Table of Content

10 August 2023, Volume 37 Issue 04

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Stratigraphy

Characteristics of Stromatolites and Its Significance in Depositional Environment Reconstruction of the Mesoproterozoic Longjiayuan Formation (2^nd Member), Western Henan

LI Qianqian, ZHENG Deshun

2023, 37(04):  845-857.  DOI: 10.19657/j.geoscience.1000-8527.2022.023

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Stromatolites recorded the life activities of early environment, cyanobacteria and microbial community, and their growth morphology was influenced by the sedimentary environment, which is of great significance for the paleo-environmental reconstruction. Stromatolites from the Longjiayuan Formation (2^nd member)of the Mesoproterozoic Guandaokou Group in western Henan have various morphological types and concentrated in distribution, which is a typical area for stromatolites development. The distribution of stromatolites is closely related to global events, geochemical environment of the Precambrian ocean and the development of microbiolites, yet detailed research is still lacking. Based on this, we conducted a systematic field investigation and petrological examination on the microbialite structure on these stromatolites, studied the macroscopic and microscopic characteristics of the stromatolites, established the sedimentary environment evolution and sedimentary model, and compared with the stromatolites from other areas. The results show that the macroscopic morphology of the stromatolites can be divided into horizontal laminae, ripple, hilly, cone, and column. Microscopically, the stromatolites are light and dark laminae, with few ooids, spherular and detrital materials locally. The shape and scale of stromatolites are closely related to the hydrodynamic conditions and water depth. Horizontal laminated stromatolites were developed in the intertidal zone, whilst corrugated and mound stromatolites were developed in the intertidal high-energy zone and low-energy zone. Meanwhile, cone and columnar stromatolites were developed in the subtidal zone. Our comprehensive analysis shows that our stromatolite samples were formed in a tidal-flat environment, and were influenced by the sedimentary evolution process of intertidal, subtidal and intertidal zones. It is beneficial to analyze the Early Mesoproterozoic development environment of microbiolites in the southern margin of North China. Besides, we compared our results with the sedimentary environment of microbiolites in Jixian area (northern margin of North China), in order to explore the relationship between marine environment, atmospheric environment, and microbiolites around the North China Craton.

Sedimentary Environment of the Phosphorus-bearing Layers and Its Phosphate Enrichment Mechanism of the Cambrian Xinji Formation, Western Henan

JIA Bingling, ZHANG Biyun, TANG Bin, ZHENG Deshun

2023, 37(04):  858-869.  DOI: 10.19657/j.geoscience.1000-8527.2022.094

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The Cambrian is an important period for global phosphate deposition, and the Cambrian Xinji Formation is an important phosphorus-bearing sequence on the southern margin of North China Craton. However, the relationship between the phosphorus-bearing stratigraphy and the sedimentary environment is poorly understood, and the phosphate enrichment mechanism needs to be further studied. Here, we studied the middle Xinji Formation at Baofeng, which contains a typical phosphorus-bearing layer. Field observations and laboratory analyses were conducted to reveal its depositional environment and explore its phosphorus source and enrichment mechanism. The results show that phosphorus nodules from the Xinji Formation are black, irregular flat disk-shaped, with size of 2 to 20 mm, and are distributed in the fine sandstone beds. Collophanite is the main mineral in the nodules. There are two forms: (1) cryptocrystalline rounded colloidal phosphorite with no internal structure and locally cracked; (2) microcrystalline oolitic colloidal phosphorite with fine veins. The depositional environment of the Xinji Formation was likely littoral-shallow marine transition. Phosphorus was likely derived from deep oceanic phosphorus-rich water and small shell biological activities. Formation of the phosphorus nodules was likely dominated by chemical deposition with indirect biological involvement. It has undergone syn-deposition and early diagenesis stages, and large amounts of phosphorus nodules were deposited in turbulent shallow water. Compared with the Cambrian phosphorus-bearing facies in the Yangtze Craton, the phosphate-bearing stratigraphy is clearly diachronic, and phosphate deposition occurred after the sedimentary hiatus. Initial deposition of the Cambrian phosphate was dominated by biological and chemical processes, and then the depositional environment and paleotectonics controlled the phosphorus-bearing stratigraphy and promoted the re-enrichment. We point out the relationship between phosphorus enrichment and the Early Cambrian sedimentary environment in the southern North China Craton, and provide abundant data for studying large-scale phosphate deposition.

