重液材料多钨酸钠在青海湖沉积物重力分离中的应用   总被引：1，自引：0，他引：1  

李善营  于炳松  Hailiang DONG  刘英超 《矿物岩石地球化学通报》2008,27(1):69-71

多钨酸钠是一种无毒、易配制、可循环使用、密度高的新型无机重液.本文利用多钨酸钠重液,用离心机重力分离的方法将青海湖沉积物分成低(≤1.9g/cm3)、中(1.2-2.8g/cm3)、高(≥2.8g/cm3)三个密度组分,平均回收率为96.5%.重力分离后的沉积物测试分析发现,有机质主要分布在富粘土矿物的中密度组,揭示了粘土矿物的表面吸附是青海湖底沉积物有机质的主要赋存形式.  相似文献   

内蒙古敖包吐萤石矿床地质和地球化学特征   总被引：2，自引：0，他引：2  

许东青  聂凤军  江思宏  张万益  云飞  杨才  张天俊  吕旭光  林日亮 《地球学报》2008,29(4):440-450

笔者总结了敖包吐萤石矿床的地质特征,并通过萤石的稀土元素的地球化学和Nd同位素研究,探讨了该矿床的成矿作用和成矿物质来源。敖包吐萤石矿床产出于下二叠统大石寨组火山—沉积岩与燕山中期花岗岩的接触带,为单一萤石矿床。萤石矿石的稀土元素的含量(∑REE)变化范围为(8.04～30.04)×10-6,平均为19.42×10-6;轻重稀土LREE/HREE值0.24～0.65,平均0.52;LaN/YbN为0.07～0.62,平均0.26;δEu为0.42～0.90,平均0.60,具Eu负异常和明显重稀土富集的特征。岩矿石的Nd同位素研究表明,萤石矿石的εNd(t)都表现为很大的负值,以成矿主期年龄138Ma计算的εNd(138Ma)为-7.30～-30.55,具有古陆壳的演化特征,暗示其成矿的物质来源主要是壳源物质。在Moller的Tb/La-Tb/Ca成因判别图解中,敖包吐矿床的萤石的结晶作用表现为重新活化的趋势,反映流体具有混源的特征,既有热液成因,又有沉积成因。二叠世的海相火山活动通过海底喷气和喷流的作用形成了初始矿源层,而燕山中期花岗岩浆的侵位与结晶分异,又对初始矿源层的活化和富集提供了流体和热能的来源。成矿流体在经历了长期的演化后在大石寨组的构造薄弱破碎的的部位沉淀析出,形成敖包吐萤石矿床。  相似文献   

A spectrophotometric measurement of soil cation exchange capacity based on cobaltihexamine chloride absorbance     

Delphine Aran  Armand Maul  Jean-Franois Masfaraud 《Comptes Rendus Geoscience》2008,340(12):865-871

Among numerous methods for cation exchange capacity (CEC) determination for soils and sediments, the cobaltihexamine chloride method is frequently used due to its ability to measure CEC at soil pH. After exchange with Co(NH₃)₆³⁺ ions, CEC is estimated via the measurement of the Co remaining in solution. The modified method proposed allows a more rapid determination of CEC based on the measurement of the absorbance at 472 nm of the cobaltihexamine chloride solution before and after exchange. This method has been applied to various soil's horizons from four sites, selected to cover a wide range of CEC and pH values. The model obtained allows one to calculate CEC from absorbance at 472 nm with 95% confidence intervals. As CEC is of relevant meaning in agronomical and environmental purposes, and more recently in ecotoxicological studies, this modified method can be proposed as a rapid test for CEC evaluation.  相似文献   

太原盆地农田区大气降尘对土壤重金属元素 累积的影响及其来源探讨   总被引：1，自引：0，他引：1  

赖木收  杨忠芳  王洪翠  周继华  王建武 《地质通报》2008,27(2):240-245

通过研究太原盆地大气干湿沉降中重金属元素的含量分布特征及年输入通量,讨论其对土壤中重金属元素累积的影响。同时采用富集因子法探讨降尘物质的来源。研究结果表明,降尘中重金属元素As、Cd主要来源于人为活动,Pb的来源可能是人为源和自然源。而Hg则主要来源于自然源。  相似文献   

滇西沘江流域水体中重金属元素的地球化学特征   总被引：6，自引：1，他引：5  

李瑞萍  王安建  曹殿华  王高尚  李以科  耿诺 《地质通报》2008,27(7):1071-1078

通过测定流经兰坪金顸铅锌矿区的沘江水体中Pb、Zn、Cd、As的含量和底泥中重金属元素的化学形态的含量,分析了重金属元素的分布和化学形态的变化。结果表明,沘江水遭到了Cd污染,底泥已经成为重金属元素的蓄积库,以国家土壤环境质量标准（Ⅲ级）衡量,Pb、Zn、Cd和舡分别超标3．4倍、15．8倍、106倍和2．6倍。沘江水中重金属元素含量的峰值在矿山附近的下游,而底泥中重金属元素的峰值在矿山下游30-50km的地方,矿业活动、水流变缓、pH等水体环境条件的变化都能影响水和底泥中重金属元素的含量。底泥中的Pb以碳酸盐结合态为主,Zn和Cd以铁锰氧化物结合态为主,而As以残渣态为主。Pb、Cd、Zn三种元素的环境有效态含量比较高,对沘江流域生态环境具有潜在的巨大的危害。  相似文献   

