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2019 Vol. 38, No. 6

Display Method:
Study on watershed boundary division for unified evaluation of surface water and groundwater resources and environment in karst areas
WANG Yu
2019, 38(6): 823-830. doi: 10.11932/karst2019y08
Abstract:
There are three types of boundary differentiation between surface water basins and groundwater basins in karst areas, that is, the surface watershed and groundwater basin boundary are basically the same in plane distribution;surface watersheds extend beyond the boundaries of groundwater basins.The boundaries of groundwater basins extend beyond surface watersheds.The top boundary of surface water and groundwater coupling basin in karst area is the surface and underlying surface of surface water basin, and the bottom boundary is the top surface of shallow circulating groundwater aquifer or aquifer between aquifer and confined aquifer. In the karst aquifer distribution area with large thickness, the top surface of weak karst development zone can be regarded as the bottom boundary.The secondary boundary between the two sub-systems of surface water and groundwater is the underlying surface of the surface water basin.Combined with the characteristics of specialized (investigation) exploration and regional investigation evaluation, the principle and method of evaluation unit division are put forward.In the new round of natural resources investigation and evaluation, it is helpful to systematically carry out the investigation and evaluation of water resources and environment with watershed as a unit, and implement the unified management of surface water and groundwater resources and environment.
Numerical simulation method for the karst development of carbonate fracture networks with both laminar and turbulent flow
GAO Yang, QIU Zhenzhong, YU Qingchun
2019, 38(6): 831-838. doi: 10.11932/karst20190601
Abstract:
The development process of karst water systems is of great significance to many resource and environmental problems. The issues such as the prediction and exploitation of water resource, oil and gas resources, and the prevention of soil erosion are all closely related to this process. Karst conduits are formed by the gradual dissolution of fractures by groundwater. In the early stage of karstification, the width of the fractures is small and the whole flow field is laminar flow. With the progress of karstification, the flow in some fractures becomes turbulent because of preferential dissolution, and the flow in other fractures remains laminar. This paper presents a numerical method to simulate the karst development of fracture networks with both laminar and turbulent flow. The initial fracture networks are constructed by Monte-Carlo simulation. The groundwater flow is simulated by the discrete fracture network method. The dissolution enlargement of fractures is calculated by the empirical equations of dissolution rate of carbonate rock surface. The nonlinear equation system for the water heads of the flow field, with both laminar and turbulent flow, is solved using the iteration method. The numerical method and software of this work are proved by comparing the calculation results of the analytical and numerical methods.
Numerical simulation for the evolution of covered karst fissure system between rivers
WU Yazun, CEN Lei, LIN Yun, QU Pengchong, WANG Zijie
2019, 38(6): 839-845. doi: 10.11932/karst2019y11
Abstract:
Initial media characteristics and boundary conditions of a karst system determine its evolution process. The purpose of this study is to reveal the development of a concealed karst aquifer system under different boundary conditions and medium characteristics. Based on groundwater seepage and carbonate dissolution theory, we construct a karst fissure network dissolution propagation model of coupled fracture network seepage and carbonate dissolution, and conduct simulation on the evolution process of the concealed karst aquifer system between rivers. The results show that the flow changes during the development of the karst system have three stages. The first stage is a slow laminar flow with a flow rate increase of 2.2×10 -6 mL·(s·a) -1, with a duration logarithmically related with the initial head difference. The second stage is a very fast turbulent with a flow rate increase of 5.5×10 2 mL·(s·a) -1, and the duration is linearly related with the initial head difference. Stage III is a fast turbulent with a flow rate increase of 26 mL·(s·a) -1. The existence of dominant cracks accelerates the dissolution of karst fracture network. The time for the heterogeneous system entering the extremely fast turbulence phase is 53% shorter than that of the homogeneous system, and the dissolution rate of cracks is accelerated by 12.5%.