Middle Late-Pleistocene Sporopollen Records of Ake River III Terrace in Southern Margin of Aba Basin, Western Sichuan

ZHU Ting, HE Zhengwei, YANG Zhenjing, KANG Guichuan, GUAN Sensen, ZHU Yuting

2023, 37(04):  870-880.  DOI: 10.19657/j.geoscience.1000-8527.2022.037

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Vegetation growth and change have important implications for climatic evolution. In this study, we used sporopollen record to reconstruct paleovegetation and paleoclimate. Based on the sporopollen study of the Ake River III-level terrace in the southern margin of Aba basin in western Sichuan (eastern Qinghai-Tibet Pla-teau)and OSL dating, the results show that PM01 is (78.4±7.1) to (71.6±6.2) ka B.P. (middle Late Pleistocene). According to the palynological assemblage and mathematical analysis, the PM01 profile was divi-ded into three palynological zones. The results show that vegetation in the Aba Basin was sparse forest and grassland from (78.4±7.1) to (71.6±6.2) ka B.P. in the middle Late Pleistocene. The paleoclimate evolution can be divided into three stages: (1) cold and arid; (2)warmer than the first stage, but still cold and dry; (3)warmer and then cooler and drier. The results are consistent with the climate evolution trend of the last ice age, and provide new data for the study of the Quaternary regional vegetation and climate evolution, which is of great significance for studying Quaternary paleoclimate in the eastern Qinghai-Tibetan Plateau.

Water Resources and Environmental Geology

Vegetation Dynamics and Driving Factors in Zhangjiakou-Chengde Area of Hebei Province from 2001 to 2020

WANG Qian, JIN Xiaomei, ZHANG Xucai, YIN Xiulan, JIN Aifang, LUO Xufu

2023, 37(04):  881-891.  DOI: 10.19657/j.geoscience.1000-8527.2023.028

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As a water conservation function area in the Beijing-Tianjin-Hebei region, the vegetation dynamics of Zhangjiakou-Chengde (Zhang-Cheng) area is of great significance for the ecological/environmental construction and protection. Based on MODIS-NDVI, temperature and precipitation, land use, groundwater depth and measured soil moisture data, Sen+Mann-Kendall trend analysis, partial correlation analysis and other methods, we analyze the spatial-temporal variation characteristics of vegetation and the response characteristics of temperature and precipitation, land use, groundwater depth and soil moisture in Zhang-Cheng area from 2001 to 2020. The results show that the annual mean NDVI value shows an upward fluctuation trend. The vegetation coverage is characterized by being low in the northwest and high in the southeast. Significant vegetation improvement areas were mainly distributed across most of Baxia, accounting for 85.79% of the study area. There are positive correlations between precipitation, temperature, and the vegetation index. Furthermore, the vegetation variation agrees well with the land-use change. The vegetation growth is best when the groundwater depth is around 6.2 m. The spatial distribution of soil moisture is low at Bashang and high at Baxia. The NDVI increases with increasing measured soil moisture.

Ecological Vulnerability Evaluation and Countermeasures of Ecological Restoration in Ecological Restoration Areas of Mountains-Rivers-Forests-Farmlands-Lakes-Grasslands,Tai’an City

XU Fei, JIAO Yuguo, TANG Liwei, WEI Kai, YIN Yanpeng, HU Qingling, ZHAI Daiting, ZHAO Xinchu

2023, 37(04):  892-902.  DOI: 10.19657/j.geoscience.1000-8527.2021.152

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Ecological protection and restoration has become a core content for the construction of ecological civilization in China. The study of ecological vulnerability is an important basis for evaluating ecological environmental problems, and for performing ecological protection and restoration. To scientifically identify the formation mechanism and ecosystem vulnerability variation in the ecological restoration area of mountains-rivers-forests-farmlands-lakes-grasslands in Tai’an City, and to clarify the direction of ecological protection and restoration, we used the pressure state response (PSR) framework model to evaluate the local ecological vulnerability. We further diagnosed the ecological environment problems in combination with the evaluation results, thus put forward countermeasures for ecological protection and restoration. The results show that the low vulnerability areas account for the highest proportion (37.97%), indicating that the overall local ecosystem is relatively stable. Among the investigated counties, cities and districts, there is higher proportion of vulnerability areas in the Taishan (48.77%) and Daiyue (37.15%) districts and Feicheng (30.97%) city, indicating that the ecosystem of the three counties is unstable. Considering the local situation, we put forward five ecological restoration suggestions, including (1) promote mine ecological restoration, (2) improve forest and grass coverage, (3) comprehensively regulate the watershed system, (4) increase biodiversity and improve ecological security system. The evaluation results and the proposed ecological restoration countermeasures are helpful to the rational layout of the project. It can also facilitate the targeted planning of the construction of ecological civilization in the implementation of the local ecological protection and restoration project of mountains-rivers-forests-farmlands-lakes-grasslands, and provide reference for the implementation of the ecological restoration project of mountains-rivers-forests-farmlands-lakes-grasslands in China.

