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This paper is the research of ophiolite. [Objective] Ophiolites, as fragments of ancient oceanic lithosphere, serve as a natural laboratory for studying the evolution of the lithospheric mantle, material cycling in subduction zones, and reconstructing paleogeographic patterns. The China-Mongolia border region is located within the Central Asian Orogenic Belt (CAOB), where ophiolite (mélange) belts intermittently crop out along both sides of the boundary, exhibiting blocky and zonal distributions. [Methods] To further clarify the tectonic evolution of the Central Asian Orogenic Belt and restore its structural framework, this paper relies on the results of the China-Mongolia collaborative 1 /1 000 000 geological map series compilation project, combined with previous studies on the ophiolite (mélange) belts in this region. [Results] Fourteen ophiolite (mélange) belts were identified in the study area. A comprehensive explanation of their spatial-temporal distribution characteristics was provided, and a spatial-temporal framework for the distribution of the ophiolite (mélange) belts was established. [Conclusions] The results indicate that the ophiolite belts along the China-Mongolia border exhibit a trend of progressively younger ages from west to east (Neoproterozoic to Early Permian). This reveals differences in the evolution of the oceanic lithospheric mantle between the western and eastern segments of the Central Asian Orogenic Belt. Most ophiolite (mélange) belts are of the SSZ (supra-subduction zone) type, closely related to subduction processes. However, the tectonic settings of fore-arc and back-arc environments remain controversial and require further study.
Highlights: This paper summarizes the spatiotemporal distribution characteristics of ophiolite (mélange) belts along the ChinaMongolia border, dividing them into 14 ophiolite (mélange) belts. This classification provides constraints for determining the tectonic evolution of the Central Asian Orogenic Belt and reconstructing the tectonic framework of the Paleo-Asian Ocean.
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This paper is the result of rock geochemistry. [Objective] Lupa terrane is the second largest gold ore concentration area in Tanzania, and its formation age and genetic mechanism are controversy. [Methods] Through the analysis of zircon geochronology and geochemical characteristics of granite, the formation age and genetic mechanism of the Lupa terrane granite are determined. [Results] Zircon U-Pb geochronology studies indicate that there are two types of granites in the Lupa terrane: Neoarchean granites (2 663 ± 22 Ma～2 778 ± 13 Ma); Paleoproterozoic granite (1 944 ± 10 Ma～2 006 ± 10 Ma), and their geochemical characteristics are similar to those of I-type granite. The other basic rocks, carbonates and other rocks distributed within the earth represent the beginning of the breakup of the Rodinian super continent.[Conclusions] The geochemical characteristics of rocks indicate that the material source of non-A-type granite is not from the mantle, but the result of crustal remelting. The tectonic environment discrimination diagram of the granite shows that the sample projection falls in the volcanic arc granite, and the granite is concentrated in the continental granite area, away from the oceanic granite, oceanic basalt and gabbro area. The Neoarchean and Paleoproterozoic granites were formed in the continental margin arc.
Highlights：Through the study of zircon U-Pb chronology and rock geochemical characteristics, it is determined that the granite of Lupa terrane was formed in Paleoproterozoic, which is the result of crustal remelting, and the tectonic environment belongs to the continental margin arc.
