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鄂尔多斯盆地东胜砂岩型铀矿床成矿水化学过程探讨 被引量:3
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作者 吴兆剑 易超 +2 位作者 韩效忠 祁才吉 惠小朝 《地球学报》 EI CAS CSCD 北大核心 2014年第3期329-337,共9页
为了研究鄂尔多斯盆地东胜砂岩型铀矿成矿水化学过程,利用光薄片、电子探针、X射线衍射、扫描电镜和化学分析等方法对比分析了氧化带无矿化样品、氧化还原过渡带中低矿化及高铀样品的矿物学和地球化学特征。矿物学研究表明:①所有样品... 为了研究鄂尔多斯盆地东胜砂岩型铀矿成矿水化学过程,利用光薄片、电子探针、X射线衍射、扫描电镜和化学分析等方法对比分析了氧化带无矿化样品、氧化还原过渡带中低矿化及高铀样品的矿物学和地球化学特征。矿物学研究表明:①所有样品中斜长石均表现出强烈粘土化和绢云母化的特征;②铀矿物主要为铀石,呈胶状吸附在矿物颗粒(部分为炭屑)表面、粒间或裂隙中;③相对氧化带,氧化还原过渡带往往含有更多的炭屑和碳酸盐胶结物。稀土元素地球化学研究表明,氧化带无矿化样品和过渡带低矿化样品表现出较平坦的低分异的稀土配分模式;而过渡带高铀含炭屑样品表现出MREE富集的配分模式,高铀富碳酸盐胶结物的样品表现出轻稀土强烈左倾、重稀土平坦的配分模式。对比分析上述差异后认为,铀成矿与水化学作用密切相关,且成矿水溶液中无机络阴离子以CO32-为主,倾向于络合UO22+和HRE3+;而阳离子主要为斜长石的粘土化释放的Ca2+和SiO44-。当水溶液从盆地边缘向中心运移时,物化环境从氧化及酸性环境向还原及碱性环境转变,此时发生铀酰离子的还原并与SiO44-沉淀形成铀石、Ca2+与CO32-沉淀形成碳酸盐以及HREE的沉淀富集。 展开更多
关键词 鄂尔多斯盆地 砂岩型铀矿 水化学过程 铀成因机理
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大冶铁矿区地下水水化学演化过程及铁和硫酸盐污染机制 被引量:4
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作者 李伟 耿函 +3 位作者 苏春利 曹慧丽 梁川 卫方成 《安全与环境工程》 CAS CSCD 北大核心 2023年第2期223-232,共10页
大冶铁矿区由于长期采矿活动,生态环境、地下水环境均衡受到严重的影响,并伴生地下水污染。通过地下水水化学特征和同位素分析,查明了大冶铁矿区地下水污染物分布特征,并通过反向地球化学模拟,探讨了地下水径流过程中区域地下水主要水... 大冶铁矿区由于长期采矿活动,生态环境、地下水环境均衡受到严重的影响,并伴生地下水污染。通过地下水水化学特征和同位素分析,查明了大冶铁矿区地下水污染物分布特征,并通过反向地球化学模拟,探讨了地下水径流过程中区域地下水主要水文地球化学演化过程以及特征污染物的迁移过程和污染机理。结果表明:大冶铁矿区地下水赋存于弱碱性氧化环境,地下水水化学类型主要为HCO_(3)·SO_(4)-Ca型水;碳酸盐岩和硅酸盐水解是研究区地下水水化学组分的主要来源,且受到不同程度蒸发盐岩溶解、矿坑排水和人类生活污染的影响;区域地下水中Fe和SO_(4)^(2-)浓度高值区主要分布在洪山溪尾矿库、矿渣堆存处附近,上邹国控点DYTKQ04泉水中硫酸盐浓度超标(>250mg/L),而Fe浓度较低;沿地下水流动路径方向,主要发生了脱白云石化、离子交换作用和黄铁矿的氧化作用,地下水中SO_(4)^(2-)浓度增加,但氧化条件下释放出的Fe^(2+)被氧化为Fe^(3+)形式,并形成难溶的氢氧化物沉淀从地下水中除去,从而使地下水中Fe浓度降低。 展开更多
关键词 地下水污染 水化学演化过程 硫酸盐 水-岩相互作用 大冶铁矿区
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乌蒙山云贵交界处地下水水化学特征及成因分析
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作者 蒲文斌 陈鹏 +3 位作者 张继 魏良帅 韩小刚 钱康 《环保科技》 2021年第1期46-53,共8页
采集103组常规地下水化学组分分析水样,采用Piper三线图、相关性分析对研究区碳酸盐岩裂隙岩溶水、碎屑岩孔隙裂隙水与玄武岩裂隙孔洞水三种不同类型地下水进行了分析,结果表明:研究区地下水中阴离子以HCO_(3)^(_)和SO_(4)^(2-)为主,阳... 采集103组常规地下水化学组分分析水样,采用Piper三线图、相关性分析对研究区碳酸盐岩裂隙岩溶水、碎屑岩孔隙裂隙水与玄武岩裂隙孔洞水三种不同类型地下水进行了分析,结果表明:研究区地下水中阴离子以HCO_(3)^(_)和SO_(4)^(2-)为主,阳离子以Ca^(2+)、Mg^(2+)为主,水化学类型以HCO_(3)-Ca、HCO_(3)·SO_(4)^(-)Ca·Mg型水为主;地下水径流活动强,水循环交替快;77组地下水为Ⅰ~Ⅲ类水,Ⅳ类和Ⅴ类水26组,主要为Al、Fe、Mn和Co含量超标,主要受采煤活动影响;以Ⅰ~Ⅲ类地下水为研究对象,根据不同组分相关性分析,碳酸盐特别是碳酸钙的溶解作用是区内的主要水化学过程,同时还存在阳离子交换吸附作用,蒸发浓缩作用较弱。 展开更多
关键词 地下水 水化学特征 相关性分析 水化学过程 乌蒙山
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喀斯特洞穴滴水水文化学过程的时空变化及其环境指示——以贵州织金洞为例 被引量:4
