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2008 Vol. 19, No. 4

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Special Issue of Mathematical Geosciences for the 33rd IGC
Cheng Qiuming* (成秋明)
2008, 10(4)
Abstract:
The papers published in this issue are selected from manuscripts submitted by invited authors and most of these papers will be presented at the 33rd International Geological Congress (33rd IGC) in Oslo, August 2008. It receives 25 manuscripts and 16 were accepted after going through the journal normal peer reviewing process. The topics of the papers cover various aspects of “metallogenic complex processes and mineral resource quantitative assessment”, one of the strategic research areas of the State Key Laboratory of Geological Processes and Mineral Resources (GPMR) sponsored by the Ministry of Science and Technology and the Ministry of Education of China. Researches in the area are also supported by the National Natural Science Foundation and Ministry of Land and Resources of China as well as by mining companies.Thanks are due to these funding programs and organizations for supporting the research activities of GPMR. Sincere thanks are due to those who have reviewed ....
Quantitative Prediction for Deep Mineral Exploration
赵鹏大, 成秋明, 夏庆霖
2008, 10(4)
Abstract:
On reviewing the characteristics of deep mineral exploration, this article elaborates on the necessity of employing quantitative prediction to reduce uncertainty. This is caused by complexity of mineral deposit formational environments and mineralization systems as increase of exploration depth and incompleteness of geo-information from limited direct observation. The authors wish to share the idea of “seeking difference” principle in addition to the “similar analogy” principle in deep mineral exploration, especially the focus is on the new ores in depth either in an area with discovered shallow mineral deposits or in new areas where there are no sufficient mineral deposit models to be compared.An on-going research project, involving Sn and Cu mineral deposit quantitative prediction in the Gejiu (个旧) area of Yunnan (云南) Province, China,was briefly introduced to demonstrate how the “three-component” (geoanomaly-mineralization diversity-mineral deposit spectrum) theory and ....
Random Difference of the Trace Element Distribution in Skarn and Marbles from Shizishan Orefield, Anhui Province, China
邓军, 王庆飞, 万丽, 杨立强, 周雷, 赵婕
2008, 10(4)
Abstract:
Spatial distribution patterns of element concentrations can reflect the information of the mineralization processes. Both the Hurst exponent calculated by R/S analysis and the generalized fractal dimension calculated by using the multifractal model are important parameters for describing the spatial distribution of elements. Five long drill holes, named as M1, S1, S2, S3, and S4, have been selected in the Shizishan (狮子山) skarn orefield in Tongling (铜陵), Anhui (安徽) Province, China. Marbles are well developed around M1 and skarn rocks are largely distributed along S1, S2, S3, and S4 drill holes. The drill holes were sampled evenly with an interval of 10 m and 16 trace elements have been measured. The mean of the △D(q) (the height of the generalized dimension spectrum) in the M1 drill hole is the lowest. In addition, the mean of the Hurst exponents of the 16 elements in the M1 drill hole is also much smaller than that of S1, S2, S3, S4 drill holes, which is in accordance with the analysis .....
Scaling Properties of Feldspar and Quartz in Micro-images of Ideal Granites
徐德义, 柯贤忠, 谢淑云, 成秋明
2008, 10(4)
Abstract:
The properties of feldspar and quartze are studied in this article from a fractal point of view using gray-scale micro-images of granite samples collected at the Fangshan (房山) granite body in Hebei (河北) Province, China, which can be regarded as an ideal granite in the sense of Vistelius. We found that there exist power-law relationships between the eigenvalues of the gray-scale matrices and their ranks for the feldspar and quartz. The fractal model used here is a λ-R model similar to the N-λ model proposed by Qiuming Cheng in 2005. Meanwhile, we found that average variances for the gray-scale matrices of feldspar are larger than those of quartz on the same sections, and this may be useful for auto-identification of feldspar and quartz as well as other minerals.
