咸淡水界面位置确定的综合方法(TEcG)及其应用

准确确定咸淡水界面位置是评价咸水入侵范围的前提。对于咸淡水界面位置的确定,传统研究以水化学法和物探法为主。为克服单一使用传统方法造成的人力、物力和财力的大量浪费,以莱州湾西南岸广饶县小清河以南咸水入侵区为研究对象,在综合分析研究区地下水开采现状、水化学监测结果的基础上,选择3个典型断面,采用水化学法中的野外现场电导率法,快速判断咸淡水界面大致位置（某两眼监测井之间）;再在一咸一淡的两眼监测井之间,采用高密度电阻率法快速、准确地确定咸淡水界面的空间分布。结果表明：该地区的地下水电导率若大于1.61 mS/cm,即可认为此处受到咸水入侵;咸淡水界面位置的视电阻率特征值为11~13 Ω·m,咸淡水界面附近咸水体呈舌状入侵并主要发生在地表以下13 m内的浅层地下水中。     

Stable isotopes （S, Cl） and hydrochemical variations in a karstic ground water system, Guiyang, SW China

A groundwater system in a karstic terrain is easily subject to pollution and its remediation is difficult once contaminated by human activities. The groundwater samples collected in both winter and summer seasons at Guiyang, SW China, show a wide range of variations in chemical composition and dominance of Ca^2＋, Mg^2＋, SO4^2-, and HCO3^- ions. The anthropogenic inputs include Cl^-, NO3^-, SO4^2-, Na^＋, and K^＋, as judged from the relationships between different elemental ratios and sewage samples. Cl^- concentrations of all water samples in the study area vary from 0 to 3.9 mmol/L in winter and are higher than in summer. In most of the samples, SO4^2- concentrations are high, ranging from 0.1 to 11 mmol/U The studies show that the cycling of sulfur plays an important role in controlling water chemistry and fate of contaminants in groundwater. In order to understand the source of SO4^2- and the geochemical cycling of some elements in the karstic groundwater environment, we have carried out a study on the variations of S and Cl isotope compositions, in addition to other isotopic tracers such as ^87Sr/^86Sr and δ^13C studied previously. The δ^37Cl values of the groundwater samples present a seasonal variation, ranging from 0.00‰ to ＋2.03‰ in winter and from -1.46‰ to ＋0.29‰ in summer. The surface water samples show a similar range of variations as observed for groundwater. Two rainwater samples collected at Guiyang have a distinct isotopic signature （mean value is -3‰） compared to the δ^37Cl values reported in literature. These results indicate that ground water is mainly derived from precipitation and suggest a fast recharge of the karst system by surface water.     

Discussion on the development of salt chemical industry chain

正China Pingmei Shenma Group is a large enterprise based on energy and chemical,with an annual output of 70million tons of coal,16 million tons of coke,680,000 tons of caustic soda,450,000 tons of PVC resin,50,000 tons of     

利用孔隙水Br/Cl、I/Cl比和氯同位素组成来示踪南海北部东沙海域浅层流体来源

The Dongsha area is one of the most promising target areas for gas hydrate exploration in the South China Sea(SCS).The study of pore water geochemistry has played a key role in Chinese gas hydrate exploration.Br/Cl,I/Cl and δ37Cl in pore water were applied here in tracing gas hydrate occurrence,chemical evolution of pore fluids and water/rock interactions in low temperature sediment environments.The samples were collected from Sites HD255 PC and HD309 PC in the Dongsha area in 2004.At Site HD255 PC,we found the elevated Br/Cl,I/Cl and decreased SO_4/Cl at the depth of 4–5 m,suggestive of a laterally migrated fluid probably generated from the gas hydrate occurrence.The range of δ37Cl is –0.54‰ to +0.96‰,and positive δ~(37)Cl at 4–5 m interval should be related with different diffusion rates between ~(35)Cl and ~(37)Cl.At Site HD309 PC,a laterally migrated fluid was also found at the depth of 3–4 m,with the Br/Cl two times to that of the seawater and decreased I/Cl,indicating the fluid has no relationship with the gas hydrate.In this site,the chlorine isotopic composition varies from –0.7‰ to+1.9‰.Extra high Br/Cl might relate with the deep generated fluid.At higher temperature and pressure,the Br/Cl of the fluid is elevated during the hydrous silicate formation,while positive δ37Cl is also associated with the same mechanism.     