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This paper is the research of uranium deposits. [Objective] Sandstone- type uranium deposits are the most important type of uranium deposits globally and the most economically recoverable type in China. The comprehensive application of various exploration techniques is an effective means of identifying the structure and composition of sandstone uranium deposits in the basin, the spatial distribution of uranium-bearing sands, and predicting the extension of uranium ore bodies. Sandstone-type uranium deposits in the Erlian Basin are generally characterised by shallow burial, paleovalley type mineralization with near-source and concentrated distribution in zones, and the establishment of comprehensive sandstone-type uranium mine detection technology methods in this type of basin according to local conditions is an important reference for prospecting and exploration. [Methods] Taking the BYH uranium deposit in the Chuanjing depression of the Erlian Basin as the research object, we extracted and geologically interpreted a variety of information such as gravity, aeromagnetism, electrical prospecting, seismicity, drilling, radon gas and gamma measurement, and established a combination of integrated detection technology.[Results] The combined model of "heavy magnetic search for rumbles, electric well seismic search for fractured sands, and radon and gamma circle anomalies" is proposed, aeromagnetic and gravity information will be used to explore the rumble and concave spreading patterns of concealed and semi-concealed rock bodies and basement, and to determine the favourable structures for regional mineralisation; then high-density electric resistance or audio geomagnetic sounding will be used to carry out the analysis of anomalous features of high resistance and low resistance uranium reservoirs. Then, high-density electrical resistance or audio geomagnetic analysis is used to analyse the characteristics of the anomaly, combined with 2D seismic profiles to finely delineate the structure of uranium reservoirs and fracture tectonic features, and to analyse the spatial distribution of orebearing sands; and radon gas and gamma total or spectral measurements are used to define the anomaly halo, analyse its spatial location in relation to the deep uranium ore bodies, and assess the extension of the uranium ore bodies. [Conclusions] Establishment of a comprehensive exploration technology combination for sandstone-type uranium deposits in the Erlian Basin, combined with the geological conditions of mineralization, is capable of guiding the exploration of regional sandstone-type uranium mines.
Highlights: Based on the information extraction and interpretation of gravity, aeromagnetic, electric method, seismic, borehole, radon gas and total gamma data, a hierarchical integrated detection combination model of "heavy magnetic search for rumble and concavity, electric well seismic search for sand fracture and radon gamma anomalies" has been proposed, which will provide a technical reference for prospecting and exploration of sandstone-type uranium deposits in the Erlian Basin.
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This paper is the result of the sandstone-type uranium deposits. [Objective] The Erlian Basin, a quintessential Mesozoic-Cenozoic basin in northern China, is renowned for its superimposed and enriched deposits of uranium and other energy resources. The Lu-hai uranium deposit, a recently discovered super-large deposit within the basin, is distinguished by its shallow burial depth, extensive scale, and favorable permeability. Investigating the geochemical characteristics of the ore can elucidate the structure and provenance of the uranium-bearing stratay. [Methods] This study examines the petrography and trace element geochemistry of conglomeratic sandstone samples from the non-ore-bearing member of the Upper Saihantala Formation, extracted from four boreholes in the Lu-hai deposit. [Results] The sandstone's detrital composition in the upper member of the Saihantala Formation predominantly consists of quartz (40% to 75%) and feldspar (20% to 30%), indicative of proximal source transportation. The rare earth elements (REEs) exhibit a light REE enrichment and heavy REE depletion, with a slightly negative europium anomaly (δEU). The discrimination diagram of major, minor and rare earth elements suggests that the Upper Saihantala Formation's provenance is associated with a passive continental margin tectonic settingt.[Conclusions] Based on the regional tectonic evolution, the sandstones of the Upper Saihantala Formation in the Lu-hai mining area are inferred to be sourced from the Bayanbaolige Uplift and Sunite Uplift's rock mass and volcanic strata.
Highlights: This research indicates that the sandstone source of the Upper Saihantala Upper Formation in the Lu-hai area originates from the Bayanbaolige Uplift and Sunite Uplift's rock mass and volcanic strata through the geochemical analysis. This provides valuable insights for predicting the material source and uranium reservoir potential of the Saihantala Formation in the Lu-hai and surrounding regions.
