共查询到20条相似文献，搜索用时 203 毫秒
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中国矽卡岩型金矿床地质研究和勘查的进展与问题 总被引：3，自引：0，他引：3
通过广泛的资料收集、统计和研究，本文全面介绍了我国矽卡岩型金矿床地质勘查与研究的进展和问题。认为，无论是矽卡岩型金矿床的时空分布、成矿构造背景、物理化学条件、地质地球化学特征，还是含矿岩体的地质地球化学特征等，都与碰撞造山成矿模式十分吻合。 相似文献
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孟宪伟 《物探化探计算技术》1994,(1)
稳健克立格及其在１∶５万地球化学异常圈定方面的应用孟宪伟（中国科学院地球化学研究所）在１：５万地球化学测量域内不但有多母体地质体分布，而且还有多期成矿作用的叠加，因而元素的统计分布形式一般都不符合正态或对数正态分布，那么用稳健统计方法估计位置和尺度是... 相似文献
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根据已有的地质和科研工作成果，探讨了大黑山金矿床地质地球化学特征、元素地球化学异常特征及某些特征及某些地球化学指标的变化规律，归纳出了该矿床的地球化学异常模式和地球化学找矿预测标志。 相似文献
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地球物理数据能够对３－Ｄ构造解释起到重要的约束作用,因为任何解释必须给磁性单元指定适中的位置、深度和几何形状以便与实测的地球物理资料相匹配。虽然得到的模型可能是非唯一性的,但它提供了一种方法。根据这种方法可以研究概念模型并且确定概念模型是否符合于地球物理和地质资料,２－Ｄ和３－Ｄ地球物理方法来确定艾萨谷的构造和构造历史。利用Ｃ．Ａ．Ｄ．程序模块建立了澳大利亚萨谷地区的３－Ｄ构造模型。 相似文献
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青海大坂山地区水系沉积物测量元素组合分区 总被引：3，自引：0，他引：3
采用R型因子分析方法,对大坂山地区水系沉积物地球化学测量所取得的数据进行了统计处理,提取了具有代表性的6种因子组合类型,并利用各因子组合得分值进行了地球化学分区,制作了元素组合分区图,由此将工作区内全部水系沉积物样品所反映的地球化学统计信息以区块的形式反映在一幅图中,通过对该图的判读分析,不仅反映了不同地段中以相应元素组合类型为主的地球化学异常和其地质成因信息,也揭示出相应元素的背景含量特征,为从整体上认识该区地质、地球化学成矿特征提供了简明、清晰的参考资料. 相似文献
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In this paper, 3D steady‐state fluid flow in a porous medium with a large number of intersecting fractures is derived numerically by using collocation method. Fluid flow in the matrix and fractures is described by Darcy's law and Poiseuille's law, respectively. The recent theoretical development presented a general potential solution to model the steady‐state flow in fractured porous media under a far‐field condition. This solution is a hypersingular integral equation with pressure field in the fracture surfaces as the main unknown. The numerical procedure can resolve the problem for any form of fractures and also takes into account the interactions and the intersection between fractures. Once the pressure field and then the flux field in fractures have been determined, the pressure field in the porous matrix is computed completely. The basic problem of a single fracture is investigated, and a semi‐analytical solution is presented. Using the solution obtained for a single fracture, Mori‐Tanaka and self‐consistent schemes are employed for upscaling the effective permeability of 3D fractured porous media. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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A new method for estimating the physical parameters of active galactic nuclei involving the analysis of observations of the compact radio sources in them is proposed. The method is based on an inhomogeneous model for a synchrotron radio source. Theoretical spectra of the radio sources are obtained via numerical solution of the transfer equation. Due to the paucity of observational data, only interval estimates of the magnetic field strength and the energy densities of the magnetic field and relativistic particles can be obtained. A mechanism for the formation of flat radio spectra is proposed. 相似文献
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介绍一种寻找隐伏岩体的好方法:岩浆热场法 总被引：1，自引：1，他引：0
隐伏岩体对于热液矿床找矿是非常重要的。寻找隐伏岩体的方法很多,其中以物探(磁法、电法、重力、地震等)方法应用得最广泛、效果最好。本文介绍的岩浆热场法,是专门寻找隐伏岩体的方法。岩浆热场法是地球物理方法的一种,它以感知温度场的差别为目的,没有多解性是它最大的优点。它以岩浆热场理论为基础,以各种能够恢复古温度场的方法为手段。能够感知岩浆热场温度的方法很多,本文介绍了其中的五种:接触变质带法、煤质和煤级法、伊利石结晶度法、牙形石色变度法和镜质体反射率法等。接触变质带是岩浆热场直接的具体的体现,传统的接触变质带范围有限(一般不超过1km)。但是,如果考虑到极低级变质作用,将大大扩展接触变质带的范围(达6~8km)。煤质和煤级是煤田地质部门应用得非常娴熟的方法,中国无烟煤分布区大多与岩浆热场有关,是隐伏岩体的良好指示剂。伊利石结晶度、牙形石色变度和镜质体反射率法是极低级变质作用研究中非常重要的三个指标。在上述各种方法中,笔者推荐镜质体反射率方法。该方法具有简单、精确、适用、经济、快速的特点。与物探方法比较,该方法有很多优点,但也有其局限性。如果能够将该方法从煤田和石油部门移植到岩石学和矿床学部门,与磁法、电法、重力法配合使用,可以提高寻找隐伏岩体的效果。 相似文献
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目前井中磁测解释大都采用水平矢量图指向确定矿体的方法,但由于磁场水平分量的定向问题,致使仅使用水平分量矢量对磁性体解释常会出现错误结果。通过描述水平产状与倾斜产状磁性体的磁场特征,对磁性体表面不同位置磁异常垂直分量及水平分量差异进行了说明,通过三个实例对反映在磁性体上、下位置的垂直分量与水平分量磁异常的空间分布特征进行了具体描述,并利用井中磁测曲线有效地解决了井底及井旁磁性体的赋存情况。多年来的工作实践证明,使用磁异常场垂直分量及水平分量特征,能准确的判定磁性矿体的主体方向及产状,该解释方法的推广有利于寻找深部磁性矿体。 相似文献
