Abstract:Eco-geology is a science that studies the interaction between ecology and geological environment and its mechanism. The technical frameworks for eco-geological surveys based on geological formation for mountainous areas are summarized, through the project of "Comprehensive Geological Survey of National Ecological Civilization Demonstration Area in Chengde City". According to the three levels of survey, i.e., background (baseline) survey-small watershed survey -research on ecological critical zone, the eco-geological characteristics and function rules of Chengde City are gradually deepened. The survey at the 1:250000 scale can quickly identify the eco-geological background (baseline) of the whole area, recognize the eco-geological units, and quickly screen the eco-geological targets (dominant ecological resource areas and ecological environment risk areas) through the geological formation analysis and mapping; the survey with a key small watershed unit (at the scale of 1:50,000) is carried out for the selected target areas so as to identify the characteristics of dominant resources and evaluate the risks of ecological environment; surveys and researches on ecological critical zones of typical geological formation (at the scale of 1:10000) are carried out to reveal the three-dimensional characteristics and interaction mechanism of the eco-geological system and provide a basis for comprehensive monitoring and prediction of the evolution trend. The framework of "Demand-Survey-Application" is demonstrated based on the survey results, and corresponding suggestions are proposed for the land spatial planning, ecological industry development and ecological protection and restoration for Chengde City.

Abstract:In order to understand the heavy metal pollution of farmland soil in northwest Xiushan, Chongqing, with quite a lot of mining activities, the authors collected 386 surface soil samples, analyzed and determined the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, Zn and Mn and evaluated the soil heavy metal pollution level, the ecological risk and health risk by using the geological accumulation index, potential ecological hazard index and health risk assessment model. The results show that the average values of 9 heavy metals in the surrounding soil of Xiushan mining area are higher than the soil background values of Chongqing, showing different degrees of accumulation effect. The concentrations of Cd and Hg significantly exceed the risk screening values for soil contamination of agricultural land, with the over-standard rates of 75.2% and 44.6% respectively. In the soil, Hg pollution is relatively serious, and its pollution level is medium pollution or heavy pollution, Mn, As and Cd are generally light pollution, and the remaining heavy metals are basically pollution-free. The potential ecological hazard index shows that Hg and Cd are the main ecological hazard elements, Hg ecological risk is mainly strong to extremely strong, and Cd ecological risk is mainly medium. The heavy metal health risk assessment results show that children are more susceptible to the heavy metal pollution. There are no significant non-carcinogenic risks for adults, children however show significant non-carcinogenic effect, and As and Cr are major non-carcinogenic factors. The carcinogenic risks for adults are acceptable, individual soil samples have carcinogenic effect on children, and As has a relatively higher carcinogenesis risk.

Abstract:On October 11, 2018, Baige landslide occurred in the upper reaches of the Jinsha River, and this was the most influential landslide event in Tibet since the Yigong landslide in 2000. The formation conditions, stability, monitoring and early warning of the landslide have been studied and reported by many experts, but the geo-mechanism of landslide has seldom been studied. On the basis of regional geological analysis, field survey, mapping and comprehensive research, the authors put forward the failure mechanism of the bank slope of the mélange in the Jinsha River structural suture zone under the sustained gravity, which mainly considers such factors as the structure of slope rock mass controlled by fracture, the weakening of the structural plane by the action of water and weak altered interlayer, and the scale and failure mode of the landslide controlled by unloading. The results have certain guiding significance for early recognition of potential landslide and risk prevention and control along the Jinsha River.

Abstract:The investigation of the relationship between the growth of genuine medicinal materials and eco-geochemical conditions is of great significance for the scientific development and standardization of traditional Chinese medicine. The geochemical background characteristics of Ge element in different geological formations and spatial scales were clarified in the regional scale of Luanhe River Basin and two Chinese herbal medicine planting demonstration areas of Jingoutun and Wudaoling. A multivariate statistical analysis method was used to analyze the eco-geochemical characteristics of germanium and its relationship with the genuine medicinal material Scutellaria baicalensis combined with mass transfer coefficient, chemical index of alteration, residual factor and bioconcentration factor. The results indicate that the average content of Ge element in the surface soil of Luanhe River Basin is 1.336 mg·kg^-1, and the content of Ge element in 43.54% of soil samples was generally categorized as belonging to rich to abundant level, while the average content of Ge element in the surface soil of Jingoutun and Wudaoling area is 1.352 mg·kg^-1 and 1.268 mg·kg^-1. The Ge element content of different geological formations and surface soil is significantly related to the TFe₂O₃ content, and the iron-bearing minerals in the soil have an adsorption effect on the Ge element. The soil-regolith-rock samples with higher degree of weathering and maturity tend to have higher Ge content. The weathering degree and soil maturity of Jingoutun area is higher than that of Wudaoling area as well as the enrichment of Ge element. The mass transfer coefficient based on Nb of Ge element is similar to that of TFe₂O₃, V, Ti, Co, P, Pb, Cu, Zn, Al₂O₃, SiO₂, K₂O and Na₂O. The ratio of Si/Ge changes significantly during the weathering process, which shows an antagonistic effect. The Ge element is mainly derived from the fracture of silicate mineral lattice and metal sulfide minerals released during their weathering process. The average bioconcentration factors of Ge element in Scutellaria baicalensis of Jingoutun and Wudaoling are 0.014 and 0.020 respectively. The root of Scutellaria baicalensis shows an obvious synergistic effect on the absorption of Fe and Ge in soil. The soil pH values have an important impact on the speciation and bioavailability of Ge element. The rich Fe, P and Sr values in the regional soil provide favorable conditions for the growth of high-quality Scutellaria baicalensis. The soil with abundant Fe group element content, slightly alkaline pH values and sand texture with better air permeability is suitable for the cultivation and growth of authentic Scutellaria baicalensis.

