China established Xiong'an New Area in Hebei Province in 2017, which is planned to accommodate about 5 million people, aiming to relieve Beijing City of the functions non-essential to its role as China's capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region. From 2017 to 2021, the China Geological Survey (CGS) took the lead in multi-factor urban geological surveys involving space, resources, environments, and disasters according to the general requirements of “global vision, international standards, distinctive Chinese features, and future-oriented goals” in Xiong'an New Area, identifying the engineering geologic conditions and geologic environmental challenges of this area. The achievements also include a 3D engineering geological structure model for the whole area, along with “one city proper and five clusters”, insights into the ecology and the background endowment of natural resources like land, geothermal resources, groundwater, and wetland of the area before engineering construction, a comprehensive monitoring network of resources and environments in the area, and the “Transparent Xiong'an” geological information platform that is open, shared, dynamically updated, and three-dimensionally visualized. China's geologists and urban geology have played a significant role in the urban planning and construction of Xiong'an New Area, providing whole-process geological solutions for urban planning, construction, operation and management. The future urban construction of Xiong'an New Area will necessitate the theoretical and technical support of earth system science (ESS) from various aspects, and the purpose is to enhance the resilience of the new type of city and to provide support for the green, low-carbon, and sustainable development of this area.
The Hot Dry Rock (HDR) is considered as a clean and renewable energy, poised to significantly contribute to the global energy decarbonization agenda. Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion, reservoir construction, and fracture simulation. In 2019, China Geological Survey (CGS) initiated a demonstration project of HDR exploration and production in the Gonghe Basin, aiming to overcome the setbacks faced by HDR projects. Over the ensuing four years, the Gonghe HDR project achieved the first power generation in 2021, followed by the second power generation test in 2022. After establishing the primary well group in the initial phase, two directional wells and one branch well were drilled. Noteworthy progress was made in successfully constructing the targeted reservoir, realizing inter-well connectivity, power generation and grid connection, implementing of the real-time micro-seismic monitoring. A closed-loop technical validation of the HDR exploration and production was completed. However, many technical challenges remain in the process of HDR industrialization, such as reservoir fracture network characterization, efficient drilling and completion, multiple fracturing treatment, continuous injection and production, as well as mitigation of induced seismicity and numerical simulation technology.
A detailed understanding of the distribution and potential of natural gas hydrate (NGHs) resources is crucial to fostering the industrialization of those resources in the South China Sea, where NGHs are abundant. In this study, this study analyzed the applicability of resource evaluation methods, including the volumetric, genesis, and analogy methods, and estimated NGHs resource potential in the South China Sea by using scientific resource evaluation methods based on the factors controlling the geological accumulation and the reservoir characteristics of NGHs. Furthermore, this study compared the evaluation results of NGHs resource evaluations in representative worldwise sea areas via rational analysis. The results of this study are as follows: (1) The gas hydrate accumulation in the South China Sea is characterized by multiple sources of gas supply, multi-channel migration, and extensive accumulation, which are significantly different from those of oil and gas and other unconventional resources. (2) The evaluation of gas hydrate resources in the South China Sea is a highly targeted, stratified, and multidisciplinary evaluation of geological resources under the framework of a multi-type gas hydrate resource evaluation system and focuses on the comprehensive utilization of multi-source heterogeneous data. (3) Global NGHs resources is nx 1015 m3, while the NGHs resources in the South China Sea are estimated to be 1013 m3, which is comparable to the abundance of typical marine NGHs deposits in other parts of the world. In the South China Sea, the NGHs resources have a broad prospect and provide a substantial resource base for production tests and industrialization of NGHs.
