新型时域谱微机激电仪的研制开发

摘 要　 以测量激发极化二次场时域谱为基础‚研制开发出以单片微型计算机为中央处理单 元 （CPU） 的新型激电仪。实现了双系列激电参数提取、二次场波谱测量及全汉化菜单操作。     

综合物化探方法在吉林某中型钼矿勘查中的应用

文章介绍了吉林某中型钼矿勘查中采用地质、化探、激电法、EH-4电磁测深等综合方法,取得了极佳的地质找矿效果。建立了物化探"一高一中三低"(即钼多金属元素含量高、中极化率、低电阻率、低磁、低密度)的综合找矿模型,结合地质因素,对在该地区找寻石英网脉型的钼多金属矿体(矿化体),具有明显的指导作用。     

Adsorption experiment of water-soluble rare earth elements in atmospheric depositions and implications for source tracing in South China

Acta Geochimica - The distribution patterns of rare earth elements (REEs) in fine-grained materials in various depositions were often found to be similar to those of the aeolian sediments deposited...     

Effect of fluid saturation and salinity on sandstone rock weakening: experimental investigations and interpretations from physicochemical perspective

Acta Geotechnica - Fluid saturation plays an important role in rock weakening. However, few researches reveal the controlling factor(s) behind the rock weakening particularly from geochemical...     

Dissolution rates of metals in Fe oxides: implications for sampling ferruginous materials with significant relict Fe oxides

A study of the pattern of dissolution of synthetic and natural Fe oxides in 6 M HCl indicates that the rate of element release from synthetic Fe oxides is strongly influenced by mineralogy and the level of element incorporation. Synthetic maghemite (γ-Fe₂O₃) samples are subject to much more rapid dissolution than goethite (FeOOH) and hematite (α-Fe₂O₃). In samples dominated by hematite and maghemite, Cu, Zn and particularly Pb, in comparison to Fe, are preferentially released during the early stages of dissolution. Similar patterns are apparent from the dissolution of hematite- and maghemite-dominated samples derived from natural gossan. Comparison of XRD scans with data from the dissolution of natural gossan samples transformed by incremental heating to hematite- and maghemite-dominated assemblages suggests that the degree of crystallinity may also be a significant factor in the release of elements incorporated in the Fe oxides. Ferruginous materials made up of varying proportions of goethite, hematite, maghemite, kaolinite and quartz are important sampling materials in a range of regolith environments. These are products of complex chemical and mechanical mobilization over long periods of geological time. If the patterns of Fe oxide dissolution in 6 M HCl and the release of incorporated metals reflect stability in such weathering regimes, knowledge of the retention characteristics of incorporated metals in different Fe oxide phases, as indicated by this study, will be useful in the planning and interpretation of geochemical surveys in such regions.     

加拿大纽芬兰岛重要金属矿地质特征及找矿方向

纽芬兰岛铜、镍、铀和稀有稀土矿化发育,成矿潜力巨大。铜矿化类型有火山岩型和与长英质侵入岩有关类型两种,主要找矿方向为火山岩分布区,如Buchans-Rouberts Arm、Humber、Avalon、Grey River区域。镍矿化类型有辉长岩型、镁铁质片麻岩型和火山热液型,主要找矿方向为古生代辉长-闪长质侵入岩和前寒武纪镁铁质片麻岩分布区,如Powderhorn Lake、Layden和岛中北部蚀变安山岩与滑石-碳酸盐岩接触带。铀矿化类型有火山岩型、变质沉积岩型和花岗岩型,主要找矿方向为过碱性火成岩分布区,如Rocky Brook、North Brook、Wigwam Brook、Grand Codroy No.4和Bay du Nord群地层分布区。稀有稀土矿化与变质沉积岩在高级变质过程中部分熔融而成的过碱性花岗岩有关,而含绿柱石花岗伟晶岩则与过碱性岩浆岩系列关系密切,主要找矿方向为Fortune Bay、Clode Sound、Trinity Bay和Lost Pond区域。     

