tiantian, FANG Qiang, YANG Tianshui, ZHANG Shihong Earth Science Frontiers    2024, 31 (1): 431-445.   DOI: 10.13745/j.esf.sf.2024.1.22 Abstract （1200）   HTML （14）    PDF（pc） （8617KB）（237）       Knowledge map    Save The Cretaceous is a typical greenhouse period with global large scale formation of organic-rich source rocks. However, we have only limited understanding of the terrestrial environmental status, climate change and biosphere responses and evolution during the greenhouse period; the effect of climate and environmental changes on the terrestrial organic accumulation and large scale source rock formation remains unclear. To study these issues the Songliao Basin in northeastern China offers an unique opportunity. The Songliao Basin has widespread distribution of Cretaceous source rocks and possesses the most complete sedimentary record of the Cretaceous in the world. One challenges, however, was the lack of high-quality rock records due to low continuity and low completeness of the records, which has caused controversies over the stratigraphic division of the Songliao Basin. Recently, the 8197 m drill core obtained from ICDP (Continental Scientific Drilling Program) boreholes (SK-1, SK-2, SK-3) provided a virtually complete terrestrial stratigraphic record of Cretaceous strata of the basin. In this study, by evidence synthesis using results of lithostratigraphy, biostratigraphy, magnetostratigraphy, radioisotope geochronology, and cyclostratigraphy, we constructed a high-resolution, integrated Cretaceous chronostratigraphic framework for the Songliao Basin, which provided fine chronological reference for studying the evolution of deep-time Cretaceous climate and environment as well as promoting sustainable oil and gas development in the Songliao Basin. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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The continental lower crust ZHANG Yanbin, ZHAI Mingguo, ZHOU Yanyan, ZHOU Ligang Earth Science Frontiers    2024, 31 (1): 28-45.   DOI: 10.13745/j.esf.sf.2023.12.27 Abstract （1196）   HTML （25）    PDF（pc） （4524KB）（442）       Knowledge map    Save The lower crust, linking the lithospheric mantle and the upper crust, is the most active place of energy exchange between the crust and the mantle; and partial melting of the lower crust and upper mantle, and delamination of the lower crust can directly lead to crust/mantle material exchange, re-cycling, recombination. In other words, the lower crust is one of the most important site for mantle-crust interactions where magma underplating, anatexis, delamination, high-grade metamorphism, and other processes take place. However, the lower crust has been largely overlooked by previous studies of the deep Earth. In this paper, the lower crustal profile of the North China Craton is described in detail. On this basis, the craton-type lower crust processes are discussed, and their dynamic significance and important position in the study of continental dynamics are emphasized. Cratonization is the transition of the formerly chaotic crust of the continent to stable upper and lower crust, and thus establishing a stable lithosphere. This unprecedented stable relationship between the crust and the mantle has been maintained from the beginning to the present, and is the basis for continental evolution, ocean-continent interaction, and crust-mantle interaction. The cratonic crust is not static after formation, and the continental boundaries can change during ocean-continental subduction-collisions. Especially during continent-continent collisions, the continental crust that can form different continental blocks is superimposed, thickened, collapsed, disassembled, underpinned and re-stabilized. At the root of the continental orogenic belt, a new lower crust is formed to become the lower crust of the orogenic belt type. We, therefore, suggest in this paper that the craton-type lower crust processes should receive full attention in the study of the deep Earth as well as in the designing of geoscience curricula. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Meta-Earth and Digital Twin: Breakthrough concept, technological revolution and paradigm shift LI Sanzhong, SUO Yanhui, DAI Liming, WANG Liangliang, JIANG Zhaoxia, CAO Xianzhi, SU Guohui, LIU Lijun, ZHOU Jianping, LI Xiyao, LIU Jie, ZHU Junjiang, QIAO Lulu, WANG Guangzeng, JIANG Suhua, WANG Xiujuan, LIU Lin, GUAN Hongxiang, LI Xiaohui, HU Jun, LIU Peng, LIU Ze, DONG Dongdong, GUO Lingli, ZOU Zhihui, DONG Hao, ZHONG Shihua, SUN Guozheng, LIU Yang, YU Shengyao, WU Lixin, ZOU Zhuoyan, SUN Yi Earth Science Frontiers    2024, 31 (1): 46-63.   