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2021, Volume 28 Issue 5
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Pollution assessment and source apportionment of shallow groundwater in Suzhou mining area, China ZHAO Weidong, ZHAO Lu, GONG Jianshi, ZHOU Wenyi, QIAN Jiazhong 2021, 28(5): 1-14.  DOI: 10.13745/j.esf.sf.2021.2.8 Abstract ( 423 )   HTML ( 30 )   PDF (10726KB) ( 452 )   Long-term coal mining in the Suzhou mining area not only led to the formation of shallow groundwater drop funnel but also caused groundwater pollution to varying degrees. In this study, in order to find out the current situation and main causes of pollution, 13 pollution indicators such as {\mathrm{NO}}_3^{-}were analyzed for 21 groundwater samples obtained from the water and soil pollution survey in the study area. Based on the quality evaluation by the improved Nemero pollution index method, factor analysis and IDW interpolation method were used to analyze the pollution source and its groundwater spatial distribution characteristics. The results show: (1) The shallow groundwater water in the whole study area was heavily polluted to mainly Class IV water and the main pollution indicators were {\mathrm{NO}}_3^{-}, Mn, Fe and F-. (2) Polluted shallow groundwater were mainly from 4 pollution sources. The first one is the origin’s geological environment (F1), with the high-value areas distributed in the Taoyuan coal mines and surrounding areas. The second one is mining wastewater formed by mine-pit drainage and leaching of Gangue Hill (F2), which caused serious pollution in the Taoyuan and Qianyingzi coal mines as well as some pollutions in other mining areas. The third pollution source is rural sewage (F3) caused by domestic waste and human and animal excreta, which mainly contaminated the areas of Zhuxianzhuang and Luling coal mines. The fourth pollution source is agricultural pollution (F4) caused by fertilizer application, with the high-value areas concentrated in the Zhuxianzhuang coal mine and surrounding areas. The main factors affecting the shallow groundwater quality in the study area were the primary geological environment of shallow groundwater and mining wastewater. About 51.04% of pollution were from a mix of the two sources, about 11.84% from coal mining wastewater alone, and the rest mainly from rural living and production sewage and agricultural non-point source. (3) The major polluted areas were Taoyuan and Qianyingzi coal mines while the pollution in Qinan and Qidong coal mines was relatively light, and the water quality in the Zhuxianzhuang and Luling coal mines was better. (4) It is suggested to comprehensively control the main sources of groundwater pollution by strengthening supervision and control of mine drainage outlet discharge up to the standard. Also coal mining enterprises can improve the overall utilization of gangue by means of making building materials, etc. Furthermore, construction of infrastructures such as sewage and landfill treatment facilities in mining areas should be strengthened. Figures and Tables | References | Related Articles | Metrics

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Groundwater quality and pollution assessment based on ‘hierarchical ladder evaluation method’: A case study of Tongchuan Cit XIE Fei, ZHANG Yuxi, LIU Jingtao, ZHOU Bing, XIANG Xiaoping 2021, 28(5): 15-25.  DOI: 10.13745/j.esf.sf.2021.2.5 Abstract ( 467 )   HTML ( 18 )   PDF (5926KB) ( 296 )   Measurements of regional groundwater quality and pollution status play an important role in groundwater pollution control, groundwater resources protection and management, especially in the western inland arid areas. In this study, groundwater in Tongchuan City of Shanxi Province was systematically sampled and the groundwater quality and pollution status were evaluated through analyses of conventional, inorganic toxicological and trace organics indicators using ‘hierarchical ladder evaluation method’. The results showed that the shallow water quality in Tongchuan City was relatively poor in 2011, with 60% of the samples qualified as drinkable water or drinkable water after proper treatment and 40% as not suitable for drinking. The quality of shallow water was affected by both natural background and human activities, and the main influencing indicators were total hardness and {\mathrm{NO}}_3^{-}, TDS, Mg2+and {\mathrm{SO}}_4^{2-} contents. In contrast, the quality of deep water was relatively good, and all sampling sites could be used as drinking water sources. The deep water was mainly affected by natural background, and the main influencing indicator was total Fe. In terms of pollution grade, the shallow water samples with pollution grades 1, 2, 3 and 4 accounted for 44%, 16%, 32% and 8% of the total samples, respectively, with pollution mainly distributed in the Qishui river valley from south of Jinshuoguan to north of Chuankou; whereas the deep water samples were all assigned pollution grade 1, i.e., unaffected by human pollution. Compared with other methods, ‘hierarchical ladder evaluation method’ has obvious advantages in distinguishing the impact of natural background versus pollution on groundwater quality. Combined with regional background analysis and field investigation, this approach can be an effective way to scientifically acquire a good knowledge of regional groundwater quality as well as pollution status. Figures and Tables | References | Related Articles | Metrics

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Characteristics of soil lithology and pollutants in typical contamination sites in China ZHU Hui, YE Shujun, WU Jichun, XU Haizhen 2021, 28(5): 26-34.  DOI: 10.13745/j.esf.sf.2021.2.15 Abstract ( 495 )   HTML ( 35 )   PDF (1628KB) ( 270 )   There are massive contaminated sites with distinct distribution pattern and regional characteristics need to be remediated in China. In order to develop suitable remediation techniques, it is necessary to understand the complexity of the aquifer system, the heterogeneity of the media and the complexity of the contaminants at each site. In this paper, we summarized the data of 136 organic contamination sites in China, focusing on the characteristics of site distribution, soil layers and contaminants. At present, the remediation projects for organic contamination sites are mainly concentrated in the Beijing-Tianjin-Hebei and Shanghai-Nanjing-Hangzhou areas. Heterogeneous soil layers are found in all organic contamination sites and they contain low-permeable media such as clay. Sixty-seven percent of the soil layers and sites show high heterogeneity. The soil permeability in the Shanghai-Nanjing-Hangzhou area is generally lower compared to the Beijing-Tianjin-Hebei area. In addition, the survey depth (20.3 m) of the contaminated sites in Beijing-Tianjin-Hebei and the central and southern Liaoning areas is generally deeper compared to the Shanghai-Nanjing-Hangzhou area (12.8 m). The most common organic contaminants in the groundwater are chlorinated organic compounds, including chloroalkanes (in 84% of sites), chlorinated benzenes (in 46% of sites) and chloroalkenes (in 33% of sites). Among chlorinated solvents, dichloroethane, monochlorobenzene and trichloromethane are the three most common pollutants. Figures and Tables | References | Related Articles | Metrics

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Distribution characteristics and influencing factors of poor-quality native groundwater in river percolation system in the lower reaches of the Hanjiang Rive HAN Zhihui, MA Teng, SHEN Shuai, DU Yao, WU Xiancang, LIU Wenhui 2021, 28(5): 35-48.  DOI: 10.13745/j.esf.sf.2021.2.12 Abstract ( 247 )   HTML ( 14 )   PDF (5677KB) ( 141 )   The problem of inferior-quality groundwater in the Jianghan plain is becoming more and more serious. The contents of arsenic, ferrous iron, manganese and ammonium nitrogen (so-called “inferior components”) in the native groundwater are well above the safety standards for drinking water, which has an negative impact on the residents’ lives, yet the related research is still relatively weak. In this study, aiming to find out the distribution characteristics of poor-quality native groundwater in the Hanjiang river filtration system, we took a typical area in the downstream of the Hanjiang river filtration system as the research object. We analyzed the chemical composition and the “inferior components” in water samples collected 5 km from the Hanjiang River and 2 km within the range of the main river branch, and discussed the main factors influencing the quality of native groundwater. The results show that on the plane, the “inferior components” of native groundwater were highly heterogeneous spatially, with their concentration varied greatly in adjacent sampling points and the maximum value points mostly found at the river bends. In the vertical direction, the high As, Fe2+, Mn and NH4-N values in groundwater occurred mostly at a depth of about 20 m. Strong reducing environment, neutral pH and rich organic matter are the main reasons that the “inferior components” are concentrated in groundwater. River leachate affect the distribution of inferior-quality native groundwater by changing the redox condition, environmental alkalinity and organic matter content in groundwater. Figures and Tables | References | Related Articles | Metrics