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作者 曹明达 周忠发 +3 位作者 潘艳喜 张结 殷超 张绍云 《水土保持研究》 CSCD 北大核心 2017年第3期339-346,共8页
洞穴水地球化学过程的研究对于洞穴内次生沉积物景观的发育有着重要的意义,2015年1—12月通过现场滴定测量和实验室仪器分析对贵州织金洞洞穴水的水化学指标进行了为期一个完整水文年的动态监测,采样时间均为每月26—28日。结果表明:(1... 洞穴水地球化学过程的研究对于洞穴内次生沉积物景观的发育有着重要的意义,2015年1—12月通过现场滴定测量和实验室仪器分析对贵州织金洞洞穴水的水化学指标进行了为期一个完整水文年的动态监测,采样时间均为每月26—28日。结果表明:(1)洞穴滴水滴率和Ca^(2+),Mg^(2+),Sr^(2+)离子浓度均与降水量有很好的响应,但同时都表现出一定的滞后性,其中Mg^(2+),Sr^(2+)离子所携带的气候信号较为持久,Ca^(2+)离子浓度在雨季波动较大。(2)滴水水化学性质在化学计量上总体符合石灰岩喀斯特地区的侵蚀方程,Ca^(2+)/HCO_3^-的比值均在1/2上下波动;(3)滴水中的SIc和SId之间存在显著的正相关关系,滴水中的液相CO_2分压[lgPCO_2(water)]与pH值之间呈现出显著的负相关,体现了上覆土壤层中的高浓度CO_2对洞穴滴水化学过程的重要影响。(4)滴水中的Mg/Ca与Sr/Ca比值在雨季到来后的曲线变化呈现出明显的同增同减性特征,证明CaCO_3在未到达洞穴之前就已经在土壤层和基岩层中发生了优先沉积(PCP),致使运移到洞内的Ca^(2+)离子浓度相对其他离子的升高程度小;(5)滴水中Mg/Ca比值与Sr/Ca比值都有较明显的季节变化,但是Sr/Ca比值季节滞后性明显,而Mg/Ca比值年际变化更具波动性,对外界降水变化响应较敏感。 展开更多
关键词 喀斯特 洞穴水 时空变化 水化学过程 织金洞
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Activating d^(10)electronic configuration to regulate p-band centers as efficient active sites for solar energy conversion into H_(2)by surface atomic arrangement
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作者 Shanshan Lai Jiakun Su +2 位作者 Shujuan Jiang Jianjun Zhang Shaoqing Song 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第10期185-194,共10页
Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electro... Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials. 展开更多
关键词 d-Band center p-Band center Localized field Photocatalytic water splitting Dynamic process
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西藏达则错盐湖沉积背景与有机沉积结构 被引量:6
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作者 刘沙沙 贾沁贤 +2 位作者 刘喜方 郑绵平 刘雷震 《生态学报》 CAS CSCD 北大核心 2013年第18期5785-5793,共9页
以西藏拟溞(Daphniopsis tibetana Sars)为优势浮游动物物种的低盐度盐湖是西藏湖泊的一个重要类型,以达则错为代表,分析了其沉积背景及沉积物组成。结果如下:(1)湖泊敞水区无机沉积以内生化学沉积为主,可代表深水盐湖无机沉积物的自然... 以西藏拟溞(Daphniopsis tibetana Sars)为优势浮游动物物种的低盐度盐湖是西藏湖泊的一个重要类型,以达则错为代表,分析了其沉积背景及沉积物组成。结果如下:(1)湖泊敞水区无机沉积以内生化学沉积为主,可代表深水盐湖无机沉积物的自然沉积过程。(2)达则错盐湖浮游植物以蓝藻、硅藻、裸藻、绿藻为主,总生物量11.35 mg/L;浮游动物生物量为4.92 mg/L,其中西藏拟溞占82.30%;浮游植物残体受盐梯度影响在盐梯度层之上聚集,而浮游动物残体及粪粒(Fecal pellets)因外表有碳酸盐附着可穿过盐梯度层沉积湖底,生物残体与浮游动物代谢产物构成了沉积有机物的物质基础。(3)表层沉积物平均含水量为66.70%,粒径0.004—0.02 mm范围内的颗粒物含量最大,占20.42%,其次为<0.004 mm的粘土,占4.53%。(4)表层沉积物总有机碳(TOC)平均含量为27.99 mg/g(干重),其中颗粒有机碳(POC)约为18.11 mg/g,占TOC的64.70%;在POC中,西藏拟溞粪粒贡献最大,约占POC的60.48%,占TOC的39.06%,占沉积物总量的1.12%,其次为西藏拟溞残体,占POC的38.85%。分析结果表明盐湖因其独特的水化学和生物学特征具有较强的沉积能力,以化学沉积为主的无机沉积及以西藏拟溞粪粒和残肢碎屑为主的有机沉积构成了该类型盐湖颗粒物沉降及沉积的主要过程。 展开更多
