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Intelligent geoscience information mining and knowledge discovery using big data analytics: A case study of the Shangfanggou Mo (Fe) mine in Henan Province WANG Luofeng, WANG Gongwen, XU Wenhui, XU Senmin, HE Yaqing, WANG Chunyi, YANG Tao, ZHOU Xiaojiang, HUANG Leilei, ZUO Ling, MOU Nini, CAO Yi, LIU Zhifei, CHANG Yulin Earth Science Frontiers    2023, 30 (4): 317-334.   DOI: 10.13745/j.esf.sf.2022.2.85 Abstract （307）   HTML （13）    PDF（pc） （8487KB）（2039）       Knowledge map    Save Industry 4.0 of the 21st century has given birth to smart mines. The multidisciplinary datasets of smart mines-such as geology, exploration, mining, geometallurgy, environment and survey/map datasets-constitute big data of mines, and they play an important role for the rapid advancements of geoscience in areas of geoscience digitization and application of information/Al technology in geoscience. Taking the Shangfanggou Mo (Fe) mine, a 5G+ smart mine, in Henan Province as an example, using big data of mines, this paper carried out geoscience information mining to highlight emerging engineering research with integrated multidisciplinary approach. Innovative results and geological knowledge discoveries from this study are summarized as follows: (1) According to theories on porphyry-associated skarns and mineralogical approach to minera resources prospecting, using borehole datasets and large-scale open-pit mapping and microscopic identification analysis, a 3D temporo-spatial model of the identified key minerals and predicted minerals in the study area was established, and a NE trending ore-bearing fault section and a penetration-type ore-bearing section were discovered. (2) Using UAV remote sensing and ground hyperspectral short-wave/long-wave infrared techniques, more than 20 types of key altered minerals in the study area were delineated, and a 3D multi-parameter mineral model was constructed. (3) Using geochemical techniques such as XRF and in-situ microscopy, a rock dataset with matching hyperspectral interpretation was established, and a dual-matrix mapping software for useful/harmful elements of rocks/ores in the study area was developed. In addition, mathematical modeling combining traditional geostatistics (gauss simulation, kriging interpolation) with machine learning (deep learning) was realized, and the composition of ore blends used between March-April 2021 was identified and the cause of the resulting low recovery rate was clarified. (4) Based on process mineralogy practice in the study area, multi-stage, multi-type mineral processing datasets (>1800 data on quarterly/monthly/daily processing of rock powder, mud powder, concentrate, tailings, etc.) were used to develop rock/mineral powder testing techniques and analysis methods, and the types of refractory ores and harmful minerals in the Shangfanggou Mo mine were identified. The multivariate, multi-type datasets of mines have the “5V” (volume, variety, velocity, veracity, value) characteristics of big data. The accurate management control of dynamic correlation measurement/analysis and rapid/efficient evaluation of big data of mines is conducive to intelligent mining decision-making and improvement of economic benefit (recovery rate). Among them, high-precision multi-parameter 3D modeling can be applied not only to deep mining of geological, structural, alteration and mineralization information models of rocks/ores as well as reserve/resources verification, but also to facilitating 4D control on real-time mining of fourth generation industrial 5G+ mines, such as 3D visualization of geological and mineral resources prediction/evaluation/storage expansion, virtual simulation of “year-quarter-month-day” dynamic ore blending and mining, and real-time digital twin for mine beneficiation. The research results provide a reference for in-depth geoscience research on mineral exploration and mineral resources assessment in smart mines. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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On the ore-forming depth and possible maximum vertical extension of the major type ore deposits QIN Kezhang, ZHAO Junxing, FAN Hongrui, TANG Dongmei, LI Guangming, YU Kelong, CAO Mingjian, SU Benxun Earth Science Frontiers    2021, 28 (3): 271-294.   DOI: 10.13745/j.esf.sf.2021.1.30 Abstract （949）   HTML （82）    PDF（pc） （6391KB）（1977）       Knowledge map    Save Based on a large number of field investigations and comparative studies of typical mineral deposits, and in considerations of the existing problems and practical needs of deep ore prospecting and evaluation, we first review in this paper the depth of ore deposits for the main deposit types, from the ultra-deep magmatic deposits controlled by large-scale magmatic accumulation in the middle-to-lower crust, to the deep, middle and shallow magmatic-hydrothermal deposits controlled by fluid permeability in the middle and upper crust. On this basis, we attempt to explore the maximum vertical extension of the major type ore deposits, and discuss the constrained depth of mineralization, degree of denudation, and possible vertical extension at depth for the copper-nickel (-chromite-PGE) deposits represented by the Bushveld and Voisey’s Bay, the porphyry copper deposits represented by Qulong, the orogenic gold deposits represented by Muruntau, and the Jiaodong gold province. The depth and vertical extension of hypogene mineralization associated with magmatic ore deposit can vary greatly; for example, the depth of mineralization in a layered igneous complex can extend to 20 km, with vertical extension ranging from 6 to 8 km. The maximum depth of magmatic-hydrothermal deposits is at the bottom of the lower crust where fluid penetration occurs. Oroganic gold deposits have the greatest depth, about 12-15 km, followed by pegmatite and granite deposits; porphyry deposits are in the middle, about 2-6 km; and the epithermal Au-Ag deposits have the shallowest depth of less than 1 km to the surface. The corresponding vertical extension of these deposits ranges in 4-7 km, 2-3 km, and 1 km, respectively. The controlling factors and some indicators are reviewed, such as high permeability of ore accumulating structural space, peak of mineralization, and suitable preservation conditions. Future research on the depth of mineralization may focus on such issues including how to determine a reasonable and uniform estimation method for the depth (pressure) of hypogene mineralization, as well as the theoretical basis, judgement markers and comprehensive identification method for determining the maximum depth and vertical extension of deposits. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Distribution characteristics and causes of arsenic in shallow groundwater in the Pearl River Delta during urbanization LÜ Xiaoli, ZHENG Yuejun, HAN Zhantao, LI Haijun, YANG Mingnan, ZHANG Ruolin, LIU Dandan Earth Science Frontiers    2022, 29 (3): 88-98.   DOI: 10.13745/j.esf.sf.2022.1.26 Abstract （534）   HTML （7）    PDF（pc） （7479KB）（1585）       Knowledge map    Save A high level of arsenic (As) in groundwater (ρ(As)>10 μg/L) is a potential threat to safe drinking water and the ecological environment. The sources of As in groundwater derived from coastal urbanized areas are complex, which mainly include various anthropogenic and geogenic sources. The rapidly urbanized Pearl River Delta was selected as the study area. The occurrence of and key driving factors for As enrichment in the shallow aquifers in areas with different urbanization levels in the Pearl River Delta were evaluated via mathematical statistics and principal component analysis. According to the results, the total dissolved As concentration in shallow groundwater ranged from below the detection limit to 420 μg·L-1 in the study area, with As(Ⅲ) as the main form. ρ(As) was found to be generally higher in porous aquifers than in fractured or karst aquifers. The proportion of As in the groundwater of urbanized areas was more than five times that of non-urbanized areas. Among the 1567 groups of groundwater samples collected from the study area, 89 high As groups, or 5.7% of total, had high level of As (ρ(As) >10 μg·L-1). Among them, 82 groups were from shallow porous aquifers, 4 groups from fissure aquifers, and 3 groups from karst aquifers, accounting for 7.8%, 0.8%, and 9.7% of total, respectively. Compared with historical hydrochemical data collected from 2005 to 2008, the average ρ(As) in shallow high As groundwater of newly added construction areas increased by 30% in 10 years. The chemical type of high As groundwater mainly included HCO3-Ca and Cl-Na types, characterized by high pH, low redox potential (Eh), low {\mathrm{NO}}_3^{-} concentration, and positive correlation between ρ(As) and concentrations of {\mathrm{NH}}_4^{+}, Fe, and Mn or oxygen consumption. Under microbial degradation and mineralization of organic matter, reductive dissolution of As-bearing iron (oxygen) hydroxide in the Quaternary basement muddy sedimentary strata in the Delta plain was identified as the cause of As mobilization. The leaking and infiltration of As-containing industrial wastewater produced during the urbanization process were also important sources of As in groundwater in Shunde District, southern Foshan City. Due to the dual effects of the original sedimentary environment and human input, the neutral to weakly alkaline, closed to semi-closed reducing environment that is rich in organic matter formed in the Delta plain, was the main cause of the occurrence of high As in groundwater. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Critical minerals in China: Current status, research focus and resource strategic analysis LI Wenchang, LI Jianwei, XIE Guiqing, ZHANG Xiangfei, LIU Hong Earth Science Frontiers    2022, 29 (1): 1-13.   DOI: 10.13745/j.esf.sf.2022.1.25 Abstract （2333）   HTML （144）    PDF（pc） （2298KB）（1438）       Knowledge map    Save Critical minerals are essential to sustainable development and in high demand in modern society. They are, however, subject to high risks due to limited quantity, uneven geological/geographical distribution, geopolitics, trade policy, and other factors. Critical minerals refer mainly to rare earth elements, rare metals, valuable constituent element dispersed in a mineral commodity, and some precious metals (e.g., platinum-group elements). The critical metals have unique physical and chemical properties (e.g., extreme high temperature resistance, corrosion resistance, excellent optical and electromagnetic properties, etc.), making them vital for the high-technology industries, emerging economies, advanced defense systems, green technologies, new energy, artificial intelligence, etc. It is predicted that global demands for critical metals will grow rapidly in the next decades, and the conflict between supply and demand will become increasingly prominent. Future international competition for mineral resources will largely involve critical metals. China has been the main consumer of mineral resources in the last decade, and its demand for critical minerals will continue to grow for a long period. The continuing high demand and increasingly stronger competition highlight the urgent needs for innovative multidisciplinary research in metallogeny, exploration, and utilization of critical minerals. China hosts a large variety of critical minerals with diverse mineralization styles; they are distributed as clusters or belts and formed by complicated geochemical processes under favorable geological settings. To advance our understanding of the genesis of critical minerals, we suggest three key issues for future studies: (1) partition and transportation of critical metals in the processes of interaction between Earth’s spheres; (2) mechanisms for unusual enrichment of critical metals in magmatic, hydrothermal, and supergene systems, as well as controls on temporo-spatial distribution of related ore deposits; and (3) mode of occurrence and technologies towards efficient, green extraction of critical metals from various minerals and ores. Based on the analysis of current situation and future trend of supply-demand for critical minerals, suggestions on improving mineral exploration, economic utilization, management policy, and resource security strategy for critical minerals in China are proposed. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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What are Mathematical Geosciences and its frontiers? CHENG Qiuming Earth Science Frontiers    2021, 28 (3): 6-25.   DOI: 10.13745/j.esf.sf.2021.1.17 Abstract （1320）   HTML （45）    PDF（pc） （4924KB）（1089）       Knowledge map    Save The lack of a unified definition of Mathematical Geology or Mathematical Geosciences as an interdisciplinary field of natural science, may lead to misunderstanding of the subject or not even treating it as an independent discipline. This has, to some extent, affected the development of the field of Mathematical Geosciences. As a decade-long (2004-2016) lead administrator of the International Association for Mathematical Geosciences (IAMG), the author of this paper has witnessed and led the transformation of IAMG from Mathematical Geology to Mathematical Geosciences, and has overseen the updates of the names and contents of various journals and conferences related to IAMG. In 2014, a new definition and disciplinary connotation of Mathematical Geosciences were put forward by the author in the IAMG President Forum in Newsletters. In 2018, in celebrating the 50th anniversary of IAMG, the definition, connotation, contribution, and leading-edge researches of Mathematical Geosciences were discussed in detail in the Handbook of Mathematical Geosciences. The current paper reviews the main contributions, scientific progress, frontiers, and public education of the field under the framework of the new discipline of Mathematical Geosciences. On the basis of reviewing the developmental history of the discipline, the difference between Mathematical Geosciences and Mathematical Geology is analyzed, and the significant contributions of Mathematical Geosciences to the advances in geodesy, geophysics, plate tectonics theory, geochemistry, sedimentology, geographic information system, and mineral resources and energy forecasting are introduced. The frontiers of Mathematical Geosciences are discussed from a viewpoint of the challenges in international Earth Sciences, while new growth directions of Mathematical Geosciences are proposed, such as quantitative research on the complexity of the Earth, big data, deep machine learning, and complex artificial intelligence. This paper aims to answer such questions: What is Mathematical Geosciences? What contributions are made by mathematical geoscientists to advance Earth Sciences? And, Is the discipline of Mathematical Geosciences at the forefront of Geosciences? Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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High purity quartz: Research progress and perspective review YANG Xiaoyong, SUN Chao, CAO Jingya, SHI Jianbin Earth Science Frontiers    2022, 29 (1): 231-244.   DOI: 10.13745/j.esf.sf.2021.8.1 Abstract （1417）   HTML （121）    PDF（pc） （5057KB）（1080）       Knowledge map    Save Quartz is widely distributed on the Earth’s surface. It has a broad range of industrial uses and other application prospects. Natural quartz, however, are not entirely SiO2 but contain other elements more or less, such as P, Ti, Ge, Al, B, Be, Ca, Na, K, H, and Li, affected by the physico-chemical conditions/properties of crystallizing melt or fluid as well as post-crystallization alterations (such as metamorphism, structural deformation, and thermal disturbance). Diagenetic study of quartz based on its trace element compositions plays a part in petrological and metallogenic investigations of mineral deposits. The impurity elements in quartz are in forms of lattice impurities or nano- to macro-scale inclusions, and the impurity type, quantity, and form (specially inclusions) affects the quality and industrial use of quartz directly. Here, topics including the luminescent properties and technical performance of quartz, quality classification and rating standard for high purity quartz, source materials of high purity quartz are systematically reviewed. Also, the distribution of fluid inclusions and types of mineral inclusions in quartz from the Zhangjinzhuang quartz sand (Northern Jiangsu) and Guposhan granite (Guangxi) were determined in this study by optical microscopy observations and laser Raman analysis to provide a basis for subsequent research. High purity quartz of high quality and value is naturally formed (such as crystal) or processed from high quality quartz raw materials. It is an environment-friendly strategic resource used in high-tech industries, such as semiconductor, high-temperature lamp tubing, fiber optics, precision optics, microelectronics, and solar energy. Researches on the evaluation system, ideal source rock and formation mechanism for high purity quartz raw materials are beneficial for ensuring a sustainable supply of high purity quartz raw materials and increasing the added value of quartz products. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Deep seismic reflection evidence on the deep processes of tectonic construction of the Tibetan Plateau GAO Rui, ZHOU Hui, GUO Xiaoyu, LU Zhanwu, LI Wenhui, WANG Haiyan, LI Hongqiang, XIONG Xiaosong, HUANG Xingfu, XU Xiao Earth Science Frontiers    2021, 28 (5): 320-336.   