Spatial distribution features and environment effect of heavy metal in intertidal surface sediments of Guanhe estuary, Northern Jiangsu Province     

Jiaxiang Huang  Yong Yin  Jun Xu  Xiaobing Zhu 《Frontiers of Earth Science》2008,2(2):147-156

In northern Jiangsu coastal zone area, Guanhe River is the biggest river and has the best navigation conditions among rivers which flow into the Yellow Sea. The grain sizes show gradual increase from the high intertidal zone to lower intertidal zone. The heavy metal values have slight changes along both sides of the river mouth, but show an evident change perpendicular to the tidal flat. In the latter case, they show a good correlation with grain size fluctuation, that is, the heavy metal values gradually decline when the grain size increases from the high intertidal zone to the lower intra-tidal zone. Analyses of the heavy metal elements show that on the Guanhe estuary surface sediment, the content of the elements Hg, As and Cu is above background values; Pb and Zn contents are rather close to the background values; and Cd content is less than the background values. The element Hg comes out to be harmful in a medium level to ecological environment, while the elements of Cr, As, Cu, Pb, Zn and Cd fall in a safe range of MPL. On the whole, Guanhe estuary tidal flat is not very harmful to the ecology in terms of the heavy metals. __________ Translated from Marine Geology & Quaternary Geology, 2007, 27(5): 23–32 [译自: 海洋地质与第四纪地质]  相似文献   

The discovery of metal trace elements in natural gas and its ecologic environmental significance.     

WANG Che-Xi DENG Mei-Zhou LIU Ying-Han LIU E-Wei LI Nie-Yun LU Ren-Ji 《地学前缘》2008,15(6):124

  相似文献   

Trace metals in suspended particulate matter and in sediment trap material from a permanently anoxic fjord — Framvaren, South Norway     

Jens M. Skei  Douglas H. Loring  Reijo T. T. Rantala 《Aquatic Geochemistry》1996,2(2):131-147

Geochemical studies of the trace metal concentrations in suspended particulate matter (SPM) and sediment trap material from a permanently anoxic fjord, Framvaren, South Norway in 1989 and 1993 indicate that extremely high concentrations of zinc (max = 183920 mg/kg), copper (max = 4130 mg/kg), lead (max = 2752 mg/kg), and cadmium (max= 8.1 mg/kg) sometimes (1993) occur in the SPM collected in the anoxic water layer. The highest concentrations of Zn occur just below the redoxcline at 22 m water depth (in 1993), and copper, lead and cadmium have maximum concentrations between 30 and 80 m depth, where the amount of total SPM is at a minimum (about 0.3 mg/L). On a mass per volume (g/L) basis, the maximum concentrations of Cd, Cu and Fe occur at the interface (21m) and those of Zn occur just below the redoxcline (22 m depth). The SPM and sediment trap data suggest that the metals are precipitated as sulfide minerals in the anoxic water. The presence of particulate sulfides was confirmed by SEM studies that show the occurrence of discrete metal (Cu, Fe, Pb, and Zn) sulfide particles in size from 10–20 m as well as framboidal pyrites (1–5 m in size). Higher levels of metal sulfides at intermediate depths rather than in the deep water of Framvaren (> 100 m), may be due to input of trace metals by water exchange over the sill in the upper part of the water column. In the deep water, less metal sulfide precipitation takes place due to depletion of trace metals, and the dilution of particulate metal concentrations by organic matter and by the chemogenic formation of calcite.  相似文献   

Modelling of the vertical fluxes of nitric acid,ammonia, and ammonium nitrate     

Gerhard Kramm  Ralph Dlugi 《Journal of Atmospheric Chemistry》1994,18(4):319-357

Results from numerical investigations regarding the exchange of HNO₃, NH₃, and NH₄NO₃ between the atmosphere and the biosphere are presented. The investigations were performed with a modified inferential method which is based on the generally accepted micrometeorological ideas of the transfer of momentum, sensible heat and matter near the Earth's surface and the chemical reactions among these nitrogen compounds. This modified inferential method calculates the micrometeorological quantities (such as the friction velocity and the fluxes of sensible and latent heat), the height-invariant fluxes of the composed chemically conservative trace species with group concentrationsc ₁=[HNO₃]+[NH₄NO₃] (total nitrate),c ₂=[NH₃]+[NH₄NO₃] (total ammonia), andc ₃=[HNO₃]-[NH₃] as well as the fluxes of the individual nitrogen compounds. The parameterization of the fluxes is based on the flux-gradient relationships in the turbulent region of the atmospheric surface layer. The modified inferential method requires only the data of wind velocity, temperature, humidity and concentrations (HNO₃, NH₃, and NH₄NO₃) measured at a reference height by stations of a monitoring network.  相似文献   

Heavy metals in stream sediments from copper and gold mining areas in southern Brazil     

Maria Heloisa D. Pestana  Milton L.L. Formoso  Elba C. Teixeir 《Journal of Geochemical Exploration》1997,58(2-3)

  相似文献