DOI: 10.13745/j.esf.sf.2024.1.48 Abstract （1186）   HTML （32）    PDF（pc） （9509KB）（391）       Knowledge map    Save Digital Twin has been used in aerospace and industrial manufacturing for more than 20 years, but it is only introduced into marine science recently. Here we adopt Digital Twin technology to realize the integration of real- and virtual-Earth, and build a virtual-real, symbiotic community of real- and digital-Earth which we call “meta-Earth.” We first summarize the essential differences between meta-Earth and the early proposed digital-Earth, virtual-Earth, glass-Earth and smart-Earth, and then highlight the great breakthroughs in the concept or idea of “meta-Earth.” The core idea is that under the current metaverse BIGANT technic system we can realize gapless, cross-sphere dynamic simulation of the Earth system, which allow to build a global, multi-sphere, real-time, all-weather, three-dimensional Earth observing system, reconstruct the deep-time Earth beyond the present-day Earth, and realize space-time travel. By doing so we can integrate all previous Earth models—digital, virtual, glass, smart, present and deep-time—into a community called meta-Earth. This novel concept should bring a technological paradigm shift surpassing real- and virtual-Earth, thus opening a new way for mankind to understand, explore and develop the Earth. Promoting multi-tier application of meta-Earth while making research paradigm shift shall advance the development of new trillion-RMB industries in the future. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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International Continental Scientific Drilling Project of the Songliao Basin: Terrestrial Geological Records of the Cretaceous Dinosaur Age WANG Chengshan, GAO Yuan, WANG Pujun, WU Huaichun, LÜ Qingtian, ZHU Yongyi, WAN Xiaoqiao, ZOU Changchun, HUANG Yongjian, GAO Youfeng, XI Dangpeng, WANG Wenshi, HE Huaiyu, FENG Zihui, YANG Guang, DENG Chenglong, ZHANG Laiming, WANG Tiantian, HU Bin, CUI Liwei, PENG Cheng, YU Enxiao, HUANG He, YANG Liu, WU Zhengxuan Earth Science Frontiers    2024, 31 (1): 412-430.   DOI: 10.13745/j.esf.sf.2024.1.4 Abstract （1183）   HTML （22）    PDF（pc） （5717KB）（319）       Knowledge map    Save Over the past century the Earth has experienced continued warming, and it may enter a Greenhouse Earth state in the future with no ice at the poles. The Cretaceous was a typical Greenhouse period in deep time; thus, understanding the Cretaceous climate is important for interpreting past climate changes and predicting future trends. The ICDP (International Continental Drilling Program) Songliao Basin drilling project is the world's first continental scientific drilling project to penetrate the Cretaceous continental strata; it is aimed to investigate Cretaceous terrestrial climate and environmental changes, and to explore the mechanisms of massive terrestrial organic accumulation and enrichment. Spanning 16 years, this project achieves a continuous, complete 8187-meter core (recovery rate >97%, establishes a high-precision chronostratigraphic framework for the Cretaceous continental strata, reconstructs multi-temporal-scale terrestrial climate cycles and climate events during the Cretaceous period, reveals the mechanisms of Cretaceous sea-level fluctuations, and confirms marine incursion events in the Songliao Basin. This project has promoted global collaboration among geologists to study the Cretaceous greenhouse Earth, leading to a series of high-impact research achievements, and it has provided crucial scientific support for the sustainable development of oil and gas exploration in the Songliao Basin, generating significant social benefits and substantial international and domestic influence. This project represents a milestone in exploring deep-time Earth, and it is foreseeable that in the future, with the aid of scientific drilling, humans will continue to enhance their understanding of deep-time climatic and environmental evolution. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Mesozoic superposed orogenic system in eastern China REN Jishun, LIU Jianhui, ZHU Junbin Earth Science Frontiers    2024, 31 (1): 142-153.   