Abstract:Urban geology has been developed for nearly one hundred years, and great progress has been made in subject property research. However, in general, there are many controversies about the subject property. In addition, it is difficult for the basic theory of urban geology to meet the needs of modern urban management and hence it can not provide a systematic and complete geoscience solution for high-quality urban development. In this paper, the development and research progress of urban geology were systematically studied. The subject property of urban geology was further clarified and a concept was put forward for urban geological system. On the basis of this concept, the research object of urban geology was clearly defined, and the research content and technical framework of modern urban geology were described. The result obtained by the authors provides a research basis for the formation of a perfect theoretical system of urban geology in the future.

Abstract:Based on groundwater pollution survey data, groundwater monitoring data and remote sensing data, the authors analyzed the groundwater environment change trend in different areas of Lanzhou City since the 1990s (1998-2013). The results show that, since 1998, the main groundwater environment change in Lanzhou has been characterized by deterioration of groundwater quality and rising of groundwater level. Typical hydrochemical indexes such as TDS, TH, nitrate and fluorine have different trends in different areas of Lanzhou, and most of them show a steady upward trend. Nitric acid groundwater has appeared in some areas. The increase of urban pollution load is an important driving factor for the rise of typical hydrochemical indicators, and there is a direct relationship between the characteristic indicators and the main functions of different urban areas. Chengguan District is the main residential and commercial area, with the typical index of water quality deterioration being nitrate. Xigu District is a concentrated area of heavy industries such as chemical industry and smelting, with the highest degree of groundwater pollution, and the increase of fluoride suggests that industrial pollution is significant. Qilihe District and Anning District are comprehensive distribution areas of commerce, residence and light industry, and TDS, TH, nitrate and other indicators have all risen in varying degrees, but the increase is not significant. The rise of groundwater level in Xigu and Santan area is more obvious, with that in other areas being relatively stable. Urban impervious interface hinders the vertical infiltration of rainfall, irrigation and other surface water, making the annual fluctuation of groundwater level gentle. Due to the reduction of groundwater exploitation, increasing construction along the Yellow river and the leakage of underground pipe network, the condition of groundwater recharge and discharge is changing. It not only causes the rise of groundwater level in the urban area, but also enhances the leaching of pollutants and the evaporation and concentration of groundwater, which has a certain impact on the hydrochemical environment.

Abstract:Gansu Province is located at the juncture of the four major geographical areas of China, i.e., north area, south area, northwest area and the Tibetan Plateau, and is characterized by various climates, strong geo-tectonic activities, complex topography, diverse geomorphologic forms, and complex geological and hydrogeological conditions; all these factors provide favorable conditions for forming strontium mineral water. The test and analysis of the mineral water samples from 644 water spots in the whole province show the strontium content of these mineral water are mainly in the range of 0.09-1.00 mg/L, the highest value is 15.6 mg/L, and there are 411 water points where the strontium content is higher than or equal to 0.40 mg/L, and reaches the level content of drinking natural mineral water, accounting for 58.1% of all water points; therefore, strontium is one of the most common and abundant trace elements in groundwater of Gansu Province. The statistic analysis of these testing data shows the following phenomena:the hydrogeological units which are most favorable to strontium enrichment are the Quaternary groundwater in the piedmont basin of the Hexi Corridor plain area and the Cretaceous pore and gap groundwater of clastic rock in the Loess hilly area in east Gansu Province; the type of groundwater which is likely to enrich strontium element is the Mesozoic and Cenozoic detrital groundwater rather than the fractured groundwater of bedrock in metamorphic rock area. The circulation characteristics are that the basin-type groundwater system with deep circulation conditions is most favorable to strontium enrichment, while the groundwater strontium content of the local flowing system where the circulation path is short and the alternate conditions are stronger is poor. The content of strontium in groundwater depends on the strontium abundance in surrounding rocks. Strontium abundance is higher in Cretaceous and Neogene clastic rocks and Paleozoic carbonate rocks than in the other rocks, so the groundwater in the Cretaceous and Neogene clastic rocks and the carbonate karst groundwater has certain material conditions for enrichment of strontium mineral water. At the same time, strontium accumulation in groundwater is related to the geo-tectonic environment in which the groundwater is located and the characteristics of groundwater circulation and migration. The basin-type groundwater flowing system and the groundwater for deep circulation are far away from the recharge area to the discharge area, and the circulation path is long. The retention time of groundwater is long in aquifers, which is beneficial to the dissolution and enrichment of strontium in groundwater.