Identification of Geochemical Anomaly by Multifractal Analysis
谢淑云, 成秋明, 柯贤忠, 鲍征宇, 王长明, 全浩理
2008, 10(4)
Abstract:
The separation of anomalies from geochemical background is an important part of data analysis because lack of such identifications might have profound influence on or even distort the final analysis results. In this article, 1 672 geochemical analytical data of 11 elements, including Cu, Mo, Ag, Sn, and others, from a region within Tibet, South China, are used as one example. Together with the traditional anomaly recognition method of using the iterative mean ±2σ, local multifractality theory has been utilized to delineate the ranges of geochemical anomalies of the elements. To different degrees, on the basis of original data mapping, C-A fractal analysis and singularity exponents, Sn differs from the other 10 elements. Moreover, geochemical mapping results based on values of the multifractal asymmetry index for all elements delineate the highly anomalous area. Similar to other 10 elements, the anomalous areas of Sn delineated by the asymmetry index distribute along the main structure orientations. ...
Using Multivariate Statistical and Geostatistical Methods to Identify Spatial Variability of Trace Elements in Agricultural Soils in Dongguan City, Guangdong, China
窦磊, 周永章, 马瑾, 李勇, 成秋明, 谢淑云, 杜海燕, 游远航, 万洪富
2008, 10(4)
Abstract:
Dongguan (东莞) City, located in the Pearl River Delta, South China, is famous for its rapid industrialization in the past 30 years. A total of 90 topsoil samples have been collected from agricultural fields, including vegetable and orchard soils in the city, and eight heavy metals (As, Cu, Cd, Cr, Hg, Ni, Pb, and Zn) and other items (pH values and organic matter) have been analyzed, to evaluate the influence of anthropic activities on the environmental quality of agricultural soils and to identify the spatial distribution of trace elements and possible sources of trace elements. The elements Hg, Pb, and Cd have accumulated remarkably here, incomparison with the soil background content of elements in Guangdong (广东) Province. Pollution is more serious in the western plain and the central region, which are heavily distributed with industries and rivers. Multivariate and geostatistical...
Platinum and Palladium in Coal Rock and Geochemical Anomaly in Eastern Yunnan Province, Southwest China
夏庆霖, 赵鹏大, 成秋明, 陈永清, 张生元
2008, 10(4)
Abstract:
series of geochemical anomalies of Pt and Pd were found in 1 358 recombined samples from a geochemical stream sediment survey in eastern Yunnan (云南) Province, China. Chemical optical emission spectroscopy, X-ray fluorescence analysis, and inductively coupled plasmas atomic emission spectrometry analyses of 22 elements and chemical compositions of 21 samples from coal-bearing strata from the Late Paleozoic, Mesozoic, and Cenozoic show Pt and Pd concentrated to some extent in coal rocks, with Pd/Pt<1. As, Pt, B, Au, Pd, V, Sb, U, Pb, and W are enriched in the Lower Carboniferous coal-bearing strata of the Wanshoushan (万寿山) Formation; B, Mo, As, Pt, U, W, Pb, Pd, and V are enriched in the Lower Permian coal-bearing strata of the Liangshan (梁山) Formation; Pt, Cu, Mo, Pd, As, V, and Ag are enriched in the Upper Permian coal-bearing....
Diversity of Mineralization and Spectrum of the Gejiu Superlarge Tin-Copper Polymetallic Deposit, Yunnan, China
张寿庭, 夏庆霖, 赵鹏大, 高阳
2008, 10(4)
Abstract:
he Gejiu (个旧) deposit is a superlarge tin-copper polymetallic ore-forming concentration area characterized by excellent metallogenic geological settings and advantageous ore-controlling factors. The deposit displays diverse mineralization properties due to different minerals and mineral deposit types. Based on the principal metallogenic factors, metallogenic mechanisms, mineralized components, and occurrence of mineral deposits or ore bodies, the Gejiu mineral district can be divided into 2 combinations of metallogenic series, 4 metallogenic series, 8 subseries, and 27 mineral deposit types. Spatial zonality is evident. The distribution regularity of the elements in both plane and section is Be-W, Sn (Cu, Mo, Bi, Be)-Sn, Pb, Ag-Pb, Zn around a granitic intrusion. The metallogenic epoch is mainly concentrated in the late Yanshanian. During this period, large-scale metallogenic processes related to movement caused by tectonics and magmatism occurred, and a series of magmatic hydrothermal deposits formed. ...