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Hydrochemical characteristics and formation mechanism of groundwater in Lhasa area, China LIN Congye, SUN Zhanxue, GAO Bai, HUA Enxiang, ZHANG Haiyang, YANG Fen, GAO Yang, JIANG Wenbo, JIANG Xinyue 2021, 28(5): 49-58.  DOI: 10.13745/j.esf.sf.2021.2.2 Abstract ( 348 )   HTML ( 21 )   PDF (1483KB) ( 155 )   Tibet is an important ecological barrier in China. Studies on the chemical characteristics and formation mechanism of groundwater in the Lhasa area play an important role in revealing the mechanism of current epigenetic changes on the Qinghai-Tibet Plateau, and they are of great significance in building ecological security in the nation. In this paper, we analyzed the chemical characteristics of groundwater and the mechanism of water-rock interaction by means of groundwater survey and water sample collection and analysis in the Lhasa area, combined with Gibbs model simulation and hydrochemical analysis. The results showed that the groundwater conductivity ranged from 38.80 to 1 193.00 μS/cm, averaging at 123.99 μS/cm; the TDS ranged from 44.05 to 1 050.55 mg/L, or 150.75 mg/L on average; the pH level of groundwater was greater than 7, weakly alkaline; and groundwater is HCO3-Ca and Cl-Na types, with the latter attributed to underground spring water. The groundwater formation process is mainly associated with the dissolution of carbonate and silicate rocks, cation exchange, and so on, and affected by human factors to a certain extent. The Na+, K+ and Cl- in groundwater are mainly from the weathering of salt minerals; the excess Na+, K+ are from the dissolution of silicate minerals, such as sodium and potassium feldspars; and {\mathrm{HCO}}_3^{-}, Ca2+, Mg2+ and {\mathrm{SO}}_4^{2-} come mainly from the dissolution of calcite, dolomite, gypsum and other calcium-magnesium minerals. Figures and Tables | References | Related Articles | Metrics

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Compaction of clay aquitard: Principle, technology and hydrogeological significanc LIU Yanjun, MA Teng, DU Yao, LIU Rui 2021, 28(5): 59-67.  DOI: 10.13745/j.esf.sf.2021.2.10 Abstract ( 291 )   HTML ( 18 )   PDF (877KB) ( 136 )   The interaction between aquitard and aquifer is a global hot topic in the field of hydrogeology, especially the interaction between clay aquitard and pore aquifer. In the past few years, affected by natural and human activities such as natural deposition, excessive exploitation of groundwater, and use of modern agricultural and heavy construction machinery, clay aquitard can become compacted and result in property changes, including increase of effect stress, pore deformation, decreases of porosity, permeability, dissolved oxygen and water storage capacity, and lateral and vertical drainage. Nowadays, land subsidence and groundwater pollution caused by clay aquitard compaction have become important global environmental issues. In this paper, we introduce the theory of clay compaction, analyze the relationship between sediment compaction and pore liquid pressure under four different states in groundwater system, review the compaction study methods and technology based on physical simulation and numerical modeling, and discuss the effect of clay compaction on the water and groundwater qualities. The trend of aquitart research and its potential applications in Earth sciences and environmental sciences are also discussed. Figures and Tables | References | Related Articles | Metrics

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Factors affecting uranium adsorption on aquifer sandstone HUI Shujun, YANG Bing, GUO Huaming, LIAN Guoxi, SUN Juan 2021, 28(5): 68-78.  DOI: 10.13745/j.esf.sf.2021.2.19 Abstract ( 222 )   HTML ( 13 )   PDF (1163KB) ( 87 )   During and after in situ uranium (U) mining, the diffusion of U-containing leachate can potentially have an impact on the groundwater quality. The range and magnitude of such impact determines the natural attenuation of U(VI) in groundwater in sandstone aquifers. This study investigates the influence of solution chemistry characteristics and pyrite content in sandstone on the U(VI) adsorption/transformation by aquifer sandstone taken from a uranium mining area in northern China. Adsorption equilibrium in sandstone particles can be reached after 12 h. The linear adsorption isotherm fits will with the observed data. The adsorption efficiency generally decreases with increasing grain size but stabilizes under grain size larger than 0.20-0.25 mm. The solution pH is the main factor affecting adsorption. By controlling the U(IV) complexes in solution as well as rock particle surface charge, adsorption is promoted at pH < 6 and inhibited at pH > 6. {\mathrm{HCO}}_3^{-} shows the most negative effect on U(VI) adsorption, followed by Ca2+, Mg2+, and {\mathrm{SO}}_4^{2-}. {\mathrm{HCO}}_3^{-} inhibits U(VI) adsorption mainly by forming negatively charged {\mathrm{UO}}_2^{2+} complexes. At near neutral pH, the increase of pyrite content significantly promotes U(VI) removal by adsorption and reduction, as the adsorbed Fe2+ reduces U(VI) to UO2+x by electron transfer on the surface of the adsorbent. Adsorption and reduction are mutually reinforcing processes. Under weakly alkaline condition, increasing pyrite content does not significantly affect U(VI) removal, as hydrolytic precipitation and low adsorption inhibit the reduction of U(VI) by pyrite. Figures and Tables | References | Related Articles | Metrics

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Effect of pressure on C-N-S-Fe-H2O system in sil PENG Ziqi, MA Teng, LIU Yanjun, CHEN Juan, QIU Wenkai, LIU Rui 2021, 28(5): 79-89.  DOI: 10.13745/j.esf.sf.2021.2.9 Abstract ( 332 )   HTML ( 14 )   PDF (3060KB) ( 71 )   Carbon, N, S and Fe are the main elements controlling the redox reactions in groundwater. Silt is the initial form of clay, and its transformation into clay can affect the quantity and quality of groundwater aquifers. Groundwater pollution may happen during the transformation process, where the water-rock interaction can be generalized as the C-N-S-Fe-H2O interaction system. The essence of silt evolution is porosity reduction under pressure and gradual consolidation into rocks. Biogeochemical reactions take place in silt while the C-N-S-Fe-H2O interaction system drives constant changes in the substance forms. Pressurization rates and modes can affect the transformation of important components, such as C, N, S and Fe, between solid and liquid phase in silt. This experiment studies the release of C, N, S and Fe to pore water under three pressurization rates (0.04 MPa per 12 h, 24 h, 36 h) and three pressurization modes (decelerating, from 0.04 to 0.02 MPa/12 h; uniform, 0.04 MPa/12 h; accelerating, from 0.04 to 0.06 MPa/12 h), using self-developed pressurization device. The results show: (1) Slower uniform pressurization rate corresponds to faster DOC, {\mathrm{SO}}_4^{2-} release rate, more {\mathrm{NO}}_3^{-}, Fe2+concentration change, and more DOC, {\mathrm{SO}}_4^{2-}, {\mathrm{NO}}_3^{-}, Fe2+release. (2) {\mathrm{NO}}_3^{-}, Fe2+ concentration fluctuation increases under accelerating pressurization, and the total DOC, {\mathrm{SO}}_4^{2-}, {\mathrm{NO}}_3^{-}, Fe2+ release is greater during accelerating pressurization versus uniform pressurization. (3) During pressurization, DOC and {\mathrm{SO}}_4^{2-} concentrations are positively correlated, and pressurization rate change can change the DOC, {\mathrm{NO}}_3^{-}, {\mathrm{SO}}_4^{2-}, Fe2+ correlations. It shows that changing the pressurization rates and modes can affect DOC, {\mathrm{SO}}_4^{2-}, {\mathrm{NO}}_3^{-}, Fe2+ release rate/quantity as well as C, N, S, Fe transformation, that is, essentially changing the magnitudes of redox reaction and water-rock interaction. This experiment provides a new understanding of the main elemental changes caused by pressure in the process of geological evolution, and demonstrates the aquitards can affect water quality/quantity in aquifer. This study provides new insights into the cause of naturally inferior groundwater and prevention of groundwater pollution. Figures and Tables | References | Related Articles | Metrics

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Multiphase flow modeling of natural attenuation of volatile organic compounds (VOCs) in a petroleum contaminated sit SHEN Xiaofang, WAN Yuyu, WANG Ligang, SU Xiaosi, DONG Weihong 2021, 28(5): 90-103.  DOI: 10.13745/j.esf.sf.2021.2.14 Abstract ( 270 )   HTML ( 15 )   PDF (9468KB) ( 150 )   The monitored natural attenuation (MNA) technology has become a generally recognized technology for remediation of VOCs. However, this technology, owing to the long remediation period and expensive monitoring costs, has certain limitations in real world applications. In this study, we use multiphase flow numerical simulation to identify the natural attenuation process and assess the attenuation capacity for typical VOCs (benzene, toluene, naphthalene) in a petroleum contaminated site. The results show that the multiphase flow numerical model established by TMVOC can predict the attenuation laws of VOCs in groundwater. In the study area, the pollution plumes of benzene, toluene and naphthalene in groundwater have different distribution patterns due to the differences in their physicochemical properties, and the natural attenuation process is affected to various degrees by volatilization, adsorption and microbial degradation. The effects of volatilization and biodegradation on VOC remediation are benzene > toluene > naphthalene, while the effect of adsorption is naphthalene > toluene> benzene. Assuming the pollution source is blocked, benzene, toluene and naphthalene are predicted to achieve ideal remediation through MNA at 7.0, 6.5 and 6.0 years, respectively, after oil leak. The above simulation results can provide theoretical support for the implementation and evaluation of MNA technology in remediation of VOC contaminated sites under similar hydrogeological conditions. Figures and Tables | References | Related Articles | Metrics

