A generalized set of discrete frequency distributions with Fortran program

Geologists unfamiliar with the application of probability theory to discrete data in other fields of research are usually acquainted with only three discrete theoretical frequency distributions: Poisson, binomial, and negative binomial distributions. In some situations these distributions may fail to adequately describe a set of experimental data. Other distributions such as the Poisson with zeros, Neyman type A, logarithmic with zeros, Poisson-binomial, and Thomas double Poisson together with the more common Poisson, binomial, and negative binomial form a generalized subset of discrete theoretical distributions, one of which should fit almost any experimental data set. A computer program is presented which allows testing of any combination of these distributions against observed discrete data.     

On the resolution of mixed frequency distributions into normal components

The resolution of mixed frequency distributions into normal components may be accomplished graphically on probability paper. By means of nonlinear regression, a method for such a resolution in the probability net is given and exemplified. It is based on the observed cumulative frequencies.     

Multivariate normality in morphometric analysis

Data on some living (salamanders and grasshoppers) and fossil (Devonian brachiopods) animals are analyzed by means of recently developed methods for the large-scale treatment of multivariate normality. Multivariate nonnormality was found to exist in all situations, even if the univariate deviations in the skewness and kurtosis statistics proved to be without significance for the most part. The effect of logarithmically transforming the data appears to be a mixed blessing. Apart from the fact that the investigator is removed one step from the biological relationships in his data by carrying out a transformation of them, the betterment in the multivariate interconnections with respect to normality tends to be slight, despite the general improvement in the univariate values. The relationship between sample size and the multivariate normality measures b_1,p and b_2,p are studied empirically.     

Statistical techniques for the classification of chromites in diamond exploration samples

A database of 1267 quality-screened major- and trace-element analyses of chromites (s.l.) from kimberlites, lamproites, ultramafic lamprophyres (UMLs) and crustal sources (‘greenstones’, including ophiolites, gabbros, basalts and komatiites) has been subjected to statistical analysis, in order to derive discriminants for use in diamond exploration. The techniques used included nearest-neighbour analysis, CART (classification and regression trees) and MARS (multivariate adaptive regression splines). The results show that both CART and MARS approaches can correctly discriminate kimberlite/lamproite chromites from UML/‘greenstone’ chromites at levels near 90%. Discrimination into the four classes separately is achieved at levels of ca. 80% by MARS and > 70% by CART; much of the misclassification is between the kimberlite and lamproite classes. These results probably represent the maximum probable level of discrimination on chemical criteria, given that ascending magmas may sample both mantle and crustal rocks. The CART approach produces a classification tree that requires no further computation to classify a given grain; the MARS approach requires the use of a simple software package. Tests on known samples illustrate the high level of accuracy of the methods in an exploration context, as well as the useful petrogenetic conclusions that can be drawn from some ‘misclassifications’.     

南海始新世海相地层分布及油气地质意义

采用古生态学及沉积学方法, 对南海北部深水区BY7-1-1井及L29井特定层段进行细致研究.通过有孔虫、孢粉藻类分析及沉积学分析, 证实南海北部白云深水区在晚始新世即出现滨浅海相沉积环境, 确定了南海北部最早接受海相沉积的时间.始新世海相地层在南海北部主要分布在台西及台西南盆地中, 并在晚始新世扩展到珠江口盆地白云凹陷.在南部分布较广, 曾母盆地、北康盆地、礼乐盆地及巴拉望盆地中均有始新世海相地层分布.南海始新世海相地层的分布受制于新南海扩张及古南海的消退, 以晚始新世为时间节点发生显著变化, 总体上分布范围增大, 反映该时期南海拉张和断裂活动的加剧.南海始新世海相地层具有良好的油气潜力, 在部分盆地中形成了优质的烃源岩与储层, 珠江口盆地白云深水区晚始新世海相地层的发现, 对南海深水海相油气勘探具有积极的参考作用.      

高光谱分辨率遥感在地质应用中的关键技术及前景

遥感技术应用于地质中的目的之一是分辨和识别出不同的岩石和矿物等地质体。宽波段遥感只能分辨不同岩石类型，而难以识别含不同成分的岩石和矿物。高光谱分辨率遥感则可通过诊断性光谱特征对岩石或矿物成分及结构进行识别。通过对高光谱分辨率遥感应用于地质中的关键技术进行分析，对未来高光谱分辨率遥感在地质中的应用进行了预测。     

Fortran IV program for grey-level mapping of spatial data

Afortran iv computer program for grey-level mapping of spatial data using a CDC 6600 is described. The program produces maps for irregularly distributed data in as many as 10 intensity levels which are displayed in grey tones by a lineprinter. Unlimited map size and unrestricted data input provide for as many as 5000 data points per 13-in.-wide strip of map. The program is easily modified for other installations. Examples are given of geochemical analyses of stream sediments in Northern Ireland.     

