超大型矿床成矿复杂性特征与成矿动力学机制探索

The applied for subject chooses the super-large Gejiu Sn-Cu polymetallic ore deposit as a research object. Based on both the known research results and multi-scale geological, geophysical and geochemical information, the nonlinear methods will be applied to explore the ore-forming complexity of superlarge ore deposits, includes multi-sources of ore-forming matter, multiplicity of ore-controlling factors, multi-stage of mineralization and diversity of ore deposit types and so on. On this basis, the dynamical mechanism of ore-forming system evolution of from the ore-forming intrusive complex to the W deposit→ Sn - Cu deposit →Sn - Pb deposit→Ag - Sn - Pb - Zn deposit around it toward outside will be explored. The research focus on as follows: (a) exchanges both energy and matter of the ore-forming system with its environment,(b)self-organized critical characteristics of both multi-times of lost stabilities and bifurcations step by step of the ore-forming system caused by the the previous mentioned energy and matter cxchanges ,(c) the intrinsic connection between the lost stabilities and bifurcations and multi-stages of mineralizations as well as the diversity of ore deposit types. And then the dynamical model of ore-forming system evolution will be established to provide theoretical and technical supports for the quantitative prediction and evaluation of superlarge deposits.

申请课题拟以云南个旧超大型Sn-Cu多金属矿床为研究对象，基于多尺度地质、地球物理和地球化学等多学科信息，在已有研究成果的基础上，应用非线性技术，从成矿地球动力学背景→区域致矿异常因素→局部致矿异常因素等方面探索超大型矿床成矿的复杂性（包括成矿物质的多元性、控矿因素的多重性、成矿的多期多阶段性以及成矿类型的多样性等）特征。在此基础上探索以成矿岩体为中心，由内向外环绕成矿岩体形成的W矿床→Sn-Cu矿床→Sn-Pb矿床→Ag-Sn-Pb-Zn矿床系列成矿系统演化的动力学机制。重点研究热液成矿系统在演化过程中与环境多次进行能量和物质交换而相继失稳导致逐级分岔的自组织临界性特征，及其与成矿多阶段性和成矿类型多样性的内在联系。进而建立其成矿系统演化的动力学模型，为超大型矿床的定量预测与评价提供理论和技术支撑。

在对研究区超大型多金属矿床成矿复杂性分析的基础上，基于重磁和地球化学数据分别应用多维奇异值分解技术（Multi-dimensional Singular Value Decomposition, MSVD）和二维经验模分解技术 (Bi-dimension Empirical Mode Decomposition，BEMD)分别提取研究区区域与局部，深部与浅部致矿地质异常因素，获得个旧超大型Sn-Cu多金属矿床及其相关的壳幔混合型花岗质杂岩产于壳幔隆起的地球动力学背景，而薄竹山超大型Ag-Pb-Zn多金属矿床及其相关的壳源花岗质杂岩则产于壳幔凹陷的地球动力学背景这一重要研究成果。其科学意义在于从成矿地球动力学背景的角度，回答了为什么产于个旧的花岗质杂岩是壳幔混合型花岗岩，相关的超大型矿床为Sn-Cu多金属矿床；而产于薄竹山花岗质杂岩是壳源花岗岩，相关的超大型矿床为Ag-Pb-Zn多金属矿床这一关键科学问题。