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Effect of humic acid on the phase distribution of sulfadiazine in shallow groundwater DUAN Lei, YANG Shengke, WANG Wenke 2021, 28(5): 104-113.  DOI: 10.13745/j.esf.sf.2021.2.20 Abstract ( 223 )   HTML ( 9 )   PDF (4207KB) ( 82 )   It is important for exploring the behavioral characteristics of antibiotics and assessing their hazards by studying the distribution characteristics of antibiotics in shallow groundwater. In this paper, the interaction of sulfadiazine (SD) with humic acid (HA) and the effect of HA on the phase distribution of SD in shallow groundwater were studied by three-dimensional fluorescence quenching method. The effects of HA concentration, pH and temperature on SD in different phases were discussed, and the distribution coefficient as well as quenching and thermodynamic parameters for the quenching process were calculated. The results showed that both low SD (0.5 mg/L) and elevated HA (0-20 mg/L) can significantly increase SD partition in the suspension phase. The mechanism of HA fluorescence quenching by SD was to form HA·SD complex via a single static process. The number of binding site was 1; the quenching constant Ksv was 5.271×103 L/mol; and the quenching rate constant Kq was 5.271×10 11 L/(mol·s). It showed the HA-SD interaction was a spontaneous exothermic process. In a low-temperature (15 ℃), neutral or weakly alkaline (pH 8-10) environment, antibiotics had the strongest quenching effect on HA, and, accordingly, HA had the most obvious promoting effect on SD entering the suspension phase. Figures and Tables | References | Related Articles | Metrics

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Complex resistivity properties and spectral parameters of TCE contaminated soils ZHANG Zhenyu, XU Weiwei, DENG Yaping, REN Jinghua, SHI Xiaoqing, WU Jichun 2021, 28(5): 114-124.  DOI: 10.13745/j.esf.sf.2021.2.4 Abstract ( 236 )   HTML ( 13 )   PDF (4588KB) ( 78 )   The complex resistivity has become a promising contaminant monitoring tool due to its sensitivity to pore water chemical properties, solid-liquid interface and fluid content. In this study, we chose trichloroethylene (TCE) as a typical organic contaminant and measured the complex resistivity of TCE contaminated soils by SIP method. We studied the effects of pore water salinity, water saturation and soil types on the complex resistivity characteristics and spectral parameters of TCE-contaminated soils. Results show that the complex resistivity of contaminated soil samples increases with decreasing water saturation and pore water salinity. The clay content affects the continuity of pore water. When the pore water is discontinuous, the real and imaginary parts change greatly. The total chargeability (M) increases with decreasing pore water salinity and decreases at first and then increases with decreasing water saturation. M is also reduced by decreasing specific surface area caused by the rearrangement of clay particles and increased by double layer polarization. The mean relaxation time decreases with increasing pore water salinity as shown by a logarithmic correlation. The main reason for the variation of M with water saturation is the change of polarizable pore size. This study establishes a relationship between geophysical and hydrogeological parameters, thus providing a theoretical basis for SIP field measurements. Figures and Tables | References | Related Articles | Metrics

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Nitrogen removal during reclaimed water infiltration in soil aquifer treatment: Experimental simulation using soil column GAO Heng, TAN Hang, REN Yu, ZHU Lecheng, BI Erping 2021, 28(5): 125-135.  DOI: 10.13745/j.esf.sf.2021.2.7 Abstract ( 387 )   HTML ( 8 )   PDF (2387KB) ( 75 )   Soil aquifer treatment (SAT) is an important method of artificial groundwater recharge. However, when reclaimed water is used as recharging source, the nitrogen species in water may pose pollution risks to groundwater in the recharging area. It is of great significance, therefore, to study the effects of various factors on nitrogen removal from reclaimed water in SAT. In this study, through soil column experiments (using a column of 200 cm in height and 50 cm in inner diameter), the effects of particle size, dry/wet ratio, biochar addition, temperature and infiltration rates on nitrogen removal were studied. The results showed that under the dry/wet ratio of 1∶1, the average removal efficiencies for NH4-N in the effluents of fine and medium-fine sand columns were 73% and 66%, respectively, by adsorption and nitrification mainly, while NO2-N was almost totally removed. Nitrification resulted in a NO3-N concentration increase in the filtration system by 3.0%-4.1% on average in the effluent. Above the depth of 115 cm, nitrification was stronger in the medium-fine sand column than in the fine sand column, which resulted in a higher NH4-N and lower NO3-N removal rates. After prolonging the drying period (using dry/wet ratio 3∶1), the filtration system showed a stronger reoxygenation capacity promoting nitrification. It led to a 20% increase in the average NH4-N removal rate and 3%-4% reduction of NO3-N, thus increasing the risk of NO3-N pollution. After adding 5% biochar (by weight) to the medium-fine sand layer, the adsorption performance was enhanced, and the average NH4-N removal rate was increased by 20%-32%, but the effect on NO3-N was not obvious. The infiltration rate was negatively correlated with NH4-N removal and NO3-N increase. Based on the comprehensive analysis, it can be concluded that the main factors affecting nitrogen removal in SAT are the dry/wet ratio and infiltration rate. When NH4-N concentration in the water source is high, biochar can be added to the surface layer in SAT to enhance its nitrogen removal efficiency. Figures and Tables | References | Related Articles | Metrics

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Influencing factors and performance of enhanced denitrification layer in the vadose zone SUN Zhaoyue, ZHENG Xilai, ZHENG Tianyuan, LUAN Yongxia, XIN Jia 2021, 28(5): 136-145.  DOI: 10.13745/j.esf.sf.2021.2.6 Abstract ( 387 )   HTML ( 14 )   PDF (2361KB) ( 201 )   The vadose zone is a natural barrier for preventing nitrate contamination of groundwater and its denitrification effect is limited by carbon contents. In order to control nitrate pollution in groundwater, the Ca(OH)2-treated corn cobs were used as a carbon source to construct a reactive layer to speed up denitrification. The effects of interactions between nitrate concentration, humidity and temperature on denitrification performance were studied by response surface method. Denitrification performance was then comprehensively evaluated in terms of nitrate removal efficiency, nitrite accumulation concentration, pH value and leaching of dissolved organic carbon (DOC). The results show that the temperature and humidity as well as the interactions between them had significant effects on nitrate removal efficiency, with temperature being the most critical factor in this process. After 74 days, the nitrate removal efficiency reached 50% and the nitrite level was mostly lower than 3 mg(N)/L; the pH of the reactive layer maintained around 7.0; and the DOC leaching flux fluctuated between 0.1 and 0.2 mg(C)/(cm2·d). A high-throughput sequencing analysis shows an decrease of microbial richness in the denitrification layer and an increase of relative abundances of microorganisms related to denitrification and carbon source decomposition. The aborigine bacteria in the vadose zone are abundant, which is beneficial for denitrification under the effect of carbon source. Figures and Tables | References | Related Articles | Metrics

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Degradation of naphthalene by microorganisms in groundwater: Characteristics and kinetics ZHANG Shengyu, ZHANG Menghuan, WANG Ligang, WAN Yuyu 2021, 28(5): 146-158.  DOI: 10.13745/j.esf.sf.2021.2.18 Abstract ( 494 )   HTML ( 18 )   PDF (1932KB) ( 84 )   The effective naphthalene degrading bacteria Acinetobacter sp. and Pseudomonas sp. were discovered through a screening of petroleum contaminated groundwater in Northeast China. These bacteria had high tolerance to naphthalene and good emulsification effect, and can automatically regulate cell surface hydrophobicity and self-aggregation. The effects of pH, naphthalene initial concentration, temperature and inoculation condition on naphthalene degradation were studied experimentally. We found that the optimal pH range for bacterial growth was 7.0-8.0; the degradation efficiency was positively correlated with the naphthalene initial concentration of 1.00-5.00 mg/L; and the bacteria performed most efficiently between 10-30 ℃. On this basis, the Guass, GuassAmp, LogNomal, Poisson and Pulse models were used to fit the degradation kinetics measurements. In the final analysis, the GuassAmp model gave the best fit and the kinetic equation of naphthalene degradation under the influence of multiple factors was derived. Figures and Tables | References | Related Articles | Metrics

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Effects of o-nitro-p-methylphenol and o-amino-p-methylphenol on the anaerobic biodegradation of 1,2,4-TCB LIU Zhitong, ZHOU Ni, QIAO Wenjing, YE Shujun 2021, 28(5): 159-166.  DOI: 10.13745/j.esf.sf.2021.2.16 Abstract ( 277 )   HTML ( 11 )   PDF (2384KB) ( 41 )   In a Nanjing chemical plant manufacturing o-nitro-p-methylphenol and o-amino-p-methylphenol, field investigation and microcosm study found contaminated groundwater where the contaminant, 1,2,4-trichlorobenzene (1,2,4-TCB), was biodegraded by indigenous anaerobic microbes. In this study, we conducted three groups of microcosm experiments to explore the effects of o-nitro-p-methylphenol and o-amino-p-methylphenol on the 1,2,4-TCB dechlorination process, using (1) 1,2,4-TCB alone, (2) 1,2,4-TCB and o-amino-p-methylphenol, or (3) 1,2,4-TCB and o-nitro-p-methylphenol as the substrate(s), and compared the degradation processes, degradation rates, and microbial communities for the three groups of experiments. The results show: (1) O-nitro-p-methylphenol was reduced to o-amino-p-methylphenol while 1,2,4-TCB dechlorination was inhibited, with 1,4-DCB as the only dechlorination product. (2) O-amino-p-methylphenol did not prohibit 1,2,4-TCB degradation but decreased degradation rate. (3) Azospira and Pseudomonas were involved in o-nitro-p-methylphenol reduction, especially Pseudomonas was probably the functional microorganism under the anaerobic condition at the site. Figures and Tables | References | Related Articles | Metrics

