青海阿尔茨托山地区地球化学（异常）场的多重分形研究

以研究区成矿地质背景为基础，将其划分为4个地球化学区，从多重分形理论出发，应用“元素含量—面积”模型方法，对各区主要成矿元素的地球化学(异常)场进行分析研究。结果表明，由于地质构造背景和化探元素富集的成因机理不同，各区元素地球化学(异常)场具有两种不同的多重分形特征模式：只有两个无标度区的简单多重分形模式和有两个以上无标度区的高丛集多重分形模式，具有相同成因的元素组合具有相似的多重分形特征。在此基础上．探讨了各区元素的成矿富集规律和空间分布特征，进而划分了地球化学背景和异常，经检验对比，证明了该方法的有效性和实用性。     

Application of the tectono-geochemistry method to mineral prospectivity mapping: a case study of the Gaosong tin-polymetallic deposit,Gejiu district,SW China

The tectono-geochemistry method as a lithogeochemical exploration tool is a process centric approach based on the premise that element migration and concentration within and adjacent to geological structures are controlled by large-scale dynamic earth processes that operate on a variety of scales to focus mass and energy flux. Here we present a case study of the Gaosong tin-polymetallic deposit, Gejiu district, SW China, illustrating how the tectono-geochemistry method can be applied to mineral prospectivity mapping. As a first step, 2216 fault rock samples collected within the Geiju district were assayed followed by a detailed examination of the assay results by means of factor analysis and multifractal singularity mapping. The main aims of these analyses were to (1) statistically explore the data with respect to specific element concentrations, associations and geochemical patterns by which the fault rock samples can be grouped, (2) better characterize the samples in terms of whether or not the rocks recorded any evidence for hydrothermal mineralization processes, and (3) identify any geochemical anomalies that may present vectors to buried ore. The results illustrate that element distribution patterns are greatly influenced by fault permeability and that NE-SW-striking faults are the most favorable in terms of concentration of ore elements. Factor analysis greatly assisted the identification and interpretation of, for example, element associations, and geochemical zonation patterns genetically related to intrusions. Recognition of singularities was of particular importance with respect to identifying and delineating primary fault tectono-geochemical anomalies that may be caused by buried ore. Of particular interest are low singularity values as these correspond with positive geochemical anomalies over known ore deposits in the Gejiu district. Anomalies delineated by local singularity exponents may represent undiscovered ore and, thus, warrant further exploration.     

空间模式的广义自相似性分析与矿产资源评价

尺度不变性(scale invariance)包括自相似性(各向同性)、自仿射性(成层结构)、广义自相似性(各向异性标度不变性),是由各种地质过程和地质事件所产生的地质特征和模式的本质属性．尺度不变性可用分形和多重分形模型来表征．这些尺度特征的定量化可为刻画地质空问模式和模式识别提供有力的工具．例如。热液矿床的群聚现象可以用局部分形特征(局部奇异性)来刻画．通过在特征空问中(如频率空问)识别空问模式的广义自相似性．可以将空间混合模式进行分解或异常的识别．介绍了几种相关的分形模型和方法。包括度量空问模式广义尺度独立性(GSI)的线性模型;基于广义尺度独立性的异常分解S—A方法;度量空问模式的局部奇异性方法;以及如何利用分形特征预测未发现矿床的2种方法．有些方法已应用于许多矿产资源评价实例中．给出了对加拿大Nova Scotia省西南部湖泊沉积物样品中的4种元素As、Pb、Zn和Cu的地球化学数据处理分析结果。证明了局部奇异性分析和S—A异常分解方法对地球化学异常的增强和分离的有效性．研究表明：由S—A方法分解的异常往往具有多重分形的特点,而且普遍具有局部奇异性．研究区内具有明显奇异性的地区(元素含量富集区)是金矿异常区域。它们与金矿成矿作用和已知矿床的赋存密切相关．     