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This paper is the result of geological prospecting model and its application. [Objective] The Yishengdian uranium polymetallic deposit (mineralization) is located in the Late Jurassic Manketou Obo subvolcanic rock mass near the Xigangou volcanic mechanism, mainly controlled by the combination of NW-NNW trending fault structures and the hidden explosive breccia belt within the subrhyolite rock mass. The study and establishment of a comprehensive information exploration model for this deposit is of great significance in guiding the exploration of mineralization zones.[Methods] On the basis of studying the geological conditions, ore-forming bodies, ore-forming structures and structural planes, and ore-forming process characteristics of uranium mineralization in the region, this article conducted a systematic and comprehensive research work by combining the soil geochemical characteristics of the mining area with information on induced polarization, gamma energy spectrum, activated carbon, and electrostatic alpha anomalies. [Results]A geological exploration model for the mining area was established through research, and the main physical and chemical exploration indicators for mineralization in the mining area were summarized and summarized, including volcanic structure control, soil geochemical anomaly areas, low resistivity high polarization body anomalies, and geometric shape anomalies formed by deep penetrating radioactivity. A comprehensive information exploration model of geology geochemistry geophysics "trinity" was constructed for the mining area.[Conclusions]The study suggests that there is potential for the formation of medium to large uranium polymetallic deposits in the overlapping areas of fault fracture zones, subvolcanic rock contact zones, and cryptoexplosive breccia structures in the Yishengdian mining area, where geochemical and geophysical anomalies coincide. New breakthroughs have been made in using models to guide mineral exploration.
Highlights：For the first time, deep penetration exploration techniques such as electrostatic alpha particle integration measurement were used to establish a comprehensive geological geochemical geophysical prospecting model for sub volcanic uranium polymetallic deposits in the survey area, achieving a breakthrough in prospecting.
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This paper is the result of geochemistry research . [Objective] The Sekong Dakcheun area in Laos is located in the geochemical prediction zone of mineralizing elements in southern Laos, with superior mineralization potential. Geochemical exploration are carried out in this area to narrow down the target area for mineralization and provide a basis for the next geological prospecting. [Methods] Based on the geochemical exploration of 1/50 000 stream sediments, 19 elements were analyzed, the distribution of each element and its characteristic parameters were statistically analyzed, the discrete and enrichment patterns of the elements, the characteristics of the element combinations and their relationship with the geological conditions of mineralization were summarized, and the distribution of the elements in the different stratigraphic layers (geologic bodies) was preliminarily investigated. [Results] The study concludes that Au, Sn and Pb are the main metallogenic elements in the study area, element Au is highly enriched and discrete in sericite schist and biotite granite, Sn is more enriched and discrete in sericite schist, and Pb is more enriched and discrete in biotite granite. [Conclusions] Combined with the geological conditions and geochemical characteristics of mineralization, 10 geochemical anomalies have been identified, and 3 prospecting areas have been divided on the basis of the comprehensive study. The anomaly verification work was carried out, and the HS8 comprehensive anomalies were finally selected to define the DaLong mineralization prospective area as having a large mineralization potential, which will provide a basis for the next stage of the geological prospecting work.
Highlights: The distribution of the elements in different strata (geologic bodies) was discussed, and three prospecting areas were identified
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This paper is the research on the suitability evaluation of engineering construction. [Objective] Xiongan New Area of Hebei Province is a city to be built soon. To ensure the geological safety of the planning and construction of the new area, the suitability evaluation of the Xiong'an New Area engineering construction is carried out. [Methods] A customized evaluation index system for the suitability of engineering construction has been developed based on the geological conditions of Xiong'an New Area and in alignment with the millennium plan for planning and construction. The evaluation of engineering construction suitability in Xiong'an New Area was conducted using a multi-factor graded weighted index sum method. [Results] The engineering construction suitability in Xiong'an New Area is favorable, with both suitable areas covering 925 km2 and relatively suitable areas covering 845 km2 . The more suitable areas are primarily located in the central and southern parts of the research area, while other areas are classified as suitable. Some parts of Xiong'an New Area face environmental geological challenges such as ground subsidence, sand liquefaction, soft soil, soil and water pollution, soil and water corrosiveness. These environmental geological issues directly impact the overall evaluation results, although they do not completely rule out the feasibility of construction in the comprehensive evaluation. [Conclusion] A comprehensive parameter system has been developed for evaluating the suitability of engineering construction in Xiong'an New Area. The evaluation factors have been quantified, reasonable weight values have been determined, and a geological survey evaluation method system has been established. The system is designed to serve national spatial layout, engineering construction and underground space development, offering valuable insights for relevant urban planning and construction.