Influence of Geological Formation on the Ecological Spatial Pattern of Soil and Vegetation in the Danjiang River Source Region

QIAN Xinyu, BIAN Xiaowei, ZHANG Yafeng, WANG Yingwei, YANG Yunjun, YOU Jun

2023, 37(04):  903-913.  DOI: 10.19657/j.geoscience.1000-8527.2023.004

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To explore the major factors affecting the ecological spatial pattern of soil and vegetation in the Danjiang River source region, and support the ecological management of the basin, we analyze the contributions of different geological formations on the soil properties and vegetation coverage. The study encompasses the aspects of the type, nutrient content and joint by combining GIS, RS and elemental geochemical analysis methods. Soil texture, physical and chemical properties, and nutrient element content in soil and vegetation have clear correlations with the rock type, and the joint development has a significant impact on forest type and vegetation coverage. The joint density of the Paleozoic mafic volcanic rock and mafic magmatic rock formation, the Triassic and Precambrian felsic magmatic rock formation is over 4 m/m². The occurrence is steep, and the content of P and other nutrient elements is high, which is conducive to the growth of deep-rooted trees. The joint density of the Precambrian clastic rock formation and the Paleozoic felsic magmatic rock formation is 3-4 m/m², and the occurrence is relatively slow. Thus, the forest type is dominated by thickets, and minor Pinus tabulaeformis grows on the slope top. The Cretaceous-Paleogene clastic rock formation is mainly composed of glutenite and mudstone interbeds, with the joint density below 1 m/m² and poor penetration, i.e., the forest type is a small number of low shrubs. The formation type plays a vital role in controlling soil properties and ecological vegetation patterns, providing the scientific basis for local governments to implement land spatial zoning control based on geological construction.

Effect of the Sand Mixing Ratio of North China Brown Soil on Sewage Purification Performance in Infiltration System

WANG Ying, HU Weiwu, CHEN Nan, FENG Chuanping

2023, 37(04):  914-924.  DOI: 10.19657/j.geoscience.1000-8527.2022.096

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Soil infiltration system is of great significance for the treatment of rural decentralized domestic sewage. However, the system can be blocked easily and the reaeration performance is poor, which limits the application. To improve the system permeability and the ammonia nitrogen removal rate, different proportions of mineral particles were added to the local brown soil to alter the porosity. The contaminations removal effects under different hydraulic loads were analyzed and the microbial response was revealed based on high-throughput sequencing and PICRUSt2 function prediction. The results showed that the {{\mathrm{NH}}_4}^{+}-N removal rate of the zeolite system (which completely replaced the soil) was 91.1% under the hydraulic load of 0.1 m³·m^-2·d^-1. The Unclassified_ f_ Enterobacteriaceae, Arthrobacter, Bacillus and other bacteria were naturally enriched, which rely on simultaneous nitrification aerobic denitrification achieving the highest nitrogen removal rate, but the phosphate removal rate was only 14%. When the soil proportion was 30%, the {{\mathrm{NH}}_4}^{+}-N removal rate was 93.4%, with the highest abundance of functional genes related to nitrification. It is a scientific ratio for constructing a nitrification module, and the phosphate removal rate increases to 25%. When the soil accounts for 50% or more, the gene abundance of nitrification function decreases and the anoxic environment increases, which is a suitable ratio for constructing a denitrification module. However, the functions of soil indigenous microorganisms are mainly nitrogen fixation and organic matter assimilation or utilization (Actinobacteria, Acidobacteria and Chl-oroflexi). It is thus difficult for the organic matter involved to be used for denitrification. This study provides a scientific basis for improving nitrogen purification efficiency, biodiversity and stability of brown soil area soil infiltration system, as well as theoretical support for future establishment and optimization of modular infiltration systems.

Enrichment Mechanism of Deep Groundwater with High Fluoride in Coastal Plains: A Case Study of the Luanhe Delta

ZHANG Zhuo, CHEN Sheming, LIU Futian, GAO Zhipeng, NIU Xiaotong

2023, 37(04):  925-932.  DOI: 10.19657/j.geoscience.1000-8527.2022.029

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High F^- groundwater has been found in deep aquifers of the coastal plain region, which seriously threatens the domestic water safety. To ascertain its enrichment mechanism, sixty-nine groundwater samples on site were collected for hydrochemical and isotopic analyses of the low- and high-fluoride groundwater. The results show that high fluoride groundwater mainly exists in Na-HCO₃-type groundwater, while the chemical type of low-fluoride groundwater is mainly Ca·Na-HCO₃. Saturation index calculation shows that the groundwater samples are mostly fluorite undersaturated but calcite oversaturated. This indicates that fluorite dissolution is favored with precipitations of Ca²⁺ as calcite, thus leading to higher F^- level in the groundwater. The linear regression results show that cation exchange occurred between Ca²⁺ and Na⁺ in deep groundwater, which could decrease the groundwater Ca²⁺ content and further promote the CaF₂ dissolution. There is good positive correlations between F^- and pH and {\mathrm{HCO}}_3^{-} in deep groundwater, indicating that the slightly alkaline environment and high {\mathrm{HCO}}_3^{-} content are beneficial to F^- desorption. In addition, there is strong positive F^- vs. Li correlation in deep groundwater, which also indicates that the local mixing of geothermal water may directly affect the F^- enrichment in deep groundwater. Comparing the hydrochemical and isotopic characteristics of deep groundwater with seawater, we found that the local F^- enrichment of deep groundwater is unaffected by seawater intrusion.