Geochemical Characteristics and Zonation of Primary Halos of Pulang Porphyry Copper Deposit, Northwestern Yunnan Province, Southwestern China
Chen Yongqing* (陈永清), Huang Jingning (黄静宁), Liang Zhen (梁贞)
2008, 10(4)
Abstract:
The Pulang (普朗) porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian (义敦-中甸) island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na2O (K1≥1.2). Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K2O (K2≥1.2). Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization: (a) Cu-Au mineralization; (b) W-Mo mineralization;...
Decrepitation Thermometry and Compositions of Fluid Inclusions of the Damoqujia Gold Deposit, Jiaodong Gold Province, China: Implications for Metallogeny and Exploration
Yang Liqiang* (杨立强), Deng Jun (邓军), Zhang Jing (张静), Guo Chunying (郭春影), Gao Bangfei (高帮飞), Gong Qingjie (龚庆杰), Wang Qingfei (王庆飞), Jiang Shaoqing (江少卿), Yu Haijun (于海军)
2008, 10(4)
Abstract:
The recently discovered Damoqujia (大磨曲家) gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping (招平) fault zone, Jiaodong (胶东) gold province, China. In order to distinguish the temperature range of cluster inclusions from different mineralization stages and measure their compositions, 16 fluid inclusions and 5 isotopic geochemistry samples were collected for this study. Corresponding to different mineralization stages, the multirange peaks of quartz decrepitation temperature (250–270, 310–360 and 380–430 ℃) indicate that the activity of ore-forming fluids is characterized by multistage. The ore-forming fluids were predominantly of high-temperature fluid system (HTFS) by CO2-rich, and SO42--K+ type magmatic fluid during the early stage of mineralization and were subsequently affected by low-temperature fluid system (LTFS) of CH4-rich, ...
Magmatic-Hydrothermal Superlarge Metallogenic Systems—A Case Study of the Nannihu Ore Field
王长明, 成秋明, 张寿庭, 邓军, 谢淑云
2008, 10(4)
Abstract:
Located in the Qinling (秦岭) molybdenum metallogenic belt on the southern margin of North China craton, the Nannihu (南泥湖) molybdenum (-tungsten) ore field, consisting of the Nannihu, Sandaozhuang (三道幢), and Shangfang (上房) deposits, represents a superlarge skarn-porphyry molybdenum (-tungsten) accumulation. Outside the ore field, there are some hydrothermal lead-zinc-silver deposits found in recent years, for example, the Lengshuibeigou (冷水北沟), Yindonggou (银洞沟), Yangshuwa (杨树凹), and Yinhegou (银河沟) deposits. Ore-forming fluid geochemistry indicates that these deposits belong to the same metallogenic system. The hydrothermal solutions were mainly derived from primary magmatic water in the early stage and from the mixture of the primary magmatic water and meteoric water in the later stage, with an obvious decreasing....
Omnibus Weights of Evidence Method Implemented in GeoDAS GIS for Information Extraction and Integration
张生元, 成秋明, 陈志军
2008, 10(4)
Abstract:
Weights of evidence (WofE) is an artificial intelligent method for integration of information from diverse sources for predictive purpose in supporting decision making. This method has been commonly used to predict point events by integrating point training layer and binary or ternary evidential layers (multiclass evidence less commonly used). Omnibus weights of evidence integrates fuzzy training layer and diverse evidential layers. This method provides new features in comparison with the ordinary WofE method. This new method has been implemented in a geographic information system-geophysical data analysis system and the method includes the following contents: (1) dual fuzzy weights of evidence (DFWofE), in which training layer and evidential layers can be treated as fuzzy sets. DFWofE can be used to predict not only point events but also area or line events. In this model a fuzzy training layer can be defined based on point, line, and areas using ....