Analysis of dynamic change and reason of water resource security in karst areas using the set pair method: An example of Guizhou Province
ZHENG Qunwei, SU Weici, YANG Zhenhua, ZHOU Feng
2019, 38(6): 846-857. doi: 10.11932/karst20190602
Abstract:
According to the features of hydrology and water resource in karst areas of southwestern China, an index system of evaluating water resource security is established involving five parts, water resource occurrence, water supply quo, water consumption situation, water resource utilization efficiency, and water resource management. With the SPA(set pair analysis), this paper dynamically evaluates the water resource security status of Guizhou Province from 2001 to 2015. The results show that the water resource in Guizhou Province from 2001 to 2007 was in a critical state, while from 2008 to 2015 it was generally safe and relatively safe (except 2009 a draught year). In terms of the change of five factors effecting water resource security, the water resource location depends on the natural environmental factors remarkably, so the H2 value was relatively instable; water supply status was influenced by water conservancy project construction, so the H2 value from 2001 to 2015 rose from 0.53 to 0.90; for water consumption status, as water consumption in production and ecological environmental purpose raised, H3 value declined from 0.87 in 2001 to 0.20 in 2015. In terms of water resource efficiency, it was drew down largely by the water using in Wanyuan GDP and farm land average irrigation, so the H2 value grew from 0.26 in 2001 to 0.88 in 2015, turning into secure and relatively secure ranks obviously. The water resource management was under the impact of increasing municipal sewage treatment rate and raising forest coverage rate, so the H2 value went up from 0.09 in 2001 to 0.58 in 2015, improving the original extremely unsecure rank into critical secure rank. But for some aspects, such as Wanyuan GDP pollution abatement rate, they still have a long way to go; the aspects of water supply, resource utilized efficiency, and resource management all indicate that human behavior has great influence on the water resource security.
Hydrogeochemical zoning characteristics of the strontium mineral spring in Xintian county, Hunan Province
ZHAO Guangshuai, SU Chuntian, PAN Xiaodong, XIE Daixing, LUO Fei, YANG Yang, BA Junjie, LI Xiaopan, BI Benteng
2019, 38(6): 858-866. doi: 10.11932/karst20190603
Abstract:
Migration and transformation of the strontium element in groundwater in karst hilly regions are affected by the groundwater agent, and its enrichment and zoning characteristics have important hydrogeochemical significance. This paper addresses these issues using an example of a large strontium-rich mineral spring in Hunan Xintian county. Sampling, water chemical composition analysis, and data processing by ArcGIS and AquaChem software permit to reveal the horizontal and vertical zoning characteristics as well as chemical composition and types of this spring. Results show that the strontium element content in the gravity springs has good zoning characteristics, while such characteristics in the motor-pumped wells are not obvious. TDS is basically consistent with the strontium content. The variation coefficients of ions have good consistence in the gravity spring and well. Ca2+ and HCO3 - content are relatively stable, while Sr2+, Mg2+, Na+, SO4 2-, and Cl-concentrations change greatly. The hydrodynamic environments of the springs and motor-pumped wells vary intensively, or the water-bearing rocks are obviously different. The main ion microgram equivalent number in the gravity springs and motor-pumped wells has the same percentage rank, but the vertical variation range is larger. The hydrochemistry components in the wells are primarily influenced by water-bearing rocks and human activities. The hydrochemical type also changes from the single type in the surface karst springs to the well’s complex hydrochemical type, showing the upward geochemical zoning in the vertical direction. The vertical zoning of strontium is abnormal and reaches the maximum at 50-80 m depth.