Arsenic-Uranium Distribution Characteristics and Risk Assessment in the Aquatic Environment of Hailar Basin

LIU Shengfeng, GAO Bai, YI Ling, FANG Zheng, SHI Tiancheng, DING Yan

2023, 37(04):  933-942.  DOI: 10.19657/j.geoscience.1000-8527.2022.020

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The Hailar Basin is located in an arid to semi-arid region, and its water resource has received widespread attention. Studying the hydrogeochemical characteristics of the local water environment and health risk assessment is conducive to better protection and utilization of water resource. Based on field sampling data, we analyzed its hydrochemical characteristics and influence factors, used the PHREEQC software to simulate the As-U occurrence, and conducted characteristic analysis and risk assessment of As-U co-pollution phenomena. The results show that the As-U concentrations in the local water environment mostly exceed the World Health Organization (WHO) standard limits. The As concentration in the water environment in the Beier Lake Depression-Cuogang Uplift is higher, and the U concentration in the Cuogang Uplift near Hulun Lake is higher. Calculated by the US EPA health risk assessment model, the average non-carcinogenic total risk HI_total of different populations all exceed the acceptable level (HI_total <1), and the average carcinogenic risk of As also exceeds the acceptable level (1×10^-6). The total non-carcinogenic risk and carcinogenic risk: children>female adult>male adult. The PHREEQC simulation results show that As in the water environment mainly exists in the form of As(V), and most of the sampling spots are dominated by {\mathrm{HAsO}}_4^{2-} and H₂ {\mathrm{AsO}}_4^{-}. Uranium occurs mainly in the form of U(VI): UO₂(CO₃) {}_3^{4-} and UO₂(CO₃) {}_2^{2-}. The chemical valence of As is readily affec-ted by the pH and Eh values. The pH decrease and the more toxic As(III) are likely formed under relatively reducing conditions. The chemical valence of U is not strongly affected by the pH and Eh values, but changing which would also form solid deposits such as bituminous uranium ore, which may cause stones and other related diseases.

Evaluation of Exploitable Groundwater Resources in the Buha River Basin Based on Groundwater Numerical Simulation

PENG Hongming, WANG Zhanwei, LUO Yinfei, YUAN Youjin, WANG Wanping

2023, 37(04):  943-953.  DOI: 10.19657/j.geoscience.1000-8527.2022.031

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The Buha River is the largest tributary of the Qinghai Lake basin, and its runoff reaches 80% of the lake inflow. To ensure sustainable development of the ecological and geological environment in the Qinghai Lake Basin, it is necessary to exploit groundwater resources scientifically in the Buha River Basin. This study discussed the hydrogeological conditions of the Buha river, and establish the river basin mode concept, set up the numerical simulation based on Groundwater Vistas. Using the measured ground flow field to correct the identification model, the prediction results show that the maximum drop depth of the planned water source is 17.99 m (based on the average runoff for 30 years) in the basin with the water source of 50,000 m³/d, 100,000 m³/d and 150,000 m³/d; and after 5 years of dry season, the maximum drop depth of water source is 20.26 m. The groundwater resource exploitation mainly comes from the reduction of hidden excretion of springs and rivers. Finally, according to the watershed planning, the exploitable groundwater resources of Buha River is 300,000 m³/d.

Current Geothermal Field of the South Jiangsu Modernization Demonstrative Area and Its Influencing Factors

YANG Lumei, KUANG Rongxi, GUO Hui, ZUO Liqiong, GOU Fugang, XU Shugang, ZHANG Shuo

2023, 37(04):  954-962.  DOI: 10.19657/j.geoscience.1000-8527.2022.095

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The South Jiangsu Modernization Demonstrative Area belongs to the Lower Yangtze region. The study area includes mainly four lower-order structural units: the Northern Jiangsu Depression, the Central Uplift, the Southern Jiangsu Depression, and the Nantong-Taihu Uplift. Distribution characteristics of the local geothermal gradient, the deep ground temperature and the terrestrial heat flow were analyzed based on the temperature data of 39 geothermal wells and previous published data. The results show that the present geothermal gradient ranges from 14.9 to 26.5 ℃/km (average 21.3 ℃/km). The present terrestrial heat flow values range from 51.0 to 73.5 mW/m² (average 64.2 mW/m²). Factors affecting the present geothermal field were further explored, including geological structure, thermal conductivity, caprock thickness and volcanic body. The depression area has lower geothermal gradient than the uplift area, and the deep ground temperature and the terrestrial heat flow exhibit the same characteristics. Vertically, the geothermal system is characterized by segmentation. Geothermal gradient of the strata with high thermal conductivity is smaller than that of the strata with low thermal conductivity.

