【作者】 王中；

【导师】 宋传中；

【作者基本信息】 合肥工业大学 ， 矿物学、岩石学、矿床学， 2012， 博士

【摘要】 我国西部地区矿产资源潜力巨大,但地质勘查工作程度较低,因此对西部优势矿产资源潜力进行科学的评价预测,可以为该地区矿产勘查工作的科学部署提供依据。新疆东天山地区已经发现多个钼矿床,如白山钼矿床、小白石头钼矿床等,以及近几年来新发现的库姆塔格钼矿点和东戈壁钼矿床,这些钼矿床(点)中以斑岩型为主。因此,通过对东天山斑岩型钼矿资源开展潜力评价和分析工作,可以为进一步在该地区寻找新的矿床提供决策支持。同时,通过此项评价研究工作,本文引入了一些新的非线性数学评价方法,可以为未来的矿产资源潜力评价工作提供新的方法、手段和思路,对丰富矿产资源潜力评价方法体系可以起到一定的促进作用。本文依托国家科技支撑项目《西部优势矿产资源潜力评价技术及应用研究》(2006BAB01A01),对东天山钼矿资源进行了多源信息成矿预测。取得的主要成果和新认识如下：1.系统收集了东天山地区的地质、物探、化探、遥感等方面的基础数据,并对收集到的数据进行处理、分析、综合及提取。提取的主要信息包括：(1)基础地质信息：工作区内各已知矿床(点)及矿化点的信息、不同层次的容矿及控矿构造、与矿化有关的岩浆岩信息及矿化带、蚀变带、接触带、韧性剪切带、含矿岩石建造信息等；(2)化探异常信息：对工作区内39种元素的地球化学异常图及综合异常图进行了编制,对区域内异常信息进行了提取分析；(3)遥感信息：应用人机交互解译的方法,对研究区域的地质构造进行了提取；综合运用了主成分分析、掩膜技术和频率直方图法等进行了遥感蚀变信息的提取并绘制了遥感异常信息图；2.东天山地区作为全国固体矿产资源十六个重点成矿区带之一,是中国有色金属、贵金属的重要成矿带。从成矿历史上来看,成矿作用自前寒武纪(天湖铁矿等)至古生代(土屋和黄山铜矿等)和中生代(大南湖煤矿等)至新生代(一些盐类矿床)均有发生。从地质特征上来看,东天山地区具有一些特点,如：地层分布较齐全、沉积建造形式多样、地质构造环境复杂、岩浆活动较频繁、变质变形作用较明显,因此该地区成矿地质条件较优越。从地质工作程度来看,总体上,目前的工作程度仍然相对较低,因此近年来国土资源大调查工作在该区不断有新的突破,发现了一些新的矿床,如找到土屋延东斑岩型铜矿床、坡北铜镍硫化物矿床、东戈壁钼矿床等。因此,综合以上分析,可以认为,在该区系统开展地质勘查工作,寻找到大型甚至超大型矿床的可能性较大。3.通过对区域地质资料的分析,可以总结以下一些认识：(1)该地区内生金属矿床在空间上分布较为集中,总体特征呈现“南铁中金北铜镍”的特点；从构造环境上看,内生矿产主要产于准噶尔地块和塔里木地块的古生代活动带上。从空间展布规律来看,其受到地壳演化过程中一定阶段的构造环境和相对应的成矿作用的控制。(2)从区内斑岩型钼矿的控矿条件来看,该类型矿床的控矿因素主要包括：中酸性侵入岩、控制中酸性侵入岩的深大断裂、控制矿体就位的次级断裂发育。此外,该类型钼矿床普遍发育有较强的围岩蚀变,成矿有利地层主要分布在石炭纪。构造方面,区内以北东东向断裂为主,这些断裂的交汇部位是有利的控矿构造。此外,区内还发育多期次的岩浆侵入活动,特别是华力西期岩浆活动对该类型矿床成矿较为有利。4.在多源信息处理方面,为更加合理和有效地圈定化探元素异常区域,本文对研究区内水系沉积物的地球化学数据进行了较为系统地统计分析,结果发现各地球化学元素具有复杂非线性关系,如分形特征。本文通过对东天山地球化学异常信息提取这项工作,在该地区率先实验了两种方法包括传统的对数正态分布截尾法和非线性方法C-A多重分形法来进行异常下限的确定并进行了效果的比较,结果显示后者确定的结果更为准确合理。本文据此圈定了多处Mo、Cu等金属元素异常区域。此外,在研究区的遥感信息处理上,本文提取了一批线、环型断裂和蚀变异常区域。并在此基础上,推断得出了一些具有成矿潜力的隐伏岩体；上述的多源信息表明该区在钼矿资源方面有良好的成矿前景。5.采用多源信息找矿模型对研究区的斑岩型钼矿进行了成矿预测。首先,较为系统地分析了该地区已有斑岩型钼矿的成因模式和产出模式,对各类矿化信息、找矿标志和综合异常信息等进行了详细的梳理,得出该地区斑岩型钼矿成矿、控矿规律与各地学影响因素间的关系,确定了5大类预测变量(地层、构造、岩浆岩、化探、遥感)为建立模型建立奠定扎实基础。由于东天山钼矿资源已知样本较少,传统的矿产资源预测方法如证据权法、特征分析法和非线性的BP人工神经网络法等皆不适用于这一地区的钼矿资源预测工作。鉴于此,本文率先使用了非线性的Kohonen人工神经网络法进行了少模型预测。此种方法不依赖预测区域的样本数量,实行非监督分类方法。分类结果显示两个典型矿床皆落入A类成矿有利区域,证明分类效果较为可信。预测结果表明该法具有操作简单、方便的特点,是一种较为快捷、有效的预测方法。6.全面收集了全国最新的矿产资源储量数据,建立了全国78个斑岩型钼矿的品位一吨位模型,利用蒙特卡罗模拟对资源量进行估算,预测结果得到在90%的概率下,东天山地区斑岩型钼矿预测资源量占已发现资源量的143.5%,预测结果说明东天山地区斑岩型钼矿资源仍具有一定的找矿潜力。更多还原

【Abstract】 In western China, mineral resources potential is tremendous, but geological exploration is low. So the scientific potentiality assessment for the western China’s advantage mineral resources, can provide the basis for the scientific deployment of mineral exploration work. Some molybdenum deposits were found in East Tianshan mountain area. These molybdenum deposits are with porphyry type primarily. Therefore, through the potential resources evaluation and analysis of molybdenum deposits with porphyry type in East Tianshan mountain area, some decision supports can be provided further in order to look for some new deposits. At the same time, through this evaluation research work, some new nonlinear mathematical evaluation method can be introduced to provide new thoughts in the the mineral resources evaluation in the future. So, for riching mineral resources evaluation method system, this work plays a certain promoting role.This paper based on the national science and technology support project:the research of potential evaluation technology and application on western advantage mineral resource (2006BAB01A01), achieved multisource metallogenic prediction for molybdenum resources in East Tianshan mountain area. The main achievements and new cognition as follows:1. Collecting the