This study aims to reveal the occurrence and origin of typical groundwater with high arsenic and fluoride concentrations in the loess area of the Guanzhong Basin—a Neogene faulted basin. Key findings are as follows: (1) Groundwater samples with high arsenic and fluoride concentrations collected from the loess area and the terraces of the Weihe River accounted for 26% and 30%, respectively, of the total samples, with primary hydrochemical type identified as HCO3-Na. The karst and sand areas exhibit relatively high groundwater quality, serving as preferred sources for water supply. It is recommended that local governments fully harness groundwater in these areas; (2) groundwater with high arsenic and fluoride concentrations in the loess area and the alluvial plain of rivers in Dali County is primarily distributed within the Guanzhong Basin, which represents the drainage zone of groundwater; (3) arsenic and fluoride in groundwater originate principally from natural and anthropogenic sources; (4) the human health risk assessments reveal that long-term intake of groundwater with high arsenic and fluoride concentrations pose cancer or non-cancer risks, which are more serious to kids compared to adults. This study provides a theoretical basis for the prevention and treatment of groundwater with high arsenic and fluoride concentrations in loess areas.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants of growing concern due to their potential ecological and human health risks. This study presents a comprehensive assessment of PAHs contamination in the surface sediments of Burullus Lake, a vital and second largest delta lake in Egypt. The aim was to evaluate the eco-toxicity and potential health risks associated with the presence of these compounds. Surface seven sediment samples were collected from various drains in the southern part of Burullus Lake. Soxhlet extraction method was employed to extract PAHs (16PAHs) from the sediment sample. Analytically, target compounds were located using HPLC. The results showed that samples contained PAHs levels ranging from 0.038×10-6 to 0.459×10-6, which is considered heavily polluted by the European standard for PAHs pollution. Additionally, there was no apparent source of PAHs in the El-Khashah drain or the Brinbal Canal, as HPLC found none of the compounds. The most prevalent compound in sediment samples along the study area was fluoranthene. The diagnostic indices in the present study indicated that the hydrocarbons in the region originated from pyrolytic and man-made sources along the drains of Burullus Lake. The principal component analysis (PCA) and diagnostic ratios revealed that coal combustion and pyrolytic sources were responsible for the PAHs contamination in the surface sediments. The non-carcinogenic risk (HI), which is the product of the HQs for the adult and child populations, respectively, was calculated. HI values under 1, therefore, demonstrated that they had no carcinogenic effects on human health. TEQs and MEQs in the sediments of Burullus Lake do not have a cancer-causing impact on people. For the safety of nearby wildlife, aquatic life, and people, all activities that raise petroleum hydrocarbon levels in Burullus Lake must be adequately regulated and controlled. According to the ecological risk assessment, there is little chance that PAHs will be found in the sediments of Burullus Lake. This study underscores the urgent need for effective pollution control measures and regular monitoring of PAHs levels in Burullus Lake sediments to protect the aquatic ecosystem and public health. It also highlights the importance of considering eco-toxicity and human health risks in integrated risk assessments of PAHs-contaminated environments.
To understand the levels of potentially toxic elements (PTEs) contamination in soils and their effects on human health from different agricultural land use in Sanya, China. 128 soil samples (64 topsoil samples and corresponding subsoil samples) were collected from the five representative land-use patterns. Inductively coupled plasma mass spectrometry (ICP-MS), Atomic fluorescence spectrometry (AFS), and Inductively coupled plasma optical emission spectrometry (ICP-OES) were used to determine the content of PTEs (As, Cd, Hg, Cu, Cr, Ni, Pb, Zn, Co, Mo, Sb, and V). Correlation analysis and factor analysis were used to determine the source of PTEs. Geo-accumulation index (Igeo), hazard quotient (HQ), and total carcinogenic risk index (TR) were used to measure the PTEs contamination and its relative health impacts. Results showed that the average values of 12 PTEs in topsoil were higher than the Hainan soil geochemical baseline, showing different degrees of PTEs accumulation effect. The concentration of PTEs in the topsoil was lower than those in the subsoil except for Cd and Hg. The Igeo revealed that the major accumulated element in soils was As followed by Mo. Source apportionment suggested that parent materials and agricultural practices were the dominant factors for PTEs accumulation in the topsoil. Non-carcinogenic risks of soil samples from five land-use patterns presented a trend of paddy field > dry field > woodland > orchard > garden plot. However, the HQ values of 12 PTEs were less than the recommended limit of HQ = 1, representing that there are no non-carcinogenic risks of PTEs for children and adults in the study area. The TR values are within 6.95×10-6-1.38×10-5, which corresponds to the low level. Therefore the PTEs in the agricultural soil of the study area show little influence on the health status of the local population.
