中国岩溶

Research on the division technology of karst groundwater source protection areas based on numerical simulation

WANG Yang, LI Juan, XI Beidou, JI Yonghong, TANG Jun, LIU Jiancong, CUI Yali

2018, 37(6): 799-809.

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Zoucheng City is located in the southwest of Shandong Province with a total area of 1，616 km2.Taking a karst water source in Zoucheng City as an example, the application of numerical simulation methods in the division of karst groundwater protection zoning and the effect of hydrogeological parameters on the classification results of water source protection zones were studied. The water source is located in the middle of the Guoliji monoclinic karst water system, with Wangyun river in the south. Groundwater is abstracted from the fractured karst aquifer comprising the Middle and the Lower Ordovician carbonate rocks, with the single well yield of more than 3，000 m3?d-1. There are two abstraction well fields in the water source, of which the first well field consists of 6 production wells and 4 production wells in second one. The karst groundwater runs from the southwest to the northeast, and mainly receives the leakage recharge of the overlying porous aquifer and the lateral runoff recharge. Using GMS software, a three-dimensional unsteady groundwater numerical model was constructed. Using particle tracing technique, the protection area of the karst water source area were divided by tracing the position and the migration trajectory of tracer particles after 100 days, 1，000 days and 25 years. Taking the change of the protection area after changing the parameters as the index to measure the sensitivity of the parameters, the sensitivity coefficient of each parameter was calculated and the influence of the hydrogeological parameters on the division scope of the protection area was studied. The numerical simulation shows that the maximum migration distance of the tracer particles after 100 d is 44.91 m, the maximum migration distance after 1，000 d is 301.85 m, and the maximum migration distance after 25 a is 1，523.27 m. According to this result, the area of the primary protection zone is 1.27×104m2, the area of the secondary protection zone is 0.42 km2, and the area of the quasi-protection zone is 3.47 km2. The sensitivity analysis result shows that when the parameter change range is within 20%, the sensitivity coefficient of vertical permeability coefficient VK1 of the first layer can reach 2.63×10-3, and the sensitivity coefficient of vertical permeability coefficient VK2 of the second floor can reach 3.64×10-3. The sensitivity of the vertical permeability coefficient is significantly higher than other parameters, indicating that the vertical permeability coefficient has the greatest impact on the division of the protection area. Therefore, when applying the numerical simulation method to divide the protection areas of karst groundwater sources, we should pay special attention to the accuracy and rationality of the vertical permeability coefficient of each aquifer in the model.

Variation of typical pollution components and pollution way of karst water in Baotu Spring region

SUN Bin, XING Liting, LI Changsuo

2018, 37(6): 810-818.

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Jinan City is famous the Baotu Spring which enjoys a reputation as The Finest Spring Under Heaven. The quality of karst groundwater has changed greatly since the end of 1950s, which imposes effects on the spring. Using hydrochemical data collected and measured in recent 60 years, this study attempts to address this issue. Selecting several chemical indexes of water quality, including salinity, NO3-、SO42-and Cl-, and the analysis of hydrogeological conditions and human activities, the hydrochemical variations of karst water are studied for three typical water-rich areas in the piedmont of the spring region. Meanwhile，the pollution ways of water quality are revealed for the three areas of the western, central and eastern parts of the Baotu Spring region. The results show that the variation characteristics of karst water quality are similar in these three areas before 1986, with small-amplitude growth of typical pollution components. While they had significant differences after 1986. Among them, the amount of increase of the typical pollution components is the least in the western spring region, where the pollution of karst water quality is mainly affected by point pollutant sources and surface sewage infiltration. The variation of typical pollution components exhibits a steady growth trend in the central area, where the water quality is mainly affected by the rainfall and the non-point source pollution in the southern area of Baotu Spring region. The amount of increase of typical pollution components of karst water is the largest in eastern Baotu Spring region, where the pollution is from point pollutant sources and the recharge of pore water due to artificial exploitation of karst water. These results would be an important guidance for the protection of karst water in the three water-rich areas of the spring region.

Effects of snowfall and tourism activities on water chemistry of surface karst springs in the Jinfo Mountain

LIU Yue, HE Qiufang, YU Zhengliang, ZHAO Ruiyi, ZHANG Tao, LIU Ningkun

2018, 37(6): 819-826.