2003年冬季空气质量趋势预测方法

使用短期气候趋势预报原理与短期空气质量预报相结合的方法，根据1～7月的气候特征（背景）、天气形势以及各种相关气象要素统计分析，对冬季采暖期空气质量进行综合预报。利用上述方法对2003年度（2003．11～2004．3）冬季采暖期空气质量进行了试预测。即：在2003年冬季气候预测的基础上，通过统计分析2003冬季相似年份的天气形势、污染气象条件，确定污染潜势和气象参数。并运用现业务使用的污染物浓度预报方程，计算冬季各月的逐日空气污染物（SO2、NO2、PM10）的浓度。最后综合2003年冬季气候特征预测和日空气质量计算结果，做出冬季空气污染趋势预报。     

Mineral isotope evidence for the contemporaneous process of Mesozoic granite emplacement and gneiss metamorphism in the Dabie orogen

Kinetics of isotopic equilibrium in the mineral radiometric systems of igneous and metamorphic rocks is an important issue in geochronology. It turns out that temperature is the most important factor in dictating isotopic equilibrium or disequilibrium with respect to diffusion mechanism. Contemporaneous occurrence of Mesozoic granites and gneisses in the Dabie orogen of China allows us to evaluate the thermal effect of magma emplacement and associated metamorphism on mineral radiometric systems. Zircon U-Pb, mineral Rb-Sr and O isotope analyses were carried out for a Cretaceous granite and its host gneiss (foliated granite) from North Dabie. Zircon U-Pb dating gave consistently concordant ages of 127 ± 3 Ma and 128 ± 2 Ma for the granite and the gneiss, respectively. A direct correspondence in equilibrium state is observed between the O and Rb-Sr isotope systems of both granitic and gneissic minerals. Mineral O isotope temperatures correlate with O diffusion closure temperatures under conditions of slow cooling, indicating attainment and preservation of O isotope equilibrium in these minerals. The mineral Rb-Sr isochron of granite, constructed by biotite, feldspar, apatite and whole-rock with the O isotope equilibrium, yields a meaningful age of 118 ± 3 Ma, which is in accordance with the mineral Rb-Sr isochron age of 122 ± 1 Ma for the host gneiss. The consistency in both U-Pb and Rb-Sr ages between the granite and the gneiss suggests a contemporaneous process of crystallizing the zircons and resetting the Rb-Sr radiometric systems during magma emplacement and granite foliation. Whereas the zircon U-Pb ages for both granite and gneiss are interpreted as the timing of magma crystallization, the young Rb-Sr isochron ages record the timing of Sr diffusion closure during the slow cooling. Protolith of the gneiss crystallized shortly before intrusion of the granite, so that it was able to be foliated by voluminous emplacement of coeval mafic to felsic magmas derived by anatexis of orogenic lithospheric keel. Therefore, extensional collapse of collision-thickened crust at Early Cretaceous is suggested to trigger the post-collisional magmatism, which in turn serves as an essential driving force for the contemporaneous high-T deformation/metamorphism.     

Experimental study on the effect of soil saturation on the electric permeability coefficient during electroosmosis process

Abstract

The electrokinetic treatments on high natural moisture content, large compressibility, and low strength dredged marine soil are regarded as an innovative method, but it has not been widely applied due to the difference between theory predictions and realities. To minimize the difference which is resulted from the electric permeability coefficient variations due to pore water drainage and the degree of saturation drops during the electrokinetic treatment of soils, several one-dimensional indoor experiments were conducted with single kaolin clay and natural soft clay. The test results indicate that the electric permeability values conform to the predicted value of Helmholtz–Smoluchowski (H-S) theory under saturated conditions. The permeability for unsaturated soils can be described with relative electric permeability, that is, k_e,rel=a(Sr)^b. The ranges of fitting parameters are 0.8–1.2 for a and 3–9 for b. The fitting parameters are dependent on the soil type, electric potential gradient, and pore size distribution and so on. The smaller the soil pore size is the more sensitive the permeability coefficient is to the degree of saturation.     

In-flight performance analysis of the navigation augmentation payload on LEO communication satellite:a preliminary study on WT01 mission

With the development of the Low Earth Orbit (LEO) communication constellations, it has become a hot area of research to provide additional navigation augmentati...