关键词 达则错盐湖 沉积物结构 沉积环境 有机沉积 水化学过程 生物过程 西藏
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Shrinking and Drying up of Baiyangdian Lake Wetland:A Natural or Human Cause? 被引量:11
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作者 LIU Chunlan XIE Gaodi HUANG Heqing 《Chinese Geographical Science》 SCIE CSCD 2006年第4期314-319,共6页
The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by... The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized. 展开更多
关键词 climate change human activities Baiyangdian Lake wetland hydrologic process North China Plain
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Hydrological Processes in the Huaihe River Basin, China: Seasonal Variations, Causes and Implications 被引量:1
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作者 SUN Peng SUN Yuyan +1 位作者 ZHANG Qiang YAO Rui 《Chinese Geographical Science》 SCIE CSCD 2018年第4期636-653,共18页
Understanding streamflow changes in terms of trends and periodicities and relevant causes is the first step into scientific management of water resources in a changing environment. In this study, monthly streamflow va... Understanding streamflow changes in terms of trends and periodicities and relevant causes is the first step into scientific management of water resources in a changing environment. In this study, monthly streamflow variations were analyzed using Modified Mann-Kendall(MM-K) trend test and Continuous Wavelet Transform(CWT) methods at 9 hydrological stations in the Huaihe River Basin. It was found that: 1) streamflow mainly occurs during May to September, accounting for 70.4% of the annual total streamflowamount with Cv values between 0.16–0.85 and extremum ratio values between 1.70–23.90; 2) decreased streamflow can be observed in the Huaihe River Basin and significant decreased streamflow can be detected during April and May, which should be the results of precipitation change and increased irrigation demand; 3) significant periods of 2–4 yr were detected during the 1960 s, the 1980 s and the 2000 s. Different periods were found at stations concentrated within certain regions implying periods of streamflow were caused by different influencing factors for specific regions; 4) Pacific Decadal Oscillation(PDO) has the most significant impacts on monthly streamflow mainly during June. Besides, Southern Oscillation Index(SOI), North Atlantic Oscillation(NAO) and the Ni?o3.4 Sea Surface Temperature(Ni?o3.4) have