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The Jinfo Mountain is a world natural heritage which attracts many tourists to visit its scenic spots in winter. The purpose of this work is to explore the effects of snowfall and tourism activities on the surface karst springs in this area. We conducted high-frequency automatic sampling monitoring of chemical changes in water springs during a large-scale snowfall in December 2014, obtaining high resolution hydrochemical change curves, which were compared with physical and chemical characteristics of atmospheric precipitation, soil water and sewage. Principal component analysis (PCA) was used to determine the main factors affecting spring water chemistry. The physical and chemical indexes of spring water show significant dynamic changes in different stages of snowfall, at the beginning of snow cover period(2014-12-10 to 2014-12-14), most of the hydrochemical indicators were stable largely; afterwards until the large area of snow melted (2014-12-15 to 2014-12-28), the amount of tourism emissions increased, spring water temperature, flow rate, turbidity, salinity and ion content exhibited an upward trend, while pH, dissolved oxygen showed a downward trend, and hydrochemical indicators changed greatly. During the melting of the snow, the melt water supply increased the dissolved oxygen and turbidity of the spring water, and other water chemical indicators first decreased and then rose. Principal component analysis shows that the sewage input of tourism activities was the primary factor causing the change of spring water quality, and the contribution rate of principal components reached 59%. The dilution effect of snow melting can relieve the groundwater pollution situation in the basin to a certain extent, which is the second influencing factor, with a contribution rate 31%.

Study on sources of chemical elements and geochemical susceptibility of a typical karst spring

SHENG Ting, YANG Pingheng, CHEN Feng, ZHAN Zhaojun, XIE Guowen

2018, 37(6): 827-834.

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To quantitatively study the prominent geochemical susceptivity and vulnerability of a karst spring in typical karst areas, the geochemical susceptibility and sources of chemical elements in Shuifang Spring, Jinfo Mountain in Chongqing was analyzed by using hydrochemical data from January 2016 to December 2016. The results show that chemical types of Shuifang Spring were Ca-HCO3 and Ca-HCO3·Cl. Under the combined influence of karst processes and human activities, the major anions and cation were HCO3-, Cl- and Ca2+. Cl- mainly come from human pollutants caused by tourism activity, and SO42- mainly comes from the effects of sulfuric acid rain. Due to seasonal change of karst processes, HCO3- and Ca2+ became the most sensitive ions. Under the influence of tourism activities, the geochemical susceptivity for major elements except for NO3- in Shuifang Spring has increased in the order of HCO3-> Ca2+> Na+> SO42-> Cl- > NO3- = K+> Mg2+ .The chemical features of karst spring are more sensitive because of human activities.Measures such as reducing and purifying the pollutants of human activities, improving the awareness of environmental protection of tourists and other related measures are strongly suggested for the protection of karst spring.

Comparison of water absorption characteristic and water retention capacity of five epilithic mosses in the karst areas of Guizhou Province

ZHANG Xianqiang, LONG Huaying, LIU Tianlei, CONG Chunlei

2018, 37(6): 835-841.

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In order to provide a theoretical basis for the water cycle and rocky desertification control of karst ecosystems, this paper studies the water retention and absorption abilities of five moss species, i.e. Erythrodontium julaceum, Barbula unguiculata, Bryum argenteum, Eurohypnum leptothollum and Racomitrium japonicum, which are commonly seen in the rocky desertification area of Puding, Guizhou Province. The results show that, the reserve mass of five epilithic mosses ranges from 0.71 t?hm-2 to 3.91 t·hm-2 , with the largest reserve of 3.91t·hm-2 for E. julaceum.The highest water retention capacity is 761.9% for R. japonicum, E. leptothollum is the second of 653.8%,and the smallest is 551.7% for B. argenteum. E. julaceum and E. leptothollum are the dominant species with the highest water retention capacity .The highest water retention rate was 38.2% for E. leptothollum, R. japonicum ia the second of 33.6% and the lowest is 15.2% for B. argenteum. The water absorption processes of the five mosses include two ways, i.e. external and internal water absorptions. There are differences in the time of water absorption and saturation for the moss species. Five species had the same water absorption dynamic reflected by the S type saturation curve. When the water content is below 25 g, the water absorption rate of the plants is directly proportional to the amount of water added. When the external water content increases to or above 25 g, the water absorption rate of the plants gradually trends to reach the maximum.