Extensive land use will cause many environmental problems. It is an urgent task to improve land use efficiency and optimize land use patterns. In recent years, due to the flow decrease, the Guanzhong Basin in Shaanxi Province is confronted with the problem of insufficient water resources reserve. Based on the Coupled Ground-Water and Surface-Water Flow Model (GSFLOW), this paper evaluates the response of water resources in the basin to changes in land use patterns, optimizes the land use pattern, improves the ecological and economic benefits, and the efficiency of various spatial development, providing a reference for ecological protection and high-quality development of the Yellow River Basin. The research shows that the land use pattern in the Guanzhong Basin should be further optimized. Under the condition of considering ecological and economic development, the percentage change of the optimum area of farmland, forest, grassland, water area, and urban area compared with the current land use area ratio is +2.3, +2.4, −6.1, +0.2, and +1.6, respectively. The economic and ecological value of land increases by 14.1% and 3.1%, respectively, and the number of water resources can increase by 2.5%.
The future inundation by storm surge on coastal areas are currently ill-defined. With increasing global sea-level due to climate change, the coastal flooding by storm surge is more and more frequently, especially in coastal lowland with land subsidence. Therefore, the risk assessment of such inundation for these areas is of great significance for the sustainable socio-economic development. In this paper, the authors use Elevation-Area method and Regional Ocean Model System (ROMS) model to assess the risk of the inundation of Bohai Bay by storm surge. The simulation results of Elevation-Area method show that either a 50-year or 100-year storm surge can inundate coastal areas exceeding 8000 km2; the numerical simulation results based on hydrodynamics, considering ground friction and duration of the storm surge high water, show that a 50-year or 100-year storm surge can only inundate an area of over 2000 km2, which is far less than 8000 km2; while, when taking into account the land subsidence and sea level rise, the very inundation range will rapidly increase by 2050 and 2100. The storm surge will greatly impact the coastal area within about 10-30 km of the Bohai Bay, in where almost all major coastal projects are located. The prompt response to flood disaster due to storm surge is urgently needed, for which five suggestions have been proposed based on the geological background of Bohai Bay. This study may offer insight into the development of the response and adaptive plans for flooding disasters caused by storm surge.
Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments. Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin, this paper studies the depositional process of the hyperpycnal flow deposits, and divides their depositional process into three phases, namely, acceleration, erosion and deceleration. In the acceleration phase, hyperpycnal flow begins to enter the basin nearby, and then speeds up gradually. Deposits developed in the acceleration phase are reverse. In addition, the original deposits become unstable and are taken away by hyperpycnal flows under the eroding force. As a result, there are a lot of mixture of red mud pebbles outside the basin and gray mud pebbles within the basin. In the erosion phase, the reverse deposits are eroded and become thinner or even disappear. Therefore, no reverse grading characteristic is found in the proximal major channel that is closer to the source, but it is still preserved in the middle branch channel that is far from the source. After entering the deceleration phase, normally grading deposits appear and cover previous deposits. The final deposits in the basin are special. Some are reverse, and others are normal. They are superimposed with each other under the action of hyperpycnal flow. The analysis of the Sangyuan outcrop demonstrates the sedimentary process and distribution of hyperpycnites, and reasonably explain the sedimentary characteristics of hyperpycnites. It is helpful to the prediction of oil and gas exploration targets in gravity flow deposits.