impacts on monthly streamflow with three months lags, and was less significant in time lag of six months. Identification of critical climatic factors having impacts on streamflow changes can help to predict monthly streamflow changes using climatic factors as explanatory variables. These findings were well corroborated by results concerning impacts of El Nino-Southern Oscillation(ENSO) regimes on precipitation events across the Huaihe River Basin. The results of this study can provide theoretical background for basin-scale management of water resources and agricultural irrigation. 展开更多
关键词 streamflow TREND PERIODICITY abrupt behavior climate indices Huaihe River Basin China
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Water Analysis for Heavy Metals Content in Selected Boreholes in Port Harcourt Metropolis (A Case Study during 2010-2011) 被引量:1
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作者 Kalagbor Ihesinachi Appolonia Mgbodom-Okah Chidinma Juliet 《Journal of Environmental Science and Engineering(A)》 2013年第7期418-426,共9页
Underground water (Borehole) has been the main alternative source of drinking water for most communities in my country. Previous studies have revealed high levels of contamination. The origin of which can be attribu... Underground water (Borehole) has been the main alternative source of drinking water for most communities in my country. Previous studies have revealed high levels of contamination. The origin of which can be attributed to geochemical processes, combustion of fossil fuels, mining and anthropogenic activities. Most borehole water and well water in local communities of Nigeria are not safe for drinking due to heavy industrial and environmental pollution. This study was undertaken to assess the quality in some selected boreholes in the Port Harcourt metropolis for a period of two years. Borehole water samples were randomly collected from thirteen boreholes in a local community in plastic bottles (100 mL) in the months of September for the years of study (2010 & 2011). Four out of the seven heavy metals analyzed were found to be present in the first year of study. These were Fe, Cu, Mn and Zn. In the second year of study, Pb, Cr, Fe and Co were not detected in all of the samples except Cu and Fe which were present in only two samples. Mn and Zn were found to be present in all of the samples for both years of study. 展开更多
关键词 GROUNDWATER BOREHOLE geochemical processes.
