Abstract:This paper is the result of mineral exploration engineering. Objective Cracking the contradiction between energy security and ecological environment protection is a major challenge for the development of coal resources in ecologically fragile areas. The large–scale and intensive extraction of coal resources not only triggers rapid changes in geological conditions but also impacts the structure and function of the Earth's critical zone in mining areas. The Earth's critical zone refers to a continuous domain that extends upwards from the bottom of groundwater or soil rock interface to the top of vegetation canopy. Methods Focusing on how to understand the relationship between the operation of the Earth's critical zone and the evolution of geological conditions for coal development, based on the analysis of coal mining geological conditions and the response of the Earth's critical zone, this paper elucidates the response mode, monitoring technology, prediction methods, guarantee strategies, and loss reduction work of the Earth's critical zone in coal mining affected areas. Based on the evolution of geological conditions for coal resource extraction and the protection of the Earth's critical zone, this paper systematically analyzes the theory and technology of reducing losses and ensuring coal development in the Earth's critical zone from four aspects: Scientific connotation, scientific problems, research ideas, and guarantee plans. Results The overall approach of the research on the response of the Earth's critical zone to coal mining is structured as "Pre–mining geological conditions and key zone structures and elements → Geological condition changes and the Earth's critical zone response modes and evolution status identification → Full time and space active and passive multi–source information response and dynamic monitoring → The Earth's critical zone structure functional dynamic evolution model and intelligent prediction evaluation → The Earth's critical zone loss reduction geological guarantee strategy and restoration reconstruction integrated technical method". The research content includes: (1) Identify the comprehensive characteristics of mining geological conditions such as geological structure, hydrogeology, rock layer combination, and crustal stress with coal occurrence, reveal the spatial relationship characteristics of the Earth's critical and lower coal seams, rock layers, and groundwater, and finely characterize the critical zone with multiple elements, modes, and scenarios, forming a fast query and intelligent analysis digital platform including environmental bearing capacity indicator system, evaluation model, and bearing capacity zoning. (2) Analyze the connection between fracture fields of rock (soil) layers under the impact of mining and the hydrological cycle of critical zones, revealing the synergistic evolution mechanism of geological conditions and critical zones and proposes methods for identifying the response patterns of the Earth's critical zone to coal development. (3) Investigate the temporal and spatial evolution of rock layer structures, fracture networks, seepage channels, stress–energy concentration characteristics, material cycles, energy exchanges, and the multi–source information field under mining factors and construct the spatial–temporal information response model of the Earth’s critical zone under the whole life cycle of coal development. (4) Construct a spatial and multi–directional multi–source information fusion monitoring system for the space–sky–earth–drill–well under the conditions of the whole life cycle of coal mining, form a monitoring and analysis system for the interfacial structure and operation process elements of the Earth's critical zone under the influence of coal mining and predict the structural changes, response patterns, operational processes and ecological and environmental effects of the Earth's critical zone in the coal development zone. (5) Propose technologies such as collaborative development of coal and coal measures resources, comprehensive utilization of mine water, and large–scale utilization of underground space in coal development, functional reconstruction. Establish a geological condition and critical zone structure monitoring technology based on multi–source information, achieving "transparency of geological structural conditions, digitization of key damage elements, informatization of evolution process monitoring, intelligent model prediction, and precision of critical zones protection technology". Conclusions The geological guarantee of the Earth's critical zone covers geological conditions, mining modes, monitoring systems, prediction methods, and loss reduction technologies. It pursues the coordinated development of coal safety mining and geological environment protection, solves the contradiction between resource development and geological environment constraints, improves the theory and technology of comprehensive development of coal and coal bearing resources in ecologically fragile areas, and the protection, restoration, and reconstruction of the Earth's critical zone functions. It provides a scientific basis for geological, mechanical, and physical foundations to build a resource–saving and environmentally friendly society, and promotes the in–depth development of coal engineering practice and safety theory.

Abstract:This paper is the result of mineral exploration engineering. Objective Vanadium is widely used in multiple fields due to its unique physical and chemical properties, playing an increasingly important role in economic development, and its demand is increasing. China is one of the countries with the largest amount of vanadium ore resources, ranking first in the world in terms of total resources, mineral product production, and consumption. It is of theoretical and practical significance to summarize the metallogenic regularity and assess the potential of vanadium. Methods We evaluated the potential of vanadium resources in China based on systematically summarizing the metallogenic regularity and mineralization patterns of vanadium deposits. Results The sedimentary vanadium deposits related to the black rock series are the type of vanadium deposits with the highest proportion of identified resources in China. This type of deposits mainly distributes in the northern edges and southeastern part of the Yangtze block, the Qinling–Dabie orogenic belt, and the northern edge of the Tarim block. The black strata deposited under the influence of marine invasion, biological organic matter, and hot water are the most important elements for searching for this type of deposit. The next important deposit type is vanadium titanium magnetite type related to basic ultrabasic rocks. The mineralization mainly related to deep and large faults. The banded structure igneous rock belt is the most important element for searching for this type of deposit. We delineated 213 prediction areas, including 32 in class A, 85 in class B and 96 in class C. Conclusions The characteristics of vanadium resources in China are abundant resources, low grade, abundant co associated minerals, and complex mineral composition. The low level of mineral processing and smelting technology leads to a low level of comprehensive utilization of vanadium resources and significant waste of resources. To consolidate and cultivate the advantages of vanadium resources in China, we suggest as follows: (1) Increase the investment in the exploration of magmatic– type V–deposits to ensure the production capacity demand of the existing V–industrial base. (2) Strengthen the research and development of sedimentary–type V ore processing and metallurgical technology, and the scientific and technological research and development of high–grade vanadium products. (3) Improve the efficient and high–end development and utilization of vanadium resources.