Chemical characteristics and environmental significance of SO42- and sulfur isotope in the karst watershed of the Niangziguan spring,Shanxi Province
ZHAO Chunhong, LIANG Yongping, LU Haiping, TANG Chunlei, SHEN Haoyong, WANG Zhiheng
2019, 38(6): 867-875. doi: 10.11932/karst20190604
Abstract:
The Niangziguan spring watershed is located in the hinterland of the Taihang mountains, eastern Shanxi Province, with an area of 7,217 km2. The middle Ordovician limestone dominates its aquifer group, and the lower Ordovician is the aquifer floor of the aquifer system in most areas except the drainage area and part of the recharge area. The middle-upper Cambrian aquifer formation is mainly located in the eastern and northeastern margins of the spring watershed. The karst groundwater in the spring area is supplied by the recharge of atmospheric precipitation infiltration and river leakage, and the Niangziguan spring and karst water exploitation are the discharge sites. The karst groundwater in Niangziguan spring is the primary source of water supply in Yangquan City, which accounts for more than 70% of the total water intake in the city. In recent years, the total hardness and sulfate radical of karst groundwater in this spring area have increased, and the water quality has been deteriorating. Therefore, it is very important to clarify the characteristics and sources of sulfate in karst groundwater of the spring area. On the basis of previous studies, this work tests and analyzes the chemical composition and sulfur isotope of karst water in the Niangziguan spring area were tested and analyzed, and studies the influencing factors of hydrochemical characteristics and the source of sulfate in karst water to provide scientific basis for the development and protection of karst water. The research shows that, (1) SO42- of karst water in the northwest and southwest of the watershed is mainly derived from the dissolution of gypsum. (2) The karst water near the Wenhe /Taohe /Nanchuanhe rivers of the central confluence area is recharged by the river water which is polluted by the mine pit water, or polluted by the drilling string in some areas. In the karst water, SO42- mainly comes from the coal mine water. (3) The SO42- in the Chengxi spring is mainly derived from coal mine water, while SO42- of the Wulong spring and Jiquan spring is mainly derived from the gypsum dissolution. (4) In the northeast of the spring and the east of the river, SO42- comes from meteoric precipitation and gypsum dissolution, and is also affected by stratum lithology.
Characteristics of the Cambrian-Ordovician karst water system in the northeastern Datong coalfield
CHEN Yazhou, REN Hujun, LI Xibin, LI Jian, WANG Fengli
2019, 38(6): 876-882. doi: 10.11932/karst2019y04
Abstract:
Cambrian-Ordovician karst water in northeast Datong coalfield exists beneath the coal seam floor with confined pressure, which is an important local water source. In order to ensure the safe exploitation of the coalfield and protect groundwater resources, the characteristics of the karst water system in the northeastern Datong coalfield should be analyzed. This work attends to make such an analysis in terms of drilling, logging, hydrochemistry, water level monitoring data, mining data and field investigation. It is concluded that the characteristics of elevation variation of the Cambrian-Ordovician karst top surface are consistent with that of coal syncline and the thickness of karst aquifer,which is very heterogeneous. Most of the research area is of weak runoff, with hydrochemical type dominated by HCO3·Cl-Na. The source for the supply of karst groundwater is from the overflowing supply of the overlying aquifer in west and infiltration supply in east. The water level in the research area is decreasing yearly with a tendency of increase, because of increasing artificial drainage sites and large artificial withdraw volume. The peak level of karst water in the research area is one to two months behind the rainy season. These conclusions have guiding significance for the safe mining of the coalfield and the rational utilization of karst water in the research area.
Remote sensing investigation to the distribution and change of karst rocky desertification from 2003 to 2015 in the Nayong area of Guizhou based on Landsat-X GEVI
KUANG Zhong, BAO Ping, WU Kaibin, JIANG Kaiyuan
2019, 38(6): 883-888. doi: 10.11932/karst20190605
Abstract:
Karst rocky desertification is a fragile ecological environment that puzzles the development of karst areas in southwest China. In order to understand the improvement of karst rocky desertification in the Nayong area of Guizhou, the authors extracted the scale information of karst rocky desertification in 2003 and 2015 by using the improved enhanced vegetation index model (GEVI) method based on Landsat data, which is 540.06km2 and 390.99 km2, respectively. Comparison of data over these two periods shows that the area of karst rocky desertification in this area has been reduced by 149.07 km2, and the improvement rate has reached 12.88%, especially in the areas of severe rocky desertification (such as Chaoyanggu, Lanba and Maochang), which have been distributed in vast swaths previously. It is also found that the karst rocky desertification in this area is migrating from southwest to northeast, with an area of 289.47 km2, dominated by a moderate degree. It indicates that the control and destruction are synchronized, and the control task remains a great challenge. Nevertheless, the total area of karst rocky desertification is reduced and ecological conditions show a benign development trend, reflecting the effectiveness of comprehensive efforts in recent years.