The construction of modern livable cities faces challenges in karst areas, including ground collapse and engineering problems. Wuhan, with a population of 13.74×106 and approximately 1161 km2 of soluble rocks in the urban area of 8569.15 km2, predominantly consists of concealed karst areas where occasional ground collapse events occur, posing significant threats to underground engineering projects. To address these challenges, a comprehensive geological survey was conducted in Wuhan, focusing on major karst-related issues. Geophysical methods offer advantages over drilling in detecting concealed karst areas due to their efficiency, non-destructiveness, and flexibility. This paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst, selected eight effective geophysical methods for field experimentation, evaluated their suitability, and proposed method combinations for different karst scenarios. The results show that different geophysical methods have varying applicability for karst detection in Wuhan, and combining multiple methods enhances detection effectiveness. The specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.
The Dongping deposit is the largest alkalic-hosted gold deposit in China containing >100 t of Au. This paper presents a new understanding for Dongping ore system, based on the previous studies. The mineralization originally occurred at 400-380 Ma, simultaneous with emplacement of the Shuiquangou alkaline complex, and was overprinted by the hydrothermal activity in the Yanshanian. Isotope compositions of ores indicate metals of the deposit are mainly provided by the Shuiquangou complex. Ore-forming fluids are characterized by increasing oxygen fugacity and decreasing sulfur fugacity, while tellurium fugacity increased in the Stage II-2 and decreased in Stage II-3. These systematic changes are closely related to the processes of mineral precipitation and fluid evolution. Sulfide precipitation from Stage I to Stage II was triggered by fluid boiling, which leads to the precipitation of Pb-Bi-Te, due to decrement of sulfur fugacity. Condensation of gas phase containing high concentration of H2Te leads to precipitation of Te-Au-Ag minerals and native tellurium. Based on these hypotheses, this paper present a polyphase metallogenic model as follow. During the Devonian, fluids were released from alkaline magmas, which carried ore-forming materials form the surrounding rocks and precipitate the early ores. During the Jurassic-Cretaceous, fluorine-rich fluids exsolved from highly factionated Shangshuiquan granite, which extracted and concentrated Au from the Shuiquangou complex and the Sanggan Group metamorphic rocks, and finally formed the Dongping gold deposit.
Black shales are important products of material cycling and energy exchange among the lithosphere, atmosphere, hydrosphere, and biosphere. They are widely distributed throughout geological history and provide essential energy and mineral resources for the development of human society. They also record the evolution process of the earth and improve the understanding of the earth. This review focuses on the diagenesis and formation mechanisms of black shales sedimentation, composition, evolution, and reconstruction, which have had a significant impact on the formation and enrichment of shale oil and gas. In terms of sedimentary environment, black shales can be classified into three types: Marine, terrestrial, and marine-terrestrial transitional facies. The formation processes include mechanisms such as eolian input, hypopycnal flow, gravity-driven and offshore bottom currents. From a geological perspective, the formation of black shales is often closely related to global or regional major geological events. The enrichment of organic matter is generally the result of the interaction and coupling of several factors such as primary productivity, water redox condition, and sedimentation rate. In terms of evolution, black shales have undergone diagenetic evolution of inorganic minerals, thermal evolution of organic matter and hydrocarbon generation, interactions between organic matter and inorganic minerals, and pore evolution. In terms of reconstruction, the effects of fold deformation, uplift and erosion, and fracturing have changed the stress state of black shale reservoirs, thereby having a significant impact on the pore structure. Fluid activity promotes the formation of veins, and have changed the material composition, stress structure, and reservoir properties of black shales. Regarding resource effects, the deposition of black shales is fundamental for shale oil and gas resources, the evolution of black shales promotes the shale oil and gas formation and storage, and the reconstruction of black shales would have caused the heterogeneous distribution of oil and gas in shales. Exploring the formation mechanisms and interactions of black shales at different scales is a key to in-depth research on shale formation and evolution, as well as the key to revealing the mechanism controlling shale oil and gas accumulation. The present records can reveal how these processes worked in geological history, and improve our understanding of the coupling mechanisms among regional geological events, black shales evolution, and shale oil and gas formation and enrichment.