Abstract:This paper is the result of mineral exploration engineering. Objective China is a major country in terms of phosphate resources and major consumer. In 2016, phosphorus ore was included in the Catalogue of Key Mineral Resources in China. With the increasing demand for phosphorus fertilizer and the depletion of resources in more and more mines, it is urgently necessary to enhance geological prospecting and exploration development of phosphate resources. The study of mineralization regularities serves as an important foundation for resource exploration and development. Methods Building upon previous research, this article further analyzes and summarizes the current status of phosphate development and utilization, types of deposits, spatiotemporal distribution patterns, and prospecting directions in China. It provides a preliminary summary of the mineralization regularities and key prospecting directions for phosphorus ore in China. Results China possesses abundant phosphate resources, but their distribution is highly uneven, primarily concentrated in four provinces: Yunnan, Guizhou, Sichuan, and Hubei. Based on the types of mineralization processes, Chinese phosphate can be classified into five categories: magmatic rock–type, metamorphic–type, sedimentary–type, secondary–type, and guano–type deposits. The mineralization epochs of phosphate in China are extensive, with the major phosphate–bearing periods being the Meishucun period of Early Cambrian, the Duoshantuo period of Late Ediacaran, and the Jinping period of Paleoproterozoic. According to the "Division Scheme of Metallogenic Belts in China," Chinese phosphate can be divided into 27 third–level metallogenic belts and four metallogenic sub–belts. Among them, the Dianzhong–Southwestern Sichuan Metallogenic Belt, the Daba Mountains–Western Hubei Metallogenic Belt, and the Xiang–Qian Metallogenic Belt are the main phosphate metallogenic belts in China. Important prospecting areas include Yunnan, Guizhou, Sichuan, Hunan, Western Hubei, and some regions in northern China. Southern phosphate resources are mainly sedimentary–type deposits, while northern phosphate resources are predominantly magmatic rock–type deposits, primarily distributed in Hebei and Xinjiang provinces. Conclusions Phosphorus is crucial for agricultural food security, as well as for important industries such as new energy and healthcare. As a populous nation, China has a significant demand for phosphorus chemicals. In the face of uneven distribution of phosphate and issues related to excessive mining, it is necessary to strengthen the investigation and research on phosphate resources, as well as study the efficient comprehensive utilization of these resources. This will ensure the stable supply of domestic phosphorus products and environmental safety, while promoting the sustainable development of resources.

Abstract:This paper is the result of oil and gas exploration engineering. Objective Geological investigations of petroleum potential suggest that the Upper Triassic black shales represent the most significant source rock interval in the Qiangtang Basin. However, the organic geochemical characteristics and hydrocarbon generation potential of these source rocks in the deep basin are still under ongoing research due to the lack of deep drilling activities. Methods The well QZ–16, located in the eastern part of the North Qiangtang Depression, has encountered the deepest Upper Triassic strata in the basin to date, revealing significant gas anomalies and a substantial amount of bitumen. This provides a new opportunity to enhance the understanding of deep basin source rocks. Here, organic geochemical analyses of the Upper Triassic black shales were conducted to investigate the organic matter quality, quantity, and levels of thermal maturity as well as the oil–source relationship between the source rock and bituminous oil. Results The TOC content of the Upper Triassic black shales in the well QZ–16 is generally poor to fair organic matter richness, ranging from 0.12% to 1.09%, with an average of 0.47%. These values are higher than the average TOC limit (0.3%) of over–mature source rocks with type II kerogen. The degree of thermal maturity is suggested to be in the over–mature stage based on significantly high T_max (536–602 ℃) and vitrinite reflectance values (R_o = 2.44%–2.77%). The chloroform asphalt A and hydrocarbon generation potential (S₁+S₂) may not reliably reflect the organic matter abundance due to the source rocks being in the over–mature stage. Kerogen type index (8.75–18.5), Ph/nC₁₈ (0.65–1.06), Pr/nC₁₇ (0.34–0.61) and C₂₇–C₂₈–C₂₉ sterane characteristics indicate a mixed organic matter source comprising of lower plankton and higher terrestrial plants of Type II₂ kerogen. Most source rock intervals were deposited under strongly reducing conditions, exhibiting a brown–black kerogen color, which align with biomarker parameters, indicating that the thermal evolution of the black shale is over mature. The oil source correlation parameters reveal a strong affinity between the Triassic bituminous oil seedling and black shale in the well QZ–16, which is self–generated and self–stored. Conclusions The Upper Triassic black shales in the North Qiangtang Depression are mature source rocks with certain hydrocarbon generation potential. The results of this study provide a new reference for evaluating source rocks and analyzing hydrocarbon generation potential in the Qiangtang Basin.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The present–day in–situ stress orientations within deep shale reservoirs of the Wufeng–Longmaxi Formation in the southern Sichuan Basin are intricate and have not been comprehensively evaluated. Moreover, the mechanisms through which local structures influence these stress orientations remain poorly understood. Methods The Yongchuan shale gas field was selected as the study area to systematically investigate the characteristics and controlling factors of in–situ stress orientations. This evaluation employed a multi–faceted approach that included paleomagnetic analysis, seismic wave velocity anisotropy measurements, specialized well logging techniques, microseismic monitoring, and numerical simulations. Results The accuracy of interpreting dipole shear wave logs significantly increased when the bidirectional stress difference coefficient exceeds 0.2 and the shear wave anisotropy index is above 18%. In the strata with steep dips (>60°), it is essential to consider the influence of bidirectional stress differentials and high–angle fracture development on the interpretation of in–situ stress orientations. The in–situ stress orientations in the northern and southern synclinal regions of Yongchuan area predominantly follow east–west trend. However, these orientations exhibit significant deviations in anticlinal and fault–influenced zones, with maximum angular discrepancies of approximately 70°±5°. Based on the observed reverse trends in stress orientations above and below a specific stratigraphic level, we hypothesize that the neutral surface is located within the 1–2 layers of the Longmaxi Formation in the Yongchuan area. Furthermore, the fold–induced stress, ranging from 10 MPa to 30 MPa, significantly impacts the principal stress field and cannot be overlooked. As the distance from the fault decreases, Poisson’s ratio (ν) increases, leading to a deflection in the in–situ stress orientations and exhibiting greater sensitivity to changes in ν. Conclusions The orientation of maximum principal stress promotes the preservation of shale gas in syncline areas, while high–angle natural fractures in anticline areas are more likely to develop into effective fractures. We recommend deploying horizontal wells with an SN–NEE orientation in syncline areas, and a NE orientation with a layered well layout in anticline and fault zones.