DOI: 10.13745/j.esf.sf.2023.7.15 Abstract （1160）   HTML （32）    PDF（pc） （5607KB）（378）       Knowledge map    Save The Indosinian and Yanshanian orogenic movements are both important Mesozoic orogenies in eastern China. The resulted tectonic belts are neither products of the third stage of crustal evolution, as proposed by Chen Guoda, nor intracontinental (or intraplate) orogenic belts generated by intraplate dynamics, as argued by some scholars—rather, they are superposed orogenic belts created on the preformed continental crust in eastern China due to Mosozoic Paleo-Pacific dynamic system. In the past, these orogenic belts were called the peri-Pacific continent-marginal reactivated belts of eastern China. In the Mesozoic, under the effect of Paleo-Pacific dynamic system, the East Asia margin orogenic system formed along Northeast Russia-Sikhote Alin (Russia)-Japan-Ryukyu-Taiwan (China)-Palawan (Philippines) regions, while simultaneously the Mesozoic superposed orogenic system formed in the pre-existing continental crust in eastern China adjacent to the East Asia continental margin. The two orogenic systems, both driven by Mesozoic Paleo-Pacific dynamic system, developed synchronously to form the giant Mesozoic orogenic system in the Pacific tectonic domain in eastern Asia, radically changing the pre-Indosian tectonic framework of eastern Asia. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Overview: A glimpse of the latest advances in artificial intelligence and big data geoscience research ZHOU Yongzhang, XIAO Fan Earth Science Frontiers    2024, 31 (4): 1-6.   DOI: 10.13745/j.esf.sf.2024.6.99 Abstract （1158）   HTML （34）    PDF（pc） （640KB）（267）       Knowledge map    Save This special issue titled “Artificial Intelligence and Big Data Geoscience” consists of 17 papers covering topics such as knowledge graphs, deep learning-based image recognition, machine-readable expression of unstructured geological information, big graph data and community detection, association rule algorithms, 3D geological simulation and mineral prospecting, and the Internet of Things and online monitoring systems. A progressive multi-granularity training deep learning method is proposed for mineral image identification; the model achieves 86.5% accuracy on a commonly used dataset comprising 36 mineral types, increasing the accuracy of mineral identification. Knowledge related to porphyry copper ore in the Qinzhou-Hangzhou mineralization belt, South China, is collected using both primary and literature data sources, and Natural Language Processing (NLP) techniques are used to semantically correlate and reason over the knowledge graph, enabling automated knowledge extraction and reasoning. The association rule algorithm is used to analyze the correlation between trace elements and gold mineralization in major Carlin-type gold deposits in the “Golden Triangle” region of Yunnan-Guizhou-Guangxi provinces, China, and combined with the migration and enrichment law of elements to analyze the genetic mechanism of deposits. By builing a quantitative prospecting indicator method based on association rule algorithm, this study provides new ideas for establishing quantitative prospecting indicators for other types of deposits. In study of machine-readable expression of unstructured geological information and intelligent prediction of mineralization associated anomaly areas in Pangxidong District, western Guangdong, China, unstructured geological information such as stratigraphy, lithology and faults is processed by machine-readable conversion, and two machine learning algorithms—namely, One-Class Support Vector Machine and Auto-Encoder network—are applied to mine the geochemical test data of the stream sediment as well as the comprehensive geological information such as faults and stratigraphy, to extract the features of the mineralizing anomalies, and ultimately realize the intelligent circling of mineralizing anomalous areas. In study of networked monitoring of urban soil pollutants and visualized system based on microservice architecture, a system capable of real-time online monitoring, processing, and analyzing urban soil pollution data to enhance the timeliness of predictions and warnings is developed, where the integrated monitoring and data visualization system is based on the microservices framework Spring Cloud Alibaba. The above mentioned studies provide highly valuable application scenarios and research cases, reflecting to some extent the latest research advances in the field of artificial intelligence and big data geoscience in China, and are worthy of peer attention. Reference | Related Articles | Metrics | Comments（0）