Abstract:Based on the study of hot water hydrogeochemical characteristics of the Oiga Graben Geothermal Waters, the authors carried out hot water heat storage temperature and recharge elevation calculation, and established the Oiga Thermal Spring mediumhigh temperature geothermal concept model. The results show that the Oiga hot spring is of medium-alkaline water with low TDS, and the water chemical types are mainly SO₄-Na type, SO₄-Cl-Na type and HCO₃^- SO₄-Na type. The hydrogeochemical characteristics of hot water indicate that the Oiga Springs are characterized by atmospheric rainfall recharge and shallow circulation groundwater in shallow geothermal systems. The hot water is heated by deep melting body and controlled by the Oiga semiinvisible controlled thermal fracture structure. but it is partially balanced or mixed with water in the Na-K-Mg triangle diagram due to the mixing effect by fissure diving or surface cold water. The mixed model is used to estimate the temperature before the influence of hot water and cold water mixing, the temperature range of the heat storage is 120-200℃, and the cold water mixing ratio is 70%-83%.

Abstract:Aquifer heterogeneity is an important factor influencing regional groundwater flow patterns. The complex structural and stochastic characteristics of regional-scale aquifer heterogeneity are difficult to characterize, which leads to insufficient understanding of the effects of heterogeneity on groundwater flow systems in practice. In this paper, the Cretaceous groundwater flow system in the Ordos Basin is studied based on the selected typical geological section. Stochastic numerical simulation of the two-dimensional section is employed to analyze the influence mechanism of aquifer layered heterogeneity on groundwater flow systems by comparing the changes of the groundwater flow field under different heterogeneity conditions. The results show that the groundwater flow net is close to the actual conditions when the ratio of horizontal to vertical conductivity (Kh/Kv) is 1000 in model for homogeneous aquifer. It is close to the actual conditions when the variance of conductivity is 0.91, the horizontal correlation length is 5000 m and Kh/Kv is 150 for heterogeneous aquifers. The stochastic simulated aquifer generated by three parameters (i.e., horizontal correlation length, variance of permeability coefficient, and anisotropy ratio) can well characterize the layered heterogeneity of aquifer and its influence on the groundwater flow systems. Due to the superposition of layered heterogeneity at different scales, equivalent homogeneous, anisotropic model for conceptualizing layered heterogeneous medium in large-scale groundwater flow simulation may lead to a much larger horizontal-to-vertical anisotropy ratio than the ratio between horizontal and vertical correlation scales.

Abstract:Karst spring is the main natural discharge form of karst groundwater in northern China and is an important natural resource with the functions of water supply, tourism and ecological environment. Nearly 30% of karst springs have been dried up, influenced by natural factors, coal mining, especially by human beings'large-scale development and utilization of karst groundwater since the last century. The dried-up springs also include some world-famous karst springs. Since the 17th National Congress of the Communist Party of China (CPC), local governments have actively responded to the call of the CPC Central Committee and the State Council to strengthen ecological civilization construction, and hence ecological restoration projects have been initiated for the reflow of some important karst springs. Based on the structural mode and genesis of the karst springs in northern China, this paper proposes the spring reflow pattern, which includes the following measures:regulating the water flow of the leakage section by using the water storage of the upstream reservoir, implementing artificial supplementary projects in the seepage section of the river, closing the wells in karst groundwater strong runoff zones and drainage areas, blocking artesian wells downstream of the spring water outlet, monitoring drainage in coal mines under pressure, and conducting afforestation measures in recharge zones. Taking Jinci spring in Taiyuan of Shanxi Province as an example and based on the quantitative optimization evaluation of the effects of these reflow measures, it is concluded that raising the storage level of the Fenhe Second Reservoir to the design elevation, closing the drainage well of Baijiazhuang coal mine in the strong runoff zone of karst groundwater to reduce water pressure, and plugging and disposing of artesian well downstream of spring outlet seem to be economically feasible and effective measures in the near future. Finally, by using the numerical model of spring groundwater, it is predicted that, after the implementation of these measures, Jinci spring water is expected to reflow in about two years. The results can provide demonstration and reference for other karst springs of the same type in northern China.

