Lateral heterogeneities in the upper and mid-mantle conductivity in Argentina

Regional studies of Sq variations measured at five permanent observatories in Argentina were performed to estimate the distribution of the electrical conductivity of the upper and mid-mantle, reaching a depth of approximately 800 km. After separating the total field into its parts of external and internal origin, the in duced field was modeled, applying two-dimensional techniques. Additionally, induction arrows and an equivalent apparent resistivity curve were calculated A north-south heterogeneity was detected, showing an increase of the conductivity of the shallower layers north of the profile, which may be related to the presence of high volcanic activity in the area.Also at CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas).     

Surface complexation at hydrous fluorapatite

The adsorption of H⁺, OH^– and ARS (Alizarin Red S) onto hydrous fluorapatite surfaces and Ca²⁺—ARS complexation in solution were studied by means of combined potentiometric and spectrophotometric titrations, as well as zeta potential and FT-IR measurements. Corresponding equilibrium constants of surface and solution reactions are determined. The application in flotation processes is discussed.     

Electrostatic Force in Blowing Snow

Separation of electrostatic charge during the transport of particles by wind adds a force to the gravitational and fluid forces that determine trajectories of particles moving by saltation. Evaluating this electrostatic force requires the electric field strength very near the saltation surface, and charge-to-mass ratios for the moving particles. Field mill readings 4 cm above the surface in a moderate blizzard showed electric field strength as high as +30 kV m^-1. Another experiment gave charge-to-mass ratios of individual saltation particles in low-level drifting that ranged between +72 C kg^-1 and -208 C kg^-1. From these measurements, we estimated electrostatic forces as large as the gravitational force on some saltating particles. Including forces of this magnitude in the equations of motion significantly alters predicted saltation trajectories from those for uncharged particles. Predictions appear reasonable that for some saltating particles, the electrostatic force prevents new surface impacts. These results should help improve models of energy transfer in the planetary boundary layer during blizzards and sandstorms.     

电吸附元素异常来源及找矿模式

电吸附元素异常来源于深部矿体,主要是在各种后期地质作用下溶解了矿体中的矿质成分,并扩散迁移至地表,形成能反映矿体的电吸附晕。电吸附找矿方法在金属矿上所捕获到的异常是在矿体中心垂直投影位置以块状异常出现的称“顶部晕”。在大红山铜矿和李坝金矿上异常也反映了这种异常特征。     

Electrification of volcanic plumes

Volcanic lightning, perhaps the most spectacular consequence of the electrification of volcanic plumes, has been implicated in the origin of life on Earth, and may also exist in other planetary atmospheres. Recent years have seen volcanic lightning detection used as part of a portfolio of developing techniques to monitor volcanic eruptions. Remote sensing measurement techniques have been used to monitor volcanic lightning, but surface observations of the atmospheric electric Potential Gradient (PG) and the charge carried on volcanic ash also show that many volcanic plumes, whilst not sufficiently electrified to produce lightning, have detectable electrification exceeding that of their surrounding environment. Electrification has only been observed associated with ash-rich explosive plumes, but there is little evidence that the composition of the ash is critical to its occurrence. Different conceptual theories for charge generation and separation in volcanic plumes have been developed to explain the disparate observations obtained, but the ash fragmentation mechanism appears to be a key parameter. It is unclear which mechanisms or combinations of electrification mechanisms dominate in different circumstances. Electrostatic forces play an important role in modulating the dry fall-out of ash from a volcanic plume. Beyond the local electrification of plumes, the higher stratospheric particle concentrations following a large explosive eruption may affect the global atmospheric electrical circuit. It is possible that this might present another, if minor, way by which large volcanic eruptions affect global climate. The direct hazard of volcanic lightning to communities is generally low compared to other aspects of volcanic activity.     

基于电磁感应仪的表聚型土壤盐渍剖面特征解译研究

针对目前黄河三角洲地区存在的土壤盐渍化问题,以该地区分布最广泛的表聚型盐分剖面类型为研究对象,运用磁感大地电导率仪EM38,建立了磁感式表观电导率和土壤盐分之间的(多元)回归模型,在分析土壤盐分剖面分布特征的基础上提出了指数衰减模型,并运用该模型对盐分剖面进行了参数拟合和验证。结果表明:磁感式表观电导率EMh和EMv呈极显著的线性相关,土壤盐分在垂直方向上的变异主要表现在表层0~25cm的深度范围内。统计分析和Friedman检验结果表明,回归模型和指数衰减模型均具有较好的拟合结果和预测效果,二者的预测精度差异也不显著,表明本文提出的指数衰减模型不仅能降低待估参数的数量、提高土壤盐分剖面磁感式解译的实用性,同时还具有较高的预测精度。该研究结果为利用电磁感应仪快速、精确地进行土壤盐分预测以及盐分剖面解译提供了一定的理论参考和实践依据。     

磁力勘探与岩性测深理论基础的对比

首先概括了岩性测深技术的理论基础和物性基础要点,强调电偶极子场是岩性测深技术的基本理论。然后通过电偶极子场与磁偶极子场的类比,以及岩性测深与磁力勘探的对比,提出了一条研究岩性测深技术理论基础及正演计算的思路。     

积分方程法三维模拟井地电法并行算法研究

在积分方程法模拟三维电磁响应原理的基础上,对井地电法三维正演模拟并行算法做了研究。同时,还利用Fortran 6.5和消息传递接口(MPI)开发了井地电法三维正演模拟并行计算程序。在求解大型线性方程组时,采用的是稳定的双共轭梯度(BICGSTAB)算法,单机正演程序与并行正演程序的计算结果有着很好的一致性,这说明了并行算法的正确性,为进一步开发井地电法三维反演并行程序奠定了基础,也为井地电法三维正、反演程序实用化提供了技术支持。     

反射系数（K）法在激电测深找矿中的应用

反射系数（Ｋ）法是一种电测深ρｓ资料的解释手段和处理方法。从湖南某砂岩铜矿利用激电测深确定红层中的含矿层,某铅锌矿利用激电测深探测两条含矿破碎带的实例,说明反射系数（Ｋ）法在对激电测深ρｓ资料解释的基础上,结合激电异常的特点,能有效地确定不同的地质构造,达到间接找矿的目的。