Characteristics of calcium fraction distribution in soil under different land use types in karst fault-depression basins
LI Jing, YANG Cheng, JIN Zhenjiang, ZHU Tongbin, CAO Jianhua
2019, 38(6): 889-895. doi: 10.11932/karst2019y14
Abstract:
Limestone soil in karst regions is characterized by high pH and calcium (Ca) content, which is one of the key elements in determining the structure and function of karst ecosystems, and is significantly affected by land use types. However, so far there are few studies on soil Ca fraction distribution under different land use types in karst fault-depression basins. This study chose four land use types including grassland, plantation, cornfield and dragon fruit landing the Bisezhai village, Xibeile country in Mengzi City, Yunnan Province as objectives, all of which are characterized by typical karst landforms. The BCR three-step sequential extraction method was used to determine the content of different Ca forms under different land use types in karst areas and influence factors. The results show land use types significantly influence soil total Ca content and its fraction distribution. Total Ca and various Ca forms in grassland soil are greatly higher than other land use types, and the lowest values appear in cornfield. The exchangeable Ca form is dominant in all soils, accounting for 59.4%-74.8% of total Ca, while the content of bound to organic matter-Ca is the lowest, accounting for 0.5%-1.0% of total Ca. The contents of total Ca and various Ca forms are significantly positively correlated with organic carbon, total N, total Mg, CEC, and pH. These data indicate that total Ca and various Ca forms interact with the physical and chemical properties of the soil to some extent.
Fuzzy evaluation of mitigating soil and water loss by cultivation of medicinal plants in karst mountainous areas
LUO Lin, ZHOU Yingshu, BI Ning, CHEN Kunhao
2019, 38(6): 896-900. doi: 10.11932/karst20190606
Abstract:
This paper evaluates the role of medicinal plants in mitigation of soil and water loss in karst mountainous areas. The data are from a test site where 20 kinds of medical plants were cultivated, including Rosa roxburghii Tratt,Fagopyrum dibotrys (D. Don)Hara,Rosa roxburghii Tratt intercropped with Polygonum capitatum Buch.-Ham. ex D. Don,Rosa roxburghii Tratt intercropped with Fallopia multiflora (Thunb.) Harald,and Rosa roxburghii Tratt intercropped with Fagopyrum dibotrys (D. Don) Hara. Regression analysis of monitoring data in raining seasons of 2016 and 2017 shows that the amount of soil erosion has an exponential relationship with plant coverage and the thickness of plant branches and leaves,and a linear relationship with the number of plant roots. In terms of the fuzzy evaluation model, the plants that can contribute to soil and water conservation are Rosa roxburghii Tratt and Bletilla striata (Thunb.) Reichb.f., followed by Aconitum carmichaeli Debx.,Prais polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz,Codonopisis tangshen Oliv,and Pleione yunnanensis Rolfi. Other plants play a medium role in water and soil conservation. These results would help choose suitable medical plants to cultivate in the areas with varied degrees of soil and water loss.
Effect of alternating wetting-drying on physiological features of water content and photosynthesis of Erythrodontium julaceum (Schwaegr.) Par. in karst habitat
ZHANG Xianqiang, LIU Tianlei, CONG Chunlei
2019, 38(6): 901-909. doi: 10.11932/karst20190607
Abstract:
This study presents a theoretical foundation for recovering and controlling the environments of rocky desertification ecology. It relies on comparing the adaptability to habitat heterogeneity in karst rocky desertification areas with arid desert of karst and seasonal drought environments and analysis of moisture content and photosynthetic physiological adaptation. Taking E. julaceum growth on rock as the object, water content and photosynthetic physiological indexes are measured in the Puding City, Guizhou Province. The results show that the drought makes water potential(Ψs), free water content(Va), water content and relative water content(RWC) of E. julaceum decrease, bound water content(Vs), water saturation deficiency(WSD) and ratio of bound water content to free water content(Vs/Va) increase, leaf water-holding ability weakened, and transpiration rate(Tr) decreased. The response sensitivities of these indices to water’s action are different. With increase of drought, total chlorophyll content first rises and then drops, finally tends to increase. qN of three kinds of mosses is negatively correlated while Fv/Fm, Yield, ETR Pn and qP decline with drought are positively correlated. The Pn gradually declines in mild drought dehydration. After 48 h Pn falls sharply, photosynthesis is affected by the serious drought. Along with the process of drought, changes of transpiration rate (Tr) have no significant differences between species. Fluorescence parameters after re watering can be restored to normal levels in mild to moderate force, and severe force is more difficult to return to the control level. The epilithic mosses has strong drought resistance ability, water metabolism and photosynthetic physiological mechanism to adapt to the karst environment, indicating a pioneer species in the process of vegetation restoration and reconstruction in the karst rocky desertification areas.
