典型俯冲和碰撞环境斑岩铜矿床成矿元素分布结构的复杂性及其矿化强度指示意义

The complexity of the spatial-temporal structure of metallogenic elements distribution is one of the hot topics in the metallogenic system research. Exploring the effective approach to quantitatively characterize the spatial-temporal structural complexity is of huge scientific significance to unravel the dispersion and aggregation mechanisms of metallogenic elements in the formation and evolution processes of the metallogenic system. In current study, two typical porphyry deposits (Pulang, Yunnan and Jiama, Tibet) generated in different tectonic settings (oceanic subduction and continental collision) are selected as study area. The fractal/multifractal and random field theory are employed to elucidate the spatial distribution and occurrence of the metallogenic elements in multiscale of deposit-body-mineral systems, and the nonlinear dependence of metallogenic elements distribution in the mineralization process and their cross interrelationship. The analysis of non-linear time-series and phase-space reconstruction method are applied to uncover the amount of the controlling factors for the enrichment of metallogenic elements, and dynamics behavior and evolution of the content sequence fluctuations. According to the entropy evaluation, the change of the dynamic structure of the migration and enrichment processes as well as the marginal feature of the chaos are identified. The simulation with interconnection method is utilized to reveal the complexity of metallogenic element structural distribution in the Cu deposits under tectonic settings of oceanic subduction and continental collision, and to seek its implication to the mineralization intensity. The research aims to provide novel theory and technical support to the prediction and assessment of the large scale of porphyry Cu deposits and other deep mineral resources.

成矿元素分布的时空结构复杂性是成矿系统研究的热点问题之一，探索定量表征其时空结构复杂性的有效方法，对揭示成矿元素在成矿系统形成和演化过程中离散与聚集的机制具有较重要科学意义。本研究以云南普朗和西藏甲玛两个典型斑岩矿床为例，采用分形/多重分形和随机场等理论，剖析矿床—矿体—矿石多尺度中成矿元素空间展布和赋存状态、演化过程中成矿元素组合分带的非线性依存关系及相互作用交叉相关性；利用非线性时序分析和相空间重构方法，阐释成矿元素富集的控制因素数量和成矿元素含量序列波动的动力学行为属性及演变规律；运用熵测度，识别成矿元素迁移、富集过程的动力学结构的变化及混沌边缘性特征；运用耦合建模方法，揭示俯冲和碰撞环境下斑岩铜矿床成矿元素分布结构复杂性特征与矿化强度之间的关联性，并探寻其对矿化强度的指示意义。可为超大型斑岩铜矿及深部矿产资源的预测与评价提供新的理论和技术支撑。

成矿元素分布结构的异常及矿化强度的差异是由于矿化过程的复杂、多重内生和外生动力学的综合叠加所致，对探明矿床成因和矿化富集规律具有重要意义。本项目主要利用复杂性和非线性的理论与方法，进一步探索定量表征成矿元素分布结构复杂性和动力学特征的有效方法，以揭示成矿元素在成矿系统形成和演化过程中离散与聚集的机制。项目结合地质数据特点，提出了基于不同除趋势方式的MFDMA、FF-MFDFA、MFDESA三种多重分形分析方法，并通过理想模型 (BMS和De Wijs)验证了这些方法的适用性和稳定性，可保证计算结果的可靠性和精度；将滑动技术与熵测度模型相结合，并利用周期函数、Logistic映射和Henon映射构造序列，模拟验证了M-SampEn、M-PermEn、M-DistEn模型可有效识别序列动力学状态改变，且优于传统滑动t检验和Mann-Kendall检验法，为解析成矿元素动力学复杂性特征提供了新的判据；运用上述三种多重分形方法，分析云南普朗和西藏甲玛斑岩型铜矿床成矿元素含量序列分布结构的复杂性，揭示了其多重分形特征与矿化强度之间存在的内在关联性；运用M-SampEn、M-DistEn模型和相空间重构技术，解析了云南普朗和西藏甲玛斑岩型矿床的Cu元素富集过程中动力学特征，探明云南普朗的强、中矿化和西藏甲玛的强矿化的Cu含量序列的动力学属弱混沌状态，指示不同构造环境下斑岩型铜矿的Cu元素的沉淀富集为复杂的混沌动力学过程。本项目研究的结果对深化认识和理解斑岩铜矿成矿过程的形成机理具有较重要科学意义，可为聚焦找矿靶区及深部矿产资源的预测与评价提供新的理论和技术支撑。