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Characteristics of scoria adsorption of Escherichia coli phage in groundwater ZHANG Yuling, YIN Siqi, SI Chaoqun, WANG Xi, CHU Wenlei 2021, 28(5): 167-174.  DOI: 10.13745/j.esf.sf.2021.2.13 Abstract ( 218 )   HTML ( 11 )   PDF (2302KB) ( 55 )   To understand the characteristics of scoria adsorption removal of Escherichia coli phage from groundwater, we investigated the effect of the Escherichia phage vB_EcoM-ep3 adsorption on scoria in groundwater through laboratory experiments. Using the same amount of zeolite and quartz sand as a contrast, we further analyzed the influence of hydrochemical factors in groundwater (Fe 2+, Fe3+, Mn2+, {\mathrm{SO}}_4^{2-}, {\mathrm{NH}}_4^{+}, {\mathrm{NO}}_3^{-}, {\mathrm{NO}}_2^{-}, Ca2+, Mg2+, {\mathrm{CO}}_3^{2-}, {\mathrm{HCO}}_3^{-}, pH) on the adsorption process. The biological characteristics of Escherichia coli phage and its microstructural change before and after scoria adsorption were analyzed by means of microscopic detection technology. The results showed that the scoria adsorption efficiency was higher than zeolite and quartz sand, with the maximum adsorbance reaching 2.245×10 5 pfu/g. The influence of each hydrochemical factors on scoria adsorption varied. Fe2+ and Fe3+ promoted scoria adsorption, while {\mathrm{SO}}_4^{2-}, nitrogen species and high alkalinity inhibited the adsorption process. The low Mn2+ ( C_{\mathrm{M}{\mathrm{n}}^{2+}}, 10 mg/L) and Ca2+( C_{\mathrm{C}{\mathrm{a}}^{2+}}, 100 mg/L) concentrations slightly promoted adsorption; beyond this concentration, the inhibitory effect was shown. The pH value had a great influence on scoria adsorption characteristics. Higher pH corresponded to weaker adsorption effect. The vB_EcoM-ep3 phage has an equilateral hexagonal head with a body diameter of about (53±2) nm, and a tail made of stretchable tail fiber with a length of about (107±3) nm. Upon adsorption the immobilized phage occupied most of the surface pores in the scoria honeycomb structure. Figures and Tables | References | Related Articles | Metrics

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An activated calcite-loaded hydroxyapatite PRB media for uranium ion removal from aqueous solution ZHANG Weimin, WANG Zhen, QIAN Cheng, GUO Yadan, LIU Haiyan 2021, 28(5): 175-185.  DOI: 10.13745/j.esf.sf.2021.2.21 Abstract ( 260 )   HTML ( 17 )   PDF (4572KB) ( 86 )   Through static and dynamic tests, this paper investigated the removal efficiency and mechanism of uranium ion adsorption by calcite-loaded hydroxyapatite composites (CLHC) that was synthesized by the sol-gel method. The experimental results show that the CLHC surface was covered by hydroxyapatite after synthesis and had a strong affinity for uranium ions. The removal rate could reach 100% under the conditions of additive concentration of 0.5 g/L, solution pH of 4, initial uranium concentration of 5.0 mg/L, and experimental period of 2 hours. The adsorption processes of uranium can be described by a langmuir isotherm adsorption model, an intraparticle diffusion-adsorption dynamics model, or a quasi secondary adsorption kinetics model. CLHC has better adsorption ability and longer service life than quartz sand-loaded hydroxyapatite. Uranium ions were always hexavalent during adsorption, mainly by means of chemical adsorption via ion exchange. The results of this study provide a theoretical basis for the application of permeable reactive wall to groundwater remediation. Figures and Tables | References | Related Articles | Metrics

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Reactive materials and structural design of PRB for remediation of a Cr(Ⅵ) contaminated sit LI Zhihong, WANG Guangcai, CAI Wutian, LIU Fei, HUANG Dandan 2021, 28(5): 186-196.  DOI: 10.13745/j.esf.sf.2021.2.3 Abstract ( 293 )   HTML ( 17 )   PDF (2764KB) ( 90 )   Permeable reactive barrier (PRB) is widely used overseas in large scale groundwater remediation. It has attracted much interest in China because of the advantages of using no external power, occupying little surface space, and low operating cost. Since hydrogeological conditions, pollutant types, and distribution of pollution plume vary in different sites, early site investigation, reactive material selection, and reaction wall structural design are highly significant for the effective operation of PRB. This paper, taking the example of PRB application in remediation of a Cr(Ⅵ) contaminated site in Henan Province, describes in detail the research process and the results of site investigation, material screening, reaction parameter determination, and PRB structural optimization in preparation for PRB application. It shows that the PRB remediation technology is applicable to this site, and material containing cast iron and activated carbon is the best remediation material. The U-shaped funnel-gate PRB has a 40 m long reaction gate and two 60 m long water barriers. It can effectively capture and rehabilitate the contaminated plume at a much less engineering cost than continuous reaction wall PRB. So the U-shaped funnel-gate PRB is thought to be the optimal PRB structure for this site. Figures and Tables | References | Related Articles | Metrics

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Electrolytic circulation well drives chemical oxidation of TCE in a simulated aquife LIU Yang, XIE Wenjing, ZHENG Yunsong, ZHANG Yaoqiang, CAI Qizheng, YUAN Songhu 2021, 28(5): 197-207.  DOI: 10.13745/j.esf.sf.2021.2.1 Abstract ( 358 )   HTML ( 11 )   PDF (3605KB) ( 70 )   Traditional groundwater remediation by in-situ chemical oxidation has the problem of short transport distance and low utilization efficiency for oxidants. In this study, a two-well groundwater circulation mode was applied to enhance mass transfer; and electrolysis in the injection well was utilized to generate O2 and H2 in-situ. In order to use Fe(Ⅱ) in sediments for TCE degradation, ethylenediamine tetraacetic acid (EDTA) was added to chelate Fe(Ⅱ) and increase •OH production. The system performance was evaluated in a two-dimensional sandy tank filled with interlayers of sand and clay. The current was set to 0.2 A and the flow rate was 72 cm/d. Results from a 9-day experiment showed that 3 mg/L TCE was degraded down to 1 mg/L (67% removal). Addition of 0.5 mmol/L EDTA before electrolysis increased the dissolved Fe(Ⅱ) concentration in the aquifer from 0-2 mg/L to 4-14 mg/L after a day of hydraulic circulation, with the higher concentrations around clay fillings. During electrolysis, groundwater circulation promoted the effective contacts and reactions of O2, Fe(Ⅱ)-EDTA and TCE for TCE degradation. In the early stage, the rates of Fe(Ⅱ) oxidation and TCE degradation were slower around clay fillings than in other areas, but the gap gradually decreased in the later stage. Adding acetate upon completion of electrolysis promoted Fe cycling and utilization in the aquifer. This remediation process improved the oxidant transport distance through groundwater circulation and the oxidant utilization efficiency through use of relatively stable O2 and Fe(Ⅱ)-EDTA from aquifer, demonstrating its potential application in the remediation of organic pollution in groundwater. Figures and Tables | References | Related Articles | Metrics

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Content and speciation distributions of Fe and As in disposed quartz sand from groundwater treatment by sequential aeration and sand filtration ZHANG Yaoqiang, HU Bingbing, XIE Shiwei, YUAN Songhu 2021, 28(5): 208-214.  DOI: 10.13745/j.esf.sf.2021.2.17 Abstract ( 184 )   HTML ( 10 )   PDF (1966KB) ( 61 )   Drinking water security is threatened by elevated iron (Fe) and arsenic (As) concentrations in groundwater. Sequential aeration and sand filtration has been widely used for the high-performance, low-cost groundwater treatment in rural areas. During filtration, Fe, As-enriched quartz sand needs periodic replacement. The disposed sand frequently piles up on land, risking As release. In this research, the content and speciation distributions of Fe and As in disposed quartz sand collected from a drinking water treatment plant in the Jianghan plain, were investigated by LA-ICP-MS, Raman spectroscopy, X-ray diffraction and sequential chemical extraction. The results show that the sand surface was coated with a 20-100 μm thick Fe, As-rich layer, with Fe and As significantly concentrated in the central layer than on the outer layers; the As and Fe spatial distributions in the coating were highly correlated (R2> 0.985). The Fe phases were mainly amorphous and weakly crystalline, and the presence of hematite and scorodite was detected. The total contents of Fe and As in the quartz were 20.1 mg/g and 53.4 μg/g, respectively. The highly dissolvable Fe (oxy)hydroxides and carbonate-bound, reducible Fe species predominated in the coatings, whereas As was mainly adsorbed on the surface of Fe phases. Due to the abundant rainfall in the study area, As release from the disposed quartz sand could occur as a consequence of rain washing or anaerobic Fe bio-reduction. Figures and Tables | References | Related Articles | Metrics