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Water Chemistry and Hydrometeorology in a Glacierized Catchment in the Polar Urals,Russia 被引量:2
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作者 STACHNIK Lukasz WALACH Piotr +3 位作者 UZAROWICZ Lukasz YDE Jacob C. TOSHEVA Zornitza WRONSKA-WALACH Dominika 《Journal of Mountain Science》 SCIE CSCD 2014年第5期1097-1111,共15页
This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range,... This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier(13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11 th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11 th to July 18 th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+. 展开更多
关键词 Polar Urals River discharge Nitrate Chemical weathering Periglacial basin Glacier
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Research on Application of Ultrafiltration Technology in Chemical Process
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作者 Xingxue YANG 《International Journal of Technology Management》 2015年第2期9-11,共3页
Ultrafiltration is a new practical technique of a chemical process, its development prospect is very broad, so it is a very wide application in chemical process, this paper combined with ultrafiltration technique in a... Ultrafiltration is a new practical technique of a chemical process, its development prospect is very broad, so it is a very wide application in chemical process, this paper combined with ultrafiltration technique in a ultrafiltration company, the ultrafiltration technique should be used to analyzes and discusses in ultrafiltration process. Finally, the article gives the process of ultrafiltration technology in city living water, ultrafiltration technology has the advantages of simple process, convenient operation, low energy consumption, good removal effect of phosphorus in chemical enhanced ultrafiltration micelle research field. 展开更多
关键词 Industrial process ULTRAFILTRATION membrane separation chemical industry
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The Influence of Full Cream Milk Powder Concentration on the Characteristics of "Rasi" Instant Cream Soup 被引量:1
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作者 Marleen Sunyoto Ranti Futiawati 《Journal of Agricultural Science and Technology(A)》 2012年第11期1218-1231,共14页
"Rasi" (cassava-by product) instant cream soup is a processed food product that is made of a mixture of"Rasi" flour, full cream milk powder, beef broth, and spices that are ready to be consumed after being brewe... "Rasi" (cassava-by product) instant cream soup is a processed food product that is made of a mixture of"Rasi" flour, full cream milk powder, beef broth, and spices that are ready to be consumed after being brewed with boiling water to become a thick solution. Complex bonding of fat in full cream milk powder and amylose in rasi flour causes the formation of a hydrophobic layer around granules, inhibiting water absorption during rehydration. The aim of experiment was to define the appropriate concentration of full cream milk powder, to be used in making "Rasi" instant cream soup with the best characteristic and the most preferable by panelist. The method used was experimental method with randomize block design with six treatments and four repetitions. The treatments on full cream milk concentration were A (12.5%), B (15%), C (17.5%), D (20%), E (22.5%) and F (25%), respectively. "Rasi" instant cream soup with E treatment (22.5%) gives the best physical and chemical characteristics and organoleptics accepted by panelists, having an average value of rehydration 405, 16%, 575 cP viscocity, 4.74% water, 16.49% fat, 12.01% protein, average value of rendemen about 28.32% and panelist preference value of Rasi cream soup instan's colour, taste, flavor, and thickness after rehydration were accepted. 展开更多
关键词 Rasi full cream milk powder instant cream soup.
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Physical, Chemical and Biochemical Changes of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) Fruits during Ripening
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作者 Angel Guadarrama Scarlett Andrade 《Journal of Agricultural Science and Technology(B)》 2012年第11期1148-1157,共10页
This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) fruits during ripening as important features to bette... This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) fruits during ripening as important features to better understand their postharvest handling. It was carried out physical analysis such as firmness and chemical analysis such as total chlorophyll, total carotenoids, soluble solids, pectins and titrable acidity and biochemical analysis such as pectin methyl esterase, polygalacturonase, cellulase, and peroxidase and polyphenoloxidase activities in crude extract. Fruits were harvested at different stages of ripening. Experimental design was completely randomized and was carried out analysis of variance and Tukey tests, Total chlorophyll was decreasing in later stages of ripening, total soluble solid contents increased as the fruits ripen, while the acidity expressed percentage of citric acid decreased during fruits ripening. The loss of firmness and soluble solids content increased as the fruit get ripped stage, while the content of pectin decreased. Activity was observed for pectin methyl esterase and polygalacturonase enzymes during all stages of maturation, presenting the highest activity for both enzymes in the mature state. No cellulase activity detected at any stage during the ripening of these fruits. Activity of the enzyme polyphenoloxidase and peroxidase, associated with pulp browning was higher in the last stages of ripening of these fruits. Physical, chemical and biochemical patterns during ripening were different according to fruit species suggesting differential postharvest handling requirements. 展开更多
关键词 FIRMNESS PECTIN pectin methyl esterase POLYGALACTURONASE peroxidase.