Highlights: The authors have innovatively constructed a suitability evaluation method system for engineering construction in Xiong'an New Area, which plays a scientific and technological support role in solving engineering geological survey work and serving the planning and construction of Xiong'an New Area.
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This paper is the research on the underground space evaluation. [Objective] As a grand project and a national event, the development and utilization of underground space resources in Xiong’an New Area can effectively alleviate“big city diseases”, such as“environmental pollution, resource shortage and traffic congestion”, and promote high-quality development of new city. [Methods] Taking the start-up area of Xiong’an New Area as the research area, this paper analyzes the geological factors that affect the development and utilization of underground space resources in the start-up area through analytic hierarchy process, establishes the evaluation index system of geological suitability, evaluates the geological suitability, and evaluates the quantity of available resources for development and utilization of underground space resources in the Start-up area. [Results] The results show that the evaluation indexes can be divided into 4 categories and 10 indexes. The main influ‐ encing indexes are water-bearing sand layer, land subsidence, liquefied sand and corrosion of soil and water, etc. According to shal‐ low, sub-deep and deep underground space, the suitability evaluation results are divided into suitable area, general suitable area and sensitive area. The total area both suitable area and general suitable area accounts for about 80% of the total area, indicating that the overall geological suitability is good for development and utilization of underground space in the Start-up area. [Conclusions] The results provide a reference for the development and utilization of underground space resources in the study area, and provide a reli‐ able technical support for the high-quality construction and sustainable development of the study area. At the same time, the develop‐ ment and utilization of underground space resources has irreversibility and is easily affected by geological environment factors, so its development and utilization must be adapted to local conditions, rational planning and scientific layout.
Highlights: The geological factors affecting the development and utilization of underground space resources are selected, and the evaluation index system of geological environment suitability for the development and utilization of underground space resources in the start-up area is established. Using analytic hierarchy process, the geological suitability zoning of underground space development and utilization in the start-up area is constructed, and the amount of available resources in the underground space of the start-up area is evaluated, which provides an important reference for the development and utilization of underground space resources in the Startup area.
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This paper is the result of the importance of ecosystem service function. [Objective] The high-quality coordinated development of Beijing-Tianjin-Hebei requires scientific identification, division and pro‐ tection of key ecological functional areas to further improve the quality and stability of the ecosystem. [Methods] Based on the "Double evaluation" guideline and the "Guideline for delineating the Red Line of Ecological Protection", this paper took the BeijingTianjin-Hebei region as the research area, and carried out the evaluation of the importance of ecosystem service functions from four aspects: water conservation, soil and water conservation, biodiversity, and wind and sand prevention with analytic hierarchy process. The comprehensive evaluation results divided the importance of ecosystem service functions into three levels: very important, impor‐ tant and generally important, and further analyzed the importance and spatial distribution characteristics of ecosystem service func‐ tions in Beijing-Tianjin-Hebei. [Results] The results showed that: (1) The evaluation area of the importance of water conservation, soil and water conservation, biodiversity, wind and sand fixation in the study area decreased from the general important to the very important. The area of water conservation service function is very important, accounting for 13.72%; The area of extremely impor‐ tant soil and water conservation function accounted for 15.20%. 25.33% of the areas were very important for biodiversity conserva‐ tion. The area of the extremely important function of wind prevention and sand fixation accounted for 11.32%. (2) The importance of ecosystem service functions in the study area showed the spatial distribution characteristics of high in the north and low in the south, and the area showed a decreasing distribution from generally important to extremely important. The area of extremely important eco‐ system service function is 34617.76 km2 , about 16.03% of the total area. (3) Forest land, grassland and a small part of cultivated land accounted for 68.74%, 16.74% and 10.86%, respectively, in the extremely important ecosystem service function area. It indicates that the vegetation coverage is higher and human activities are less in the extremely important area. [Conclusions] The spatial distri‐ bution of ecosystem service importance in the study area is relatively uneven, and the overall distribution is dominated by the gener‐ al important area. In addition, vegetation such as forest and grassland plays an important role in maintaining the stability and service function of the ecosystem in the study area.
