共查询到18条相似文献，搜索用时 290 毫秒
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在岩石地球化学理论的框架下,用该领域专家在实际工作中的思维方法来描述岩石地球化学数据处理与分析的固有流程,以岩石地球化学参数和图解为应用研究对象,利用岩石地球化学与计算机软件技术交叉的研究方法,概括岩石地球化学数据的特征及其处理方法。通过对双变量图解、三变量图解特征的分析,将数据计算分为主量和微量元素相关参数计算、主量和微量元素标准矿物计算、同位素相关计算,设计合理、有效的算法,实现岩石地球化学图解的数据管理、分类、参数选择与计算、表达式识别、绘制、坐标转换、投点等图解成图全过程的自动化。 相似文献
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本文的自动图解判别的岩石化学系统，是和计算机代替代人工完成地质图解方法中的绘图，计算与样品投点等工作，实现图解过程的全部自动化，不但大大提高了工作效率，而且保证了样品投蹼的准确性。 相似文献
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关于岩石微量元素构造环境判别图解使用的有关问题 总被引：42，自引：9，他引：42
赵振华 《大地构造与成矿学》2007,31(1):92-103
针对目前应用愈来愈广泛的不同岩石,特别是岩浆岩的微量元素构造环境判别图解使用过程中存在的问题,从这些判别图解建立的原理,介绍了微量元素构造环境判别图解的使用原则。强调指出所采集的样品必须新鲜(无蚀变或极弱蚀变)、非堆晶的岩石;选择的判别图解必须与判别的岩石类型相一致,即对花岗岩类要用花岗岩的判别图解,不能用玄武岩的判别图解;对特殊类型岩石要选择专门用于该类型岩石的判别图解,如碱性花岗岩,钾质火成岩;要应用多种图解综合判断;不能用单个样品,而应作多个样品分析;要注意所选择判别图解的特别说明等。此外,一些构造环境判别图解还能给出岩石的成岩过程和源区。 相似文献
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地球化学数据统计分析图解是目前岩石地球化学研究工作中常用的手段。目前常用的软件或多或少都存在一些不足之处。本文提出的MATPLOT是一款应用MATLAB编写而成的地球化学数据成图软件,可以在Windows/Mac OS/Linux多种操作系统平台中运行。与现有常用软件相比,该软件更具优势:可以更方便地实现较大地球化学数据量的导入,无需对数据进行繁琐的格式整理;更便捷地对数据进行二元散点图、三角图、标准化折线图、柱状图、概率密度图和同位素演化图等6种常用图解类型的成图,以及对数据图的展示内容和效果进行各种调整。此外,MATPLOT还可以对数据进行多种平均值计算(普通平均值、图基双权加权平均值和误差相关加权平均值)和相关性分析。 相似文献
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应用常量元素、微量元素对岩浆岩进行构造环境、成因及岩源示踪时 ,首先必须在宏观区域地质、地球化学调查基础上 ,结合当时所形成的各类地质体岩石类型组合来恢复 ,它是宏观构造环境判别的基础 .其次 ,由于构造环境时空复杂性 ,需采用“两结合”的研究方法 ,一是多元地球化学信息示踪 ;二是不同岩类的时空配套 .第三 ,在选择判别图解时 ,需弄清前人图解的应用前提、适用范围和条件 ,以正确投点 .在此思想指导下 ,侧重对滇西北金沙江结合带各磨茸中酸性岩体进行了常量、微量元素的多元地球化学示踪 ,获得了较好的效果 相似文献
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地质地球化学图解自动绘制的技术研究 总被引：1，自引：0，他引：1
介绍的软件及绘制技术成功地处理报目前国内文献发现的１００多幅常用的地质地球化学图解的自动化绘制问题。其自动化程度、工作效率及精度均较高,适用性极强。除绘图功能外,该软件还具有扩充功能和彩色绘图及彩色输出功能。 相似文献
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地质地球化学图解的计算机绘图系统 总被引：2，自引：1，他引：1
根据目前国内外发表的常用地质地球化学图解特征,研制了一套容纳１５０多幅常用地质地球化学图解的绘图系统。系统界面友好,操作方面,适用性极强,具有可扩充性。 相似文献
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浙江龙泉地区变质基性岩年代学、地球化学特征及构造意义 总被引：1，自引：0，他引：1
浙西南龙泉地区集中出露一套中深变质岩系,是华夏地块的重要组成部分,对其形成时代和成岩构造属性等问题历来存在争议。本文通过对龙泉变质岩中变质基性岩的地球化学研究,认为这些岩石的原岩成岩环境至少有两类:Ⅰ类岩石稀土配分曲线、微量元素蛛网图特征均显示与IAB的相似性,微量元素比值和图解判别均指示这套岩石形成于与俯冲有关的岛弧构造环境;Ⅱ类岩石稀土配分曲线和微量元素蛛网图均与OIB有相似性,微量元素比值和图解判别也指示这套岩石形成于与俯冲无关的OIB构造环境。多种不同构造属性的岩石共生,佐证了原龙泉岩群变质岩系为一形成于早古生代的俯冲增生杂岩。变质基性岩锆石U-Pb测年获得其峰期变质时间为404~402Ma。龙泉俯冲增生杂岩的厘定对重新认识丽水-余姚断裂带构造属性、区域构造格架的建立以及进一步分析华夏造山系物质组成与结构提供了新资料。 相似文献
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An evaluation of the Rb vs. (Y + Nb) discrimination diagram to infer tectonic setting of silicic igneous rocks 总被引：25，自引：0，他引：25
The most commonly used tectonic discrimination diagrams for granites were introduced by Pearce et al. [Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J. Petrol. 25, 956–983.]. Since then, many studies have shown that some granites defy classification or their geochemical assignment does not fit with the geodynamic environment in which they are thought to have formed. In this paper we evaluate the performance of the Pearce et al. tectonic discrimination method, specifically, the most widely-used Rb-(Y + Nb) diagram, using a new data base of over 250 occurrences worldwide, the tectonic settings of which are fairly well known. We conclude that a correlation of geochemistry and tectonic position exists, but that ambiguities and misclassifications arise from one or both of the following factors. First, complex or polyphase orogeny can mix source rocks of different tectonic provenance. This is common in continental arcs and collisional settings, which can be closely associated in space and time with extensional regimes. Second, differentiation can produce compositional trends which cross field boundaries, especially the VAG to WPG boundary. One can minimize this problem by using less felsic, noncumulate members of cogenetic series.
We demonstrate the inherent weaknesses of trace element tectonic discrimination diagrams. Such diagrams are of little use if applied alone, but they can be valuable in combination with other methods such as dating and geologic assessment. 相似文献