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The intercultural awareness in Korean Teaching
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作者 Xiaomang LIAN 《International Journal of Technology Management》 2015年第6期57-59,共3页
Language is the carrier of culture. We should not only focus on skills in teaching Korean culture, but also conduct a comprehensive analysis and guidance to penetrate culture and education of Korea in the teaching pro... Language is the carrier of culture. We should not only focus on skills in teaching Korean culture, but also conduct a comprehensive analysis and guidance to penetrate culture and education of Korea in the teaching process. Which enhance the overall level. This thesis analyze and elaborate the characteristics of Korean teaching intercultural education. What' s more, it will propose corresponding solutions in penetration problems of culture and education for the Korean teaching. 展开更多
关键词 Korean teaching culture and education Intercultural awareness
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Impact of Changing Climate in the Kairouan Hydrological Basin (Central Tunisia)
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作者 B. Chulli G. Favreau +1 位作者 N. Jebnoun M. Bedir 《Journal of Environmental Science and Engineering》 2011年第6期682-688,共7页
The Merguellil catchment (central Tunisia) has undergone rapid hydrological changes over the last decades. The most visible signs are a marked decrease in surface runoff in the upstream catchment and a complete chan... The Merguellil catchment (central Tunisia) has undergone rapid hydrological changes over the last decades. The most visible signs are a marked decrease in surface runoff in the upstream catchment and a complete change in the recharge processes of the Kairouan aquifer downstream. Fluctuations in rainfall have had a real but limited hydrological impact. Much more important are the consequences of human activities such as soil and water conservation works, small and large dams, pumping for irrigation. Several independent approaches were implemented: hydrodynamics, thermal surveys, geochemistry including isotopes. They helped to identify the different terms of the regional water balance and to characterize their changes over time. 展开更多
关键词 Climate change water balance GEOCHEMISTRY HYDRODYNAMICS Tunisia.
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Geochemical processes and origin of boron isotopes in geothermal water in the Yunnan-Tibet geothermal zone 被引量:10
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作者 Lü YuanYuan ZHENG MianPing +1 位作者 ZHAO Ping XU RongHua 《Science China Earth Sciences》 SCIE EI CAS 2014年第12期2934-2944,共11页
Boron concentrations and isotope compositions have been measured for 93 water samples from the hot springs and drill-holes in the geothermal system in the Yunnan-Tibet Geothermal Belt(YTGB),China.Boron concentrations ... Boron concentrations and isotope compositions have been measured for 93 water samples from the hot springs and drill-holes in the geothermal system in the Yunnan-Tibet Geothermal Belt(YTGB),China.Boron concentrations range from 0.036–472.4ppm,and theδ11B values range from -16.0‰to 13.1‰,indicating the non-marine origin for each geothermal system.We observed a clear binary mixing relationship between the B concentrations and B isotope compositions in Tibet geothermal area.This relationship can be well explained by two sources,i.e.,marine carbonate rocks and magmatic rocks,for the Tibet geothermal water.No evidence supports a mantle contribution to B.In addition,we found that the precipitation only plays a dilution role for B of geothermal waters.δ11B values for the precipitation across the southern Tibetan Plateau area range from -6.0‰ to -6.8‰at least.Due to data scarcity in Yunnan geothermal area,we observed possible different boron sources from the Tibet geothermal system.Comparing it with other geothermal systems in the world,we found that the samples from YTGB have the lowestδ11B values and the largest range of B concentration,which might be related to their special geological background.On the whole,the world geothermalδ11B-Cl/B relation suggests a mixing process between marine and non-marine sources.Additionally,we suggest that B source of B-enriched geothermal waters is mainly from B-enriched crustal country-rocks,instead of mantle. 展开更多
关键词 Yunnan-Tibet geothermal zone Boron isotope geothermal water TRACING
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Contribution of baseflow nitrate export to non-point source pollution 被引量:8