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Research progress on groundwater contamination and remediation in in situ leaching uranium mines SUN Zhanxue, MA Wenjie, LIU Yajie, LIU Jinhui, ZHOU Yipeng 2021, 28(5): 215-225.  DOI: 10.13745/j.esf.sf.2021.2.11 Abstract ( 640 )   HTML ( 33 )   PDF (2412KB) ( 259 )   In situ leaching is a mainstream technology that has been widely used in uranium mining around the world, and groundwater restoration in the leaching area is of public concern. In this article, groundwater environments are systematically characterized in the three-leaching (i.e., alkaline, neutral and acidic leaching) technology-based mines. Considering acidic leaching of uranium has the most significant environmental impact, remediation technologies including physicochemical remediation and bioremediation as well as their mechanisms and applications are critically reviewed. The advantages and disadvantages of the remediation technologies are highlighted. Finally, the potential research gaps are identified, which include (1) new technology for uranium fixation and long-term stability in acidic and oxidizing environments; (2) breeding, domestication technology for highly active and strongly adaptive repair bacteria; (3) ex situ and in situ cooperative bioremediation technology of groundwater; and (4) studies on the mechanisms and controlling factors of the adsorption-desorption, oxidation-reduction, dissolution-precipitation of radionuclides and heavy metals in the groundwater environment of in situ leaching uranium mining. Figures and Tables | References | Related Articles | Metrics

A spacial section on The India-Eurasia Collision and Its Long-Range Effec

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Foreword to a spacial section on The India-Eurasia Collision and Its Long-Range Effect (with an illustration of programmatic themes 2021, 28(5): 226-229.  Abstract ( 236 )   HTML ( 39 )   PDF (300KB) ( 227 )   References | Related Articles | Metrics

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Crust-mantle structure and geodynamic processes in western China and their constraints on resources and environment: Research progress of the ANTILOPE Project ZHAO Junmeng, ZHANG Peizhen, ZHANG Xiankang, Xiaohui YUAN, Rainer KIND, Robert van der HILST, GAN Weijun, SUN Jimin, DENG Tao, LIU Hongbing, PEI Shunping, XU Qiang, ZHANG Heng, JIA Shixu, YAN Maodu, GUO Xiaoyu, LU Zhanwu, YANG Xiaoping, DENG Gong, JU Changhui 2021, 28(5): 230-259.  DOI: 10.13745/j.esf.sf.2021.9.38 Abstract ( 512 )   HTML ( 37 )   PDF (13033KB) ( 553 )   In order to systematically and thoroughly study the crust-mantle structure and deep geodynamic processes of basins, mountains and plateaus of western China, we proposed and led the implementation of the ANTILOPE Project (Array Network of Tibetan International Lithospheric Observation and Probe Experiments) in 2003. So far, we have completed four 2D broadband arrays, ANTILOPE-I to ANTILOPE-IV, on the Tibetan Plateau, and deployed two 3D broadband arrays, ANTILOPE-V and ANTILOPE-VI, at the eastern and western Himalayan syntaxis, respectively. In addition, we included in our study framework nine comprehensive geophysical observation profiles previously obtained from the Junggar Basin, Tienshan Orogenic Belt, Tarim Basin, Altyn Orogenic Belt, and Qaidam Basin. Through the implementation of the ANTILOPE Project, we collected a large amount of high-quality, comprehensive first-hand observational data from western China (including the basin-mountain system surrounding the Tibetan Plateau in the northwest and the Tibetan Plateau in the southwest). The fine crust-mantle structure systematically reveals the deep geodynamic processes of the basin-mountain-plateau geosystem in western China. The up-to-date main research progress can be summarized as follows. The structure and properties of the basement of the Junggar Basin have been determined, and the basement structural framework has been optimized. A new intracontinental orogenic model of lithospheric subduction with crustal interlayer intrusion in the Tienshan Orogenic Belt has been established, which reveals the fate of the 44% shortened Tienshan lithosphere after the India-Eurasia collision and the conversion mechanism from ocean-continent subduction to continent-continent collision and subduction. Our results reveal the basin-mountain contact relationship between the Tarim Basin, Altyn Orogenic Belt and Qaidam Basin. We have obtained the deep geometric, kinematic and geodynamic evidence for the clockwise rotation of the Tarim Basin, and determined the collision boundary between the Indian and the Eurasian Plates under the Tibetan Plateau. We also found that the current Tibetan Plateau consists of the Indian Plate in the south, the Eurasian Plate in the north, and the giant crush zone—also called the “Tibetan Plate”—between them. For the first time, the respective lithospheric bottom boundaries are determined; two end-member models of plateau deformation are corrected; and the constraints of deep structures on the surface topography are established. Our result systematically reveals the changing pattern and controlling factors of the horizontal advancing distance and the subduction angle of the Indian Plate along the Himalayan Orogenic Belt. By combining a huge observation network with comprehensive geophysical detection technologies, the ANTILOPE Project adopts different methods, including geophysical, geological and geochemical methods, to reveal the subduction of the Indian continent, the development of the giant crush zone in Tibet, the clockwise rotation of the Tarim Block, the accelerated closure of the western water vapor channel, and the advance of aridification and desertification in northwest China and their constraints on surface topography, oil and gas resources, and environmental variations. The above results have promoted the development of the Earth system theory in the Tibetan Plateau. Figures and Tables | References | Related Articles | Metrics

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Geological-geophysical models of the Earth’s crust along the Russian-Mongolian geotransects Evgeny Kh. TURUTANOV, Evgeny V. SKLYAROV, Valentina V. MORDVINOVA, Anatoly M. MAZUKABZOV, Viktor S. KANAYKIN 2021, 28(5): 260-282.  DOI: 10.13745/j.esf.sf.2021.3.10 Abstract ( 1284 )   HTML ( 32 )   PDF (7300KB) ( 309 )   Transects are vertical sections of the Earth’s crust, which reveal the nature of tectonic zones, as well as their spatial relationships through a combined analysis of their geology and geophysics. Transect documents contain a geological map for a strip of land 100 km wide, a geological section of the upper crust, gravity and magnetic maps (and/or corresponding profiles along the transect), and a geophysical profile of the crust, differentiated by seismic velocities, densities and other geophysical properties. These data are used to compose a combined cross-section (the resulting section), which shows a set of rocks typical of various geodynamic conditions (rifts, oceans, collision zones, orogenic basins, continental platforms and magmatic arcs, including Andean island arcs, active continental outskirts, trenches, basins of front and rear arcs). The objective of this project was to build deep sections according to unified legends based on the interpretation of all available geological and geophysical data in order to determine the spatial relationship of terranes and their geodynamic nature in terms of plate tectonics. A number of terranes have been discriminated in the territory of the southern part of Eastern Siberia and the territory of Mongolia, and their geodynamic nature and space-time relations were analysed. The terranes were found out to be Vendian-Early Paleozoic, Middle-Late Paleozoic and Late Paleozoic-Early Mesozoic island arcs and microcontinents. Moreover, Middle-Late Paleozoic and Late Paleozoic-Early Mesozoic Andean-type active continental margins and Late Paleozoic-Early Mesozoic passive margins and Early Cretaceous rifts were identified and studied. The rock complexes related to the island arcs and Andean-type active continental margins are thrust over the bordering continents and microcontinents, the width of the respective tectonic nappes attaining 150 km. Schematic paleogeodynamic reconstructions for the area of the Mongolia-Okhotsk ocean have been performed, spanning the period from Devonian to Late Jurassic. “Non-geosyncline” granitoid magmatism finds straightforward and sound explanation in terms of plate tectonics where provinces of Devonian-Carboniferous and Permian-Triassic magmatism correspond to Andean-type active continental margins and Middle-Late Jurassic magmatism is associated with Siberia/Mongolia-China collision. The presence of a subalkaline (mantle) element in collisional magmatism and the great extent of the area it occupies can be explained by suggesting that an oceanic rift (a mantle hotspot) was buried under thick continental lithosphere after closure of the Mongolia-Okhotsk ocean. In the Early Cretaceous, the setting of collision gave way to that of continental rifting. The existence of an Andean-type active margin over the great extent of the southern border of Siberia is likewise responsible for minor abundance of ophiolites along the Mongolia-Okhotsk suture. When one colliding continent has an Andean-type active margin and the other has a passive margin, the continental crust of the former thrusts over the latter, and no conditions arise for ophiolites to expose. Blocks of dismembered ophiolites, that are remnants of truncated seamounts, can be part of chaotic complexes building accretion-subduction wedges. However, accumulation of such wedges in the Late Permian-Early Jurassic was not typical of the active margin of Siberia because of rapid subduction. An analysis of geological and geophysical data on transects shows that the Asian continent was formed in the Phanerozoic as a result of accretion of terranes, some of which were microcontinents with a Precambrian foundation. Precambrian blocks are separated by deformed and strongly eroded Phanerozoic igneous arcs of various widths, also classified as specific terranes. Figures and Tables | References | Related Articles | Metrics