Characteristics of soil nutrient in karst rocky regions with heavy desertification under different land-use patterns

ZHU Zihong, YANG Cheng, XIE Yincai, WANG Qun, ZHU Tongbin

2018, 37(6): 842-849.

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This study used the principal component analysis(PCA) method to analyze the variation characteristics of soil nutrient under different land uses in the karst rocky desertification regions of Bisezhai village, Mengzi City, Yunnan Province. The results show that，(1) the variation coefficient of nutrient content in soil is between 0.14 and 1.76, indicating the relatively great differences in soil nutrients among different land uses；(2) Twelve soil nutrient indexes could be reduced to three principal components, which provide information accounting for 90.69% of the total. Among them, PC1 contains total P, effective P, rapidly effective K and available Mn. PC2 includes total organic carbon, total N, total Ca and available Zn. The contribution of available Fe to PC3 is the greatest；(3) The comprehensive score of principal components of soil nutrients in different land uses are ranked as follows， Pitaya > Plantation > undisturbed grass > Corn. The ranking result shows that forestation and Pitaya plantation can effectively improve soil nutrient status in rocky desertification areas. Collectively, the rocky desertification control in the study area should be on the premise of forestation to ecological restoration. We suggest that planting pitaya or eucalyputs is conducted to improve the soil conditions in the sampled area , thus gradually forming the integrated management system of rocky desertification, which is beneficial to the coordinated development of the ecological environment and social economy

Change of vegetation coverage and its response to climatic factors in the Guanling-Zhenfeng demonstration area for reduction and control of rock desertification

CAO Yang, XIONG Kangning, DONG Xiaochao, XIAO Hua, QUAN Mingying

2018, 37(6): 850-858.

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This paper studies the variation of vegetation coverage and the effect of climatic factors on the vegetation coverage in a demonstration area for reduction and control of karst rocky desertification. Based on the 30 m(16 d) resolution Landsat images during 2006-2015, using the method of maximum value composite (MVC), normalized difference vegetation index (NDVI), and correlation and partial correlation analyses, we systematically examine the spatial and temporal variation characteristics and the trend of vegetation index of the demonstration area and its relationship with climate factors. The results show that, (1) the annual maximum average value of NDVI between 2006 and 2015 is 0.39, which is higher in the north and south boundary regions of the demonstration area and lower in the south bank of the Huajiang river; (2) Since 2006, the places with extremely low(-1.210), low(-0.669) and moderate(-0.729) NDVI values exhibited a falling trend, those with high(1.359) and extremely high(1.247) increased overall significantly; (3) On the monthly scale, the NDVI of this month and the rainfall and temperature of this month, last month and month before the last one all pass the correlation coefficient test(P<0.05), and the correlation between NDVI and rainfall this month is higher than that between NDVI and temperature(RNDVI rainfall =0.782), the correlation between NDVI of this month and temperature of last month is higher than that between NDVI of this month and rainfall of last month(RNDVI temperature =0.771). (4) The vegetation growth of the demonstration area has no lag phase to rainfall, but a month lag to air temperature.

Study on the humanistic driving framework based on territory space change in southwest karst mountainous area, China

WAN Jiangjun, DENG Wei, ZHANG Jifei, SONG Xueqian

2018, 37(6): 859-865.

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Karst mountainous area is a special type of mountain land space. To identify anthropogenetic factors and their mechanism on the change of karst land is of great significance to properly regulate the intensity of human activities. The ecosystems in southwestern China karst mountainous area present poor anti-interference ability and are highly fragile. The spatial heterogeneity and scale correlation of land use are strong. Irrational human activities have led to a sharp conflict of man-land relationship in local areas. This paper put forward and analyzed the four human driving factors affecting the change of land space in the southwestern China karst mountains, which are social-economic development, folk culture and custom, policies and regulations, and population change. From game theoretical perspective between regulators and users and the idea of "Driver Factors Identification- Decision Analysis Process-Behavioral Results-Feedback Paths", this paper constructed a human driving framework for the change of land space in the karst mountains in southwest China. Accordingly, this study may provide a new theoretical perspective for the territory space optimization in karst mountain areas of China.