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作者 HE ShengJia 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第10期1912-1929,共18页
As a common pollutant of nitrogen in groundwater, nitrate contamination has become a major concern worldwide. Baseflow, one of the dominant hydrological pathways for nitrate migration to streamflow, has been confirmed... As a common pollutant of nitrogen in groundwater, nitrate contamination has become a major concern worldwide. Baseflow, one of the dominant hydrological pathways for nitrate migration to streamflow, has been confirmed as a leading nitrate source for stream water where groundwater or subsurface flow contaminated heavily by nitrate. That is, sufficient improvements of water quality may not be attained without proper management for baseflow, even if non-point sources(NPS) pollutants discharged through surface runoff are being well managed. This article reviews the primary nitrate sources, the main factors affecting its transport, and the methodologies for baseflow nitrate estimation, to give some recommendations for future works, including:(1) giving sufficient consideration for the effects of climatological, morphological, and geological factors on baseflow recessions to obtain more reliable and accurate baseflow separation;(2) trying to solve calibration and validation problems for baseflow loads determining in storm flow period;(3) developing a simple and convenient algorithm with certain physics that can be used to separate baseflow NPS pollution from the total directly in different regions, for a reliable estimation of baseflow NPS pollution at larger scale(e.g., national scale);(4) improving groundwater quality simulation module of existing NPS pollution models to have a better simulation for biogeochemical processes in shallow aquifers;(5) taking integrated measures of "source control", "process interception" and "end remediation" to prevent and control NPS nitrate pollution effectively, not just only the strict control of nutrients loss from surface runoff. 展开更多
关键词 BASEFLOW Groundwater NITRATE Non-point source pollution Water quality WATERSHED
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Glacier meltwater runoff process analysis using δD and δ^(18)O isotope and chemistry at the remote Laohugou glacier basin in western Qilian Mountains, China
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作者 王彩霞 董志文 +3 位作者 秦翔 张杰 杜文涛 吴锦奎 《Journal of Geographical Sciences》 SCIE CSCD 2016年第6期722-734,共13页
Stable hydrogen and oxygen isotope has important implication on water and mois- ture transportation tracing research. Based on stable hydrogen (6D) and oxygen (6180) isotope using a Picarro Ll102-i and water chemi... Stable hydrogen and oxygen isotope has important implication on water and mois- ture transportation tracing research. Based on stable hydrogen (6D) and oxygen (6180) isotope using a Picarro Ll102-i and water chemistry (e.g. major ions, pH, EC and TDS) meas- urement, this study discussed the temporal variation and characteristics of stable hydrogen and oxygen isotope, chemistry (e.g. TDS, pH, EC, Ca^2^, Mg2+, Na^+ and CI) in various water bodies including glacier meltwater runoff, ice and snow, and precipitation at the Laohugou g^acier basin during June 2012 to September 2013. Results showed that 6D and δ18O in the meltwater runoff varied obviously with the temporal change from June to September, showing firstly increasing trend and then decreasing trend, with the highest values in July with high air temperature and strong glacier melting, which could indicate the temporal change of glacier melting process and extent. Variations of 6D and δ18O in the runoff were similar with that of snow and ice on the glacier, and the values were also above the GMWL, which probably im- plied that the glacier runoff was mainly originated from glacier melting and precipitation supply The glacier meltwater chemical type at the Laohugou glacier basin were mainly composed by Ca-Na-HCO3-SO4 and Ca-Mg-HCO3-SO4, which also varied evidently with the glacier melting process in summer. By analyzing the temporal change of stable hydrogen and oxygen isotope and chemistry in the melting period, we find it is easy to separate the components of the snow and ice, atmospheric precipitation and melt-runoff in the river, which could reflect the change process of glacier melting during the melting period, and thus this work can contribute to the glacier runoff change study of large-scale region by stable isotope and geochemical method in future. 展开更多
关键词 meltwater runoff stable hydrogen and oxygen isotope CHEMISTRY runoff process
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