Abstract:This paper is the result of oil and gas exploration engineering. Objective With the rapid expansion of shale gas production in China, deep shale gas reservoirs at burial depths of 3500–4500 m have become critical targets for exploration. However, complex geological conditions and stress disturbances from fracture systems significantly hinder development. Methods This study focuses on the Wufeng–Longmaxi Formation in the North Luzhou district of the southern Sichuan Basin. By analyzing the spatial distribution of fractures and conducting single–well geostress evaluations, the characteristics of stress disturbance caused by fractures were clarified. A comprehensive table and distribution map of stress disturbance elements were created. Results (1) Fractures in the study area exhibit diverse types and phases, with a tectonic style dominated by "syncline, slope, and anticline slope." The fracture combinations primarily follow a pattern of "syncline, superposition, and anticline backslope". (2) The regional geostress state is complex, with average stress values of S_H(112.7 MPa) >S_v(106.6 MPa) >S_h(98.8 MPa). Fractured zones exhibit stress values 5–35 MPa lower than non–fractured zones. The maximum horizontal stress orientation ranges from 75° to 120°, showing significant variability across wells. (3) Fractures influence stress distribution, with stress disturbance increasing alongside fracture levels. The disturbance range of Class II fractures spans 1.43–1.85 km. NEE—EW fractures exhibit the largest disturbance ranges 0.94–1.85 km. Conclusions A fracture disturbance distribution map was developed for the North Luzhou district, dividing the area into fracture and non–fracture zones to enable hierarchical evaluation of development units. Optimized layouts for horizontal well sections in fractured and non–fractured zones were proposed, offering guidance for future production.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The Yichang area of Hubei Province is one of the important frontier areas of shale gas exploration on the middle Yangtze platform. Field investigation and drilling works in recent years show that the Cambrian Shuijngtuo Formation in this area is a shale gas exploration target with great potential industrial value. Methods Based on the latest borehole data in this area, the characteristics of high–quality shale reservoirs and the hydrocarbon accumulation patterns are identified by means of multidisciplinary methods. Results The shale of the Shuijngtuo Formation has high organic matter abundance, with TOC mainly distributed in the range of 0.56%–8.42%. Organic matter is dominated by type II₁ and type I kerogen, and R_o equivalent value is distributed in the range of 2.4%–3.2%. Porosity and permeability values of shale reservoirs within the Shuijngtuo formation are mainly in the range of 0.5%–9.1% and 0.019×10^–3–0.540×10^–3 μm². Reservoir pore spaces of shales within the Shuijngtuo Formation mainly includes organic pores, inorganic pores and fractures. Occurrence of pore spaces is mainly related to the enrichment degree of organic matter, the content of clay minerals and the development degree of fractures. Natural gas is mainly attached to the shale reservoir in the form of adsorbed gas (45.21%–81.44%) and free gas (18.56%–54.79%), and the proportion of dissolved gas is relatively small. The gas bearing property of the shale reservoir is mainly related to the content of organic carbon, the proportion of brittle minerals and the degree of fracture development. The higher the proportion of organic carbon, the proportion of brittle minerals, and the degree of fracture development, the better the gas bearing property of the reservoir becomes. Conclusions Based on the geochemical, petrophysical and field measurement data, the shale gas of the Shuijingtuo Formation in Yichang area has great commercial value and is one of the ideal targets for shale gas exploration and development in southern China.