Spatial-temporal pattern of vegetation changes in Southwest China during 2001-2014

FENG Guoyan, MA Mingguo

2018, 37(6): 866-874.

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The study of temporal vegetation dynamics has been one of focused issues on global change, which has great significance to regional ecological management. Based on time series of MODIS vegetation index data from 2001 to 2014 and the DEM data and land use data in southwest China, the trends of the vegetation changes were calculated and the spatial differentiation characteristics of the changes with the other relative factors were analyzed. The results indicate that 74.52% of change trends of Seasonally Integrated Normalized Difference Vegetation Index (SINDVI) are not significant. The areas with significantly increasing trends account for 22.07% and the areas with significantly decreasing trends account for 3.41% of the total, respectively.So the increasing areas are much more than the decreasing areas. Through analysis results of the terrain factors, the trend of vegetation change in the low or middle altitude areas and gentle slope areas are the most obvious. The trend of vegetation change below the altitude of 3,500 m is more significant than that above 3,500 m. With the increase of slope, increasing and decreasing trends are both smaller. From the analysis results of land use, the SINDVI change trend is the most remarkable on the artificial surface, with relatively faster increasing and decreasing trends. With the influence of human activities, the increases of the artificial surface and the bare land and the decreases of the forest land are the main reasons for the vegetation degradation.

Arsenic vertical distribution and its controlling factors in paddy soil profiles in a typical karst area, northwest of Guangxi, China

ZHONG Cong, WANG Cheng, LI Jie, HUANG Jinlan, CHEN Meijun, HE Ping, ZHANG Xinying, HU Baoqing

2018, 37(6): 875-882.

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The characteristics of topsoil soil arsenic (As) accumulation and vertical migration in karst areas is of great significance to understand the migration and transformation of soil As and its geochemical behavior in soil environment. To explore the concentrations and migration characters of As in karst region, three paddy soil profiles in a typical karst mining area, northwest of Guangxi, were investigated and analyzed. This study area is located in the Dachang mining area in the southwestern part of Nandan district, characterized by the south-middle subtropical monsoon climate. The contents of the soil samples collected from the soil profiles were analyzed in a geochemistry laboratory,where the soil As concentrations were analyzed using the atomic fluorescence spectrometric method; the concentrations of MgO, K2O, CaO and Na2O were analyzed using ICP spectrometric method; the soil organic carbon concentrations were analyzed using redox volumetric method; and the soil pH was analyzed using ion selective electrode method. Afterward, the statistical software SPSS was applied to perform the data analyses, combined with the background of study area. Results show that the soil profiles consists of limestone soils with high degree of chemical weathering originated from soil parent materials. The soil As concentration in all the profiles studied has similar character, with relatively high As levels near the surface which becomes stable at the deeper portions of the soil. The dominant controlling factor of As migration and transformation was considered to be the soil organic carbon. In the periphery of the mine, the analytical result of two soil samples shows that the soil As mainly concentrated at the depth of 10-20 cm, rather than 0-10 cm . The mean concentrations of soil As in these soil profiles are 5.5 mg·kg-1 and 5.0 mg·kg-1 , respectively, with the ranges of 2.7 mg·kg-1 -9.9 mg·kg-1 and 2.5 mg·kg-1 -8.5 mg·kg-1 . The soil As concentrations of the profile closer to the mining area are characterized by high As background value, and the mean concentration of soil As is 46.2 mg·kg-1 ranging from 34.2 mg·kg-1 to 84.5 mg·kg-1 . The higher soil As concentrations in this soil profile gathers at the depth of 20-40 cm，while it is relatively lower in 10-20 cm deep. Notably, the soil As concentrations in this soil profile at 0-10 cm is also significantly higher than that of 10-20 cm deep, indicating that exogenous sources had significant effects on the surface soil of this profile. The ecological environment of karst mining area is extremely vulnerable, and the issue of agricultural soil As pollution in the surrounding areas should be paid sufficient attentions.