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Earth sphere interaction reflected in microbial fingerprints through Earth's history—a critical review XIE Shucheng, ZHU Zongmin, ZHANG Hongbin, YANG Yi, WANG Canfa, RUAN Xiaoyan Earth Science Frontiers    2024, 31 (1): 446-454.   DOI: 10.13745/j.esf.sf.2023.10.4 Abstract （1148）   HTML （7）    PDF（pc） （2996KB）（183）       Knowledge map    Save Interactions between Earth's spheres, particularly between deep Earth and surface processes or within the surface system between sea, land and the atmosphere, are a critical issue in Earth system science. Such a large-scale geological process could be recorded by tiny microbes preserved in the fossil record. Triggered by volcanic activities during the Permian-Triassic transition and in the Late Ordovician, the bloom of nitrogen-fixation bacteria including cyanobacteria and the subsequent expansion of eukaryotes including algae, radiolarians and foraminifers clearly reflected a volcanism-induced shift from prokaryotes to eukaryotes. Furthermore, it has been shown that microbial activity could lead to banded iron formations to trigger Pre-Cambrian volcanic activity and even initiate plate movement in the early Earth. These data demonstrated the critical interaction between volcanic activity and the microbial community impacting carbon cycling. Microbes could also trace the complex interaction between sea, land, and the atmosphere and its associated long-range material transport process. Using microbial proxies for hydroclimate we identified the tri-pole mode of spatial variability of dry/wet status in eastern China on different time scales, as well as the extreme drought events in northwestern China triggered by the upper-ocean thermal condition in the tropical western Pacific Oceans. The spatiotemporal variations in dry/wet status reflected in the microbial records are due to variations in sea-land-atmosphere interactions between high- and low-latitude environments. The carbon- and water cycle-associated cross-sphere processes reflected in microbial fingerprints only represent a small portion of Earth sphere interactions. The great contribution of the microbial community in shaping the habitable Earth has yet to be fully deciphered. With research advancement and technical/methodological innovation in geobiology more questions can be addressed, including the interaction between geomicrobiological and deep Earth processes, microbial contribution to the major paleoclimatic shifts and paleoenvironmental changes, and impact of the microbial community on ecological evolution. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Application of the magnetotelluric method in the Sichuan-Yunnan region—a review DENG Yan, XU Yuchao, FAN Ye, SUN Guicheng, DONG Zeyi, HAN Bing Earth Science Frontiers    2024, 31 (1): 181-200.   DOI: 10.13745/j.esf.sf.2024.1.25 Abstract （1140）   HTML （17）    PDF（pc） （5030KB）（249）       Knowledge map    Save Magnetotelluric sounding (MTs, including audio-magnetotelluric, broadband-magnetotelluric and long-period-magnetotelluric) is a geophysical method to probe the near-surface to the upper mantle. Due to its sensitivity to low resistivity bodies, magnetotelluric plays an important role in deep structure, seismogenic environment, geothermal and resource exploration and geodynamics. The Sichuan-Yunnan region, located in the eastern section of the Tethys tectonic domain where many (micro) plates collide and merge, serves as an important channel for the eastward flow of materials and lateral extrusion of blocks within the Tibetan Plateau. The region is an important window to study the regional tectonic deformation, seismogenic environment and material migration due to the mutual cutting and influence of fault zones or suture zones of the plate boundary. This review first gives a brief introduction to the theory of magnetotelluric, then focuses on its application in the Sichuan-Yunnan region as well as the emerging CSELF (control source extremely low frequency) electromagnetic technique in recent years, and finally discusses the application of magnetotelluric in seismogenic environment, volcanic and geothermal activities, metallogenic activities, tectonic and dynamics, and electromagnetic coseismic effects. This review offers a comprehensive perspective on the application of magnetotelluric in the Sichuan-Yunnan region. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Very low-grade metamorphic rocks in southern Tibet and their significance on geological processes and resources BI Xianmei, MO Xuanxue, LIU Yanbin Earth Science Frontiers    2024, 31 (1): 201-210.   