Principles and methods for preventing and controlling the hourglass-type karst ground collapse
LIANG Ligang, CHEN Liang, LIU Jianfang
2019, 38(6): 910-915. doi: 10.11932/karst20190608
Abstract:
There are 6 limestone belts trending in nearly EW trending fold structures in the Wuhan area, where karst ground collapse occurs frequently. Such failure can be divided into three basic types, i.e. hourglass type, soil cavity type and vacuum erosion type, each has its special geological conditions and corresponding collapse mechanism. As the disaster caused by hourglass-type collapse is the most serious and most difficult to control, this paper focuses on its geological conditions, collapse mechanism, prevention principles and methods. Analysis shows that the key factor to cause the hourglass is the groundwater (karst water and pore water ) seepage, of which original power is the karst water seepage. Consequently, the fundamental measure to prevent hourglass collapse is to set up curtains to cut off karst water seepage. At last, the principles and methods of preventing and controlling the hourglass collapse of subway stations and section shield are proposed, which have attained good effects in practice.
Discussion on lining strength of railway tunnels in karst areas under instantaneous heavy rainfall: An example of the Yuanbaoshan tunnel of Zhijin-Bijie railway in Guizhou Province
YU Hongzhang
2019, 38(6): 916-923. doi: 10.11932/karst2019y21
Abstract:
Guizhou is a karst highly developed province, where heavy rainfall often destroys tunnel lining. A typical case is that on the eve of opening of the Yuanbaoshan tunnel of the Zhijin-Bijie railway in Guizhou, an instantaneous heavy rain caused many damages of second-time linings at many places in the tunnel, such as extrusion, collapse, spalling, cracking, water inrush, and dripping, resulting in the cancellation of the railway opening planned. This work attempts to analyze the mechanism of this hazard. In terms of MIDAG GTS numerical simulation software, we calculate the displacement, axial force, bending moment and shear stress of the second-time linings under normal conditions and 50 m water pressure on linings, respectively, and examine the effect of instantaneous heavy rainfall on the strength of lining. Results show that, (1) without considering the water pressure, the second lining structure is relatively safe. When the instantaneous increase of 50m water pressure is posed, the lining structure is not safe because of the excessive internal force. (2) For the karst sections with groundwater development, if there is no specific data of water pressure, it is recommended that in the third-grade surrounding rock section, reinforced concrete lining is used to increase the lining’s resistance to local instantaneous water pressure rising. (3) Discharge and decompression are the key measures to solve the problem that the lining is destroyed because of the excessive water pressure.
Safe pumping in areas prone to karst collapses: A case study of the urban emergency water source of the Guanghua basin in the Pearl River Delta
MENG Yan, ZHENG Xiaozhan, QI Shihua, LEI Mingtang, LI Zhuojun, JIA Long
2019, 38(6): 924-929. doi: 10.11932/karst2019y30
Abstract:
How to realize safe pumping by control in areas prone to karst collapses is an urgent problem for groundwater managers and scientific and technical personnel of the urban emergency water source. Taking the Guanghua basin of Pearl River Delta as an example, this paper presents a comparative analysis of pumping in the field and critical hydraulic gradient tests in the laboratory to determine the control conditions for safe pumping. The results show that the karst collapse can be prevented and controlled by proper choice of the depth of the water level. The probability of sinkhole collapse is greatly reduced when the water level is lower than 9 meters. This result can be directly used as the control index of groundwater safety exploitation by enterprises and the decision-making index of safety management and control by government management departments. At the same time, it is pointed out that due to the differences of geological conditions, in the process of actual groundwater exploitation, it is not possible to rely mechanically on a single control index of groundwater level drawdown. The depth of groundwater level should be controlled according to the influence radius of pumping water and the different critical hydraulic slopes in different regions, or the mining method should be changed to make full use of groundwater resources. It is suggested that emergency disaster plan should be made during the actual pumping period, groundwater monitoring should be strengthened, and groundwater and other influencing factors should be monitored in real time.