Detection of karst leakage passages in sick reservoirs by the self-potential method on the water: An example of the first-class hydropower station on the Jinjihe reservoir

CHEN Yixiang, WU Jianqiang, HUANG Qibo, GAN Fuping, HAN Kai, WEI wei, ZHENG Zhijie

2018, 37(6): 883-891.

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Reservoir water or sewage leakages often occur beneath buildings of man-made reservoirs or mine tailings reservoirs in karst areas because of the complicated geological conditions. To clarify passages of these leakages, geophysical prospecting tools are commonly deployed on in dams, abutments and other lands of reservoir areas, which cannot detect and evaluate the karst collapses at the bottom of the reservoirs directly, leading to poor effect of control to this problem. This paper takes the karst leakage passage beside culvert of the first-class hydropower station on the Jinjihe reservoir in North Guangxi as an example to study the principle, field working method and effect of detecting karst leakage passages in reservoir areas using the self-potential method on the water. Outcropping formation in the study area mainly consists by of limestone intercalated with dolomite, dolomitic limestone of Devonian Liujiang Formation (D3l) and dolomite, limestone, argillaceous limestone of the Devonian Donggangling order (D2d), where developed intermedium-degree hidden karst. When the outlet pipe of the hydropower station in the area releases water, a strong negative center regional field of self-potential on the water can be producd. By dividing the regional field of self-potential on the water using the circumferential mean method and calculating the residual local anomalies, 6 secondary negative center residual local anomaly areas of self-potential on the water covered by a strong regional field, which are quasi-equiaxis or elliptical shape, are identified. Checking in the reservoir by the diver, these 6 negative center residual local anomaly zones correspond to karst collapses, karst opening or leaking skylight at the bottom of the reservoir, respectively. Among them, the negative center residual local anomaly with quasi equiaxis shape near the survey points 46-48 of line 16 corresponds to the largest karst collapse at the bottom of the reservoir. The diameter of the collapse pit is about 1.8m, and its depth is about 2.5m. The karst opening or leaking skylight at the bottom of the reservoir which correspond to the other anomaly areas are relatively smaller on scale. The simple connected experiments of internal and external water and the engineering geological drilling show a good effect of the geophysical survey. This work demonstrates that the self-potential method on the water can be used to investigate of karst geological problems such as the emergency on the water of karst sick reservoirs, and rapid delineation of the range of the shallow karst leakage passages.

Application of high-resolution tracer technique in identifying the source of water gushing and the structure of aquifer medium in karst tunnel

XIE Guowen, YANG Pingheng, LU Bingqing, CHEN Feng, ZHANG Yu, CHI Yanbin, DENG Shujin

2018, 37(6): 892-899.

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The study area is located in the Longyan river basin, a tributary of Wujiang river, and is in Sanquan town, Nanchuan district, Chongqing. The strata of this area comprise the upper Cambrian dolomite. The terrain is dominated by medium mountain and mid-low mountains, with topographic high in the northeast and low in the southwest. Dissolution karst depressions and dolines are well developed in the area, below which is the Changtan underground river basically recharged by the source from Shangwan depression and Maiyincao depression. The Sanquan tunnel is located at 60 m under the Changtan underground river, where water inrush disaster occurred during the rainstorm on 15 and 16 April 2016. This study focuses on the verification of the connection between gushing water and Changtan river, identification of the source of gushing water and the discussion on the properties of the karst aquifer media. A highresolution tracer test using sodium fluorescein and Tinopal CBS-X was applied to the localities between the tunnel water bursting point and Shangwan and Maiyincao depressions . The results show that,(1) The receiving point received the Tinopal CBS-X released at Maiyincao depression , but no sodium fluorescein from Shangwan depression was received. The recovery rate of the Tinopal CBS-X at the left and right caves were 28.7% and 36.6%, respectively;(2) The maximum flow velocity of groundwater is 246.1 m?h-1 , with an average value of 118.5 m?h-1 . Two breakthrough curves (BTCs) presented a double-peaked shape, with the main peak in the front and the second peak in the back;(3) Based on the application of Qtracer2 software, the geometric and hydrogeological parameters such as flow channel volume, flow channel surface area, average diameter, distance of underground river, the friction coefficient, Sherwood number, Schmidt number, hydraulic depth and molecular diffusion boundary layer thickness are 1,148.4 m3 , 1.30×106 m2, 1.37 m, 780 m, 0.51, 1，055.1, 1，140, 1.08 m and 1.3 mm, respectively. From the analytical results, it is realized that there is a hydraulic connection between Maiyincao sinkhole and the tunnel gushing point, affected by Changtan underground river. The low recovery rate of Tinopal CBS-X is perhaps attributed to the presence of other discharge points and the properties of the flow systems. The groundwater flow field is a typical turbulent flow pattern. Two conduits are developed in this karst aquifer, controlled by parallel fissures without underground lakes. The hydraulic connectivity between Shangwan depression and water gushing section needs a further study. The accuracy of the study depend on flow condition, test period, density of monitoring points, and a contrastive test is necessary. Tunnel excavation disturbance and continuous precipitation are the main causes of water inrush to the tunnel, which is a type of karst pipeline inrush disaster. Due to the water inrush point of the Sanquan tunnel has direct hydraulic connection with surface water, and the amount of water gushing is large, it is suggested to drain the water from the depression, fill the Maiyincao sinkhole above the tunnel, or build a drainage ditch at the bottom of the tunnel.