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The single prism approximation SPA of the cluster variation method has been used to model the antiferromagnetic-paramagnetic transition in hematite. This calculation yields insight into the accuracy of the SPA and other approximate methods for modeling order-disorder phenomena. Published values of the magnetic coupling constants were used to calculate the Néel temperature, sublattice magnetization, and magnetic specific heat. The calculated Néel temperature is found to be 1.21 times the observed value, as compared to 1.36 times observed for a mean field theory approximation, an improvement that reflects the superior treatment of configurational entropy in the SPA. Qualitative to semiquantitative agreement is obtained between observed and calculated values for sublattice magnetization and magnetic specific heat; however we find that previously published values for the magnetic specific heat are too large by a factor of two. 相似文献
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Tilt-depth方法是一种可以快速反演磁源上顶深度的新兴方法。二维、三维模型试验表明,tiltdepth法反演误差与地质体的上顶埋深、厚度及水平尺度均有关,同时叠加异常也会对反演结果产生影响。实例中,将tilt-depth法应用于广东省下庄矿田航磁数据反演中,tilt梯度图上展示出了两条明显的近东西走向条带异常,推断为浅部基性辉绿岩脉在深部汇聚形成,并反演了两条高磁异常带上11个位置的磁源上顶埋深。反演结果揭示了下庄矿区内北侧高磁性体深度较浅,且具有南浅北深的构造特征,而南侧高磁性体规模较大,且埋深较厚,为该区深部矿产勘查提供了有利依据。 相似文献
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Mohamed Sharif Berguig Mohamed Hamoudi Jean Louis Lemouël Yves Cohen 《Arabian Journal of Geosciences》2013,6(4):1063-1072
In this work, we report a global mapping of vector lunar magnetic field based on new method of separation of internal and external fields. The magnetic measurements collected during the lifetime of lunar prospector (LP) extended mission during 1999 were strongly disturbed by the solar wind, a period which coincided with a maximum of the 23 cycle activity. The multiscale wavelength external fields were analyzed using spherical harmonic transform. The external field determined by inversion was then removed from each magnetic field component for each half orbit. To map the vector magnetic crustal anomalies, all LP magnetometer data collected at low altitudes in the three different lunar environments: (1) geomagnetic tail, (2) solar wind, and (3) geomagnetic sheath were processed using this new approach. The results obtained using these selection criteria allow us to get a global coverage of the lunar surface by the vector magnetic field at variable spacecraft low altitudes. To validate our mapping, we have developed and applied a method based on properties of potential fields functions. This method can be used to determine both horizontal north and east components using only vertical component. The validated lunar internal magnetic measurements obtained at variable spacecraft altitudes were then continued to a common altitude of 30 km using an inverse method. This mapping confirms firstly the nature of the crustal sources of lunar magnetic field and clearly shows that the strongest concentrations of anomalies are associated with high albedo and/or located antipodal to large young basins (Orientale, Serenitatis, Imbrium, and Crisium) of age about 3.9 Ga. 相似文献
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A Green’s function solution of Laplace’s equation for the potential magnetic field in an external spherical region is found using the derivative of the potential along a selected direction as a boundary condition. A set of programs applying this solution to construct the potential magnetic-field lines in solar active regions based on the photospheric line-of-sight field component has been developed. The method is tested using some model fields, and the optimal step size is found for realistic conditions. The developed software is applied to four real solar active regions, adopting HMI/SDO magnetograms as the boundary conditions. The potential magnetic field in the chromosphere and corona have been reconstructed for the selected regions. The calculated field lines are compared with flux tubes observed by AIA/SDO in the EUV. This comparison is used as a basis to discuss the applicability of a potential field approximation to the magnetic fields in solar active regions. 相似文献