稀有气体同位素测试技术及其在矿床学研究中的应用

稀有气体包含He、Ne、Ar、Kr、Xe、Rn六种元素,由于其化学性质十分的稳定,一般不参与各种化学反应过程。其在地球不同圈层及地外物质中的丰度和同位素组成差别巨大,是地球科学研究的重要示踪剂。稀有气体同位素组成的测试方法主要有分阶段加热熔融、真空压碎、激光微区熔蚀等气体采集方式,获得的气体经多级纯化后在静态稀有气体同位素质谱中进行测试。在矿床学研究中,作为灵敏示踪剂的稀有气体同位素大多用于判别成矿物质、成矿流体的来源,特别是幔源物质的贡献大小及壳幔相互作用与成矿的关系,用于揭示矿床在成矿各阶段(期)中的物质和流体源区差异,用以追踪和揭示成矿流体的演化、反演成矿过程并在一定程度上指示成矿流体在成矿过程中的行为。稀有气体同位素为精细成矿作用研究、不同矿种成矿作用差异分析、探寻大规模成矿作用提供了重要的科研手段。     

Statistical properties of accumulated values and their application in mining estimations

This paper presents results of some investigations on the statistical properties of accumulation of discrete as well as continuous values when a two-dimensional stationary random function is reduced to a one-dimensional function. Based on the results of these investigations, an indirect technique of estimating covariances or variograms of point support grade values is proposed. The efficiency of the technique, particularly in relation to the conventional procedure of covariance estimation, has been demonstrated by an actual case study of a pre-Cambrian high-grade iron ore deposit in eastern India.     

构造地质学若干术语的涵义解析和使用探讨

随着构造地质学科领域的学生、专业研究人员和出版论文、著作等数量的迅猛增长,以及该学科领域新创立术语的大量引入,一些术语被误用、滥用和不准确使用的现象时有发生。针对这一情况,从6个方面：①外延很广的术语;②有关联但涵义不同的术语;③不符合构造逻辑的术语;④可能不符合地质实际的术语;⑤“形”近“意”异的术语;⑥易被滥用的若干术语,对其中的若干术语进行涵义的解析和使用探讨,旨在满足同行顺利交流的需要和促进构造地质学科的发展。     

Statistical graphics in geochemical journals

A quantitative investigation of types of statistical graphics and maps being used for presentation of geochemical data has been made for the 1984 volumes ofGeochemica et Cosmochimica Acta, Chemical Geology, Contributions to Mineralogy and Petrology, Geochemistry International, Journal of Geochemical Exploration, Journal of Petrology, and the 1983 volume ofOrganic Geochemistry. Although a number of significant differences exist between relative proportions of text, tables, statistical graphs and maps, and other illustrations in the various journals, overall figures are comparable broadly to those found by Cleveland (1984) in a recent survey of usage in 57 journals in natural, mathematical, and social sciences. Between 18% and 35% of 1463 graphs and maps in these journals contain at least one item of error or poor presentation, indicating the need for substantial improvement in both standards of preparation and refereeing of diagrams, and we suggest guidelines for both authors and referees.Presented at the Computer Graphics in Geology meeting of the Geological Information Group of the Geological Society of London, held at the University of Bristol, England, 23 May 1985.     

Some principles of data storage and information retrieval and their implications for information exchange

The definition of objectives and question of interpretation must be considered when setting up data banks. The objective will determine the type of data to be collected. A hierarchy of data-processing systems exists where the amount of interpretation in the data increases as the order of the system increases. The remarkable continuity of basic data can be embodied in the axiom: Any fundamental data free of interpretation cannot be discontinuous. The measurement of space and time remain invariant for all orders of data systems and are essential for relating data containing various amounts of interpretation. In general, only basic data should be exchanged. Where this is not feasible the object described should be clearly defined in space and time.     

Preliminary assessment of a nonlinear mapping algorithm in a geological context

A new algorithm has been developed by J. W. Sammon for the nonlinear-point mapping of high-dimensional data in two dimensions such that the inherent structure of the data is approximately preserved. This paper describes results using several sets of geologic data including stratigraphic thickness, petrographic modal analysis, and morphological or geochemical measurements. Comparisons are made with hierarchical cluster analysis using dendrogram representation. Initial results are encouraging and suggest that the technique could have widespread geological applications.     

Some methods for statistical analysis of multimodal distributions and their application to grain-size data

Some of the methods used in the resolution of mixed normal distributions are discussed under three headings: analytical, graphical, and numerical methods. Attention is given to their applicability in the analysis of grain-size data as derived from sieving. Comparisons are made by applying several methods to published data. It is concluded that the numerical methods offer most scope, especially the method of nonlinear least squares. Some analyses of beach sediments, using this method, are presented. The adoption of a convention for the number of individuals in the sample increases ease of interpretation.     

