沙漠-草原覆盖区矿产综合预测理论与隐伏矿床含矿信息提取方法

Mineral resources prediction and mineral exploration in areas with extensive Quaternary and Ternary covers has globally attracted substantial attention in several fields of geosciences and mining industry. Widespread cover sequences of various types mask potentially mineralized basement and the effects of covers on mineral exploration are from reducing to completely block geochemical anomalies caused by buried mineralization. The general geochemical exploration techniques have been found with less success in covered areas than in outcropped areas in supporting mineral exploration. The key challenges in prediction mineral deposits in covered areas identified may include but not limited to “weak information”, “overlapped information” and “incomplete or missing information” caused by covers especially by transported thick covers. In this proposal, the main objective of study is to develop proper theories and effective methodologies and techniques for predicting mineral resources in two covered areas. A region in Tianshan mineral district with extensive desert covers in Xinjiang and a region in southern Daxinanlin mineral district with Quaternary and Ternary deposits in Inner Mongolia of China are chosen as study areas. Iron, Copper, Molybdenum, Tungsten, Lead and Zinc ore deposits of porphyry, skerns and hydrothermal types are considered and several world-class mineral deposits are used to create mineral deposits models and exploration models for data interpretation and quantitative modeling. Three main problems to be studied are: (1) the mechanism of generation of geochemical anomaly and nonlinear property of distribution of ore trace element dispersion in covers. Systematic sampling and comprehensive geochemical and mineralogical properties of trace elements and mineral associations, texture-structures and isotopes of rocks and soils in drill cores and vertical and horizontal profiles are conducted in the study areas in order provide guidance for application of geochemical exploration techniques and interpretation of geochemical anomalies; (2) innovative nonlinear models and methods are developed in the contexts of fractals, multifractals, singularity and generalized self-similarity for processing geological, geochemical, geophysical and remote sensing data for extracting weak anomalies caused by buried mineralization and for decomposing overlapped components related to mineralization from those affected by other processes; (3) new models including modified weights of evidence models are investigated for diverse geo-anomalies extracted and related to mineralization for probabilistic prediction of locations of mineral resources in covered areas. New theoretical models and methods are demonstrated for several mineral deposit types using existing database including geological, mineralogical geochemical and geophysical data from 1:200,000 to 1:50,000 scales, and also validated by relevant field ground truth investigations.

沙漠-草原覆盖区分布范围广、资源潜力大、找矿难度高倍受国际关注，覆盖区找矿理论和勘查方法技术创新也已成为当今国际矿产资源领域十分重要的前缘研究课题。覆盖层可以导致找矿信息“弱缓”、“复合和叠加”、“缺失和不完整”等影响，造成找矿困难。本项目以新疆东天山戈壁沙漠覆盖区和内蒙大兴安岭南部草原覆盖区为示范研究区，以斑岩型、矽卡岩型和热液型铁、铜、钨、钼等内生金属矿床为主要研究对象，开展深部成矿物质和成矿元素在覆盖层中的扩散、迁移、富集变化规律的定量模拟研究，探讨在地表介质中形成地球化学弱异常的机理和特征,在此基础上，从非线性理论出发研究弱异常提取、变化背景和叠加异常分解、综合异常集成的定量模型和方法。力争在深部矿化有关的地质-地球物理-地球化学-遥感等找矿信息提取原理和方法以及对覆盖区异常形成机理的研究中获得重要创新成果，丰富和完善非线性矿产预测理论和方法，为覆盖区矿产预测提供有效的科技支撑。

国内外多年来的研究表明，受覆盖的影响，导致在覆盖区找矿的主要困难包括：能获取的深部含矿信息主要为间接信息，且信息微弱；获取数据的方式主要依赖探测和测量，取得的信息大多数为复合叠加信息；以小样本观测为主，常常会信息缺失或不完整。本项目选择沙漠戈壁覆盖区和草原覆盖区，以与岩浆活动有关的铁、铜、钼、钨等内生金属矿床为主要研究对象，开展覆盖区矿产综合预测理论和深部矿床含矿信息的提取方法研究。具体研究内容包括：. （1）研究内生成矿系统的矿物与元素空间聚散的奇异性和矿化系数及在成矿域中的变异性，揭示成矿系统的结构的复杂性；（2）揭示深部成矿物质和成矿元素在上覆盖层中的扩散、迁移、富集、保存机理和变化规律；（3）探讨有效识别和解释地球化学弱异常的原理和非线性分析方法，提升深部源异常圈定与识别的能力；（4）探讨多元地学信息综合处理和融合模型，提高异常识别和靶区圈定的可靠性；（5）选择典型示范研究区，在已经建立的地质、地球物理、地球化学和遥感GIS综合数据库基础上，开展矿产资源潜力预测与评估，为类似覆盖区开展相应工作提供方法与示范。. 本项目在研究过程中，通过揭示典型研究区（沙漠戈壁覆盖区和草原覆盖区）隐伏矿引起的地球化学异常形成机理，定量评价了覆盖区地球化学异常形成的可能特征和分布规律，建立了适合覆盖区深部矿床含矿信息的提取技术和矿产预测信息融合模型，攻克制约覆盖区矿产预测的难题，形成和完善矿产综合预测新理论和方法体系，为提高覆盖区矿产预测和勘查水平作出努力。主要成果包括：（1）完善了极端事件定量模拟和预测的奇异性理论，为覆盖区矿产预测奠定了理论基础；（2）完善了覆盖区矿产非线性预测的理论与方法；（3）基于非线性理论研究推进了对于成矿系统的认识；（4）非线性理论及算法的拓展和应用。