Abstract:Located in the Lushui County of Yunnan Province, the Denggeng hot spring and the Mabu hot spring emerge on the western bank of the Nujiang River valley. Sand of the Quaternary (Q₄²), basalt of the Upper Carboniferous Woniusi Group (C₃w) and limestone of the Lower Formation of Triassic Hewan Group (T₂h¹) underlie the study area. The temperature of hot springs range from 48.9 to 69.6℃, and TDS from 0.493 to 0.782 g/L. The hydrochemical types of hot water are of HCO₃·Ca-Mg type and HCO₃·Ca-Na type. The hot springs are of low to moderate temperature and weak acid. The F^- concentrations of the hot springs range from 0.78 to 2.13 mg/L, and the H₂SiO₃ concentrations from 41.0 to 70.2 mg/L. Li, Sr, Rb, Cs and Ba are relatively abundant in the hot water. The values of δ²H and δ¹⁸O of the spring water indicate that the hot springs in the study area are meteoric in origin. The elevation of the hot spring's recharge area is estimated to be from 1260 to 1435 m, the temperature of the recharge area varies in the range of 6.18-9.02℃, and the temperature of the geothermal reservoirs varies in the range of 100 -127.5℃. The content of Ca²⁺ and HCO₃^- in hot water is rich, and the percentages of milliequivalent concentrations of anions and cations are high, accounting for more than 60% and 82% respectively. Calcite and aragonite in the hot water are in the saturated state, the content of CO₂ in water is high and the pCO₂ in the hot water is much higher than atmospheric pCO₂. The hydrochemical and hydrodynamic conditions are favorable to CaCO₃ deposition. Travertines are precipitating near YLS3-1, YLS3-3 and YLS3-4 of the Denggeng hot spring and YLS4-1 of the Mabu hot spring. Thermal groundwater rises up to the land surface on the western bank of the Nujiang River valley after groundwater receives recharge from infiltration of precipitation in the recharge areas of the mountainous areas to the west of the Nujiang River, undergoes deep circulation and obtains heat from heat flow. The hot springs are of the deep infiltration-cycle type and are of low to moderate temperature. The hot water mixes with the shallow cold water when it rises to the land surface. The proportion of mixing cold water is about 60%-73%, and the circulation depth of the hot water ranges from 2375.2 to 3161.7 m.

Abstract:Jinci Spring, which is composed of Nanlao Spring, Shengmu Spring and Shanli Spring, is exposed at the foot of Xishan Mountain in Taiyuan. The average horizontal discharge of Jinci Spring was 1.94 m³/s from 1954 to 1958. Pingquan spring, located in the piedmont fault zone with Jinci spring, became the source of superlarge karst water self-flowing wells in 1978, with the maximum self-flowing rate reaching 1.56 m³/s. Because of the exploitation of these self-flowing wells, the flow of Jinci Spring dropped sharply and was cut off on April 30, 1994. The study of the hydraulic connection between Jinci Spring and Pingquan Spring in Taiyuan, Shanxi Province, is of great significance for the formulation of Jinci Spring recharge plan. With Jinci spring and Pingquan spring as the research objects and through sample collection and water quality monitoring, hydrochemistry (ion ratio, sulfur isotope, hydrogen and oxygen isotope) methods were comprehensively applied. The result has revealed hydrogeochemical characteristics and environmental isotope characteristics of Jinci spring to Pingquan spring as well as the characteristics of groundwater flow system and hydraulic connection. From 1980 to 1992, the change of groundwater level in Jinci Spring showed a steady downward trend. The main reason was that a large number of karst groundwater was exploited in Taiyuan Chemical Industry Company, Kaihua Valley, Pingquan Village and Liangquan Village in Zhaoxu County, which resulted in the decline of groundwater level. The hydrogen and oxygen isotope values of karst groundwater in Jinci spring to Pingquan spring area were close to each other, indicating that the source of recharge and the way of recharge were quite similar. Water quality monitoring analysis shows that the change trend of each ion in Jinci spring and Pingquan spring is basically the same, suggesting that Jinci spring and Pingquan spring have close hydraulic connection, so Jinci spring and Pingquan spring must have a strong water channel. The water level of Jinci spring can be raised by curtain grouting on the downstream water channel of Jinci spring, so that Jinci spring can flow out.