data of geological, geophysical exploration, geochemical exploration and remote sensing systematically in East Tianshan mountain area. And the processing of comprehensive analysis and extraction for the collected data included that:(1) fundamental geological information:the information of all the known deposits and mineralization points, different levels of let ore and the ore-controlling structures, mineralization relevant magmatic rocks information, mineralization belt, alteration zones,contact zones, ductile shear belts, contained mineral rock, etc.(2) geochemical anomaly information:drawing the39elements in the geochemical anomaly and comprehensive anomalies map of the area, and extracting and analyzing the the anomaly information with the area.(3) remote sensing information:Application of man-computer interactive interpretation method to extract the geological structure; using the principal component analysis, membrane technology and frequency histogram to extract the alteration of remote sensing information and drawing the remote sensing anomaly information maps.2. East Tianshan mountain area, as the one of the16major mineralization zones about solid mineral resources, is the important China’s ore-forming belt of nonferrous metal and precious metals. From the metallogenic history, the metallogenesis have happened since the Precambrian metallogeny (heavenly lake iron deposits, etc) to Paleozoic (Tuwu and Huangshan copper deposits, etc) and since the Mesozoic (Huge south lake coal, etc) to the new generation (some salt deposits). From geological features perspective, East Tianshan mountain area has some characteristics:completely strata distribution, various sedimentary build, complex geological structure environment, frequently magma activities, obvious metamorphic deformation effect. So, the region ore-forming geological conditions are the superior. From geological work ways, in general, the current work level is still relatively low. So, in recent years, investigation of the resources in the area broke new ground, some new deposits found, such as Tuwu porphyry type copper deposits, Pobei Cu-Ni sulfide deposits, East gobi molybdenum deposits, etc. Therefore, in conclusion, it can be argued that, it is very likely to discover some large even superlarge deposits from geological exploration in the future.3. Through the analysis of the regional geological data, the following cognition can be concluded:(1) The endogenous metal deposits in the distribution were relatively concentrated in the area. General characteristic of present is south iron, middle gold, north copper nickel. From structural environment, endogenous mineral resources are mainly generated in Junggar plot and Tarim plot of the terrigenous Paleozoic activities belt. From the spatial distribution law, endogenous mineral resources are mainly controlled by tectonic environment and the corresponding mineralization in the evolution process of earth’s crust is with a certain stage.