白音诺尔矿区土壤地球化学纵向迁移特征

土壤地球化学测量工作对发现土壤中与成矿有关的地球化学异常进而对指导找矿具有重要的意义.内蒙古白音诺尔铅锌矿床是我国北方一个典型的矽卡岩型矿床, 具有大而富的特点.选取内蒙古白音诺尔铅锌矿区某已开采矿体上方6号土壤垂直剖面、以及距离6号剖面分别约1.0 km和4.5 km的非矿土壤垂直剖面3和8,垂向上通过每隔10 cm取样,进行了系统的土壤磁化率测试和与成矿有关的部分微量元素的总量测试分析.结果显示,尽管近矿剖面6和远矿剖面3中磁化率与土壤深度之间呈良好的负相关关系,但剖面6中9种元素含量均显示“顶底低中间高”的“倒C型”分布,而远矿剖面3和8中元素含量多呈动荡波动.这些研究思路与结论可为覆盖区表生土壤地球化学测量及矿产预测研究提供借鉴,对系统模拟和研究地球化学组分在矿区及周边残积土剖面中的迁移演化规律及其影响因素亦具有指示意义.      

广西贵港银山岭铅锌矿土壤地球化学找矿研究

通过在广西贵港银山岭开展1∶10 000地质简测工作和1∶10 000土壤剖面地球化学测量工作,总结了银山岭出露的地层、岩性、构造、围岩蚀变等地质特征,在此基础上,进行土壤地球化学找矿研究,得到以下认识:(1)微量元素参数统计表明,Pb、Zn、Ag元素含量相对较高,变化系数较大,易次生富集形成实质性的地球化学异常;(2)元素组合分析、元素分布型式、元素分形特征显示,Pb、Zn、Ag元素代表了主要成矿元素的次生富集组合,其分布范围广,离散度大,可作为找矿的主要指示元素;(3)综合地质和地球化学数据资料分析,在工作区发现了3个土壤地球化学异常块段,并对各个土壤地球化学异常进行解释评价,从而圈定找矿靶区,进一步提出了新的工作建议。     

Geochemical Baselines of Nickel and Chromium in Various Surficial Materials in the Barents Region, NW Russia and Finland

The geochemical baselines of nickel and chromium were studied from the data produced by the Barents Ecogeochemistry project, a large international regional geochemical mapping exercise. The project surveyed major and trace element distributions in stream water, organic and mineralogically-modified soil horizons, and terrestrial moss in the northwestern part of Russia and in Finland. Other materials were collected during the pilot phase and later from thirty special sites. The results on respective materials by XRF, ICP-MS and ICP-AES showed that both geological and anthropogenic factors have an influence on the geochemical baseline concentrations of Ni and Cr in organic soil and stream water. The main explanation of the observed distribution patterns in terrestrial moss is human activity, but geological factors can also affect the baselines. The variation of geochemical baselines in the mineral-rich soil horizon depends only on variations in bedrock. The mineralogy of samples mainly controls the leachability properties of soil samples.     

Analysis of High Density Regional Geochemical Soil Samples at the Council for Geoscience (South Africa): The Importance of Quality Control Measures

The Council for Geoscience (CGS, South Africa) has a statutory mandate to carry out regional geochemical mapping in South Africa that needs to be rapidly and accurately analysed. Both simultaneous X-ray fluorescence spectrometry (S-XRF) and a newly developed method using inductively coupled plasma-mass spectrometry (ICP-MS) were employed. Various trace elements that could not previously be analysed by S-XRF can now be analysed by ICP-MS for the regional geochemical mapping programme, e.g., Cd, Mo, Te and Li. Using both techniques, the CGS aims to report element distributions for some fifty elements. To ensure that element concentration levels correlate over map boundaries, quality control measures in the sampling, sample preparation and analyses were of critical importance. This paper aims to discuss the sample preparation and quality control measures as applied to the ∼5500 samples of the Giyani and Tzaneen 1:100000 scale map sheets sampled at a density of one soil sample per km². ICP-MS batch- and instrumental drift-correction procedures will be discussed. As a final step, geochemical data were overlain over simplified geological maps using geographical information system software. These maps complement existing geological information of South Africa, help in the identification of exploration targets, test exploration models and initiate further geological research.     