Suitability Zoning for Groundwater Source Heat Pump Based on Adaptive BPNN-GIS Method

YAN Baizhong, SUN Jian, CHEN Jiaqi, SUN Fengbo, LI Xiaomeng, FU Qingjie

2023, 37(04):  963-971.  DOI: 10.19657/j.geoscience.1000-8527.2021.063

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Based on the geological and hydrogeological conditions of Shijiazhuang City, the suitability evaluation index system of groundwater source heat pump is established. The adaptive BP neural network and GIS coupling method were used to evaluate the suitability of groundwater source heat pump, and the results were compared with the fuzzy analytic hierarchy process. The results show that in addition to the difference in the area, the suitability distribution of the two methods is basically the same. The proportion difference of the suitable area between the BP neural network and fuzzy analytic hierarchy process is only 3.80%, 8.06%, and 11.86%, respectively. The self-adaptive BPNN-GIS evaluation method could resolve the drawbacks of traditional manual adjustment and subjective weighting. Meanwhile, both the evaluation efficiency and accuracy are higher, which can reflect the degree of single point suitability in the study area.

Study on Seepage Mechanism Characteristics of A Single Fracture Based on Fracture Deformation Under Different Confining Pressures

CHENG Zhiyu, LIU Rui, ZHANG Jinfeng, MA Haichun, WANG Jingping

2023, 37(04):  972-976.  DOI: 10.19657/j.geoscience.1000-8527.2023.059

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It is necessary to study the seepage flow under different confining pressures in laboratory because the real groundwater flow and solute transport are affected by the extensive and complex distribution of in-situ stress. In practical projects such as groundwater pollution prevention and control, the permeability of fractures is signi-ficantly affected by confining pressure. Based on the basic constitutive law, the seepage flow under confining pressure is analyzed quantitatively in this paper. Based on the deformation of hydraulic aperture and the defor-mation law of fracture, the relationship model between seepage characteristics (seepage pressure P_s, hydraulic aperture e_h and permeability k) and confining pressure P_c under confining pressure is established. The hydraulic experiment of a single fracture of marble is carried out in a core holder, and the experimental data are regressed. It is verified that the model has a high fitting effect. It can effectively predict the relationship between the seepage characteristics (seepage pressure, hydraulic opening and permeability) and the surrounding pressure.

Research Progress and Prospect of Groundwater Pump and Treat Technology

ZHANG Li, LIU Fei, YUAN Huiqing, LIANG Kaixuan

2023, 37(04):  977-985.  DOI: 10.19657/j.geoscience.1000-8527.2022.030

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Groundwater pump and treat technology (P&T) is a representative technology of groundwater reme-diation, and is at present widely used also to control and repair groundwater pollution. However, in the practical application of P&T technology, it is often interfered by the complexity of hydrogeological conditions and the special behavior of ground pollutant migration and transformation. The most important problem is tailing or rebound, which leads to low efficiency and high cost in the later stage of treatment. Based on expounding the development and evolution of P&T technology, we systematically analyzed its application conditions, technological pros and cons, system design optimization methods and its combined use with other technologies. We concluded that with the application of pumping treatment, it is more used for the pump of high concentration pollutants in the initial stage of pollution and hydraulic control to avoid pollutant diffusion. Currently, the goal of pumping changes from treatment to flow field control. The pumping/injecting wells are often located at the contamination source and plume and their upstream and downstream. The purposes of controlling pollutant diffusion and clean water diversion were achieved by pumping the contaminated water or injecting uncontaminated water into the ground to form a watershed. Our results provide suggestions for the flexible application of groundwater pump technology and the selection of prevention and control solutions for site groundwater pollution in China.

Variation Regularity of Groundwater Level in the Yongding River Basin Under Ecological Replenishment

HU Xinyu, SHEN Yuanyuan, CHU Tingwen, HE Wei, WEI Wei, SHEN Xiaopeng

2023, 37(04):  986-993.  DOI: 10.19657/j.geoscience.1000-8527.2021.155

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In the spring of 2020, the ecological water replenishment in Yongding River Basin (Beijing section) was officially started on the 20^th of April. To understand the variation regularity of groundwater level in the Beijing section of the Yongding River basin and the surrounding areas under the influence of ecological water replenishment, based on the observation data of groundwater level within six months after the spring water reple-nishment in 2020, the data were classified by clustering method. Subsequently, each type of variation regularity was analyzed separately. The results show that the dynamic change types of groundwater level in Yongding River Basin under the ecological water replenishment influence can be divided into (1) continuous decline type, (2) decline type and then increase, and (3) continuous constant type, among which the groundwater level in the Beijing section, Tianjin section, and part of Hebei section shows type 2, and there is an obvious lag. However, the other parts of the Hebei section and Shanxi section show type 3, and only a few sites show type 1. These regularities can provide a technical reference for making scientific ecological water replenishment scheme.