Highlights: The importance of water conservation, soil and water conservation, biodiversity, wind prevention and sand fixation in the Beijing-Tianjin-Hebei region was systematically evaluated and analyzed, and the spatial distribution characteristics of ecosystem service importance in the Beijing-Tianjin-Hebei region were further discussed based on ecosystem types.
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This paper is the result of geothermal geology. [Objective] Zhangjiakou City is rich in geothermal hot springs,but at present, geothermal resources exploration and research work is mainly concentrated in geothermal hot springs outcropping areas,and the rest of the area is basically blank. Analysis and research of deep geothermal features, hydrochemical characteristics, formation mechanism and thermal reservoir structure relationship, research and summarize different types of geothermal resources and thermal reservoir structure of geothermal resources in the waterrich features, guide the blank area of geothermal resources exploration, development and utilization of mountainous areas and re‐ search, and help th‘e double-carbon’goal to achieve. [Methods] Based on the detailed investigation project of geothermal hot spring resources in Zhangjiakou carried out by Hebei Geology and Mining Bureau,we fully analyze and study the distribution of geother‐ mal resources in Zhangjiakou,the conditions of thermal reservoirs and reservoir characteristics, conduct research on the mechanism of genesis and analysis of the environment for the formation of geothermal water and analyze the characteristics and advantages of the storage of each geothermal type with examples. [Results] Taking the typical district as a representative, after a large amount of data analysis and research,it is found that there are certain differences in the water volume, water temperature and hydrochemical components of geothermal hot springs(wells) in different geothermal resource types and thermal reservoir structures. [Conclusions] The geothermal resources of Zhangjiakou are divided into three types and seven types of thermal reservoir structure models,provid‐ ing scientific theoretical support for the exploration and development of geothermal resources in the mountainous areas of Hebei Province.
Highlights: Regarding the geothermal resources in Zhangjiakou City, three types of geothermal resources have been divided and sev‐ en thermal reservoir structure models have been proposed
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This paper is the result of titration of ferrous oxide. [Objective] Due to the different compositions of silicate rocks and soil, conducting comparative studies on ferrous oxide in silicate rocks and soil is beneficial for more accurate titration of ferrous oxide. [Methods] This article compared the titration of ferrous oxide in silicate rocks and soil using potassium dichromate titration method, with a focus on the effect of sample dissolution time on ferrous oxide.The sample was dissolved with sulfuric acid (1+1) and hydrofluoric acid, the excess fluorine was complexed with boric acid, and ferrous oxide was titrated with sodium diphenylamine sulfonate as indicator and potassium dichromate standard solution.[Results] The results showed that the dissolution time had great influence on the ferrous oxide in rock and soil, and it was appropriate to titrate the rock and soil samples when the solution was completely boiled for 0～2 min and 8～10 min, respectively. The results were verified by the national standard material analysis, the results agreed with the reference values.The precision RSD (n=10) of rock and soil were 1.94%、1.78% respectively.[Conclusions] Therefore, in practical operation, the appropriate dissolution time should be selected according to the type of sample, in order to more accurately titrate the content of ferrous oxide.
Highlights: According to the different types of samples, choosing the appropriate dissolution time can get more accurate titration results.
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