GEMAS: Source,distribution patterns and geochemical behaviour of Ge in agricultural and grazing land soils at European continental scale

Agricultural soil (Ap-horizon, 0–20 cm) and grazing land soil (Gr-horizon, 0–10 cm) samples were collected from a large part of Europe (33 countries, 5.6 million km²) as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil mapping project. GEMAS soil data have been used to provide a general view of element mobility and source rocks at the continental scale, either by reference to average crustal abundances or to normalized patterns of element mobility during weathering processes. The survey area includes a diverse group of soil parent materials with varying geological history, a wide range of climate zones, and landscapes.The concentrations of Ge in European soil were determined by ICP-MS after an aqua extraction, and their spatial distribution patterns generated by means of a GIS software.The median values of Ge and its spatial distribution in Ap and Gr soils are almost the same (0.037 vs. 0.034 mg/kg, respectively). The majority of Ge anomalies is related to the type of soil parent material, namely lithology of the bedrock and minor influence of soil parameters such as pH, TOC and clay content. Metallogenic belts with sulphide mineralisation provide the primary source of Ge in soil in several regions in Europe, e.g. in Scandinavia, Germany, France, Spain and Balkan countries.Comparison with total Ge concentrations obtained from the Baltic Soil Survey shows that aqua regia is a very selective method with rather low-efficiency and cannot provide a complete explanation for Ge geochemical behaviour in soil. Additionally, large differences in Ge distribution are to be expected when different soil depth horizons are analysed.     

滁州地区土壤地球化学基准值与背景值研究

基于滁州地区多目标区域地球化学调查数据资料,统计获得了表、深层土壤地球化学基准值、背景值及相关的地球化学参数。研究表明：成土母质类型对土壤元素地球化学基准值影响显著,表层土壤元素含量相对于深层土壤既有继承性,又有差异性。在不同的土壤层的一些元素含量明显不同。土壤的形成过程和人类活动已经对土壤中元素含量的分布有显著的影响。因此,土壤地球化学基准值与背景值研究中应多考虑地质背景、物质来源等因素的影响,     

多龙矿集区控矿构造信息提取、识别与融合

西藏多龙矿集区近年来发现了大量的铜、金矿床,具有可观的资源潜力而倍受关注。通过对区内地质调查及矿产勘查数据的系统梳理与二次开发,利用基于分形理论的空间分析方法对该区成矿背景、构造格架等方面进行了深入细致的研究与探索。通过主成分分析方法,将水系沉积物地球化学数据中与斑岩铜金成矿相关元素和构造活动指示元素进行融合,并利用S-A(能谱-面积)模型对元素组合异常进行信息挖掘工作。结果表明,与区内构造格架相关的地球化学异常空间分布模式在指示矿化的同时,还对其与区域断裂构造之间的成生关系具有相当程度的指示意义。此外,区内开展的空间定量研究同时表明,S-A(能谱-面积)模型对描述由特定地质作用所造成的异常空间分布模式的自相似性有效,特别是针对地球化学背景模式的空间定量化描述,能更加深刻地刻画区内的构造格架并反映成矿背景。其结果推断了控制区内斑岩成矿系统的网格状断裂体系。此外,数据分析建模过程为在该区开展进一步的多元信息提取与融合提供了思路和借鉴经验,有利于找矿新靶区的发现与圈定。     

Multifractal Simulation of GeochemicalMap Patterns

INTRODUCTIONThe mathematical modeling of geochemical data continuesto present an important challenge to earth scientists. Basically,the available data are 2-dimensional realizations of 3dimensional patterns, which are the results of one or more genetic processes that usually are poorly understood. It may bedifficult to project from the observations into the rock mass. Inthis paper, multifractal modeling is advocated as a methodologyto characterize geochemical patterns. If a geochemical pa…     

地质体方法圈定化探异常——以张家口某地区为例

如何确定元素异常下限是化探工作的关键问题。由于元素在不同的地质体内具有不同的分布形式和背景含量,因此在地质情况较复杂地区采取统一值作为元素异常下限值存在一定缺陷。文章以张家口某地区1？20万水系沉积物数据为例,在分析不同地质体内元素分布规律的基础上,确定了不同地质体内元素异常区域,研究表明该方法可有效弥补全区采用统一值圈定异常所造成的不足。     