Hazard Geology

Multi-Source Remote Sensing Recognition of Reactivation Characteristics of An Ancient Landslide Group at Taipingqiao in the Dadu River Catchment, Eastern Tibetan Plateau

ZENG Shuai, MA Zhigang, ZHAO Cong, YANG Lei, ZHANG Su, DONG Jihong, LIANG Jingtao, YAN Shengwu

2023, 37(04):  994-1003.  DOI: 10.19657/j.geoscience.1000-8527.2023.060

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The Dadu River catchment in the eastern Tibetan Plateau is one of the most developed areas of ancient landslides in the world. Due to the increasing human engineering activities and the frequent heavy rainfall occurrence, the problem of ancient landslide resurrection in the Dadu River catchment has become increasingly serious. In this study, we selected the ancient landslide group at Taipingqiao county, and used multi-source remote sensing technology of Unmanned Aerial Remote Sensing (UAV) and Interferometric Synthetic Aperture Radar (InSAR) monitoring to analyze the resurgence deformation characteristics and mechanism of the landslide in the Gulozhai village. Based on the UAV aerial remote sensing images, the landslide deformation characteristics at Gulozhai can be clearly identified. Two sets of large tensional cracks extend horizontally through the upper and middle landslide bodies, and the large secondary landslide on the left of the leading edge indicate that the landslide shows overall resurgence signs. Based on the InSAR time-series monitoring results, we confirmed that the two-month heavy rainfall from May to June 2020 was the main trigger for the resurrection of the ancient landslide, which is still in continuous deformation. Under heavy rainfall or earthquake, the secondary landslide on the left of the leading edge may slide further and even trigger the overall slope destabilization and sliding in the Luozhai village. Our results on the deformation characteristics and mechanism of the landslide resurrection at Gulozhai based on multi-source remote sensing technology can provide effective technical support for disaster prevention and mitigation related to the resurrection of ancient landslides in the Dadu River catchment.

Deformation Characteristics and Revival Mechanism of Yahuokou Multi-stage Landslide in Zhouqu, Gansu Province

YANG Xiaohui, ZHU Peng, YUAN Zhongxia, ZHANG Weixiong, DING Baoyan

2023, 37(04):  1004-1012.  DOI: 10.19657/j.geoscience.1000-8527.2021.157

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On July 19^th, 2019, a multi-stage landslide (volume: 215.5×10⁴ m³) with a reactivated sliding in the middle groove of the paleo-landslide occurred in Yahuokou (Zhouqu County,Gansu Province). The landslide started from the cliff mouth at the top of the slope body, and slowly slid down to the Minjiang River with flow shape. This blocked the Minjiang River channel and raised the water level, seriously threatening the safety of nearby residents and downstream towns. To study the deformation characteristics and revival mechanism of the landslide, the landslide geo-environmental background and deformation history were first investigated through field survey and historical data analysis. With data interpretation on remote sensing, landslide monitoring and rainfall, the landslide initiation and evolution processes were elucidated, and the landslide revival mechanism revealed. The multistage landslide resurrection is characterized by stepwise loading, stress transfer, and initiation. The landslide revival comprises three stages: (1) the upper slide began to flow slowly in a plastic form; (2) the middle platform of the gentle slope was prepressed by the upper sliding body, forming the “cut-fill” effect. Its failure mode is creep slip-tensile crack-sliding; (3) the lower block slid.

Development Characteristics and Risk Assessment of the Damogou Debris Flow in Mentougou District, Beijing

NIE Qiong, NIE Zhibao, CHEN Jian, DING Shijun, WU Saier, LI Duo, GE Runze, CHEN Ruichen

2023, 37(04):  1013-1022.  DOI: 10.19657/j.geoscience.1000-8527.2022.086

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Debris flow is one of the most common types of geological disasters in western and northern Beijing mountainous areas during stormy seasons. In the history of Damogou Gully (Qingshui town, Mentougou district, Beijing), there were many periods of debris flow disasters. At present, there are still many artificial deposits and collapse accumulations that constitute a potential debris flow source, and there are serious debris flow hidden dangers. This study identifies the types of debris flow sources, their storage and distribution, simulates the debris flow impact range under the frequency of once every 10, 20, 50 and 100 year rainfall, and evaluates their respective risk. The results show that the potential debris flow source is mainly man-made waste slag and coal gangue, with the residual reserve of ~447,000 m³. The high-risk debris flow area accounts for 13.1%-20.0%, mainly distributed in the gully mouth accumulation area and the confluence of main and branch gullies. The proportion of medium-risk area is 29.9%-31.2%, and the proportion of low-risk area is 48.8%-57.0%. It is advisable to set up prevention and control measures of upstream interception and downstream drainage in the circulation area of Damogou gully, and strengthen the rainfall monitoring and warning in the formation area in the heavy rainfall seasons.