Abstract:This paper is the result of agricultural geological survey engineering. Objective Cadmium pollution in soil has become an important environmental issue concerned both at home and abroad. This paper focuses on the research status and development direction of cadmium pollution in soil and plants and the remediation technology, and tries to provide help for the related theoretical research and production practice. Methods Based on consulting a large number of literature related to cadmium pollution in soil and plants and the remediation technology, the harm of cadmium, the current situation of cadmium pollution in soil, the influence mechanism of cadmium on plants, the mechanism of migration and transformation of cadmium from soil to the plant system and the remediation technology have been systematically introduced and objectively reviewed. Results Soil cadmium pollution in China shows a trend of diversified development, Cadmium pollution has been found in cultivated land, woodland, grassland, in both gardens and unused land, especially in cultivated land. Cadmium has a significant impact on plant growth and development, antioxidant enzyme activity, photosynthesis and respiration. The migration of cadmium from soil to plant systems is mainly in the form of cadmium ions and clathrate, related to the interface process, in virtue of the carrier and channel to achieve. The remediation technology can be divided into chemical and biological categories, mainly includes biochar, mineral materials, organic fertilizers, microorganisms, plants, animals and combined restoration technology. Conclusions Cadmium has great harmfulness and the cadmium pollution is still a serious problem for farmland soil in China. The effects on plants and migration and transformation of cadmium in soil plant systems involve multiple mechanisms. Kinds of the remediation technology for cadmium pollution in farmland soil has its own principles and advantages, and the joint remediation technology has a good development prospect. Continuous efforts in theoretical and practical research must be made on cadmium pollution in soil and plants and the remediation technology, to build an effective cadmium pollution prevention and control technology system to ensure the safe production of food.

Abstract:This paper is the result of CCUS (Carbon Capture Utilization and Storage) engineering. Objective At present, global warming is one of the most serious challenges in the world. To reduce carbon emissions, carbon dioxide geological storage emerge as an effective way. However, the process may bring a series of impacts on both the reservoir and the cap layer, creating a risk of carbon dioxide leakage. The change of reservoir physical parameters before and after carbon dioxide injection lays a theoretical basis for geophysical monitoring methods such as logging, seismic, electromagnetic and gravity. Methods This paper firstly outlines the potential risks of carbon dioxide geological storage and the corresponding geophysical monitoring methods, then discusses the research progress of various geophysical monitoring techniques in the field of carbon dioxide geological storage, and finally analyzes the technical challenges and application limitations faced by current geophysical monitoring techniques, while also looking ahead to their future development. Results In the face of numerous geomechanical difficulties that may develop throughout the carbon dioxide geological storage process, we can use a variety of geophysical monitoring approaches to target them. For example, we can utilize InSAR, microseismic and time–lapse gravity methods for surface deformation; microseismic methods for induced seismicity; and well–logging methods to damage wellbore integrity. For tracking carbon dioxide plume transportation and potential leakage, time–lapse gravity/seismic, microseismic, and resistivity tomography methods can all play important roles. The advancement of geophysical monitoring technology has given us tremendous confidence in practical applications, but the limitations of the technology itself, the complexity of data processing, and the constraints of the field environment remain significant difficulties that must be addressed. With the booming development of artificial intelligence, geophysical monitoring technology also has new development prospects. In addition, the comprehensive utilization of multi–source information will foster innovation and progress in geophysical monitoring technologies. Conclusions Carbon dioxide geological storage is a new opportunity for the geophysical industry brought by the dual–carbon target, and vigorously developing a suitable long–term and stable monitoring system for carbon dioxide geological storage is an important application field for geophysics to develop new markets. Leveraging the wave of artificial intelligence and integrating multiple geophysical methods to monitor carbon dioxide geologic storage projects is a trend for the future.

Abstract:This paper is the result of energy exploration engineering. Objective Geological hydrogen storage has the outstanding advantages of large scale, long period and cross–season energy storage, which is an important development direction of large–scale hydrogen energy storage in the future. Methods This review systematically collects and collates the research results in the field of geological hydrogen storage, and discusses the current situation of geological hydrogen storage engineering based on literature investigation. At the same time, the review makes full reference to the experience of salt cavern gas storage engineering construction, analyzes the challenges in the construction of salt cavern hydrogen storage in China, and puts forward solutions. Based on the salt basin resource condition and the comprehensive utilization experience of salt cavern in Jintan District of Jiangsu Province, the possibility of constructing the technical route of salt cavern hydrogen storage is explored. Results (1) Geological hydrogen storage facilities are classified according to geological structures into salt caverns, depleted oil and gas reservoirs, aquifers, and abandoned mines. Among these, salt cavern storage facilities have the highest number of operational and research projects. They achieve hydrogen storage with purity exceeding 95%, making them the primary direction for large–scale geological hydrogen storage development. (2) The construction cycle of salt cavern hydrogen storage can be divided into eight stages, including site selection, drilling, solution mining, injection and production completion, gas first fill, snubbing, operation and monitoring, which can refer to the construction experience of salt cavern natural gas storage, but there are still problems in policy, materials and construction technology. (3) In Jintan area of Jiangsu Province, the salt cavern hydrogen storage technology route can be combined with the salt cavern compressed air energy storage and salt cavern natural gas storage technology to form a set of comprehensive technical solutions, including renewable energy power generation technology, high–pressure air compression technology, electrolytic water hydrogen production technology and natural gas pipeline hydrogen mixing technology. Conclusions In recent years, the site selection, investigation, and experimental verification of geological hydrogen storage facilities abroad have been accelerating, with several geological hydrogen storage projects in the pilot stage. Considering factors such as safety, economy, and technical difficulty, salt cavern storage is considered the primary direction for large–scale geological hydrogen storage in our country. Establishing a salt cavern hydrogen storage verification platform and advancing demonstration project construction will help to form a salt cavern hydrogen storage technology system with independent intellectual property rights.