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蛇绿岩生成构造环境的Ba-Th-Nb-La判别图 总被引：58，自引：24，他引：58
Pearce的Ti-Zr-Y图不能很好区分洋脊和岛弧玄武岩,Ti对岩浆分离结晶作用很敏感,因此用这个图判别蛇绿岩生成构造环境效果不好,本文利用分配系数相近的Ba,Th,Nb,La四个非常不相容元素的(Ba/Nb)-Ba,(Nb/Th)-Nb,(La/Nb)-La和(Ba/Nb)-(Th/Nb)图解很好区分了洋脊、岛弧、洋岛玄武岩。弧后盆玄武岩同时具有洋脊和岛弧玄武岩的特征。这些元素在海水蚀变中较稳定,它们的比值在分离结晶过程中保持不变,因此这些图解有利于判别蛇绿岩(包括熔岩和均质辉长岩)生成的构造环境。 相似文献
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John S. Armstrong-Altrin 《International Geology Review》2015,57(11-12):1446-1461
Two discriminant-function-based multidimensional major-element diagrams for the tectonic discrimination of siliciclastic sediments were recently published from a coherent statistical methodology of loge-ratio transformation and linear discriminant analysis. These diagrams were constructed based on worldwide examples of Neogene–Quaternary siliciclastic sediments from known tectonic settings. In this work, these two tectonic discrimination diagrams were first successfully tested from Holocene (<0.0117–0 Ma) beach and deep-sea sediments from the Gulf of Mexico. These diagrams were used to decipher tectonic settings of 11 case studies of the Precambrian clastic sedimentary rocks (~512–2800 Ma) from Argentina, USA, Ghana, Spain, Norway, India, China, and Australia. The test and application results obtained from these discrimination diagrams were generally consistent with the geology of the Precambrian source areas. Therefore, the two multidimensional diagrams can be considered as a useful tool for successfully discriminating the tectonic setting of older sedimentary basins, which may consist of one or more tectonic assemblages. Comparison of results of this study with the previously published tectonic discrimination diagrams is illustrated and the probable reasons for some inconsistent inferences were also discussed. 相似文献
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A. V. Maslov V. N. Podkovyrov G. A. Mizens A. D. Nozhkin A. M. Fazliakhmetov A. I. Malinovsky A. K. Khudoley L. N. Kotova A. V. Kuptsova E. Z. Gareev R. I. Zainullin 《Geochemistry International》2016,54(7):569-583
An attempt is made to compare discrimination diagrams of the first (mid-1980s) and second (early 2010s) generations compiled using data for sedimentary successions of different ages. Our results suggest that the diagrams of different generations allow more or less correct discrimination only between the platform, rift, passive margin, and island arc settings. The data for collision sediments do not form separate fields in these diagrams. 相似文献
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Surendra P. Verma Lorena Díaz-González John S. Armstrong-Altrin 《Earth Science Informatics》2016,9(2):151-165
TecSand is a new Java software that is used for deciphering the tectonic setting of clastic sediments and sedimentary rocks through two new multidimensional discrimination diagrams. For each sample, TecSand calculates four complex discriminant functions: DF1m1 and DF2m1 for the high-silica diagram and DF1m2 and DF2m2 for the low-silica diagram, each representing linear combinations of log-ratios of all major elements. These functions determine the position of each sample within island or continental arc, continental rift, and collision/convergent settings. The program also calculates the probability values for the three tectonic fields. TecSand provides a “ready for publication” report for each locality, including the adjusted major elements, log-transformed variables, DF1 and DF2 results, and probability values for individual samples. Validations from samples of known tectonic settings, evaluation of chemical changes, and applications to Precambrian clastic sediments have previously been demonstrated in the literature. Therefore, we illustrate the use of TecSand in 10 case studies covering ages from the Early Cambrian to the Holocene. The results obtained from these two diagrams were not only mutually consistent but also with other geological constraints. As an innovation, TecSand provides an overall synthesis of the two diagrams as total percent probability values. Comparison of the results of this study with the previously published tectonic discrimination diagrams reveals that two recent multidimensional discrimination diagrams are more efficient in discriminating tectonic settings. Although TecSand does provide graphics, which can be imported and modified in commercial software, plotting of the sample diagram is no longer required. 相似文献