Evaluation of Geological Disaster in Chengde Area Based on GIS and AHP Coupling Technology

WANG Ruifeng, ZHAI Yanliang, ZHANG Baojun, SHEN Guoqiang, ZENG Yifan

2023, 37(04):  1023-1032.  DOI: 10.19657/j.geoscience.1000-8527.2021.160

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To evaluate the impact of geological disasters, this study selected the Chengde area of Hebei Province as an example. Firstly, we used AHP and ArcGIS to evaluate the susceptibility of geological disaster. Secondly, the geological disaster bearing body vulnerability was established based on the current local land use. Finally, based on the constructing the judgment matrix, the geological disaster impact evaluation was established by overlaying the geological disaster susceptibility zoning map on the geological disaster vulnerability zoning map. The results show that the high-impact and relatively high-impact areas of geological disasters are mainly distributed in the north of Kuancheng county, east of Xinglong county, and south of Pingquan city. The medium-impact areas are mainly distributed in the central and southern parts of Luanping county, the south of Xinglong county, the central and northern parts of Pingquan city, the south of Shuangqiao district, and the south of Shuangluan district. The low-impact and relatively low-impact areas are mainly distributed in the north of Chengde, Longhua, Fengning and Weichang counties. This study comprehensively considers the dual attributes of geological disasters, and accurately evaluates the geological disaster susceptibility and the vulnerability of geological disaster bearing body in different combination states. The evaluation results can effectively avoid the problem of geological disaster prevention and control planning based on the geological disaster vulnerability. In addition, the evaluation results can provide scientific basis and technical guidance for geological disaster prevention and control planning in Chengde area.

Geological Hazard Susceptibility Evaluation Based on CF,CF-LR and CF-AHP Models in National Tropical Rain Forest Park:Taking Baoting County, Hainan Province as An Example

LI Xin, XUE Guicheng, XIA Nan, LIU Changzhu, YANG Yongpeng, MA Bo

2023, 37(04):  1033-1043.  DOI: 10.19657/j.geoscience.1000-8527.2023.002

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The national tropical forest park has steep topography and geological disasters occur frequently. It is of great significance to evaluate the vulnerability of national tropical forest park to geological disasters for risk reduction. Taking Baoting County, Hainan Province as the study area, the fault, elevation variation coefficient, profile curvature, NDVI index, water system and road were selected as evaluation factors. The deterministic coefficient model (CF), the coupling model of deterministic coefficient and logistic regression (CF-LR), and the coupling model of deterministic coefficient and analytic hierarchy process (CF-AHP) were used to evaluate the vulnerability of geological disasters and its accuracy of the study area. The result shows that the topography controls function to the development of geological disasters, and geological disasters influenced by fracture, highway and water distribution are obvious. All the three models have high accuracy (highest for CF-LR), which is a highly reliable model for the evaluation of geological hazard susceptibility.

Reactivation Characteristics and Mechanism of Engineering Disturbed Dumi Landslide in Western Sichuan Province, China

ZHOU Hongfu, FANG Tian, XIA Chenhao, RAN Tao, XU Ruge, ZHANG Jinghua

2023, 37(04):  1044-1053.  DOI: 10.19657/j.geoscience.1000-8527.2022.084

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Human engineering activities are an important factor that induce the reactivation and instable failure of landslides. In this study, taking the Dumi landslide in Yajiang County in Sichuan Province as an example, we summarize the deformation and failure characteristics and zoning evaluation, based on the Dumi landslide characteristics investigation by field investigation, Insar interpretation, engineering drilling, numerical analysis, and stability calculation. We analyzed the formation mechanism of the Dumi landslide reactivation, and the relationship between the stability coefficient FOS and excavation distance to the toe of the Dumi landslide. The results show three sliding surfaces, corresponding to strong, medium, and weak deformation areas. Slope toe excavation is the main trigger for the reactivation of the Dumi landslide, and a consequent deterioration in the shear strength of sliding zone soil caused by rainfall infiltration is the boosting factor. When the horizontal excavation distance at the slope toe is over 10.0 m, the sliding body would be clearly deformed and damaged under rainstorm conditions. Our results have good reference significance for avoiding small geological disasters in generating large losses, caused by landslides similar to that at Dumi.