Abstract:This paper is the result of geohazard survey engineering. Objective The occurrence of geohazards are influenced by various factors, which have uncertainty and complexity, making it difficult to assess the risk of geohazards. With the development of AI technology, intelligent algorithms can more accurately calculate the complex and nonlinear relationships between geohazard triggering indexes, greatly improving the accuracy of geological hazard risk assessment models. Methods Based on the field geological survey data of Da'an Town, Ningqiang County, 12 indexes closely related to the occurrence of geohazards were selected, namely elevation, slope, slope height, slope direction, slope type, engineering geological rock formations, fault distance, water system distance, road distance, vegetation coverage, rainfall, and seismic ground motion, as risk zoning evaluation factors. By constructing a sample set, Bayesian, strategy gradient neural network, random forest, KNN and neural network algorithm are used to model and compare the geohazard risk assessment result in Da'an Town, Ningqiang County. Results The experimental results show that the Bayesian model (AUC 0.894) performs the best, with the vast majority of geohazards located in the extremely high and high–risk evaluated areas, and meets the requirements for prediction accuracy evaluation. Conclusions It is feasible to choose Bayesian algorithm models for geological hazard risk assessment when the number of geohazard samples is small.

Abstract:This paper is the result of hydrogeological survey engineering. Objective Due to the dual impacts of climate change and human activities, there is an urgent need to deepen the understanding of the evolution of water resources in the Greater Bay Area of Guangdong, Hong Kong and Macao, with a view to providing a scientific basis and decision–making support for the realization of the sustainable management of regional water resources. Methods This paper employs a combination of qualitative and quantitative methods, leveraging in–depth analysis of historical literature alongside multi–source water resource monitoring data to comprehensively examine changes in hydrology, precipitation, land cover, and other environmental factors related to water resources in the Greater Bay Area over the past 40 years (1980–2020). It also explores the regional patterns of differentiation in these changes. Results Our findings reveal a general water resource distribution trend of "abundance in the west and north, scarcity in the east and south," with an average temperature of 22.2℃ and annual precipitation of 2022.1 mm from 1980 to 2022. The study observes a major cyclical change every 4.1 years. The average runoff of the Xijiang, Beijiang, and Dongjiang Rivers is quantified, alongside the variation in runoff coefficients, reflecting a warm and humid climatic trend. Concurrently, the total volume of water bodies exhibits a declining trajectory, while vegetation cover overall shows an increase but with local degradation. Conclusions The study identifies 41 potential emergency backup water sources, with a sustainable extraction capacity of 2342600 m³/day.It highlights the ongoing mismatch between water resources and economic development in the Greater Bay Area, the reduction of water ecosystem service functions, the spatial and temporal imbalances in water resource distribution, and the region's over–reliance on a predominantly surface water–based supply structure.

Abstract:This paper is the result of marine geological survey engineering. Objective The heavy metal contents in the Xiamen Bay have been greatly changed due to the ecological management in the bay and the port construction in Xiamen City. Identifying the distributions, evolution, and sources of heavy metals in the bay is significant for the prevention and control of heavy metal pollution, as well as ecological risk management. Methods This study determined the contents of seven heavy metals in 87 surface samples from bottom sediments in the Xiamen Bay and the Jiulong River estuary, investigated the distributions and the degrees of enrichment of these heavy metals, and quantitatively analyzed the primary sources of these heavy metals using factor analysis and principal component analysis. Results The western Xiamen Bay displays the highest average mass contents of heavy metals Cu (26.37 mg/kg), Zn (122.58 mg/kg), and Cr (57.25 mg/kg). In contrast, the Jiulong River estuary exhibits the highest contents of Pb (48.03 mg/kg), Cd (0.25 mg/kg), Hg (0.085 mg/kg), and As (9.35 mg/kg). Cu in the western Xiamen Bay exhibits the highest over–limit ratio of up to 25%, followed by Zn (20.69%) in the Jiulong River. In the Xiamen Bay, the enrichment coefficients of heavy metals decrease in the order of Cu (1.01), Cr (0.99), Cd (0.70), Zn (0.64), Pb (0.63), As (0.48), Hg (0.33), indicating that Cu is moderately enriched, Cr approximate to their background values, and Hg is severely enriched. Conclusions The potential sources of the seven heavy metals in the Xiamen Bay include mine smelting, the weathering of natural parent rocks, the discharge of agricultural and domestic sewage, and fossil fuel combustion, which account for 36.16%, 22.03%, 21.98%, and 19.83%, respectively. Among these heavy metals, Cu, Zn, Cd, and Cr originate primarily from mine smelting, As from fuel combustion (85.76%) and agricultural non–point source pollution (14.16%), and Pb and Hg principally from the weathering of parent rocks. Zones with moderate and high ecological risks induced by heavy metals in sediments are concentrated in the Jiulong River estuary and the Xiamen Harbor.