DOI: 10.13745/j.esf.sf.2021.8.10 Abstract （816）   HTML （282）    PDF（pc） （14121KB）（865）       Knowledge map    Save The collision between the Indian and Asian plates uplifted the Himalayan- Tibetan Plateau, thickening and expanding the crust. It is a scientific mystery of global concern as how the two continents collide and how the continent-continent collision deforms the continent. Deep seismic reflection profile detection is one of the most effective ways to unlock this scientific mystery. For more than 20 years using this technology, we have detected fine structures of the thick crust of the Tibetan plateau after overcoming technical bottlenecks to access the lower crust and Moho thus revealing the continental collision processes. This paper systematically summarizes the deep behaviors of the India-Asia collision and subduction beneath the Tibetan Plateau, from south to north, east to west and further into the hinterland of the plateau. The Indian crust undergoes underthrusting beneath the Himalayan orogenic belt on the southern margin of the plateau. Meanwhile, the lithosphere of the Alxa block in the Asian plate subducts southward beneath the Qilian Mountain in the north of the plateau, driving the northward overthrusting of the Qilian crust. Additionally, the Tarim and West Kunlun blocks undergo face-to-face collision in the northwestern margin of the plateau. In the easternmost part of the plateau, the Longriba fault, instead of the Longmen Shan fault zone, marks the western margin of the Yangtze block. It is also seismically evidenced that the Moho geometry in the plateau’s hinterland appears thin and flat, indicating lithospheric collapse and extrusion. Multiple deep reflection profiles revealed the collisional behavior under the Yalung-Zangbo suture zone and longitudinal variation in subducting geometry of the Indian crust from west to the east. In the middle of the suture zone, it shows a decoupling between the upper and lower crusts of the Indian plate, where the upper crust undergoes a northward overthrusting while the lower one experiences a northward underthrusting. It is also seismically evidenced a down-and southward crustal duplexing of the subducting Indian crust thickening the northern Himalayas, leaving over a thinning subducting lower crust of the Indian slab. The subduction front of the Indian crust collides with the lower crust of the Asian plate at the mantle depth. A near-vertical collision boundary is seen between the Gangdese batholith and the Tethyan Himalayas, where the Gangdese batholith shows almost transparent weak reflections in the lower crust with localized bright spot reflection that indicates partial melting. Additionally, the near-flat Moho geometry implies an extensional tectonic environment of the southern margin of the Asian plate. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Metallogenic background, process and exploration as one: A trinity concept for prospecting for super-large ore deposits CHEN Yongqing, MO Xuanxue Earth Science Frontiers    2021, 28 (3): 26-48.   DOI: 10.13745/j.esf.sf.2021.1.11 Abstract （667）   HTML （22）    PDF（pc） （5566KB）（801）       Knowledge map    Save Super-large ore deposits are giant storages for one or some kinds of mineral resources. About Roughly 70%-85% of world’s known ore reserves are concentrated in super-large deposits that account for 10% of the world’s total in terms of deposit numbers. Thus the discovery of super-large deposits is of great importance to the socioeconomic development of a country. The geological background of a super-large deposit is the basis of its formation; the metallogenic process is the key to its mineralization; and conceptual exploration, evaluation is the fundamental approach to its discovery. In this paper we attempt to explore the idea of trinity—metallogenic background, process and exploration as one—for prospecting for super-large deposits. For hidden and new types of super-large deposits, ore prospecting based on the trinity concept is the key to the success of mineral exploration. According to the theory of Earth dynamics, we define the geological anomaly area (e.g., various kinds of plate boundaries) with a complex crustal structure as the feasible ore prospecting area; within this area, the subarea associated with key metallogenic factors (source, transport, storage, cover) is defined as the favorable ore prospecting area according to the concept of metallogenic system; inside the favorable ore prospecting area, the district with variable mineralization types is defined as the ore prospective area based on the concept of ore-forming series. According to the theory of self-organization, metallogenic system in an ore-rich area follows the power-law distribution, hence it requires multi-scale oriented ore prospecting; while the uncertainty of single information on geology and mineralization warrants collection of comprehensive ore-forming information. Metallogenic system-based mineral exploration, combined with prediction model based on comprehensive ore-forming information, is the most effective way to determine the possible mineralization area as it takes account of two factors simultaneously: the mechanism of mineralization (essence) and the correlation (phenomenon) between ore deposit and various ore controlling factors. The search for super-large deposits should be regarded as a scientific exploration from the viewpoint of geoscience. It involves first integrating the ore-forming information extracted from various sources, including geological, geochemical, geophysical, and remote sensing data; then transforming the obtained information of key ore-forming processes and parameters into spatial information of ore prospecting; next identifying and confirming such spatial information according to the target selection model; and finally delineating the ore-prospecting target area of varying scales, from global ore deposit zones to metallogenic provinces to ore-rich areas. The trinity concept lays a theoretical, methodological foundation for future exploration of super-large deposits and provides a reasonable engineering scheme for the application of direct prospecting technology in ore exploration. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Overview of magmatic differentiation and anatexis: Insights into pegmatite genesis ZHOU Qifeng, QIN Kezhang, ZHU Liqun, ZHAO Junxing Earth Science Frontiers    2023, 30 (5): 26-39.   