DOI: 10.13745/j.esf.sf.2024.1.66 Abstract （1140）   HTML （10）    PDF（pc） （4083KB）（136）       Knowledge map    Save Very low-grade metamorphism is one of the contemporary topics of frontier research since very low-grade metamorphic rocks contain important information on the geological processes related to oil and gas resources. Diagenetic sedimentary rocks, very low-grade metamorphic rocks and low-grade metamorphic rocks are widely distributed in southern Tibet, and these rocks preserve critical information on the evolution of the Neotethys and the Tibetan Plateau, as well useful clues for the exploration of oil and gas resources. This paper presents 71 data sets on illite crystallinity (Ic) and other parameters of clay mineral-bearing rock samples collected from different locations and tectonic units in southern Tibet. The illite crystallinity (Ic) of these rocks is in the range of 0.21°-1.61°(Δ2θ), and falls in the lower diagenetic, higher diagenetic, very low-grade metamorphic and low-grade metamorphic zones respectively. The different tectonic units display diverse metamorphic characteristics. Strata of P2, J-K, K2 in the North Himalayan carbonate platform all underwent very low-grade metamorphism, but N strata show the characteristics of early diagenetic stage. Strata of P1, T1, T2, T3, J1, J-K, K1 and K2 are developed in the Laguigangri passive marginal basin, most of which experienced low-grade metamorphism, and show patterns of normal burial with increasing metamorphism from younger to older strata. The Ic of some samples also falls in the diagenetic zone, which provides clues for finding oil and gas. Two sets of data were obtained from sedimentary rock samples in the Yarlung Zangbo ophiolites. One is in the diagenetic stage, and another group corresponds to very low grade metamorphism. Preliminary interpretation suggests that the former may reflect the paleo-environmental conditions at the time of ophiolite formation, whereas the latter may represent the tectonic position of the ophiolite during collision. The strata of K2 in Xigaze fore-arc basin are only in the high diagenetic grade, presumably indicating that Late Cretaceous strata in the fore-arc basin were not involved in subduction. Intrusive rocks, volcanic rocks and sedimentary rocks are all developed in the Gangdisê magmatic arc. The illite crystallinity (Ic) of the sedimentary rocks falls within a wide range of low-grade metamorphic-very low-grade metamorphic-diagenetic zone, and shows the characteristics of burial metamorphism superimposed by magmatism. Also, the very low-grade metamorphic rocks and diagenetic sedimentary rocks in southern Tibet contain information about oil and gas. In particular, the worldwide oceanic anoxic event that took place in the middle of the Cretaceous also affected southern Tibet, and very thick beds of typical black shale were found in the Gamba-Tingri basin. Previous studies also suggested that the Tingri-Gamba passive continental margin, Qiangtang peripheral foreland basin and Gangdese back-arc basin have good prospects for oil and gas exploration. The preliminary study on very low-grade metamorphism and very low-grade metamorphic rocks in southern Tibet in this paper opens scope for further detailed studies in future. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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High-resolution reconstruction of carbonate compensation depth in the South China Sea since 27 Ma WANG Jiahao, HU Xiumian, JIANG Jingxin, MA Chao, MA Pengfei Earth Science Frontiers    2024, 31 (1): 500-510.   DOI: 10.13745/j.esf.sf.2024.1.35 Abstract （1135）   HTML （6）    PDF（pc） （4027KB）（95）       Knowledge map    Save The reconstruction of carbonate compensation depth (CCD) in the Cenozoic Ocean has been a focus of attention from the academic community. In this paper, based on the IODP (Integrated Ocean Drilling Program) substances data and age-depth models from 20 boreholes at 14 sites in the South China Sea, the paleo-water depths in the boreholes were restored, the carbonate accumulation rate (CAR) was calculated, and CCD changes in the South China Sea since 27 Ma were reconstructed using linear regression method. Results showed that CCD in the South China Sea significantly decreased by more than 2000 m during the basin stretching period (27-18 Ma), while during Middle Miocene Climate Optimum (MMCO) it became shallower by 800 m. Since 8 Ma, CCDs in the South China Sea and the equatorial Pacific Ocean exhibited different evolutionary trends, with the former fluctuating between 3500-4000 m and the