Evolution trend of KRD based on high-resolution remote sensing images: An example of the east mountain, Mengzi ecological management region

TU Jienan, WANG Yi, TONG Liqiang, PEI Lixin, WANG Shanshan, GUO Zhaocheng, HE Peng, MA Zulu

2018, 37(6): 900-909.

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The purpose of this work is attempt to quickly and accurately determine the karst rock desertification (KRD) evolution trend with high-precision in small areas and provide scientific evidence and basic data for quantitative evaluation and precise treatment of KRD. We select the typical area of KRD-ecology management area in the east mountain of Mengzi as the study area. Based on SPOT5 data acquired in November 2006 and Pleiades data in January 2015, we use a method combining NDVI and FVC of the ecological management region to collect KRD information form remote sensing data. Statistical analysis on the data of 2006 to 2015 shows that the KRD were very serious, high KRD accounting 73.55%, moderate KRD 5.36%, and slight KRD 0.53%, respectively, while none-KRD only 14.86, with the shadow and water area accounting for 5.71% of the total. From the year 2006 to 2015, the area of high KRD increased slightly, from 72.37% to 73.55%, and the area of moderate KRD reduced from 11.58% to 5.36%. Although the area of mild KRD was small, it represented the significant reduction, from 4.35% to 0.53%, nearly disappeared. The area of non-KRD increased substantially, from 6.06% to 14.86%, so on the whole the occurrence of KRD tended to decline.

Difficulty degree zoning for 1∶50,000 geological mapping in karst area based on RS and GIS

CHENG Yang, PAN Xingcheng

2018, 37(6): 910-917.

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In light of technical requirements for 1∶50,000 geological mapping in karst area, the techniques of Remote Sensing (RS) and Geographic Information System (GIS) was employed to perform the geological interpretation and associated data analysis. On the basis of detailed interpretation of regional geology, geomorphology, environment, hydrology and other factors, the difficulty degree for mapping process was qualitatively divided by using parameters such as stratigraphic extension, topography, drainage pattern and gully density. The field studies show that the research results using this method are basically consistent with the actual geological conditions in the study area. This method can be used as the basis of the work arrangement of 1∶50,000 geological mapping in karst area, which can significantly improve the working efficiency and reduce the field workload on the premise of ensuring the accuracy of the results. It also can improve the quality of the RS technique system of 1∶50,000 regional geological survey in the karst area of Southwest China.

Application of audio magnetotelluric method to find water in the red beds of the Fangshiping village, Huaihua City

WU Jianqiang, GAN Fuping, ZHANG Wei, LIU Yongliang, WEI Wei, ZHU Chaoqiang

2018, 37(6): 918-924.