Abstract:80 shallow groundwater samples were collected from Tacheng Basin and analyzed for their chemical composition, and the distribution and source of Fe and Mn in groundwater in Tacheng Basin were studied. Generally, the shallow groundwater in Tacheng Basin is significantly polluted by Fe and Mn. 25% and 5% of the groundwater samples show Fe and Mn exceeding the groundwater standard, respectively. The concentrations of iron and manganese in deep confined water do not exceed the standard. The concentrations of Fe and Mn are controlled by the original geological and sedimentary environment and the superstition of human activities. High concentrations of iron and manganese in groundwater are distributed in stripes or patches in the copper and molybdenum metallogenic belts in northern mountains, middle alluvial plains and southern hilly areas of Tacheng Basin. The spatial distribution characteristics of iron and manganese in the groundwater of the study area are basically the same. The heavy pollution points of iron and manganese are mainly distributed in Tacheng of Emin County and its surrounding areas. The distribution of iron and manganese in groundwater in the study area is closely related to soil and aquifer composition, human activities and some other factors. Redox and groundwater runoff conditions are the main factors affecting the migration and enrichment of iron and manganese in groundwater. Infiltration of polluted water from sewage ditches is an important factor affecting the content of iron and manganese in underground water of heavy pollution spots in Tacheng Basin.

Abstract:The suitability evaluation of the land space development is the base of the territory development plan, the city and county are the basic units to implement the main function zoning, and the suitability evaluation of land space development at the city and county level can provide effective support for the more refined management of land resources and space. In this study, the authors built the indicator system with the nature factors and social economy to evaluate the suitability of agricultural production and urban construction processes in Yichang City. Five category areas are distinguished according to the evaluation results. The results show that the land area suitable for agricultural production reaches 3412 km², while 7143 km² of land area is not suitable. Only 748 km² land area is suitable for urban construction. The results indicate that the suitable area is mainly distributed in the east area of Yichang City, whereas the western montane area is not suitable and hard for land space development. The results of the suitability evaluation are in good agreement with the present land utilization, but there are some discrepancies between the results and planning data. The suitable area for agricultural production is 132 km² larger than the reserved cultivated land. The present cultivated land distributed in the suitable and comparatively suitable areas for agricultural production accounts for 73.98% of the total cultivated land area. The suitable area for urban constructions is 611 km² less than the bottom line of construction land. The current construction land distributed in the urban construction suitable and comparatively suitable areas accounts for 73.98% of the total construction land area. Compared with the remote sense image, the accuracies of the evaluation results including agricultural production and urban construction area were analyzed, and the result shows that the accuracy of suitable area evaluation reaches 100%, while the evaluate accuracies of the unsuitable area for agricultural production and urban construction are 93% and 100%, respectively.

Abstract:Gypsum mineral salt enriched layers are common bad geological body in the process of utilizing urban underground space in the red beds area. The detection of the burial depth and spatial distribution of gypsum-salt enriched strata in advance is of great significance for the development of urban underground space resources, the determination of foundation bearing capacity, bearing stratum and foundation type selection. Taking the International Biological City of Tianfu New District of Chengdu as the experimental area, the authors chose a fast, non-destructive and anti-jamming new transient electromagnetic method, opposing coils transient electromagnetic method (OCTEM), to detect and study the gypsum-salt enriched layer in red mudstone of Cretaceous Guankou Formation. Firstly, according to the resistivity characteristics of different strata in the study area, the authors established geoelectric models such as three-layer model, four-layer model and five-layer model, and carried out OCTEM forward response analysis for these models, respectively. The forwarding calculation shows that, with OCTEM method, the gypsum salt enriched layer can be effectively identified from surrounding rocks with obvious resistivity difference. Then, the authors took the practical measurement in the test area covered about two square kilometers, and swept the field with a network of 100m×10 m. Finally, the authors obtained the inversion results and established the three-dimensional electrical structure of strata in the depth greater than 200 m in the study area. With the comprehensive verification and analysis of drilling results, the spatial distribution pattern of gypsum mineral salt enriched layer was successfully inferred, which proves that this method is effective for the detection of gypsum-salt enrichment layer in urban underground space of the red bed area.