低渗透介质孔隙溶液的提取及其应用综述

弱透水层释水,污染物迁移转化及高危废物深埋选址等水文地质和工程地质活动中,孔隙溶液的地球化学行为越来越受到重视。但孔隙溶液提取技术研究发展相对缓慢。介绍了目前应用较多的孔隙溶液提取技术,及其应用局限性与适用条件。综述了孔隙溶液在地球化学、土壤学、环境地质及水文地质学中的应用现状,并提出在地下水越流计算,弱透水-含水系统相互作用,地下水年龄问题研究上,孔隙溶液的测试分析具有良好的应用前景。     

Use of multivariate statistical methods in data-base maintenance

Multivariate statistical methods may be used to enhance large data bases by predicting missing information and verifying unchecked data vectors. In addition, new techniques may be used for exploratory purposes to investigate the interrelationships between variables. The techniques are being applied successfully in coal mining.     

Statistical theories of crack propagation

The mechanism of crack growth in rocks has been the subject of much recent interest, not only on account of its engineering importance, but also as a background to the study of precursory phenomena for earthquakes. One feature which appears to play a significant role in the fracture mechanism is the formation of microfractures prior to a major failure. Microfractures also play a key role in statistical theories as developed by Weibull and later writers. Some recent work in these two fields is reviewed and the suggestion is put forward that it may be possible to extend the statistical models so as to describe the dynamics of crack formation. As a preliminary step in this direction, it is shown that a branching model for the coalescence of microfractures lead to a simple derivation of the frequency-magnitude law of fracture energies. Other methods of introducing statistical ideas into the dynamics of crack propagation are also briefly reviewed, and compared to deterministic models of crack growth.Paper presented at the 25th International Geological Congress, Section 16B, Sydney, Australia, August 1976.     

Statistical considerations for grain-size analyses of tills

Relative percentages of sand, silt, and clay from samples of the same till unit are not identical because of different lithologies in the source areas, sorting in transport, random variation, and experimental error. Random variation and experimental error can be isolated from the other two as follows. For each particle-size class of each till unit, a standard population is determined by using a normally distributed, representative group of data. New measurements are compared with the standard population and, if they compare satisfactorily, the experimental error is not significant and random variation is within the expected range for the population. The outcome of the comparison depends on numerical criteria derived from a graphical method rather than on a more commonly used one-way analysis of variance with two treatments. If the number of samples and the standard deviation of the standard population are substituted in at-test equation, a family of hyperbolas is generated, each of which corresponds to a specific number of subsamples taken from each new sample. The axes of the graphs of the hyperbolas are the standard deviation of new measurements (horizontal axis) and the difference between the means of the new measurements and the standard population (vertical axis). The area between the two branches of each hyperbola corresponds to a satisfactory comparison between the new measurements and the standard population. Measurements from a new sample can be tested by plotting their standard deviation vs. difference in means on axes containing a hyperbola corresponding to the specific number of subsamples used. If the point lies between the branches of the hyperbola, the measurements are considered reliable. But if the point lies outside this region, the measurements are repeated. Because the critical segment of the hyperbola is approximately a straight line parallel to the horizontal axis, the test is simplified to a comparison between the means of the standard population and the means of the subsample. The minimum number of subsamples required to prove significant variation between samples caused by different lithologies in the source areas and sorting in transport can be determined directly from the graphical method. The minimum number of subsamples required is the maximum number to be run for economy of effort.     

虚拟仪器技术及其在电磁成像仪研发中的应用

本文介绍了虚拟仪器的基本概念、基本结构和特点,详细阐述了根据虚拟仪器技术开发的电磁成像仪的硬件结构、采集软件的功能和系统的总体特点.     

深圳岩溶空间发育规律统计分析

粤港澳大湾区建设是国家重大发展战略,而深圳市又是大湾区建设的核心引擎之一。深圳市岩溶地区行政区划上主要发育在龙岗区和坪山区,岩溶地质灾害给地下空间开发利用与城市安全构成极大挑战。通过收集深圳市岩溶勘察钻探数据,从地层岩性、基岩埋深与埋藏类型、地下水主要侵蚀指标、地下水埋深与年变化幅度、溶洞埋深、顶板厚度、洞高、充填情况、线溶率、见洞率、地表岩溶发育密度等方面对深圳市岩溶空间发育特征进行了统计分析。结果表明：深圳市岩溶主要为浅覆盖型,但溶洞空间特征变异性极大。从统计上讲,溶洞平均埋深约为20 m,平均洞高为2.5～4.0 m,以半充填为主,充填物主要为粉质黏土;平均线溶率约为15%,见洞率约为40%,地表岩溶发育密度超过300个/km²,综合上看,深圳场地岩溶发育等级超过90%为强发育。上述主要岩溶特征参数服从对数正态分布和Weibull分布。总体上,灰岩地层溶洞顶板厚度随着岩面埋深而呈现递减的趋势,而大理岩地层溶洞顶板厚度则与岩面埋深无关;已发育的溶洞高度与基岩面埋深、溶洞顶板厚度、地下水主要侵蚀指标及地下水埋深无关或弱正相关。研究成果为深圳市岩溶灾害风险评估提供了重要的先验信息。