Abstract:This paper is the result of geothermal exploration engineering. Objective Gaoyang geothermal field rich in low–medium temperature geothermal resources. Hydrogeochemical research of geothermal fluids is an effective method to understand the processes of deep geothermal water circulation and to reveal the genesis mechanism of geothermal systems. Methods Through analyzing hydrochemical and isotopic data of geothermal water samples in Gaoyang field, we can explore the formation and development process of deep geothermal water. Results The hydrochemical type of carbonate reservoirs is Cl–Na type, and that of sandstones reservoirs is HCO₃·Cl–Na and Cl·HCO₃–Na type. The ionic components in geothermal water are mainly controlled by the dissolution of salt rock and carbonate rock and the alternating adsorption of cations. Geothermal water is recharged from precipitation in the Taihang and Yanshan mountains, The recharge elevation of geothermal water is 759.12–1092.33 m. The geothermal reservoirs temperature of Jxw is 102–154℃, and the depth of thermal cycle is 2524–4020 m; the geothermal reservoirs temperature of Ng is 61–84℃, and the depth of thermal cycle is 1357–2024 m. Conclusions In Gaoyang geothermal field, the γNa⁺/γCl^– of samples from the Jxw reservoirs is smaller than that Ng reservoirs, and the γSO₄^2–/γCl^– and γCl^–/(γHCO₃^–+CO₃^2–) are larger than that of the Ng reservoirs. This indicates that Jxw reservoirs has a higher degree of metamorphism, better confinement, slower geothermal water circulation and higher degree of salinization than the Ng reservoirs. The heat from the deep thermal storage is partly transferred upward by thermal convection through hot water along the fault channels, and partly transferred upward by thermal conduction through rocks, forming a convection–conduction type geothermal system.

Abstract:This paper is the result of ecological geological survey engineering. Objective Changdu City serves as a critical ecological corridor on the eastern Qinghai–Xizang Plateau. The ecosystem service evaluation methodology recommended by the existing "dual evaluation" guidelines fails to adequately capture the unique characteristics of the ecosystem within the study area. This paper enhances the assessment methodology regarding the significance of ecological protection, thereby improving the feasibility of integrating the research findings into practical ecological conservation efforts. The evaluation outcomes will provide a foundational basis for establishing ecological protection boundaries and inform subsequent ecological restoration initiatives. Methods In light of the distinctive characteristics of the plateau environment, the evaluation system incorporates carbon sequestration and freeze–thaw erosion processes. Utilizing enhanced methodologies for assessing ecosystem services and ecological sensitivity, this study evaluates the significance of ecological protection in Changdu City. Results The highly significant ecological protection zone in Changdu City encompasses 51.35% of the total land area and is primarily categorized into two distinct types. The first category consists of regions exhibiting favorable ecological conditions that play crucial roles in water and soil conservation; These areas are predominantly located in the mountainous regions along the Jinsha River, Lancang River, and Nujiang River. The second category comprises areas experiencing vegetation degradation, land desertification, soil and water erosion, and other environmental challenges, which are mainly found in the northern part of Dingqing County, as well as the central and southern regions of Basu County and the western section of Bianba County. Conclusions The majority of regions within Changdu City are situated in areas designated as critically important and significant for ecological protection, exhibiting robust ecosystem service functions. However, certain areas also demonstrate heightened sensitivity to ecological disturbances. Consequently, it is imperative to devise and rigorously implement tailored ecological protection measures that correspond to the specific characteristics of each area during the development process. This approach aims to mitigate the adverse impacts of various anthropogenic activities on the ecosystem in the context of climate change, thereby ensuring the integrity of the ecological barrier of the Qinghai–Xizang Plateau.

Abstract:This paper is the result of agricultural geological survey engineering. Objective Metal elements mainly enter the human body through the food chain, thus affecting health. Research on the geochemical characterization of heavy metal elements in the soil–rice system is significant for the scientific management of arable land, the guarantee of food security and the implementation of the strategy of a healthy China. Methods A total of 129 sets of rice seeds and root soil samples were systematically collected, analyzed by chemical analysis to obtain geochemical data such as As, Cd, Hg, Pb, Cr, pH, and soil Cd morphology, thus using the human health risk model to assess the health risk in the study area. Results (1) The average soil Cd content in the study area was 0.49 mg/kg, which was significantly higher than the n background value of Jiangxi surface soil. There were 80 soil samples Cd content higher than the risk screening value, accounting for 62%. There were 57 rice seeds with excessive Cd content, the rate of exceeding the standard was 44%. (2) The results of the pollution evaluation of soil Cd and safety evaluation of rice seeds Cd in the study area were poorly correlated. Soil pH was the major influencing factor, with soil alkalinity increasing, soil Cd content increased by 2.3 times, but rice seeds Cd content decreased by 4.5 times. (3) The three fugitive forms of water–soluble, exchangeable and residual Cd in the soil had a significant effect on the Cd content of rice seeds, and the bio–efficacy of Cd was enhanced in a strongly acidic soil environment. (4) Children in the study area have greater health risks than adults, with non–carcinogenic and carcinogenic risk factors dominated by the heavy metal Cd. Conclusions The correlation between soil Cd and rice seeds Cd content in the study area is relatively poor, and there are some limitations of misjudgment and omission according to the current norms; the health risk evaluation results revealed that there is a human health risk caused by rice Cd intake in the study area.