Effect of moisture content and dry density on shear strength of Guilin red clay
CHEN Jiayu, LIU Zhikui
2019, 38(6): 930-936. doi: 10.11932/karst20190609
Abstract:
This work studied the influence mechanism of water content and dry density on the shear strength of Guilin red clay. A series of direct shear tests to control water content and dry density were carried out and the relationship between water content and dry density and shear strength was established. The results show that under the same dry density condition, the cohesion and internal friction angles decrease with the increase of water content. When the water content is the same, the cohesion decreases with the dry density, while the internal friction angle increases. The analysis shows that with the increase of water content, the cementation with "water stability" is weakened, causing the cohesive force to decline; when the crystalline iron oxide content in the soil is higher than the cemented state, the internal friction angle increases, and vice versa. When the dry density becomes larger, the remolded soil cannot be recovered after breaking due to the cement bond, so that the effective cementation area of the soil particles is reduced more than the degree of increase, causing the cohesion to decrease. The growth of the dry density can change the microstructure model of the red clay, where the increase of closed pores of the soil leads to a decrease of cohesive force. The microstructure of the soil sample increases with the increasing dry density, resulting in an increase of the internal friction angle.
Checklist, distribution and conservation of typical cavefish in China
ZHANG Peiling, HUANG Taifu, WU Tao, HUAND Xinlong, ZHANG Youxiang, LIU Zhixiao
2019, 38(6): 937-945. doi: 10.11932/karst20190610
Abstract:
A latest checklist on the diversity, distribution, threatened status and some features of typical cavefish species in China was prepared and statistically analyzed based on the updated taxonomic system. The results indicate that there are a total of 90 fish species belonging to 2 orders, 4 families and 13 genera, of which Sinocyclocheilus (38 species) and Triplophysa (25 species) are the dominant genera. These typical cavefish are of relatively small body size, rare population size, and narrow distribution with few research literature, and 63% species are deficient of data or not evaluated in the Endangered Category. The statistic morphology of scales, eyes and skin pigments show that their degradations are not synchronized, presumably the evolution of them fin cavefish might be independent of one another.
Characteristics and value of geological relics in the Bijie Jiming Sansheng•Guizhou geopark
LUO Shuwen, YANG Tao, DENG Yadong, QIN Xingming
2019, 38(6): 946-956. doi: 10.11932/karst2019y13
Abstract:
This paper explores the characteristics and value of geological relics in the Bijie Jiming Sansheng ? Guizhou geopark. Based on field investigations, we study the types and development characteristics of the geological relics in the park, and make qualitative and quantitative evaluation to its landscape. Our research suggests that, (1) The Bijie Jiming Sansheng ? Guizhou geopark is a typical representative of karst in the slope of the transition from the Yunnan-Guizhou plateau to the Sichuan basin; (2) From the watershed to the Chishui River valley, the karst landform changes are expressed by peak cluster depressions e karst doom depressions kkarst canyons with significant zoning, showing the development of karst landforms in the hydrological unit system; (3) The resource landscape types are complementary and have high values for research, ornamental and tourism development;(4) The types of geological relics in the park are divided into six big categories, ten small categories and ten sub-categories, dominated by karst gorges, caves, natural bridges, Tiankeng, peak clusters, karst dooms, stone forests and pictographic mountains, with waterscapes, geological sections, paleontology, environmental geological relics and geological structure relics as complements. Our work determines 3 national-level geogoical relics and 11 provincial-level geological relics in the park, which provides a basis for rational development and protection of geological relics in the park and advancing local tourism industry.