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N. E. Kozlov E. V. Martynov N. O. Sorokhtin A. A. Ivanov N. M. Kudryashov N. E. Kozlova 《Geochemistry International》2008,46(6):608-613
Rock associations characterized by heterogeneous sets of petrogeochemical parameters were compared by quantifying the degree of their similarity-dissimilarity and searching for discrimination trends between them. Using procedures specially developed for this purpose, it was demonstrated for the first time that the lithotectonic complexes of the Murmansk domain are fundamentally different from those of typical granulite-gneiss terrains and resemble the granite-greenstone terrains of the Baltic shield, Greenland, and Canada. Based on the whole data set, the Murmansk domain can be considered as a deeply eroded Archean granite-greenstone terrain retaining only the tonalite-trondhjemite-gneiss basement with abundant supracrustal enclaves. A trend of the compositional difference between the older and younger rock associations is similar to that between the tholeiitic and boninitic volcanic series. It was suggested that the petrogeochemical “age” trend reflects the initial stage of the compositional evolution of the metamagmatic rocks of the region from metamorphic rocks similar to tholeiites at the early stages to the Paleoproterozoic boninite-like rocks, which are believed to be linked to the unique PGE-bearing province of the northeastern Baltic shield. This implies that the specific metallogenic features of the region emerged already in the Archean, which supported the suggestion on the long duration of geological processes in the Early Precambrian. 相似文献
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Petrologic hypothesis testing with Pearce element ratio diagrams: derivation of diagram axes 总被引：3，自引：0，他引：3
In petrology, Pearce element ratio (PER) diagrams have been used: i) to determine whether members of a rock suite are co-genetic, ii) to identify the minerals involved in differentiation processes, and iii) to evaluate the extent to which those mineral are involved. The axis coefficients of each diagram are chosen such that sorting of minerals or combinations of minerals will generate unique and predictable trends. Unfortunately, selection of the optimal combination of axis coefficients is a difficult task, especially if the system being investigated has a large number of phases or complicated solid solution minerals. Our work has established a formal set of rules and matrix operations which facilitate the determination of PER diagram axes coefficients. This methodology can be used to determine the unit molar vector displacement caused by the addition or subtraction of a specific mineral, given a set of axis coefficients. It can also be used to create PER diagrams on which minerals have predetermined vector displacements. By designating all vector displacements to be parallel, axis coefficients for assemblage test diagrams can be determined to test the following hypothesis: the observed chemical variation is due to the addition (or removal) of a specific set of minerals. Alternatively, by designating all vector displacements to be mutually perpendicular, phase discrimination diagrams can be created which test whether the observed chemical variations require a specific phase to be involved in differentiation. Phase discrimination diagrams also provide a means to estimate the extent of that involvement. This methodology facilitates construction of powerful yet simple PER diagrams which provide an effective means of testing alternative differentiation hypotheses.
Current address: Department of Geological Sciences, Queen's University Kingston, Ontario K7L 3N6, Canada 相似文献