Abstract:This paper is the result of environmental geological survey engineering. Objective This study investigated the contents and spatial distributions of heavy metals in surface soils in Yuanzhou District, Guyuan City, Ningxia, evaluating heavy metal accumulation and its associated ecological risk. Methods A total of 12988 soil samples were collected and the levels of eight heavy metals, namely, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, were measured. The single–factor index, Nemerow comprehensive pollution index, and potential ecological hazard index were used to estimate the ecological risks associated with heavy metal contamination in soils. Results Compared to the background values of the Ningxia Autonomous Region, the average enrichment coefficients of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were 1.01, 1.42, 1.04, 0.99, 1.03, 0.81, 1.01, and 1.07, respectively. Similar distributions of the eight heavy metals, with high concentrations, were observed in areas characterized by high human activity, such as the east and west sides of Liupan Mountain, as well as Guyuan City, Zhangyi Town, and Huangduobao Town. In contrast, low concentrations were observed in Tanshan Township and Zhaike Township in the northeast Quaternary areas with loess–covered soil. Single–factor index evaluation revealed that the soil was "clean" in the Yuanzhou area. Evaluation using the Nemerow comprehensive pollution index indicated that the soil pollution index of all heavy metals was less than 0.7, which is considered "clean." While the single–element potential hazard index of Cd and Hg showed a level of moderate risk, the comprehensive potential ecological hazard index of the heavy metals showed slight risk levels. Conclusions The soil quality in Yuanzhou District, Guyuan City, is in good condition, although slight enrichment of heavy metals was seen in the topsoil due to human activities in some areas.

Abstract:This paper is the result of environmental geological survey engineering. Objective Taking the eastern part of Leizhou as research area, this paper studies the concentration and spatial distribution characteristics of heavy metals in soil, analyzes the sources of heavy metals, evaluates the degree of heavy metal pollution, and assess the health risks to human health. Methods A total of 381 soil samples are collected to measure the concentration of heavy metal elements such as As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. GIS technique is used to analyze the spatial distribution characteristics of soil heavy metals; the single factor pollution index and Nemerow comprehensive pollution index methods are used to evaluate the degree of soil heavy metals pollution, and Monte Carlo health risk model is used to assess human health risks. Results (1) The average concentration values of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil are 5.85×10^–6, 0.079×10^–6, 64.03×10^–6, 14.11×10^–6, 0.07×10^–6, 21.23×10^–6, 35.38×10^–6, 76.45×10^–6, respectively. Among them, the average concentration values of Cd, Cr, Ni and Zn in the surface soils exceed the background values of soils in Guangdong Province, which indicates that these four heavy metal elements in the soil are relatively enriched. (2) The single factor pollution index and Nemerow comprehensive pollution index show that the soil is "clean" in the study area, with only a few points being polluted slightly. (3) In addition to geological background sources, heavy metals in surface soil also come from sources such as transportation, agriculture, and industry. (4) The health risk assessment of heavy metals shows that the non–carcinogenic health risks of children and adults could be ignored, but there are tolerable carcinogenic risks for both children and adults. The major carcinogenic factor is As. Sensitivity analysis indicates that the SL (Skin adhesion coefficient) is the primary factor affecting non–carcinogenic health risk, while the SL and As are the primary factors affecting carcinogenic health risk in adults and children, respectively. The main exposure routes of carcinogenicity are skin exposure and hand–oral exposure. Conclusions The pollution of soil heavy metals in the eastern of Leizhou is relatively low, and the ecological risk is low on the whole. However, Hg and Cd should be given sufficient attention. As is the main carcinogenic factor affecting human health, and pollution prevention and control of As should be strengthened.

Abstract:This paper is the result of oil–gas exploration engineering. Objective Dingbei area of Ordos Basin is rich in tight gas resources of Upper Paleozoic and has great exploration potential. However, faults are widely developed in this area, and the characteristics of geostress field near the fault zone are unknown, which seriously restricts oil and gas exploration and development in this area. Methods This paper conducts a detailed analysis of the characteristics of the Upper Paleozoic geostress field in the study area based on differential strain experiment, acoustic emission experiment, logging interpretation of geostress size, wave velocity anisotropy experiment, paleomagnetism experiment, imaging logging and dipole acoustic logging data interpretation of geostress direction, numerical simulation and other methods, in order to find out the distribution characteristics and disturbance mechanism of the geostress field in Dingbei area. Results The three–dimensional stress of Upper Paleozoic in Dingbei area has the characteristics of vertical principal stress>maximum principal stress>minimum principal stress, and the regional geostress field is mainly controlled by the fault zone, and the stress disturbance degree is related to the fault location, fault scale, fault genesis and other factors, among which the three–dimensional stress in the karst fault zone is relatively lowest. The direction of regional principal stress field is N35°E~N45°E. The direction of reservoir geostress is mainly controlled by the direction of regional principal stress field and fault zone, and the range and degree of geostress disturbance caused by different types of fault zones are different, among which the range of geostress disturbance is mainly affected by fault strike and fault length. Conclusions Based on the research on the characteristics of geostress field, this paper clarifies the distribution characteristics and disturbance law of geostress size and direction in Dingbei area, discusses the disturbance mechanism of different genetic fault zones on geostress size, and establishes a prediction model for the disturbance width of geostress direction in the research area, which has important reference value for subsequent well pattern deployment and fracturing reconstruction.

