Origin of fluids in iron oxide–copper–gold deposits: constraints from δ 37Cl, 87Sr/86Sri and Cl/Br

The origin of the hypersaline fluids (magmatic or basinal brine?), associated with iron oxide (Cu–U–Au–REE) deposits, is controversial. We report the first chlorine and strontium isotope data combined with Cl/Br ratios of fluid inclusions from selected iron oxide–copper–gold (IOCG) deposits (Candelaria, Raúl–Condestable, Sossego), a deposit considered to represent a magmatic end member of the IOCG class of deposit (Gameleira), and a magnetite–apatite deposit (El Romeral) from South America. Our data indicate mixing of a high δ ³⁷Cl magmatic fluid with near 0‰ δ ³⁷Cl basinal brines in the Candelaria, Raúl–Condestable, and Sossego IOCG deposits and leaching of a few weight percent of evaporites by magmatic-hydrothermal (?) fluids at Gameleira and El Romeral. The Sr isotopic composition of the inclusion fluids of Candelaria, Raúl–Condestable, and El Romeral confirms the presence of a non-magmatic fluid component in these deposits. The heavy chlorine isotope signatures of fluids from the IOCG deposits (Candelaria, Raúl–Condestable, Sossego), reflecting the magmatic-hydrothermal component of these fluids, contrast with the near 0‰ δ ³⁷Cl values of porphyry copper fluids known from the literature. The heavy chlorine isotope compositions of fluids of the investigated IOCG deposits may indicate a prevailing mantle Cl component in contrast to porphyry copper fluids, an argument also supported by Os isotopes, or could result from differential Cl isotope fractionation processes (e.g. phase separation) in fluids of IOCG and porphyry Cu deposits.     

稳定氯同位素在地球科学研究中的进展

本世纪初到八十年代中期由于氯同位素的测试精度很低（＞１．０‰）导致氯同位素地球科学研究未获得任何进展。１９８４年Ｋａｕｆｍａｎｎ等人建立测试精度高达±０．２４‰的方法，并且首次发现了氯同位素在自然界的变异。在此以后氯同位素的测试精度不断提高，各国学者相继对海水、温泉、火山湖水、油田卤水、地下水盐湖、冰雪、环太平洋的斑岩铜矿和美国密西西比型铅锌矿床造岩矿物和造矿矿物流质包裹体中氯同位素进行了测定并对其中氯同位素的分布规律做了比较深入的研究。在此基础上对各类水体及矿床的成因与物质来源进行了有益的探索，另外还以自然界氯同位素产生分馏的原因及机理做了初步的研究。     

Hydrogen incorporation in enstatite in the system MgO–SiO2–H2O–NaCl

The incorporation of hydrogen in enstatite in a hydrous system containing various amounts of NaCl was investigated at 25 kbar. The hydrogen content in enstatite shows a clear negative correlation to the NaCl-concentration in the system. The most favourable explanation is the reduction of water fugacity due to dilution. Other reasons for the limited hydrogen incorporation at high NaCl levels, such as a significant influence of Na⁺ on the defect chemistry or an exchange between OH^- and Cl⁻in enstatite, appear much less important. A partition coefficient D _Na ^En/Fluid = 0.0013 could be determined, demonstrating that Na is less incompatible in enstatite than H. The new results support the idea that dissolved components have to be considered when the total hydrogen storage capacity in nominally anhydrous minerals is estimated, especially in geological settings with high levels of halogens, such as subduction zones.     

氯化物型钾盐矿床氯同位素地球化学研究

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）；钾石盐高于光卤石（岩）。例如：西班牙Catalonia盆地钾盐矿床，其石盐岩为0．31958—0．31941和＋1．002─＋0．470‰，钾石盐岩为0．31913和─0．407‰，光卤石岩为0．31887和─1．221‰，等等。这说明了这些蒸发岩是在水体浓缩的不同阶段形成的，是氯同位素分馏作用长期不断进行的结果。其氯同位素组成与Br、K和Mg含量有着密切关系。困而在我国找钾过程中，可将氯同位素组成及Br、K、Mg含量结合起来作为找钾标志考虑。     