Abstract:Gansu Province possesses rich geothermal resources, and the potential for geothermal resources development and utilization is great. In this paper, the distribution of geothermal resources in Gansu was presented, In combination with the regional geological structure, the chemical characteristics of geothermal water, and the current situation of development and utilization of geothermal resources, the authors investigated the occurrence characteristics of geothermal resources of sedimentation basin conduction type and apophysis mountain convective type, and estimated the potential of the two types of geothermal resources. The results show that sedimentation basin geothermal resources are distributed in Hexi, Longxi and Longdong basins, the thermal reservoirs are of pore-type and fissure-type, thermal reservoirs were developed from Proterozoic to Cenozoic, and the reservoirs are dominated by sandstone; the apophysis mountain geothermal resources are mainly distributed in Qilian Mountain and western Qinling orogenic belt, the thermal reservoir type is of fault ruptured zone, and the lithology mostly is granite. From the potential calculation of geothermal resource, the proportion of heat recovery coefficient of greater than 0.4 is simply 29.16% in Gansu, indicating that the geothermal resources in Gansu are in a low mining degree, and hence has great mining potential.

Abstract:The problem of how to use geological results or data, especially from the eco-geochemical survey engineering, has been an issue attracting extensive attention since the 21^th Century. By studying the regional eco-geochemical survey and some petrogeochemical survey data of Se distribution in soil, the authors investigated and summarized relevant selenium-rich soil space distribution characteristics in Jiangsu Province, element geochemistry, material sources and genetic types, and some other problems. The main research results are as follows:1) The proportion of selenium-enriched soil is less than 3% in Jiangsu Province, and Se concentration in the selenium-enriched soil is generally 0.3-15.0 mg/kg. In addition,, there are restively higher element values of S, TOC (total organic carbon), Zn, Sb, Cd, Pb, As, Cr, Ni, Fe, etc., in the soil; 2) the above selenium-enriched soil can be divided into 6 genetic types,i.e., the original rock weathering residual type, coal gangue weathering migration type, local lacustrine sediments Se-rich type, coal flyash type, superposition type of some heavy metals pollution, and polymetallic mineralization associated type. Meanwhile, the utilization values of the original rock weathering residual type selenium-rich soil are the highest and it is mainly from acid soil environment in southern Jiangsu Province, and this type Se-rich soil is the main production area of Jiangsu's natural selenium-rich agricultural products; 3) the material sources present multi-origin compound attributes in the Se-rich soil, and they are manifested as three main material forms in the Se-rich soil, namely the congenital materials sources of natural origin, acquired materials sources of man-made origin, and compound materials sources of natural and man-made common origin; 4) there exist significant positive correlation between Se and S, TOC, etc., in the Se-rich soil formed by congenital materials sources of natural origin, and the values of some heavy metals such as Cd, Zn, Pb and As rarely exceed the standards of national farmland security utilization in this kind of Se-rich soil. Moreover, the category or thickness of this kind of Se-rich soil are not restricted by the cultivated layer, and the most thick soil of Se-rich areas can exceed 2 meters in depth.

Abstract:Germanium has application prospects in both industrial and medical fields, organogermanium compounds exhibit low toxicity and antitumor activity. It is valuable to develop Ge-rich soil, whereas the research on soil Ge is still insufficient in China. Based on multi-purpose regional geochemical survey in Guangxi, the authors studied the spatial distribution of Ge in top soil and deep soil in Beibu Gulf in this paper. The Ge values of top soil as well as deep soil derived from various parent materials were elucidated, and the factors that influence soil Ge content were summarized. The results show that the average values of Ge in top soil and deep soil are 1.43 mg/kg and 1.64 mg/kg, respectively. The Ge values are critically controlled by parent materials, and the soil derived from carbonates has the highest Ge content, followed by soil that has originated from granites, Quaternary sediments, sandstones and shales. The ratios of top soil Ge values and deep soil Ge values indicate that Ge values of top soil are effected little by anthropogenic activities. The influencing factors of Ge contents vary in soils derived from different parent materials. As for top soil and deep soil derived from granites, Ge values are primarily influenced by clay minerals, gibbsite and quartz in soil. In contrast, for soils derived from carbonates, Quaternary sediments, sandstones and shales, top soil Ge values are primarily influenced by clay minerals, gibbsite, secondary Fe-bearing minerals, amorphous Fe oxyhydroxides, quartz and organic matters in soil, and deep soil Ge values are primarily influenced by clay minerals, gibbsite, secondary Fe-bearing minerals, amorphous Fe oxyhydroxides and quartz in soil. 53.32% of top soil have a slightly-rich level of Ge values and 30.21% of top soil have a rich level of Ge values, which are beneficial for Ge-rich agricultural crops cultivation and worthwhile for further exploitation. The objects of this study are to provide basic information for Ge ecogeochemistry, support Ge-rich soil and agricultural products development.