多维分形理论和地球化学元素分布规律

多维分形模型不仅采用常规的低阶矩统计, 而且采用高阶矩统计对多维分形分布进行度量, 从而能较细致地刻划正常值以及异常值.地球化学元素的正常值往往服从统计学中的大数定量, 即满足正态分布或对数正态分布, 然而异常值会服从分形分布(Preato).介绍了多维分形领域中的最新发展以及在地球化学研究中特别是研究超常元素空间分布和富集规律中的应用.结果表明, 通常的统计方法只对应于多维分形围绕均值周围的局部特征.为了有效地研究异常值的分布和富集规律, 建议采用高阶矩统计方法和多维分形方法, 并给出了两种分析地球化学元素, 并突出异常值贡献的方法.这些方法不仅可应用于研究微量元素的空间分布和富集规律, 而且可以区分地球化学背景与矿化有关的异常值.还介绍了该方法在对加拿大B.C.省西北部Mitchell-Sulphurets地区金铜矿化蚀变带研究中的应用.      

新疆塔里木盆地艾协克—桑塔木南地区油气地球化学指标的多重分形性分析

用分形与多重分形的方法研究地球化学场中地球化学指标的分布规律具有重要的意义。本文运用多重分形矩方法研究了新疆塔里木盆地艾协克一桑塔木南地区2000km^2内采集的2085个土壤样中20项油气化探指标的多重分形谱函数形态特征。结果表明，主要成油气指示指标的多重分形谱基本上呈单一“钩状”，显示较弱的多重分形或单一分形；而其他指标多显示较强的多重分形特征。这些性质在研究区广泛存在，将对区域含油性研究有重要的指示意义。     

地球化学图纹理的多重分形模拟

利用一个简单的基于De Wijs模型的多重分形模型, 可以模拟元素富集值的各种地球化学纹理.每种纹理在平均值上是自相似的, 因为将乘积阶次模型(multiplicative cascade model) 应用到任何子区均能得出类似的纹理样式.在其他的试验中, 通过叠加一个二维趋势纹理(2-dimensional trend pattern) 以及把它与一个常值富集模型混合, 原始的自相似纹理就产生畸变.本文将要研究这些畸变是如何改变用三步矩(3-step method of moments) 所估测的多重分形谱(multifractal spectrum).推导出了满足De Wijs模型纹理的离散和连续频率分布模型.这些模拟纹理满足离散频率分布模型, 当乘积阶次模型(multipicative cascade model) 无限细分时, 假设离散频率分布模型的上界是一连续频率分布, 这个离散分布就在形式上逼近该连续频率分布的上边界.这一极限分布在中心是对数正态的, 但有两个巴利多(Pareto) 分布的尾.这种方法在矿产和油气评价中有重要的潜在意义.      

Fractal and Multifractal Properties of Geochemical Fields

A fractal model, introduced by De Wijs to study the distribution, redistribution, or enrichment/depletion of element concentrations in a region, has become widely accepted. This paper uses it to simulate various geochemical fields for element concentration values. The frequency distribution and spatial pattern of the simulated values or concentrations are analyzed by the method of moments and the concentration–area (C–A) model. The spatial pattern of the original De Wijs model is shown to be intrinsically characterized by -shaped and symmetrical multifractal spectrum curves, whose center and width change systematically with the enrichment factors set in the simulation. The corresponding frequency distribution pattern on the log–log plot of frequency versus concentrations is called simple continuous multifractal (SCM) by the authors. In other experiments, when a De Wijs model is locally superimposed by another De Wijs model of different enrichment factors, the symmetry of the multifractal spectrum graph is broken and a different pattern of frequency distribution is found. It is referred to as highly accumulated continuous multifractals (HACM). Concentrations of 12 elements in 1448 rock samples from Shaoguan district, North Guangdong Province, South China, and 12 oil/gas indexes in surface soils from Sangtamu region, Tarim Basin, Northwest China, have been applied. The real geochemical fields, both metallic and oil/gas, are found to be remarkably compatible to those simulated patterns of De Wijs models with backgrounds of various enrichment and different degrees of superimposition, indicating that the frequency and spatial distribution patterns revealed by the authors are most possibly universal features of geochemical fields. It is particularly interesting to note that the major geochemical indicators of oil/gas geochemical fields are closer to the results of De Wijs models with a small enrichment factor, either with or without local superimposition, whereas those of the metallic geochemical field correspond more closely to De Wijs models with a background field of larger enrichment factors. The results obtained herein potentially have important implications in mineral and oil/gas resource assessment.     