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Crustal deformation, long-term plate motion and earthquake occurrence process of the Shan Plateau region, Northern Sunda Arc: Constraints from geodetic measurements Raja SEN, Dibyashakti PANDA, Bhaskar KUNDU 2021, 28(5): 283-300.  DOI: 10.13745/j.esf.sf.2021.9.10 Abstract ( 281 )   HTML ( 20 )   PDF (2529KB) ( 156 )   In the present article, we explore the present day crustal deformation and long-term plate motion of the Shan Plateau and surrounding region by constraining geodetic measurements to provide an updated status of geodynamics and associated seismic hazard of this region. The Shan Plateau is laterally bounded by two prominent master faults on either sides (i.e., Sagaing fault in the western side and Red River fault in the eastern side), where extrusion of the ductile flow the Tibetan crust has been considered to be a predominant factor of the deformation in this sandwiched deformable unit. Geodetic measurements clearly indicate a dextral motion of 18 mm/yr and 4-5 mm/yr across the Sagaing fault and Red River fault segments, respectively. Moreover, the cumulative geodetic slip-rate across the networks of faults within the Shan Plateau indicates an overall sinistral motion of 12-13 mm/yr. We argue that the distributed deformation and long-term plate motion of the Shan Plateau region, with respect to the rigid (undeformed) Sundaland block, is primarily controlled by the regional bookshelf faulting, which is evident by the differential fault motion along the two master faults on the either sides (i.e., the Sagaing fault and Red River fault). Figures and Tables | References | Related Articles | Metrics

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Neotectonics of the Altai-Sayan Mountains and reactivation of regional faults controlling seismicity Mikhail M. BUSLOV, Lyudmila P. IMAEVA 2021, 28(5): 301-319.  DOI: 10.13745/j.esf.sf.2021.9.9 Abstract ( 277 )   HTML ( 16 )   PDF (2408KB) ( 155 )   The formation of mountain system and neotectonic structure of the Altai-Sayan region is regarded to be a result of intercontinental deformations, related to a distant effects of tectonic stress from the Indo-Eurasian collision. Within this tectonic model we carried out the joint analysis of the geology, seismicity data and topographic materials enable to assume that the maximum changes in the relief and seismic activity in the northern part of Central Asia mountain belt are confined to the zones of intersections of the Late Paleozoic regional faults. The intersections and junctions of faults should be considered as one of the most important structural factors that increase the fragmentation of the substrate, affect changes in the local stress field and predetermine the localization of large earthquake foci with a magnitude M≥5. Some regularities were revealed, based on the example of helium and travertine manifestations in the junction zone of the Charysh-Terekta and Kurai regional faults, which can be used as precursors of earthquakes. Figures and Tables | References | Related Articles | Metrics

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Deep seismic reflection evidence on the deep processes of tectonic construction of the Tibetan Plateau GAO Rui, ZHOU Hui, GUO Xiaoyu, LU Zhanwu, LI Wenhui, WANG Haiyan, LI Hongqiang, XIONG Xiaosong, HUANG Xingfu, XU Xiao 2021, 28(5): 320-336.  DOI: 10.13745/j.esf.sf.2021.8.10 Abstract ( 816 )   HTML ( 282 )   PDF (14121KB) ( 865 )   The collision between the Indian and Asian plates uplifted the Himalayan- Tibetan Plateau, thickening and expanding the crust. It is a scientific mystery of global concern as how the two continents collide and how the continent-continent collision deforms the continent. Deep seismic reflection profile detection is one of the most effective ways to unlock this scientific mystery. For more than 20 years using this technology, we have detected fine structures of the thick crust of the Tibetan plateau after overcoming technical bottlenecks to access the lower crust and Moho thus revealing the continental collision processes. This paper systematically summarizes the deep behaviors of the India-Asia collision and subduction beneath the Tibetan Plateau, from south to north, east to west and further into the hinterland of the plateau. The Indian crust undergoes underthrusting beneath the Himalayan orogenic belt on the southern margin of the plateau. Meanwhile, the lithosphere of the Alxa block in the Asian plate subducts southward beneath the Qilian Mountain in the north of the plateau, driving the northward overthrusting of the Qilian crust. Additionally, the Tarim and West Kunlun blocks undergo face-to-face collision in the northwestern margin of the plateau. In the easternmost part of the plateau, the Longriba fault, instead of the Longmen Shan fault zone, marks the western margin of the Yangtze block. It is also seismically evidenced that the Moho geometry in the plateau’s hinterland appears thin and flat, indicating lithospheric collapse and extrusion. Multiple deep reflection profiles revealed the collisional behavior under the Yalung-Zangbo suture zone and longitudinal variation in subducting geometry of the Indian crust from west to the east. In the middle of the suture zone, it shows a decoupling between the upper and lower crusts of the Indian plate, where the upper crust undergoes a northward overthrusting while the lower one experiences a northward underthrusting. It is also seismically evidenced a down-and southward crustal duplexing of the subducting Indian crust thickening the northern Himalayas, leaving over a thinning subducting lower crust of the Indian slab. The subduction front of the Indian crust collides with the lower crust of the Asian plate at the mantle depth. A near-vertical collision boundary is seen between the Gangdese batholith and the Tethyan Himalayas, where the Gangdese batholith shows almost transparent weak reflections in the lower crust with localized bright spot reflection that indicates partial melting. Additionally, the near-flat Moho geometry implies an extensional tectonic environment of the southern margin of the Asian plate. Figures and Tables | References | Related Articles | Metrics

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When the northeastern margin of the Qinghai-Tibet Plateau was involved in its present tectonic system: Constraints from the Cenozoic sedimentary sequence GUO Jinjing, ZHAO Haitao, LIU Chongqing, WU Yanwang 2021, 28(5): 337-361.  DOI: 10.13745/j.esf.sf.2020.12.13 Abstract ( 266 )   HTML ( 15 )   PDF (15679KB) ( 228 )   Since the Cenozoic era, the continuous collisional convergence between the Indian-Eurasian Plates led to the formation of the Qinghai-Tibet Plateau that is often called the third pole in the world. The geodynamic process of the spreading, growth of the Qinghai-Tibet Plateau and the formation of the tectonic system are key issues in Earth sciences. The Cenozoic tectonic evolution of the northeastern margin of the Qinghai-Tibet Plateau and its dynamic coupling relationship with the Indian-Eurasian collisional convergence have important geological constraints on the spreading and growth process of the Qinghai-Tibet Plateau. Although various tectonic uplift models have been proposed in previous studies, there is no consensus on when the northeastern margin of the Qinghai-Tibet Plateau was involved in the Indian-Eurasian collisional convergence tectonic system. The Zhangxian area on the northern margin of West Qinling, a typical region of the northeastern margin of the Qinghai-Tibet Plateau, has not only complete Cenozoic stratigraphic records, but also well-developed faults and abundant tectonic deformation phenomena. It provides a good opportunity for studying the Cenozoic tectonic evolution of the area as well as revealing the formation of the plateau tectonic system and the spatial-temporal spreading and growth model of the Qinghai-Tibet Plateau under the dynamic background of India-Eurasian collisional convergence. Based on a detailed field study of the stratigraphic framework, sedimentary stratigraphic sequence and sedimentary cycle of the Zhangxian Cenozoic sedimentary basin, combined with the geometry-kinematics and deformation history analyses of the regional faults, the following conclusions were reached: (1) The Zhangxian Cenozoic sedimentary stratigraphic framework is mainly composed of two tectonic stratigraphic units: Oligocene-Miocene extensional rift basin deposits and Pliocene regenerated foreland molasse basin deposits, separated by an angular unconformity. (2) The extensional tectonic setting during the Oligocene-Miocene is contrary to the compressional setting resulting from India-Eurasia collisional convergence, implying the northern margin of West Qinling was not involved in the present India-Eurasia collisional convergence system during the Oligocene-Miocene. (3) Pliocene molasse basin sedimentation marked the tectonic transition from extension to compression on the northern margin of West Qinling, which may imply the response to compression setting led by India-Eurasia collisional convergence in the area. (4) In the above area, Pliocene coarse conglomerate, strata of the western Qinling orogenic belt and Mesozoic sedimentary strata experienced uplift and denudation, finally resulting in the wide development of planation plane. Since Quaternary, the uplift and disintegration of this planation surface, and afterward the appearance of modern river system and multi-stage river terraces, marked the northeast margin of the Qinghai-Tibet Plateau unevenly and massively uplifted and then entered into its present tectonic system. Figures and Tables | References | Related Articles | Metrics