Abstract:In order to study the heavy metal pollution characteristics, potential ecological risks and causes of the soil in the abandoned tungsten and molybdenum mine area in Chifeng City, Inner Mongolia, the authors collected 83 surface soil samples and 6 soil borehole samples. The spatial distribution of As, Cd, Cr, Cu, Ni, Pb, Mo and Zn was studied by ArcGIS spatial interpolation analysis. Heavy metal disturbance index was constructed to study the anthropogenic pollution degree. The geo-accumulation index method was used to verify the pollution degree of heavy metals in the mining area. The correlation analysis was used to judge the sources of heavy metals and discuss the causes of pollution. The results show that the average content of As, Cd, Cu, Pb, Zn and Mo in the soil around mining area is obviously higher than the background value around the mining area, and the high content is mainly distributed around the tailings pond, and the main source is mining activities of the mine. Cr and Ni are basically pollution-free, and the main source is the weathering of the parent rock. Through the calculation of the heavy metal disturbance index function, it is found that the use of regional background values to evaluate heavy metal pollution around the mining area exaggerates the pollution of heavy metals by the mining activities of the mine. The heavy metal pollution in the soil around the mining area is caused by the "double-drive mode"under the combined action of natural heavy metal enrichment and mining activities. The degree of heavy metal pollution in the soil around the tailings pond gradually decreases with the increase of the horizontal distance from the tailings pond and the increase of the depth. At the same time, the richness of precipitation is a key factor affecting the migration capacity of heavy metals. However, the mine is located in an area where precipitation is scarce, which makes the tailing pond exhibit a limited range of heavy metal pollution in the surrounding soil and slight impact on the ecological environment.

Abstract:"Yichang Orange" enjoys a long reputation, and Yaqueling area is one of its typical producing areas. In this paper, the geochemical survey of vertical profile of rock-soil was carried out in the center of orange production of Yaqueling area, Yichang City. Through the analysis of nutritive elements and rare earth elements, the migration characteristics of related elements from rock to soil were investigated, and the suitability of orange production was evaluated. The results show that most of the soil elements will inherit their content level in the parent rock, as shown by such phenomena as the similar REE distribution pattern and the similar degree of relative enrichment or dilution of Si, Na, K, Ca, Mg, Mo, Sr and other elements. According to correlation analysis and cluster analysis, three groups of elements of positive correlation such as Al-Fe-Ge-Ni-B-K-Si, S-N-Se-P and Cu-Zn-Mo were identified. The sequence of the suitability of the soil forming parent rock for planting orange soil is feldspathic quartz sandstone of Honghuatao Formation, calcareous sandstone of Pailoukou Formation, marl of Duodaoshi Formation, and calcareous conglomerate of Luojingtan Formation. In addition, some suggestions for planting optimization are put forward.

Abstract:In order to explore the dominating influences on the composition of vegetational community in the Qaidam Baihe River Basin of Chengde, Hebei Province, for supporting the ecological environment protection, the authors conducted detailed investigation of the community and field survey of the geological formation as well as test on elemental geochemistry, and then analyzed the response of vegetational community composition to the geological formation, which includes granite intrusive rock, rhyolite volcanic rock, dolomite carbonate rock and sandy conglomerate clastic rock from the perspective of spatial feature, nutrient as well as water supply under the similar climate condition. The granite formations are characterized by thick soil, non-continuous fractures, high nutrient content of phosphorus and optimal water retention capacity, which are favorable for the deep-rooted arborous species. The rhyolite formations have relatively less thickness of soil, with interpenetrating fractures in the substrate, high nutrient content of phosphorus, but relatively poor water retention capacity compared with granite formations, which are beneficial to deep-rooted shrub. The dolomite formations have the features of thin soil layer, with tightly closed through fissures, high nutrient content of calcium, but poor water retention capacity, which are favorable for the growth and development of shallow-rooted shrub and a small amount of calcium-like shallow-root trees. Compared with another formations, the dolomite formations are characterized by the thinnest soil, low nutrient content, and poor water retention capacity, without fracture developing, which are suitable for the drought-tolerant shrub.

Abstract:Based on the geological formation zoning and watershed landform evolution theory and using a combination of technical methods such as geological construction analysis, DEM digital landforms, remote sensing interpretation, unmanned aerial vehicle and field route survey, the authors quickly identified 63 single geological heritages in Chengde Panlong Lake, and this enriches the geo-tourism resources of the scenic area and enhances the scientific connotation of the scenic area. Geological formation determines the inherent "gene" of the basic geological heritage, is the material basis for the formation of geological heritage of geomorphic landscapes, and affects the development of geological heritage of geological disasters through lithology and structure. The evolution of watershed geomorphology affects the exposure of basic geological heritage; it is the main geological force that shapes the formation of geological heritage of geomorphic landscapes and affects the development of geological heritage of geological disasters. The idea of combining geological formation and watershed geomorphology runs through the whole process of geological heritage survey, and a large-scale geological heritage survey technical method flow of "defining the potential areaidentifying geological heritage resources-inquiring laws-summary method" is initially formed. Large-scale geological heritage surveys strive to bridge the"last mile"of geological heritage surveys and local needs as well as the development of the tourism industry, and provide scientific and technological support for the protection and development of geological heritages and the construction of beautiful villages and characteristic towns.