latter continuing to decline from 4000 m to ~4500 m. Prior to 27 Ma, extensive terrigenous input and development of upwelling led to shallow CCD in the South China Sea. The deepening of the sea basin and the weakening of the upwelling caused by tectonic tension during 27-18 Ma were interpreted as the main factors contributing to the decline of CCD during this period. Climate-driven sea-level fluctuations during MMCO led to changes in the core region of carbonate deposition, which was an important reason for CCD fluctuations. The differential evolution of CCD in the South China Sea and the Pacific Ocean since 8 Ma was the result of poor bottom water exchange between the Pacific Ocean and the South China Sea. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Neoarchean magmatism in the North China Craton: Implication for tectonic regimes and cratonization WAN Yusheng, DONG Chunyan, XIE Hangqiang, LI Pengchuan, LIU Shoujie, LI Yuan, WANG Yuqing, WANG Kunli, LIU Dunyi Earth Science Frontiers    2024, 31 (1): 77-94.   DOI: 10.13745/j.esf.sf.2023.12.21 Abstract （1120）   HTML （18）    PDF（pc） （4886KB）（329）       Knowledge map    Save Following a brief introduction to the Archean basement of the North China Craton (NCC), this paper summarizes the age distribution pattern, geochemistry and Nd-Hf-O isotopic compositions of late Neoarchean (mainly 2.55-2.5 Ga) magmatic rocks in the NCC. The late Neoarchean basement has the following features: 1) Late Neoarchean rocks are widespread while late Mesoarchean-early Neoarchean strata occur in many areas. 2) The magmatic zircon ages are mainly between 2.55-2.5 Ga and has a peak around 2.52 Ga. 3) Compared with pre-early Neoarchean (> 2.6 Ga) TTG (tonalite, trondhjemite, granodiorite), late Neoarchean tonalite and granodiorite are much more abundant, so are potassic granite, diorite-gabbro and sanukitoid with increased distribution range and scale. Voluminous potassic granites are mainly distributed in the east, forming a potassic granite belt-one of the double magmatic rock belts of the late Neoarchean (another is a TTG belt in the west). 4) Late Neoarchean supracrustal rocks are present in almost every area of basement outcrop, but occurring on a small scale when associated with TTG and potassic granite. The supracrustal rock types include metabasalt, meta-andesite, metadacite and clastic metasedimentary rocks, with meta-ultramafic rocks occurring in some areas. 5) In general, geological evolution of the late Neoarchean basement rocks began with supracrustal rock formation, then TTG intrusion, followed by metamorphism, deformation and emplacement of crust-derived potassic granite. The 2.6-2.55 Ga interval was a “quiet period” of magmatic and tectonothermal activity. 6) The late Neoarchean TTG rocks show large variations of Sr/Y and La/Yb ratios, consistent with medium-high formation pressures; their high abundances indicate significant continental crustal thickening in the late Neoarchean. Potassic granites were mostly derived from re-working of continental crust, with some, at least, involving sedimentary rocks. 7) All TTG rock types have similar whole-rock Nd and magmatic zircon Hf isotopic compositions, and the Nd-Hf isotope depleted mantle model ages are mainly between 3.0-2.5 Ga, similar to or slightly younger than that of late Mesoarchean-early Neoarchean rocks. The Nd-Hf isotopic composition of potassic granites is mostly constrained by the formation and evolutionary history of the source region on early Earth. Magmatic zircon has similar but more variable O isotopic composition compared to Archean magmatic zircon worldwide. Combined with results from other studies we arrive at the following conclusions: i) Similar to many other cratons, the late Mesoarchean-early Neoarchean was the most important period of rapid production of continental crust in the North China Craton, however, the NCC underwent strong magmatic and tectonothermal modification during the late Neoarchean. ii) “Modern-style” plate tectonic regimes began to form in the late Neoarchean in the NCC. iii) BIFs (banded iron formations) are mostly distributed along the double magmatic rock belts along the western margin of the Eastern Ancient Block of the NCC, thus the important exploration targets for BIF-hosted Fe resource should be between Anshan-Benxi and eastern Hebei and between eastern Hebei and western Shandong. iv) The initial cratonization of the NCC had completed by the end of the late Neoarchean. Table and Figures | Reference | Related Articles | Metrics | Comments（0）