Application and Research of Remote Sensing Integrated Geological Interpretation in China-Nepal Railway Survey

TIAN Shequan

2023, 37(04):  1054-1064.  DOI: 10.19657/j.geoscience.1000-8527.2021.154

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The geological conditions along the China-Nepal railway are complex: strongly incised terrain, high elevation (over 4,000 m), harsh climate, and field geological engineering investigation is extremely difficult. To reduce the workload of field investigation and improve the work efficiency, this study presents the advantages of remote sensing technology, and adopts remote sensing integrated engineering geology interpretation analysis to conducted detailed analysis and research on basic geology, hydrogeology, adverse geology and other elements along the line. We show that the stratigraphic age span in the region is wide, the lithology is complex, and the fault structure is extremely developed. The regional EW-trending faults control the main strata distribution, and there are several groups of secondary faults in the near parallel direction on both sides of the faults. The NE-NEE-rending faults are active at a later time, and most of them cut the near EW-directed faults. Landslides are mainly distributed in the eastern Requ, Xiabuqu and Sajia Chongqu basins, and are mainly composed of bedrock landslides. Debris flows are widely distributed in the area, typically along the two banks of Chongqu river in the east and Sajia Chongqu, with large-scale and massive occurrence. Dangerous rocks and rockfalls are mainly distributed in the western part of the Jilong Zangbo River Valley and the eastern part of the Pengqu River Valley, which has greater impact on the selection of the tunnel entrance and the mountain line. There are two sets of near-EW-trending high geothermal abnormal zones, which are closely related to regional faults. Our results support the field engineering geological survey and line scheme design, and illustrate the supporting role of remote sensing technology in railway geological engineering survey.

Tourism Earth Science

Characteristics, Genesis and Evolution of Daigu Landform in Yimengshan UNESCO Global Geopark

CAI Yinlu, WU Fadong, HAN Jinfang, HUANG Zhen, ZHOU Ying, LIU Baoyin, CHEN Yangyang

2023, 37(04):  1065-1074.  DOI: 10.19657/j.geoscience.1000-8527.2023.085

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The Yimengshan UNESCO Global Geopark (UGGp) is the origin of the “Daigu Landform”. Through field investigation of the characteristics of Gu landform, based on the measurement of river valley stratigraphy and profiles, and using the OSL dating of the river terrace to calculate the cutting rate, the formation time of Daigu Landform has been determined. The results show that the geomorphological features of the Daigu Landform are related to the strata lithology of the Gu body. Daigu Landform is a type of mesa structure, with a flat top, steep margin and gentle slope. Gu body is mainly composed of two strata with different lithologies: The top comprises Cambrian limestone with strong weathering resistance but develops many joints, while the Gu body with weak erosion resistance is dominated by mudstone and siltstone. We estimated that the formation time is about 1.77 Ma by using the erosion rate, based on the dating results of the river terrace. The Daigu Landform formation and evolution can be divided into four main stages: (1) the material was formed in the Early Cambrian; (2) tectonic uplift, and the strata gradually exhumed and the shaping stage began; (3) long-term weathering and denudation of various external forces, such as surface water that gradually created the mature Daigu Landform; (4) the landform ended its development when the upper limestone collapsed. The systematic study of the Daigu Landform has great importance in understanding the Daigu Landform and its scientific value, which also contributes to the spreading of geoscience knowledge of UGGps.

Characteristics and Geological Significance of Geoheritage in the Arxan Global Geopark, Inner Mongolia

WANG Lulin, ZHU Qingfeng

2023, 37(04):  1075-1088.  DOI: 10.19657/j.geoscience.1000-8527.2023.086

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The scientific classification and characterization of geoheritage is the premise and foundation of rational utilization and protection of geoheritage. The Arxan Global Geopark has distinctive and extremely rich geoheritage, which has high touristic value and geological research significance. In this paper, based on geolo-gical survey and evaluation of the geoheritage, we divided the geoheritage resource into two categories,i.e. geomorphological landscape and water landscape,and six landform/landscape types,i.e. volcanic, rock, fluvial, structural, and spring water,and 9 subcategories,i.e. volcanic formation, volcanic lava landform, volcanic lake, granite landform, fluvial erosion landform, fluvial accumulation landform, structural landform, hot spring, and scenic river sections, with 47 geosites in total. Among them, volcanic landforms and hot spring landscapes are of great significance in the comparative analysis of global geoheritage. Additionally, the authors analyzed the characteristics of various geoheritage and discussed the important geotouristic significance of the geoheritage in the Arxan Geo-park. Studies have shown that the geoheritage of Arxan Geopark have important scientific value in the fields of geomorphology, hydrogeology and geotourism. This provides a scientific basis for the protection of geoheritage and tourism route planning, and promotes the sustainable development of geoscience research, science popularization and geoscience tourism in the Arxan Geopark.