(2) From the ore control conditions of porphyry type molybdenum deposits, the ore-controlling factors of this deposits type including:the neuter and acidic intrusive rocks, deep fault that control acidic intrusive rocks, second-order faults that control the development of orebody in place. In addition, there is a stronger development of wall-rock alteration in this type of molybdenum deposits generally, and the favorable mineralization strata were mainly distributed in the carboniferous. Tectonically, the fracture is given priority to NNE, the magmatism in Variscan period is favorable ore-controlling for the deposits type.4. In multi-source information processing, this paper statistically analysed stream sediments geochemical data in this area. The results indicated that there is a complicated nonlinear relation between the geochemical elements such as the fractal characteristics. This paper extracted the East Tianshan mountain geochemical anomaly information to delineate the geochemical element anomalies areas. For making the work reasonable and effective, the paper take the lead in the two methods including traditional logarithmic normal distribution truncated method and nonlinear method C-A multiple fractal method for the determination of abnormal information. Comparison of the two methods, the results showed that the latter determine the result was more accurate and reasonable.The author delineated the Mo and Cu abnormal area on the basis of the above results. In addition, in the remote sensing information processing work, this paper extracted a batch of line and ring type faults and altered anomaly areas. And on the basis, it has come to some of the potential metallogenic concealed rock mass. From the multisource information, it is indicated that the molybdenum resources in this area was with a good metallogenic prospects.5. This paper taking the multisource information prospecting model to study the metallogenic prediction for porphyry type molybdenum deposits in East Tianshan mountain area. First of all, the genetic mode and the output mode for porphyry molybdenum deposits were analysed systematically, all kinds of information for mineralization, ore-prospecting criteria and comprehensive anomaly information in detail were concluded. The relationship between affecting factors such as the metallogenic and ore-control regularity for porphyry type molybdenum deposits was learned. The5prediction variables types (stratum, geological structure, magmatic rocks, geochemical exploration and remote sensing) are used to establish the model.Due to the less samples for the konwn molybdenum resources in East Tianshan mountain area, the traditional mineral resources prediction methods such as weights of evidence method, characteristics analysis method and nonlinear BP artificial neural network method are not fit for molybdenum resources prediction in the area. In view of this, the paper took the lead in using Kohonen nonlinear artificial neural network method for the the less models prediction worLThis method is not dependent on the sample numbers of forecast area, implementing the principle of unsupervised classification. Classification results show that two typical molybdenum deposits fall into "A" class of mineralization favorable area. It is supposed to the classification effect was more credible. Prediction results show that the method has characteristic of simple operation. It is a kind of relatively fast and effective forecast method.6. The latest China’s mineral resource reserve data was collected comprehensively. The grade-tonnage model of national78porphyry type molybdenum deposits was established. The resource was estimated by Monte Carlo simulation. The forecast results of the porphyry type molybdenum resources that the proportion accounts for43.5%compared with the discovered resources with90%probability. The forecast resources results of porphyry type molybdenum show that there is still some of the prospecting potential in East Tianshan mountain area.更多还原