海洋的稳定氯同位素组成

用Cs2Cl+正热电高质谱法,测定了海洋中不同区域表层海水样品的稳定氯同位素组成。结果表明海洋中的δ37Cl值并非均匀一致,尤其在高经度地区变化明显。δ37Cl值的变化与海水的盐度和所处的经度有一定机关性。建议使用一个统一确定的海水样品做为稳定氯同位素地球化学研究的氯同位素标准参考物质。     

Chloride and Organic Chlorine in Soil

Chloride is ubiquitous in soil, but the past years of research have revealed that organic matter also contains chlorine, in amounts similar to that of phosphorus. Hence, one of the major constituents of soil organic matter has previously been overlooked, and still very little is known about the turnover of organic chlorine in soil. In spite of the obvious connection between chloride and organic chlorine, organic chlorine rarely is considered when the biogeochemical cycling of chloride is in focus, and chloride rarely is taken into account when the occurrence and formation of natural organic chlorine compounds are in focus. The aim of the paper is to review ten years of research concerning the biogeochemical cycling of organic chlorine in soil, and to tie the biogeochemical cycling of organic chlorine to that of chloride.     

Effect of Preozonation on the Formation of Chlorinated Disinfection By‐products for River Ruhr

The purpose of the study is to gain a better understanding about the formation of THM (trihalomethanes), HAA (haloacetic acids), and AOX (adsorbable organic halogen) in river water (river Ruhr, Essen) through a chlorination kinetics approach. The effect of chlorination time and preozonation on the formation of THM, HAA, and AOX substances was studied. Preozonation can reduce the chlorine demand and the precursors for AOX and THM. THM generation was reduced further, when the ozone dosage consumed increased from 3.5 to 12.5 mg in the 1.4 L reaction vessel. AOX and TCAA (trichloroacetic acid) concentrations also decreased dramatically when 3.5 mg of ozone had reacted with the river water, but a higher dose of ozone did not further reduce AOX and TCAA formations. Besides, the characteristics of organic matter in raw water, ozonated water, and preozonated/chlorinated water was investigated. The results suggest the formation of low‐molecular‐weight acids with low UV absorbance when high‐molecular refractive matter is oxidized.     

NaClO法漂白江蓠时不同工艺对氯气浓度及漂白效果的影响

为解决NaClO法漂白江蓠时漂白空间氯气浓度过高导致环境的污染。对NaClO法漂白江蓠时影响漂白空间氯气浓度的几种主要因素进行了研究。通过改进生产工艺 ,对酸化后的江蓠进行水洗后再漂白 ,同时增加草酸作后处理 ,在保证江蓠漂白效果的前提下 ,使漂白空间氯气浓度从最高值 80 5 4mg m3 降低到约 0 0 5 0mg m3 ,车间及环境的氯气浓度远低于国家安全标准 ,解决了江蓠漂白中氯气污染的问题 ,达到了清洁生产的效果。     

盐湖硼氯同位素地球化学研究进展

对与盐湖硼、氯同位素地球化学研究有关的样品中硼、氯的提取、分离纯化 ,硼、氯同位素质谱测定方法以及盐湖卤水、粘土沉积物和蒸发硼酸盐矿物的硼同位素地球化学和盐湖卤水与盐类矿物的氯同位素地球化学研究进展进行了系统总结。所总结的内容代表了世界范围内此领域研究的最新进展 ,其中很大部分内容是中国科学院青海盐湖研究所 VG35 4课题组的研究成果 ,反映了中国科学院青海盐湖研究所在此研究领域的水平。     

焦作市某碱渣堆放场对岩溶水氯离子污染的初步研究

结合某碱渣堆放场的水文地质状况,通过对碱渣的静溶和淋溶试验,分析了淋滤液中氯离子的析出过程,探讨了碱渣堆放场对岩溶地下水中氯离子污染的影响。通过实验数据的分析,认为该渣场对焦作市岩溶地下水氯离子浓度的升高具有很大的影响。在此基础上应用数学拟合方法,进行了碱渣淋滤总量的估算,认为碱渣场在其建成的13年以来,共向焦作市岩溶水排放的氯离子总量高达35k t之多。