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Carboniferous tectonostratigraphic regionalization and stratigraphic framework in China ZHANG Xionghua, HUANG Xing, ZHANG Meng, GAO Lu, ZHANG Kexin 2021, 28(5): 362-379.  DOI: 10.13745/j.esf.sf.2020.12.5 Abstract ( 501 )   HTML ( 24 )   PDF (9882KB) ( 349 )   Frequent tectonic activities occurred in the Carboniferous. Between the stable tectonic units, such as the North China Craton, the Yangtze Craton and the Tarim Craton, there are numerous orogenic belts. Particularly in the fossil oceanic basins, various ocean plate strata are widely distributed, which include the North Tianshan Ocean, the South Tianshan Ocean, the Buqingshan-Mianlue Ocean, the Jinshajiang Ocean and the Ganzi-Litang Ocean. Thus the tectonic subdivision of China is extremely complex. The traditional stratigraphic regionalization mainly refers to the distribution of stable blocks, and the stratigraphic regions are divided according to the recent geographic framework. In this contribution, we reestablished the Carboniferous tectonostratigraphic framework of China. According to tectonic units and evolution stages, and in reference to the Chinese classical tectonic subdivision and by authors’ own definition, there are 11 tectonostratigraphic super regions: Altai-Xing’an-Mongolia, North Junggar-Xar Moron, Tianshan-Beishan, Tarim-Alxa, North China, Qinling-Qilian-Kunlun, Yangtze, Cathaysia, North Qiangtang-Sanjiang, Bangonghu-Nujiang and India. Among the tectonostratigraphic super regions, Altai-Xing’an-Mongolia approximately overlaps with the Altai-Xing’an-Mongolia arc-basin system. It contains numerous ocean plate strata and arc-related magmatism and could be divided into the Altai and Xing’an stratigraphic regions. The location of North Junggar-Xar Moron is similar to the Erqis-Xar Moron paleo-oceanic basin. This super region comprises abundant arc-related strata and ocean plate strata, and it could be divided into the North Junggar and Xar Moron stratigraphic regions. Tianshan-Beishan occupies the same territory as the Tianshan-Beishan orogenic system. It possesses several stratigraphic regions, including South Junggar, North Tianshan, South Tianshan, Yili and Ejin-Beishan, and is characterized by considerable volcanic rocks. The location of Tarim-Alxa is equivalent to the Tarim Block, the southeastern Tarim-Dunhuang Uplift and the Alxa Block. This super region contains widespread stable coastal to neritic deposits and locally distributed paralic sediments. It could be divided into the Tarim and Alxa stratigraphic regions. North China overlaps with the North China Craton and Helanshan continental margin rift. It comprises the Helanshan, North China and north-marginal North China stratigraphic regions and is mainly occupied by the paralic strata. Moreover, Mississippian strata are absent in the North China stratigraphic region. The Qinling-Qilian-Kunlun super region occupies a similar territory as the Qinling-Qilian-Kunlun orogenic belt. It possesses several stratigraphic regions, involving Qilian, Eastern Kunlun-Qaidam, Western Kunlun, Qinling and Southern Qinling-Sulu. The Yangtze super region overlaps with the Yangtze Craton. It is divided into several units, including Yanyuan-Lijiang, middle to upper Yangtze, lower Yangtze, Xiang-Zhe-Gan and Dian-Qian-Gui stratigraphic regions. Stable carbonate sediments occupy most of the Carboniferous outcrops, and the paralic strata are only preserved in the Xiang-Zhe-Gan stratigraphic region. Cathaysia takes a large territory of the Wuyi-Yunkai orogenic system. Some stratigraphic regions including Yue-Min, southern Yue, Qinfang, Northern Qiong, Middle-Southern Qiong and Cathaysia are identified in this super region. Except for Qinfang, which contains shemipelagic to pelagic, siliceous and argillaceous sediments, other stratigraphic regions are dominated by coastal-neritic sediments and rare paralic deposits. North Qiangtang-Sanjiang overlaps with the North Qiangtang-Sanjiang archipelagic arc-basin system. It comprises multiple micro-blocks, with ophiolitic mélange distributed between the blocks. This super region is characterized by the widespread ocean plate strata and divided into several stratigraphic regions, including Hoh Xil-Bayan Har-Mianlue, Jinshajiang-Ailaoshan, Zhongdian-Changdu-Simao, Xianshuihe-Ganzi-Litang, Northern Qiangtang and Tianshuihai. The territory of Bangonghu-Nujiang could be regarded as the Bangong Lake-Shuanghu-Nujiang-Menglian oceanic basin. The Carboniferous sediments in this super region are dominated by ocean plate strata. The India super region coincides with the passive margin distributed along the northern margin of the Indian Craton. It is characterized by the preservation of particular paleontological assemblages and glacial sediments located in the Gondwana, and could be divided into the Gangdise, Northern Himalaya and Baoshan stratigraphic regions. Various lithostratigraphic, paleontologic assemblages and stratigraphic successions in each stratigraphic super region, region or subregion are briefly introduced. The standards for the establishment of the Carboniferous stratigraphic framework in China are proposed, and correlation of strata is suggested based on the systematic stratigraphic correlation of Carboniferous in each region. Figures and Tables | References | Related Articles | Metrics

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Geochronology, petrogenesis and tectonic implications of the Qiaodian granite porphyry from the western Dabie Orogenic Belt, Central China HUANG Haiyong, XU Yang, YIN Xuwei, YANG Kunguang, LIU Yu 2021, 28(5): 380-412.  DOI: 10.13745/j.esf.sf.2020.12.9 Abstract ( 183 )   HTML ( 9 )   PDF (14447KB) ( 331 )   The ca. 145-120 Ma granitoids were regarded as important products of the thickened, delaminated partial melting Cretaceous crust beneath the Dabie Orogenic Belt. Our newly identified Qiaodian granite porphyry in the western Dabie Orogenic Belt can provide new constraints on the progression of lithospheric thinning and the transformation of tectonic regime to an extensional setting. SIMS and LA-ICP-MS zircon U-Pb dating suggests the Qiaodian granite porphyry was emplaced at 129 Ma. It has a negative zircon εHf(t) value (between -24.5 and -14.7) with a two-stage model age of 2.4-1.9 Ga, and is characterized by coarse-grained feldspar phenocrysts. It has variable SiO2 contents (63.07%-73.22%) and A/CNK values (0.87-1.73), with high K2O(4.51%-5.47%) and low MgO(0.42%-1.82%) contents, suggesting high-K calc-alkaline granite affinity. It exhibits LREE-enriched rare earth elemental distribution patterns ((La/Yb)N=29.6-34.2) with negative Eu anomalies ((Eu/Eu *)=0.77-0.92). The primitive mantle-normalized trace element patterns show enrichments of Rb, Ba and Pb and depletions of Nb, Ta and Ti. Compared with typical adakites, the Qiaodian granite porphyry has variable Sr((78-724)×10-6) and relatively high Y((11.8-14.8)×10-6) and Yb((1.09-1.37)×10-6) contents, yielding a low Sr/Y ratio (6.7-55.5). These geochemical features, together with Paleoproterozoic residual zircon and two-stage Hf model ages, indicate the Qiaodian granite porphyry mainly derived from partial melting of Paleoproterozoic mafic materials at medium to low pressures. On the basis of our new results and previously published data, we consider the tectonic collapse and transformation of the western Dabie Orogenic Belt probably occurred around 130 Ma. Figures and Tables | References | Related Articles | Metrics

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Cenozoic fault system in the southern East Chengdao low rise of Bohai Sea area and its control on oil and gas distribution XIE Zongkui, WANG Zhiwei, MING Yukun, WANG Ming, ZHANG Zaizhen, YANG Bin, MA Zichao, SUN Shijie, HUANG Yuanjun 2021, 28(5): 413-420.  DOI: 10.13745/j.esf.sf.2021.1.62 Abstract ( 270 )   HTML ( 9 )   PDF (7143KB) ( 140 )   The structural sedimentary evolution in southern East Chengdao low rise was controlled by both extension and strike-slip effects in the Cenozoic. The fault combination in this area is complex. It is generally believed that the NE and EW faults in the middle-deep stratum belong to contemporaneous and syngenetic faults. In response to this view and the questions it raised, the fracture system is analyzed on the basis of structural geological theory using drilling and seismic data. In the study area, the main types of faults in Cenozoic strata are normal faults and strike-slip normal faults, and there are three types of fault cutting through the blocks of basement-Dongying Formation, Pingyuan-Dongying Formation, and Pingyuan Formation-basement. Taking the regional unconformity between the Dongying and Guantao Formations as a time boundary marker, the existing faults are divided into the early and late fault systems. The early faults, belonging to synsedimentary fault, primarily grew from the basement to the lower part of the Dongying Formation; the late faults mainly cut through the block of the Pingyuan-Dongying Formation reaching the basement, and their evolution was restricted by pre-existing faults. The NE and near-EW faults belong to these two fault systems, respectively, which played a key role in hydrocarbon distribution. The extension caused by the differential elevation and subsidence of the basement formed the NE faults in the early stage, which controlled the trough landform and the sedimentary environment of deep-water gravity flow, and the continuous layered sandy debris flow was developed. The right strike-slip movement of the Tanlu fault initiated the formation of the near-EW en echelon normal faults in the later stage. Fault planes provided not only shielding for developing upward dip direction of reservoirs, but also vertical migration channels for oil-gas due to poor sealing during near-EW compression. Faults and faulting controlled the order of trap distribution and hydrocarbon accumulation. In the E-W direction, fault block traps and oil-water interface increased in proper sequence, and the degree of fullness successively decreased as full, under filled and half filled, etc. Fault system research, putting the geological body in a certain tectonic stress field, analyzes the spatial arrangement and intersectional relationship of fault combination as well as the mechanical mechanism and displacement characteristics of fault, and explores the control effect of space-time evolution on oil and gas distribution. Its research method is applicable in the areas of superimposed tectonics, which has practical significance for oil and gas exploration and development in such areas. Figures and Tables | References | Related Articles | Metrics