DOI: 10.13745/j.esf.sf.2023.5.8 Abstract （369）   HTML （62）    PDF（pc） （3044KB）（781）       Knowledge map    Save The origin of granitic pegmatites is significant for the understanding of their formation processes and rare-metal metallogenesis. Granitic pegmatites are mainly formed by fractional crystallization of granitic magmas or by anatexis. In discussing pegmatite genesis, pegmatite classification and its mineral assemblage characteristics can provide the preliminary evidence, whilst parental granite plutons provide the final proof of origin. Studies have shown that granite pluton and its pegmatite swarm are nearly coeval, with less than 10 km apart in location and continuing to differentiate, and they have a common material source. To determine the degree of fractional crystallization and to decipher the formation process of granite magmas major element/trace element/REE/stable isotope Rayleigh fractional crystallization models have been used. Current evidences for an anatexis origin include regional metamorphic-tectonic events; metamorphism features; close spatial and chemical compositional relationships and consistent isotopic compositional relationships between pegmatites and metamorphic rocks; formations of unique mineral assemblages and mineral inclusions in pegmatites; and similar chemical components between the parental granite magma and partial melt. The following research approaches have been used to discuss the partial-melting process and melt-extraction history and to clarify the pegmatite-forming process via anatexis: determining protolith by elemental comparison, isotope tracing, and trace-element simulation; clarifying major melting model using Rb/Sr-Ba diagram; and determining the melting condition and melt production based on mineral composition of protolith and element partitioning between mineral and silicate melt. Researchers have found that rare-metal pegmatites mainly formed from extreme fractional crystallization of highly evolved granitic magmas and, in rare cases, from low-degree partial melting of fertile metasediments. Besides, rare-metal pegmatite swarm could be formed from magmatic differentiation without a parental pluton, or from further differentiation of anatectic granite. Future researches need to gain a deeper understanding of the partial melting and fractional crystallization controls on granitic magmas, explore the physical and chemical processes during the formation of granitic magmas—especially melt escaping and migration mechanisms and their affects on rare-metal enrichment, and establish petrogenetic discrimination criteria for granitic pegmatites. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Rare earth mineralization in Bayan Obo super-large deposit: A review DENG Miao, WEI Chunwan, XU Cheng, SHI Aiguo, LI Zuoqi, FAN Chaoxi, KUANG Guangxi Earth Science Frontiers    2022, 29 (1): 14-28.   DOI: 10.13745/j.esf.sf.2021.8.9 Abstract （812）   HTML （56）    PDF（pc） （12121KB）（725）       Knowledge map    Save Rare earth elements (Y, Sc, La-Lu), the “vitamins” of modern industry, are regarded as critical strategic resources in today’s society. The Bayan Obo REE-Nb-Fe deposit located in Inner Mongolia, China, is the world’s largest rare earth deposit. The diagenesis and mineralization processes of this deposit have attracted a great deal of attention from geologists around the world, and a considerable amount of research has been conducted. These researches were mainly focused on the whole-rock chronology and geochemistry of H8 ore-bearing dolomite rock, which, however, led to confusions over different metallogenic models as the deposit has rather complex ore texture and structure due to late stage deformation and metamorphism. In recent years, with the rapid technological development in modern geochemical analysis, high-precision in-situ isotopic analysis and in-situ U-Th-Pb dating can be performed directly on dolomite and rare earth minerals (such as monazite, apatite, bastnasite, etc.), which yielded valuable information on the age of the deposit as well as the source of ore-forming fluids. This paper summarizes the latest research results on the diagenesis and metallogenic model of the world class Bayan Obo REE-Nb-Fe deposit, and proposes that Mesoproterozoic (1.3 Ga) carbonatitic magmatism initiated REE mineralization and Early Paleozoic metasomatism subsequently caused REE reenrichment and reprecipitation which resulted in the accumulation of large amounts of REE minerals to form the Bayan Obo deposit. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Modern science and technology in metallogenic and prospecting model studies ZENG Qingdong, DI Qingyun, XUE Guoqiang, WANG Gongwen, JING Linhai Earth Science Frontiers    2021, 28 (3): 295-308.   DOI: 10.13745/j.esf.sf.2021.1.3 Abstract （458）   HTML （14）    PDF（pc） （3432KB）（695）       Knowledge map    Save To ensure sustainable development of resources, exploration and exploitation of deep underground resources is an important strategic choice for many countries. Whether there are high-quality mineral resources underground is the premise of deep prospecting. While an ideal metallogenic model has great theoretical significance for guiding the construction of prospecting model, establishing a reasonable prospecting model has great practical significance for guiding deep ore prospecting. With the continuing development of modern science and technology, various new technologies have been used in geological research and exploration. Presently, some new techniques such as mineral in-situ U-Pb dating and in-situ compositional and isotopic analyses have played an important role in the study of metallogenic models, guiding researchers with renewed focus to building new metallogenic models; and some geophysical and geochemical exploration techniques also play an important role in model building by providing a more reliable basis for deep ore exploration. The application of modern science and technology such as metallogenic theory, integrated geophysical-geochemical analysis, etc., is the present and future trend in mineral prospecting. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Machine learning for mineral prospectivity: A case study of iron-polymetallic mineral prospectivity in southwestern Fujian ZHANG Zhenjie, CHENG Qiuming, YANG Jie, WU Guopeng, GE Yunzhao Earth Science Frontiers    2021, 28 (3): 221-235.   DOI: 10.13745/j.esf.sf.2021.1.4 Abstract （836）   HTML （58）    PDF（pc） （3724KB）（694）       Knowledge map    Save As a rapidly evolving technology in recent years, machine learning (ML) provides a novel approach for mineral prospecting (MP). In this paper, we discuss the progress on the methodology and theory of machine learning and summarize the applications of ML in MP in the areas of pattern recognition/information mining and information integration. We also point out the difficulties and challenges of ML in MP, such as data imbalance, lack of training data, lack of uncertainty evaluation in model selection, feedback feeding, and method selection. Here, we use mineral prospecting of the Makeng-type iron deposit in southwestern Fujian, China as an example to illustrate the process of using the ML method in MP. A complete prediction procedure should include (1) establishing a metallogenic model and identifying ore controlling factors by studying metallogenic systems; (2) building an exploration model and obtaining relevant data by researching exploration systems;(3) establishing a prediction model and extracting predictive factors by researching prediction evaluation systems;(4) obtaining metallogenic probability through information integration of predictive factors using ML models;(5) evaluating uncertainties of prediction performances and results; and (6) delineating prospecting/target areas and estimating resource reserves. Lastly, a future research roadmap for developing big-data based quantitative mineral prospecting theory and methods is proposed, guided by the geological big data and Earth system theory in following the research route of earth system-metallogenic system-exploration system-prediction evaluation system. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Carbon sequestration assessment methods at home and abroad for terrestrial ecosystems: Research progress in achieving carbon neutrality XIE Lijun, BAI Zhongke, YANG Boyu, CHEN Meijing, FU Shuai, MAO Yanchao Earth Science Frontiers    2023, 30 (2): 447-462.   DOI: 10.13745/j.esf.sf.2022.2.78 Abstract （1082）   HTML （79）    PDF（pc） （3170KB）（689）       Knowledge map    Save The purpose of this paper is to differentiate the characteristics of different mainstream carbon sink accounting methods developed in the past 30 years for the four main terrestrial ecosystems—forest, grassland, farmland, and wetland—in order to accurately assess the current status of the carbon sink capacity and future carbon sink potential of terrestrial ecosystems. Through literature review, comparative analysis, and induction we show that 1) the existing carbon sink accounting methods are mainly based on formula model calculations, and are affected by sample size, measurement and parameter errors, inconsistent data sources, and model universality when analyzing the spatial pattern of vegetation carbon sinks, which lead to great uncertainty in the calculated result; thus, China urgently needs to establish an unified standard terrestrial ecosystem carbon sink monitoring system. 2) Accurate carbon sink calculation for terrestrial ecosystems requires reliable data sources, reasonable calculation methods and models, multi-channel cross-validation, appropriate error analysis, and interpolation corrections. 3) Methods such as site survey, model construction, micrometeorology, and remote sensing monitoring should be effectively integrated to solve the problem of multi-scale coupling. Future research should be based on a large number of measured data, explore differentiated carbon sink accounting methods according to ecosystem types, regions, and climates, and establish a full-scale, generalized carbon sink calculation model to provide reference for a carbon sink accounting standard for terrestrial ecosystems in China. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Deep seismic reflection profile reveals the deep process of continent-continent collision on the Tibetan Plateau GAO Rui, ZHOU Hui, LU Zhanwu, GUO Xiaoyu, LI Wenhui, WANG Haiyan, LI Hongqiang, XIONG Xiaosong, HUANG Xingfu, XU Xiao Earth Science Frontiers    2022, 29 (2): 14-27.   DOI: 10.13745/j.esf.sf.2021.7.13 Abstract （548）   HTML （51）    PDF（pc） （13493KB）（680）       Knowledge map    Save The collision between the Indian and Asian plates uplifted the Himalayan-Tibetan Plateau, thickening and expanding the crust. The deep structure of the plateau-a scientific mystery of global concern-can reveal how the two continents collide and how the collision deforms the continent. One of the most effective ways to unlock this scientific mystery is deep seismic reflection profiling. For more than 20 years using this technology we have detected the fine structure of the thick crust of the Tibetan Plateau, overcoming the technical bottleneck of accessing the lower crust and the Moho and revealing the intracontinental collision process. Based on the research results, this paper systematically summarizes the deep behavior of the collision and subduction between the Indian and Asian plates under the Tibetan Plateau, on topics ranging from the NS-EW correlation to the plateau’s hinterland. The deep behavior includes the underthrusting of the Indian crust beneath the Himalayan orogenic belt on the southern margin of the plateau, the subduction of the lithosphere of the Alashan block in the Asian plate under the Qilian mountain in the northern rim of the plateau, the outward crustal extension in the Qilian mountain range, and the face-to-face collision between the Tarim block and the West Kunlun in the northwestern margin of the plateau; in the eastern margin of the plateau it was discovered that the