Abstract:This paper is the result of hydrogeological survey engineering. Objective In hydrogeological contexts, biological growth and human health are closely linked to the concentrations of elements present in the surrounding environment, including water and soil. Investigating the formation and evolutionary conditions of both macro and trace elements associated with health in groundwater, as well as establishing regional health geology, is beneficial for advancing the implementation of the Healthy China strategy. Methods Xiong'an New Area was chosen as the primary research site. The hydrogeochemical characteristics and sources of mineral composition in shallow groundwater were analyzed using multivariate statistical analysis, as well as the Piper and Chadha diagrams. This study restored the water quality by identifying the material element sources of shallow groundwater along a typical profile, delineated hydrochemical types, and classified the differentiation areas of macro and trace elements based on biological necessity, environmental factors, and element abundance or deficiency. Furthermore, it established a health geology regionalization for Xiong'an New Area. Results The parameters of groundwater exhibited significant variability. The water–rock interactions indicate that the dissolution of albite contributes sodium ions (Na⁺), while the dissolution of fluorite and gypsum contributes fluoride ions (F^–) and sulfate ions (SO₄^2–), consuming calcium ions (Ca²⁺), magnesium ions (Mg²⁺), and bicarbonate ions (HCO₃^–), alongside the precipitation of calcite and dolomite, with reverse ion exchange also occurring. In the northern part of the study area, the predominant hydrochemical types were HCO₃–Ca and HCO₃–Ca·Mg. This composition transitioned to HCO₃·SO₄–Na·Mg·Ca, HCO₃·Cl–Na·Ca·Mg, and HCO₃·SO₄·Cl–Na·Mg in the middle section, ultimately evolving into SO₄·HCO₃–Na·Mg in Baiyangdian and downstream of the Daqing River. Xiong'an New Area can be categorized into three regions: A health geology regionalization characterized by a deficiency of elements in the northern alluvial–proluvial plain; A health geology regionalization with moderate element levels in the interaction zone between the alluvial–proluvial plain and the alluvial–lacustrine plain; And a health geology regionalization with an excess of elements in the alluvial–lacustrine plain. Prolonged consumption of groundwater from both the deficient and excess areas may lead to health issues. Conclusions It is essential to examine the endemic diseases associated with the local surplus and deficiency of fluoride (F^–), sulfate (SO₄^2–), total hardness, and iodide (I^–) in Xiong'an New Area. Additionally, identifying alternative water sources or supplementing the necessary elements for human health is crucial to support the Healthy China strategy.

Abstract:This paper is the result of hydrogeological survey engineering. Objective There are many tectonic karst areas with complex karst hydrogeological structures, diverse recharge sources, and abundant groundwater in the eastern part of the Qinghai–Xizang Plateau. Analyses and research of the recharge sources and details about the controls on groundwater cycling in the tectonic karst on the plateau are important for guiding the development and utilization of karst water resources, protecting the ecology, and preventing and reducing disasters. Methods Using information from field investigations, flow measurements, hydrochemistry and stable isotope analysis, we analyzed the groundwater recharge sources in the karst areas in the eastern part of the Qinghai–Xizang Plateau, considered the factors that influenced the recharge sources and recharge progress, and made recommendations for the development and utilization of the groundwater. Results Atmospheric precipitation was the main recharge source of the main karst springs on the eastern Qinghai–Xizang Plateau. There were four main recharge modes, including direct recharge through high–level fissures, continuous recharge from high–level lakes, continuous seepage recharge in catchment depressions, and river seepage. Conclusions The different recharge modes in the eastern Qinghai–Xizang Plateau developed over sustained time periods because of the coupling of internal factors, such as the history of the karst formation and its evolution, the geological structure, and the lithologic combination, and external factors, such as the meteorology, the landforms, and glacier movements. From our analysis of the characteristics of the water quality and quantity of the karst springs, we developed three categories for the development and utilization of the groundwater resource, namely karst springs with water quality in classes Ⅰ–Ⅲ, the development and utilization of which can be expanded; brackish water, which can be developed and utilized after mixing with other water; and salt water, which can be transformed and used for developing tourism.

Abstract:This paper is the result of soil geochemical survey engineering. Objective Selenium (Se) is one of the essential trace elements for human body. The development and utilization of Se–rich land and Se–rich agricultural products have become a pivotal practice in rural revitalization. Nonetheless, it is challenging to accurately guide the local government to develop Se–rich land resources in accordance with nothing more than the content of Se in soil. Methods The northwestern part of Longshan County, Hunan Province were selected as the explored area in this paper. The influencing factors of Se bioconcentration factors of rice were systematically and comprehensively explored on the basis of 1∶50000 land quality geochemical survey data and national land survey results data. Accordingly, the prediction model of Se bioconcentration factors of rice was established. Aside from that, the Se–rich land quality evaluation system was put forth by integrating with land fertility and ecological environment. Results (1) The soil Se content was 0.19–0.84 mg/kg, with an average value of 0.48 mg/kg. The Se content of rice seeds was 0.02–0.23 mg/kg, with an average value of 0.10 mg/kg, and the Se–rich rate of rice seeds was 82%. (2) The Se bioconcentration factors of rice seeds displayed negative association with soil Cd, S, and TC, among which the correlation coefficients were -0.617, -0.452, and -0.574, separately. (3) As suggested by the zoning results, the pollution–free medium–high yield cultivated land with Se enrichment in the explored area accounts for 78%; The pollution–free medium–high yield cultivated land, the pollution–free low yield cultivated land, the cultivated land of safe utilization, the cultivated land of prudent utilization account for 13%, 4%, 4% and 1%, respectively. Conclusions On the basis of scientific prediction of crop seeds Se content, a block scale Se–rich land quality evaluation system was innovatively constructed based on Se content of crops, land fertility and ecological environment in this paper. On this basis, this research is expected to offer paramount reference and demonstration significance for local governments to develop Se–rich land resources.

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