Abstract:In order to determine whether the increase of gas radon concentrations at the monitoring point of the Jiayuguan fault since June 2015 can reflect the stronger activity of the Jiayuguan fault or not, the authors applied the cross-fault measurement method based on the typical distribution pattern of soil gas across faults and analyzed comprehensively the relationship between the abnormal changes of gas radon concentrations and the fault activity through multi-component correlation analyzing and theoretical modeling. The results show that the concentrations of CO₂, CH₄, and H₂ from the same monitoring point do not increase during the rapid increase of the gas radon concentrations from the monitoring point of the fault. There is no positive correlation between them. The adding of gas radon concentration does not come from deep crust and it does not mean the stronger activity of the Jiayuguan fault. The results of the gas radon measurement across faults which lie on both sides of the monitoring point show that the gas radon concentrations are different, and this is consistent with the typical distribution pattern of fault gas on the unchanged side of the surface environment but it does not conform to the typical distribution pattern of fault gas on the changed side of the surface environment. The increase of gas radon concentrations is correspondingly with the change of the surface environment in time. Therefore, the increase of gas radon concentration at the fault monitoring point is caused by the change of the surface environment, and the activity of the Jiayuguan fault does not increase. This method provides a thinking for the improvement of reliability in using fault soil gas to judge fault activity.

Abstract:Landslide hazard assessment is one of the important measures for disaster reduction and prevention. Field investigations show that 138 landslides are developed along the slopes around the city area in Qingjian, which seriously threaten the safety of the city. In order to accurately evaluate the hazard of landslides in Qingjian City, the authors divided the slope zone of Qingjian City and surrounding areas into 925 slope units according to the development of river valleys and the integrity of topography. The slope units were calculated according to different slope gradients, slope heights and slope patterns under different soil moisture values. The calculation results show that, with the gradual increase of the soil moisture content of slope, the area of the stable slope gradually decreases, and the area of the unstable slope gradually increases. According to the monitoring data of soil moisture content of loess slope in northern Shaanxi, the probabilities of occurrence of soil moisture content (w) were analyzed and calculated. The probability of occurrence of w ≤ 0.15 is 0.622 (very high probability), that of 0.15<w ≤ 0.2 is 0.2963 (high probability), that of 0.2<w ≤ 0.25 is 0.0816 (medium probability), and that of w>0.25 is 0 (low probability). The hazards of slope units were assessed in combination with the slope stability calculation results and the soil moisture content occurrence probability. The assessment results show that the very high hazard area is 3.27 km², which includes 112 slope units and 92 landslides; the high hazard area is 4.19km², which includes 128 slope units and 36 landslides; the medium hazard area is 8.75 km², which includes 251 slope units and 6 landslides; the low hazard area is 15.20km², which includes 434 slope units and 4 landslides.

Abstract:In order to evaluate the pollution risk of heavy metals in road dust of the oasis city, the authors collected a total of 54 typical road dust samples from Korla, Xinjiang, and analyzed the concentrations of Hg, Cd, As, Pb, Cr, and Cu elements. The pollution and potential health risk of heavy metals in road dust were analyzed on the basis of GIS technology and geostatistical analysis methods and by using the Pollution Load Index and the US EPA health risk assessment model. The obtained results indicate that the average concentrations of Hg, Cd, As, Pb, and Cu elements in the road dust of Korla City are less than the screening values of the Soil Environmental Quality-Control Standard for Soil Contamination of Development Land (GB 36600-2018), but the average concentration of Cr exceeds the corresponding screening value by factor of 9.90 times. The results of pollution assessment indicate that heavy metals in the collected dust samples are heavily polluted by Cr, without pollution by Hg, Cd, As, Pb, and Cu. The Pollution Load Index of heavy metals in road dust varies in the range of 0.0142~0.0522, with an average value of 0.0266, at the no pollution level. The spatial distribution patterns of the six heavy metals in road dust indicate that the high concentrations are distributed mainly in the northeastern and northern areas of Korla City. The results of health risk assessment indicate that the handmouth ingest intake is the dominant pathway of the average daily exposure and health risks of road dusts in Korla, and the health risk of heavy metals in road dust for children are higher than that for adults. The non-carcinogenic and carcinogenic risk of metals such as Hg, Cd, As, Pb, Cr, and Cu in road dust in Korla is within the safe range. As contributes most to non-carcinogenic risk, whereas Cr contributes most to carcinogenic risk of road dust in Korla City.

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