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Sedimentary characteristics of intersalt fine-grained sedimentary rocks and their control on oil-bearing ability of shales in the Qianjiang Formation, Qianjiang Sag CHEN Chen, JIANG Zaixing, KONG Xiangxin, WU Shiqiang, CHEN Fengling, YANG Yepeng 2021, 28(5): 421-435.  DOI: 10.13745/j.esf.sf.2020.12.8 Abstract ( 238 )   HTML ( 13 )   PDF (15522KB) ( 290 )   The Jianghan Basin is a typical inland salt lake basin in China. The Qianjiang Sag, in the middle of the basin, developed intersalt petroliferous fine-grained sedimentary rocks, and it has seen a recent breakthrough in oil and gas exploration. In order to study its sedimentary characteristics and depositional control, eight kinds of lithofacies are identified in the sedimentary rocks using core and various tests: calcite-bearing argillaceous dolomite, dolomite, argillite or calcite mixed fine-grained sedimentary rocks, calcareous mudstone/mudstone, dolomitic mudstone, sulfate mixed fine-grained rock, and dolomitic/argillaceous glauberite. In addition, two lithofacies associations, types A and B, are identified. The type A association contains calcite-bearing argillaceous dolomite, dolomite or argillite mixed fine-grained sedimentary rocks, with small amounts of calcite mixed fine-grained sedimentary rocks, dolomitic mudstone, sulfate mixed fine-grained rock, and dolomitic/argillaceous glauberite. The type B association involves dolomitic mudstone, sulfate mixed fine-grained rock dolomitic/argillaceous glauberite, small amounts of calcareous mudstone/mudstone and argillite mixed fine-grained sedimentary rocks. The type A lithofacies association is rich in carbonate and organic matter; its cores are gray-black argillaceous rocks (argillite and calcite mixed fine-grained sedimentary rocks) and yellow-brown dolomitic rocks (calcite-bearing argillaceous dolomite and dolomite mixed fine-grained sedimentary rocks) frequently interchanging, with white sulfate rocks interspersed in the form of lenses or layers, indicating the environmental salinity at that time was relatively low. Laminates under the microscope mostly show continuous fine wave or aligned horizontally. The sedimentary characteristics show the type A association is formed in a reductive and low salinity deep water environment. The type B lithofacies association, on the other hand, is rich in sulfate and has low organic matter content; its cores are white high sulfate rocks with black argillaceous layers or yellowish-brown dolomitic layers. Microscope observation reveals rhombohedral glauberite, commonly with interspersed twin crystals, and obvious grained sequence change can be seen. The thin slices with high dolomite content are characterized by the absence of laminates under the microscope. The sedimentary characteristics show the formation environment of the type B lithofacies association is shallow water with weak reducibility and high salinity. Geochemical parameters, such as V/(V+Ni), (S1+S2)/TOC, Sr/Ba, and Ga/C31H, combining with lithofacies characteristics, further support the above assessment and show the types A and B associations are formed in humid and dry climate, respectively. The intersalt deposition is divided into three stages, B, A, B, in a proposed sedimentary model: In the first stage, the climate is dry and the water is shallow, a lot of salts precipitate from the lake water to form mainly the type B lithofacies association. With increasing sulfate minerals, organic matter oxidation is facilitated by sulfate-reducing bacteria, which is not conducive to organic matter enrichment. In the second stage, increasing rainfall and large-scale fresh water injection cause the water salinity and depth to increase. At this time, the water has good stratification and strong reducibility to develop the type A lithofacies association, which improves the preservation conditions for organic matter. Therefore, the type B association, with low TOC content, is not the main lithofacies for oil and gas accumulation, as enriched sulfate minerals can dilute the organic matter, and the high salinity environment in the lithofacies can slow down the microbial activity. Conversely, the type A association, with high TOC content, is the main lithofacies for oil and gas enrichment. In its forming environment, frequent rainfall lowers the water salinity to create a good environment for the organic matter-producing planktonic microorganisms to grow; at the same time, pores between minerals beneficial to hydrocarbon storage develop in the dolomitic laminate, making it a high-quality source rock and favorable lithofacies for oil and gas exploration and development in the area. Figures and Tables | References | Related Articles | Metrics

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Carbon isotope excursion and its genetic mechanism during the Sinian to Cambrian transition in the northern Tarim Basi FAN Qi, FAN Tailiang, LI Qingping, ZHANG Yan, GU Yu, SHANG Yaxin 2021, 28(5): 436-447.  DOI: 10.13745/j.esf.sf.2020.7.5 Abstract ( 465 )   HTML ( 13 )   PDF (10195KB) ( 154 )   The Sinian to Cambrian transition is a time node for the Earth evolution, yet carbon and oxygen isotopes, which are well preserved in the Tarim Basin during this period, are barely studied. Here, based on the measurements of the Sugaitebulake outcrop, a comprehensive analysis of paleontology, microscopic identification, and carbon isotope excursions is carried out, and the genetic mechanism of the N1 (BACE) and P1 (ZHUCE) excursion events is explained. The correlation coefficient between δ 13Ccarb and δ18Ocarb (R2= 0.05) or δ 18Ocarb and Mn/Sr (R2= 0.09), as well as microscopic characteristics, shows that the later diagenesis did not lead to fractionation of carbon and oxygen isotopes significantly, and the original carbon isotopic characteristics are basically preserved. Six carbon excursions were detected from the bottom to the top of the formation, which comprise, respectively, excursions P-1 with δ 13Ccarb between 1.9‰ and 2.4‰, N1 with δ13Ccarb between -6.8‰ and -10.3‰, P1 with δ13Ccarb between 1.4‰ and 4.1‰, N2a-c with δ13Ccarb between -0.4‰ and -2.8‰, P2a-c with δ13Ccarb between 0.2‰ and 0.6‰, and N3 with δ13Ccarb peaked at -3.4‰. Together with paleontological and chronological constraints, the interface between silica-phosphorus shale of the bottom Yuertusi Formation and algal-dolomite of the top Qigebulake Formation is confirmed as the boundary of the Sinian to Cambrian of the northern Tarim Basin. Also completed is a structural correlation framework comparing the northern Tarim with Tabei, Laolin, Xiaotan, Three Gorges, Siberia, Oman, and Morocco plates. It reveals the carbon isotope excursions during the Sinian to Cambrian transition in northern Tarim are more controlled by the fluctuation of carbon fixation rate (forg) due to paleo-marine redox changes. The decreased productivity and carbon fixation, caused by large-scale anoxic events in the transgression of the Yuertusi Formation, is the main reason for the N1 excursion; then the recovered productivity and carbon fixation from oxygen increase during regression forms the P1 excursion. The above results are beneficial for the further study of the Cambrian paleo-environments and evaluation of the deep to ultra-deep resources in the Tarim Basin. Figures and Tables | References | Related Articles | Metrics

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Spatial distribution characteristics and risk assessment of heavy metals in surface sediments in Lake Yunmeng CAO Wei, ZHANG Lei, QIN Yanwen, CHI Minghui, ZHAO Yanmin, YANG Chenchen, SHI Yao 2021, 28(5): 448-455.  DOI: 10.13745/j.esf.sf.2021.1.57 Abstract ( 330 )   HTML ( 9 )   PDF (3274KB) ( 148 )   To explore the pollution characteristics of heavy metals in Lake Yunmeng, the distribution, source and ecological risk of six heavy metals (Cu, Zn, Pb, Cr, Cd and As) in lake surface sediments were analyzed to provide a basis for the pollution treatment and ensure drinking water safety for Lake Yunmeng. The source of heavy metals was investigated by enrichment factor, correlation and cluster analysis, and the contamination and potential ecological risk of heavy metals were evaluated by using geoaccumulation, enrichment factor and potential ecological risk indexes. The results indicate the average contents of Cu, Zn, Pb, Cr, Cd and As were 20.9, 73.1, 23.1, 62.0, 0.4 and 4.5 mg/kg, respectively. Compared with the soil background values, elevated Cd, Zn and Cr levels were found in Linyi City, and Cd pollution was the most serious. Source analysis shows that Cd was greatly affected by human activities likely related to local fertilizer use in agriculture and forestry, whereas Cu, Zn, Pb, Cr and As were mainly from natural sources. The evaluation results indicate Cd was the main polluting element in surface sediments posing relatively high ecological risk in Lake Yunmen. Figures and Tables | References | Related Articles | Metrics