Study on tourism images of karst caves based on web text analysis: An example of the Zhijin cave in Guizhou Province
HE Xiaoqian, XIE Jia, ZHANG Yanrong
2019, 38(6): 957-966. doi: 10.11932/karst20190611
Abstract:
Tourists’ perception of tourism images of tourist destinations directly affects the satisfaction and loyalty of tourists, and plays an important role in the marketing and development of tourist destinations. Using the ROST CM content mining software and content analysis method, this paper analyzes the tourism images of the Zhijin Cave by reviews and travel notes on travel websites. The main research conclusions are as follows, first, 232 high-frequency words are extracted from 40 travel note samples and 2,591 comment samples, and the top 60 words show that the main focus of tourists is on the natural landscape of the Zhijin cave. The semantic network matrix of high-frequency vocabulary is centered at “Zhijin cave” and “karst cave”, while other characteristic words diverge to the surrounding areas. The intensity of the relationship between the related words indicates that the magnificent and peculiar karst landscape in the Zhijin cave has left a deep impression on tourists. Second, in the main category of tourism image attributes, most of the high-frequency features are related to tourism landscape, followed by tourism services and management, and tourism facilities. The karst landscape with different forms and unique features is the biggest feature of the Zhijin cave, and the lighting effect in the cave has the most direct impact on tourist activities. Third, the proportion of positive vocabulary occurrence reaches 81.85%, and the frequency of negative emotion vocabulary appears less than 10%. Negative evaluation focuses on the service and management of tourist destinations. Tourists have a high overall recognition of the Zhijin cave and a very positive attitude towards the overall image of tourism, but the willingness to revisit is not high.
Spatial distribution characteristics and the geomorphological evolution process of the Jiudongtian cave system in Guizhou Province
AN Dan, ZHOU Zhongfa, XUE Bingqing, YANG Enlin, FAN Baoxiang, ZHU Cancan
2019, 38(6): 967-976. doi: 10.11932/karst20190612
Abstract:
The study of cave distribution characteristics and geomorphological evolution provide a solid basis for can aid of the development of scientific activities and tourism of cave. In order to understand the distribution of the large scale bead-like skylights in the cave system of Jiudongtian Scenic spot, in situ investigations have been made to the discover the scale, shape, development direction and distribution elevation of karst caves in this area. Then the spatial distribution characteristics and geomorphological evolution process of the cave system are discussed by combining the idea of “from the present to infer the ancient” in geography with the Geographic Information system (GIS). The results show that the strata of the Jiudongtian cave system are dominated by Permian Maokou formation, of which the development is controlled by fault and hydrological conditions. The karst caves are mostly in NE and NW directions, largely consistent with the regional structure. Affected by Quaternary intermittent motions of uplifting and erosion datum plane, the caves are mostly distributed at at elevations of 1,170 m, 1,220 m and 1,310 m, which are similar to that of the ancient river courses in the area. The evolution of this cave system and geomorphology experienced three major stages, (1) Youcai river current and Dinazhai dry valley formation, (2) Ladder cliff current and Zhangjiazhai dry valley formation, (3) Jiudongtian volute current and Datianqiao dry valley formation, resulting in a typical karst pattern of skylight caves, bright and dark currents and ancient river courses coexisting in the Jiudongtian scenic spot.
Study on the human living environment in Guilin City since the upper palaeolithic
YIN Jianjun, LIN Yushi, TANG Wei, RUAN Jiaoyang
2019, 38(6): 977-982. doi: 10.11932/karst20190613
Abstract:
Because of abundant historical and cultural remains, Guilin is one of the famed national historical and cultural cities of China. And plenty of pre-historical cultural remains are an important character. The pre-historical remains is about 35 ka BP, and continuously extend to 3 ka BP. When we start studying the pre-historical remains in Guilin, something special characters were found, such as the climate transition and the life style change with it. They may indicate the great effects of global and local climatic and environmental changes. This paper discusses the relationship between evolution of pre-historical culture and climate and environment changes on global and local sales, and hopes to contribute the research of pre-historical culture in Guilin.