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In order to find water in the red beds of the Fangshiping village, Huaihua City, the audio magnetotelluric method was used to conduct water application research. The results of the study indicate that， (1)The audio magnetotelluric method is an effective geophysical method in the red beds. It is to comprehensively use the electrical characteristics and magnetic characteristics of the rock to distinguish the anomaly. Although the resistivity value of red beds is low, and the electrical difference is small, it has a relatively small influence on them by this method. (2)The results of data processing can better indicate the characteristics and position of the abnormity. The inference results are basically consistent with the drilling verification results and the maximum water inflow is 82.94 m3· d-1 . (3) The apparent resistivity sounding curve ρs in the drilling can effectively evaluate the electrical structure of underground. Its K curve can effectively enlarge the slight change of curve ρs to highlight the abnormity. Therefore, it can effectively mark the specific depth and the stratified position of the abnormal under the ground in the red beds, and the stratified results are basically consistent with the drilling results.

Determination of 36 volatile organic compounds in landfill leachate in karst area

QUAN Xiqiang, TAO Xin, QIN Suni, DU Wenyue, YU Jianguo, GUO Yongli

2018, 37(6): 925-931.

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The area of karst accounts for about 1/3 of the total area of China, and the amount of groundwater resources account for about 1/4 of the total water resources. Karst groundwater is an important source of water in China, which is also a major source of drinking water in Southwest China.In recent years, with the acceleration of urbanization, the scale of cities has been expanding, the population has been growing, and the living rubbish and waste water generated by urban residents have been constantly increasing. A large amount of waste water and landfill leachate is discharged directly without treatment and infiltrated into the underground through infiltration and burst irrigation, which seriously threatened the quality of underground water resources and the health of people downstream.In this paper, the content of 36 volatile organic compounds (VOCs) in landfill leachate were analysed by method of purge and trap Gas Chromatography-Mass Spectrometry(GC-MS). 5 mL of sample solution was obtained in the purge and trap bottle, and the samples were directly injected using TELEDYNE TEKMAR type purge and trap into the instrument for GC-MS analysis. The samples were separated by DB-VRX GC column, and then detected by the full scanning mode with positive electron ionization. The ion mass were selected and quantified by external standard method. The results showed that, the mass concentration of 36 VOCs was linear with the peak area in the range of 1-100 μg·L-1 . The method detection limit found for 36 VOCs test were in the range of 0.03-0.27 μg·L-1 . The spike recovery were performed by additional mixed standard of 36 VOCs, and the results were in the range of 88% to 110%, with RSD（n=7）ranged from 2.32% to 6.51%.The results showed that a few VOCs were found in the landfill leachate.

Comprehensive value evaluation of geological heritage resources based on township division：Taking Yanjin county as an example

DENG Yadong, LUO Shuwen, SHI Wenqiang, MENG Qingxin

2018, 37(6): 932-939.

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Yanjin county is located in the northeast of Yunnan Province. It is a typical mountainous area with rich geological heritage and high potential for geological tourism development, which requires reasonable protection and utilization. Presently, the management and protection of the geological heritage landscape of Yanjin county has been implemented to the township-level administrative institutions. At the same time, Yanjin county is a national poverty-stricken county with limited funds for protection and development of geological heritage landscape. Therefore, the classification of quality grades of township geological heritage sites has a clear guiding role in the protection of geological heritages in towns. The comprehensive valuably evaluation of township geological heritage is beneficial to the Yanjin government to prioritize the limited funds to the town with higher comprehensive value of geological heritage resources. Based on the analysis of the characteristics of the geological heritage resources of Yanjin county and taking the geological heritage resources of Yanjin county as the research object and the township division as the unit, this article uses the Delphi method to classify the quality level of township geological heritage sites in Yanjin county according to the classification standard of geological heritage quality in the Geological Relics Survey Specification. The results of the division can correctly reflect the quality status of geological heritage resources in various towns in Yanjin county.At the same time, this paper uses the Delphi method and the analytic hierarchy process to construct a comprehensive evaluation index system for the geological heritage resources of Yanjin township and adopt the Fish by-Rosenberg model to quantitatively evaluate the comprehensive value of the township geological heritage resources of in Yanjin. The results show that the order of the comprehensive value of the geological heritage resources of Yanjin county is，Shizi town>Dousha town>Miaoba town>Niuzhai town> Pu’er town>Zhonghe town>Yanjing town>Tantou town>Luoyan town>Xinglong town.

2018 Vol. 37, No. 6

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