岩石中元素背景值变化对地球化学成矿预测的影响

勘查地球化学是利用元素在各种介质中的含量变化来进行找矿勘查,因此,地球化学填图是勘查地球化学的最基础性的工作,正如地质图对于地质工作的重要性一样。在利用地球化学进行找矿预测过程中,元素在不同类型岩石中背景值的变化会对预测过程产生很大的影响,在利用中国西南地区76种元素编图的数据进行成矿预测过程中,将元素分成两类:一类是岩性变化对成矿预测影响较小的元素,这类元素的各类岩石最大背景值与预测区的异常下限比值小于1,且岩石中背景值的最大值与最小值比值也较小,一般小于4。这些元素包括Hg、Cd、Sb、Au、Sn、 Mo、Ag、U、Pb、Bi、W,它们都是地球化学方法应用最有效的矿种。另一类是岩性变化对成矿预测影响较大的元素, 这类元素有Pt、Co、Cr、Cu、Ni、V、Ti等,其岩石中的最大背景值与异常下限比值大于1,且岩石中的背景值最大值与最小值的比值大于8。以Sn和Cu两种元素为例,Sn属于岩性变化影响较小的元素,西南地区的Sn矿床与Sn地球化学异常之间的对应关系很好。而Cu属于岩性影响较大的元素,西南地区的Cu矿床分布与西南地区的巨大的 Cu地球化学异常对应关系较差。对于这组元素,应采用多重分形滤波技术,压制不同背景的干扰,从中提取出矿化信息。     

非线性成矿预测理论:多重分形奇异性-广义自相似性-分形谱系模型与方法

介绍了“奇异性-广义自相似性-分形谱系”(“3S”: Singularity-generalized self-Similarity-fractal Spectrum)为核心的多重分形现代成矿预测理论与模型(Multifractal Mineralization Prediction Theory and Models)的基本内容和前沿研究方向.讨论了作为非线性、复杂性理论的重要领域之一, 多重分形理论所提供的“奇异性-广义自相似性-分形谱系”等概念和相关的模型.这些新概念和模型不仅能够合理地描述成矿系统、成矿过程、成矿富集规律、矿产资源时空分布, 还提供了定量模拟和识别成矿异常(地质、地球物理、地球化学、遥感异常)的有效模型和实用方法.将多重分形原理与成矿过程、矿产资源分布规律、矿产资源信息获取研究相结合, 可形成具有良好应用前景的现代成矿预测理论与模型.采用该多重分形矿产资源预测理论和在此基础上所开发的专用地学非线性空间信息GeoDASGIS技术, 对国内外多个金属成矿区带进行了矿产资源勘查与评价, 均取得了较理想的预测效果, 表明对开展矿产资源勘查和评价是有效和可行的.      

非线性地球化学矿化元素组合求异方法在西藏洞噶普矿区的应用

复杂的地质作用和控制因素常常使得地球化学元素的分布特征呈非线性,传统的线性模型在处理元素非线性分布具有一定的局限性和不适应性。文中以研究地球化学矿化元素组合为主线,应用aiNet网络模型(带权的不完全连接网络)对地球化学数据做预处理,应用FastICA算法(快速定点独立分量分析)求取矿化元素组合,应用分形含量面积法圈定元素异常下限,应用分形含量梯度法确定元素异常浓集分带,形成了一套地球化学矿化元素组合求异的非线性方法体系,并在西藏洞噶普矿区1∶1万土壤地球化学测量资料的应用中取得了良好的效果。     

寿光市高氟地下水的分布规律和成因

寿光市曾经是山东省地氟病防治的重点地区,通过在病区开展野外调查和岩土、水样测试等工作,总结了该区地氟病分布及地球化学环境特征,探讨了地氟病与地层岩性、土壤、地形地貌、浅层地下水、生活用水等的关系。在系统环境地球化学调查的基础上,研究了当地高氟地下水的成因,认为岩石、土壤、海水是高氟浅层地下水的主要来源,高氟浅层地下水形成可能有海侵富集型和蒸发浓缩型。分析了地下水中氟富集的因素与过程,提出了地氟病的防治措施。