3D Property Modeling of VoidRatio by Cokriging
姚凌青, 潘懋, 成秋明
2008, 10(4)
Abstract:
Void ratio measures compactness of ground soil in geotechnical engineering. When samples are collected in certain area for mapping void ratios, other relevant types of properties such as water content may be also analyzed. To map the spatial distribution of void ratio in the area based on these types of point, observation data interpolation is often needed. Owing to the variance of sampling density along the horizontal and vertical directions, special consideration is required to handle anisotropy of estimator. 3D property modeling aims at predicting the overall distribution of property values from limited samples, and geostatistical method can be employed naturally here because they help to minimize the mean square error of estimation. To construct 3D property model of void ratio, cokriging was used considering its mutual correlation with water content, which is another important soil parameter. Moreover, K-D tree was adopted to organize the samples to accelerate neighbor query...
Extraction of Mineral Alteration Zone from ETM+ Data in Northwestern Yunnan, China
赵志芳, 张玉君, 成秋明, 陈建平
2008, 10(4)
Abstract:
Alteration is regarded as significant information for mineral exploration. In this study, ETM+ remote sensing data are used for recognizing and extracting alteration zones in northwestern Yunnan (云南), China. The principal component analysis (PCA) of ETM+ bands 1, 4, 5, and 7 was employed for OH- alteration extractions. The PCA of ETM+ bands 1, 3, 4, and 5 was used for extracting Fe2+ (Fe3+) alterations. Interfering factors, such as vegetation, snow, and shadows, were masked. Alteration components were defined in the principal components (PCs) by the contributions of their diagnostic spectral bands. The zones of alteration identified from remote sensing were analyzed in detail along with geological surveys and field verification. The results show that the OH- alteration is a main indicator of K-feldspar, phyllic, and prophilized alterations. These alterations are closely related to porphyry copper deposits...
Solution of Multiple-Point Statistics to Extracting Information from Remotely Sensed Imagery
葛咏, 白鹤翔, 成秋明
2008, 10(4)
Abstract:
Two phenomena of similar objects with different spectra and different objects with similar spectrum often result in the difficulty of separation and identification of all types of geographical objects only using spectral information. Therefore, there is a need to incorporate spatial structural and spatial association properties of the surfaces of objects into image processing to improve the accuracy of classification of remotely sensed imagery. In the current article, a new method is proposed on the basis of the principle of multiple-point statistics for combining spectral information and spatial information for image classification. The method was validated by applying to a case study on road extraction based on Landsat TM taken over the Chinese Yellow River delta on August 8, 1999. The classification results have shown that this new method provides overall better results than the traditional methods such as maximum likelihood classifier (MLC).
Monte-Carlo Method for Coalbed Methane Resource Assessment in Key Coal Mining Areas of China
杨永国, 陈玉华, 秦勇, 成秋明
2008, 10(4)
Abstract:
Monte-Carlo method is used for estimating coalbed methane (CBM) resources in key coal mining areas of China. Monte-Carlo method is shown to be superior to the traditional volumetric method with constant parameters in the calculation of CBM resources. The focus of the article is to introduce the main algorithm and the realization of functions estimated by Monte-Carlo method, including selection of parameters, determination of distribution function, generation of pseudo-random numbers, and evaluation of the parameters corresponding to pseudo-random numbers. A specified software on the basis of Monte-Carlo method is developed using Visual C++ for the assessment of the CBM resources. A case study shows that calculation results using Monte-Carlo method have smaller error range in comparison with those using volumetric method.
A Grey Fuzzy Comprehensive Model for Evaluation of Geological Structure Complexity
周云霞, 周永章, 谢淑云, 曹代勇, 邱向荣
2008, 10(4)
Abstract:
everal structure sets (faults and folds) are characterized by their self-similarity properties. Herein, we discuss the degrees of complexity of fractures by introducing the box-counting fractal dimension of faults as a key criterion to be used in comprehensive fuzzy analysis model for evaluation of the complexity of structures. Totally, eight criteria including density, intensity, length of faults, types and box-counting fractal dimension of faults, the intersection angle between faults and coal beds, gradient coefficients, dip angles of the coal beds, and variation coefficients of dip angles of the coal seams, were used for the evaluation purpose. The grey fuzzy comprehensive assessment model was used to rank the relative importance of these criteria. Scores indicating the complexity of structure were calculated on the base of criteria values and their weights for each sub-area of the study area in...