氯化物型钾盐矿床氯同位素地球化学的初步研究

根据国内外许多钾盐矿床大量样品测定的结果,通常石盐（岩）的３７Ｃｌ／３５Ｃｌ比值和δ３７Ｃｌ值高于钾石盐（岩）,而钾石盐（岩）又高于光卤石（岩）,说明这些蒸发岩是在不同水体、不同浓缩阶段形成的,是氯同位素分馏作用长期进行的结果。这些蒸发岩的氯同位素组成与其Ｂｒ、Ｋ、Ｍｇ含量变化有密切关系。今后在我国找钾过程中,应把氯同位素组成及其Ｂｒ、Ｋ、Ｍｇ含量结合起来,作为找钾标志考虑。     

海洋沉积物中孔隙水的氯同位素测量方法研究

采用Ba型、H型和Cs型三步阳离子交换树脂法,对海洋沉积物中孔隙水的氯进行了分离和提纯。氯的回收率达99．6％,能满足氯同位素质谱测定的需要。氯同位素的测量采用基于Cs2Cl^＋离子的高精度正热电离质谱法,对ISL354NaCI标准物质的多次测量结果为”CI／”CI=0．319130±0．000029,对一个南海海底沉积物中孔隙水的多次测量结果为^37CI／^35CI=0．319144±0．000043,表明此方法的稳定性好,测量精度高,可用于海洋沉积物中孔隙水的氯同位素示踪研究     

高精度测定稳定氯同位素的制样方法

以Ｔａｙｌｏｒ和Ｇｒｉｍｓｒｕｄ（１９６９）提出的＾３７Ｃｌ测量的测样原理为基础，介绍了不同地质样品的化学处理方法，研究了ＣＨ３Ｉ的纯化技术，将ＡｇＣｌ转化为ＣＨ３Ｃｌ的过程以及用气相色谱（ＧＣ）法分离ＣＨ３Ｃｌ和ＣＨ３Ｉ的技术。文中详述的制样方法可用来查明近地表地下水和岩石系统中δ＾３７Ｃｌ的天然变化。     

库车盆地中始新统岩盐氯同位素特征及其成钾指示意义

评判盐湖卤水蒸发浓缩阶段对指示成钾具有重要的意义,由于库车盆地始新统含盐系地层岩盐溴氯比值很低,导致这种传统的找钾地球化学指标方法受限.然而,得益于近年来稳定同位素的快速发展,氯同位素组成可以很好地指示含盐系的蒸发阶段.本文以库车盆地DZK01钻孔13个原生石盐岩为研究对象,分析结果显示,δ37Cl值均为负值,介于-1.20‰～-0.51‰之间;KCl含量介于0.13％～0.29％之间.在剖面上从下往上,δ37Cl值有升高的趋势,KCl含量有降低趋势,指示了库车盐盆中始新世古卤水经历了一个逐渐淡化的演化过程.早期卤水蒸发浓缩程度较高,并析出钾盐或含钾矿物;晚期卤水蒸发浓缩程度较低,较少发现甚至未发现钾盐或含钾矿物.此外,库车盐盆中始新统蒸发岩系的成盐物质主要为海相来源,且蒸发浓缩程度较高,具有较好的成钾前景.     

地质样品痕量氯溴和硫的X射线荧光光谱法测定

报道了粉末压样－X射线荧光光谱法测定地质样品中痕量Cl、Br、S的分析方法。采用水系沉积物、岩石和土壤等国家一级标准物质进行校准。实验表明，对于不同岩性样品中Br的分析，特别是当Br的含量低于2μg/g时，采用谱峰强度（未扣除背景）与背景强度的比进行校准所得到的结果，明显优于铑靶线的Compton散射线内标法，分析精度（RSD,n=6)为2.4%-15.3%，大多数优于10％；平均值的相对误差低于24％。对于Cl的分析，只需对Ca的影响加以校正即可得到非常好的结果；不同样品中Cl的分析精度（RSD，n=6)为2.1%-13.6%，大多数优于5％；平均值的相对误差不大于25％，多数优于10％。S的校准曲线的离散性较大，矿物学效应是影响S分析准确度的主要因素，其分析精度（RSD,n=6)为0.87%-5.6%，除个别样品外，平均值的相对误差优于36％。Cl和S均存在分析结果随测量时间（次数）的增加而增高的现象，必须在制样后立即测量。方法的检出限（μg/g)Br、Cl、S分别为0．43、5．8和2．2。