Longriba fault, not the Longmenshan fault, is the western border fault of the Yangtze plate. In the plateau’s hinterland the Moho lines are thin and flat and lithosphere extension collapses. Multiple deep reflection profiles reveal the collisional behavior of the Indian and Asian plates under the Yalungzangbo suture zone. The subduction of the Indian continental crust varies from east to west, and the crust travels northward to different locations inside the Lhasa terrain. In the central suture zone, the upper and lower parts of the Indian crust become detached as the upper crust overthrusts while the lower crust subducts northward. During the subduction, material return and structural superposition cause the thinning and thickening of the Indian and Himalayan crust, respectively. The leading edge of the subducting Indian crust collides with the Asian crust and sinks into the mantle, while a near-vertical collision occurs between the Gangdise at the leading edge of the Asian plate, and the Tethys. Together, the partial melting of the lower crust of the Gangdise, the seismic data that show near transparent weak reflection and localized bright spot reflection, and the near-flat Moho, all reflect the extensional tectonic environment of the southern margin of the Asian plate. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Digital geology and quantitative mineral exploration ZHAO Pengda, CHEN Yongqing Earth Science Frontiers    2021, 28 (3): 1-5.   DOI: 10.13745/j.esf.sf.2021.1.22 Abstract （851）   HTML （31）    PDF（pc） （999KB）（642）       Knowledge map    Save The concept of mineral exploration, or so-called “exploration philosophy” in the Western countries, is the thoughts, methodology, technology, goal and organization guiding mineral exploration. The three basic elements of mineral exploration are “what to find”, “where to find” and “how to find”. As these elements evolve with time, it provides a powerful force to gradually changing the concept, methodology and technology of mineral exploration. Innovative ideas of mineral exploration come from the continuing scientific exploration and development keeping pace with the times. Digital geology, the data analysis component of geoscience, is the combination of mathematical geology and information technology.Geological data science uses the general methodology of data science to study geology based on the characteristics of geological data and the needs of geological work. And digital mineral exploration is the application of digital geology in mineral exploration to reduce uncertainty in ore prospecting. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Marine science in China: Current status and future outlooks WU Lixin, JING Zhao, CHEN Xianyao, LI Caiwen, ZHANG Guoliang, WANG Shi, DONG Bo, ZHUANG Guangchao Earth Science Frontiers    2022, 29 (5): 1-12.   DOI: 10.13745/j.esf.sf.2022.4.60 Abstract （1740）   HTML （103）    PDF（pc） （4828KB）（636）       Knowledge map    Save Oceans as the cradle of life, the treasure trove of resources, and the protective barrier for national security play an important strategic role in the future sustainable development of mankind. Until now only 5% of oceans have been explored. For the national development it is vital to accelerate the marine science and technology innovation, improve the marine resources exploration capability, and protect the marine ecological environment. However, due to its inherent complexity, the “ocean problem” cannot be solved within a single discipline. Presently marine study in China is gradually catching up with the world, yet research originality is still lacking. This paper reviews the domestic marine research progresses and trends, points out the gaps between China and advanced countries, and proposes future directions. Focusing on the major scientific frontiers e.g., multiscale inter-ocean interaction, climate change, healthy ocean, marine life cycle, cross-sphere fluid-solid interaction, rapid changing polar system, and sustainable development of coastal zone-this paper proposes that China should strengthen its top-level design and strategic planning, carries out cross-scale, cross-sphere interdisciplinary research, and pursues leadership roles in major international scientific programs. These efforts are essential to enhancing China's influence in international marine research, effectively improving its national security capability, supporting its socioeconomic development, and providing scientific and technological support in achieving maritime power and building a global community with a shared future. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Thermal regime and metallogenesis of collisional orogens ZHANG Hongrui, HOU Zengqian Earth Science Frontiers    2022, 29 (2): 1-13.   DOI: 10.13745/j.esf.sf.2021.10.36 Abstract （387）   HTML （55）    PDF（pc） （5274KB）（628）       Knowledge map    Save Previous studies have shown that the thermal regime of continental collisional orogen has important controls on the shape, size, tectonic pattern, magmatism and metamorphism of collision zones. However, the relationship between the thermal regime and metallogenesis of continental collisional orogen is unclear. Here, we compared the Pyrenean, Alpine, Caledonian, Zagros-Iranian, Himalayan-Tibetan and Variscan orogens in terms of their thermal regimes and mineral deposits, focusing especially on the relationship between the thermal regime and ore-forming temperatures. We found three types of deposits in these continental collisional orogenic belts: basin brine (e.g., Mississippi Valley-type Pb-Zn deposits), metamorphic fluids (e.g., orogenic Au deposits) and magmatic hydrothermal (e.g., porphyry Cu-Mo-Au deposits and greisen W-Sn deposits) deposits. Among them, the Mississippi Valley-type Pb-Zn deposits and orogenic Au deposits can occur in all types of collisional orogens. The ore-forming temperatures in these deposits are relatively high in hot collisional orogen and low in cold collisional orogen. However, magmatic hydrothermal deposits only occur in hot collisional orogens as the pressure-temperature conditions for hot collisional orogen overlap largely with that for wet granite solidus in the p-T diagram. The thermal structure of collisional orogens is affected easily by thermal disturbance conducive to crustal partial melting and forming ore-bearing magmas. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Key elements and human health: Is China’s arable land selenium-deficient? WANG Xueqiu, LIU Qingqing, LIU Hanliang, HU Qinghai, WU Hui, WANG Wei Earth Science Frontiers    2021, 28 (3): 412-423.   DOI: 10.13745/j.esf.sf.2021.1.13 Abstract （685）   HTML （14）    PDF（pc） （3943KB）（626）       Knowledge map    Save Everything on Earth, living or non-living, is made from one or a combination of the 92 naturally occurring chemical elements. Life survival depends on the bioavailability of these essential elements at appropriate concentrations and proportions. A comparison between the element concentration in human blood and the corresponding baseline element concentration in arable soil shows a very good correlation for 40-50 key elements. The essential element selenium (Se) has a dual character, that both Sn deficiency and excess are harmful for human health. Previous researches concluded that Se deficiency was predominant in China. In this work, we collected the China geochemical baseline data from 3382 grid sampling sites covering the entire country. We found the proportion of Se deficient area to be 21.1% according to the WHO limit (0.1 mg/kg) or 31.6% by the Chinese guideline standard (0.125 mg/kg). The Se-deficient regions are distributed in Tibet and Inner Mongolia where grain crops are scarcely produced. No Se deficiency is observed in the arable plains of the 9 major grain producing regions except the Hetao plain. Specifically, Selenium is enriched (>0.4 mg/kg) in the Pearl delta, Guangxi, Chengdu, and middle and lower Yangtze plains; between marginal and appropriate levels (0.125-0.4 mg/kg) in the Sanjiang, Northern, Northeastern and Guanzhong (Central Shaanxi) plains; and deficient (<0.125 mg/kg) in the Hetao plain. The study shows that the spatial distribution of Se-poor soils is geographically situated in a discrete NE-SW-trending belt from the eastern part of Inner Mongolia to the Qinghai-Tibet Plateau, controlled mainly by geological background, parent rocks, soil types and geographical landscapes. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Triassic deposits in South China: Geological characteristics, ore-forming mechanism and ore deposit model XIE Guiqing, MAO Jingwen, ZHANG Changqing, LI Wei, SONG Shiwei, ZHANG Rongqing Earth Science Frontiers    2021, 28 (3): 252-270.   DOI: 10.13745/j.esf.sf.2021.1.26 Abstract （459）   HTML （15）    PDF（pc） （4748KB）（601）       Knowledge map    Save South China is characterized by intensive, large-scale Mesozoic metal mineralization. The mechanism of ore formation during the Yanshanian period has been well studied. Recently, plentiful Triassic deposits have been discovered or recognized in South China, however, few studies are focused on their regional distribution pattern and ore deposit model. In this study, the geological characteristics, spatial-temporal distribution pattern and metallogeny of these Triassic deposits are summarized. So far, forty-six deposits of Late Triassic (230-200 Ma) have been discovered, mostly in five regions of South China. These deposits can be subdivided into four types based on mineralization styles. They, showing a zonal distribution from east to west, are the granite-related W-Sn deposits, the intrusion-related distal Au-Sb deposits, the Carlin-type Au deposits, and the MVT Pb-Zn deposits. The granite-related W-Sn deposits are situated to the south of the Carlin-type Au deposits. Multiple mineralization events took place within a single region as overprinting mineralization in the Indosinian and Yanshanian periods is commonly found in all five regions, and overprinting mineralization in the Caledonian and Indosinian periods was found in the Miaoershan-Yuchengling district of western Nanling and in the Laojunshan district of southeastern Yunan Province. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Data science-based theory and method of quantitative prediction of mineral resources ZUO Renguang Earth Science Frontiers    2021, 28 (3): 49-55.   DOI: 10.13745/j.esf.sf.2020.12.1 Abstract （617）   HTML （43）    PDF（pc） （1178KB）（583）       Knowledge map    Save Quantitative prediction of mineral resources needs the support of data science urgently as the field has now changed from qualitative to quantitative, from data sparse to data intensive. On the basis of previous studies, this paper discusses data science-based theory and method of quantitative prediction of mineral resources. The theoretical basis of such theory and method are correlation theory and anomaly theory. The former, via supervised machine learning algorithms, provides a theoretical basis for the prediction of undiscovered mineral deposits by mining the correlations between geological prospecting big data and locations of mineral deposits; the latter, by detecting geological anomaly present in geological prospecting big data, provides a theoretical basis for the prediction of mineral deposits. This data science-based approach emphasizes the importance of geological prospecting big data and machine learning algorithms, as the type, diversity, quality and accuracy of geospatial data can affect the final prediction results, whilst machine learning algorithms can improve the efficiency of feature extraction and information integration fusion. This paper presents the workflow of quantitative prediction of mineral resources by the data science-based theory and method, introduces the methods for feature extraction and prospecting information fusion, and discusses potential prediction uncertainty inherent in such theory and method. Table and Figures | Reference | Related Articles | Metrics | Comments（0）