黔西北富银铅锌矿集区冲断褶皱构造系统的成矿机制及找矿潜力分析

The characteristically metallogenic system of thrust-fold structures and more than forty small-scale and medium-sized Zn-Pb deposits (mimeral points) occur in the Northwestern Guizhou deposit concentration area due to the special tectonic background. These deposits are similar to those in Northeast Yunnan, but they are different from the known types of Zn-Pb deposits around the world. Therefore, study on the metallogenic mechanism of thrust-fold structure system and ore-finding prognosis potential in Northwestern Guizhou have the great geo-scientific research value and the huge economic significance. The Shashulin and Changpingzi-Wuliping Zn-Pb deposits are dissected to study in the project. The Weining-Shuicheng and Yadu-Mangdong thrust-fold structure belts will be finely dissected under the guidance of the mainline for evolution of tectonics-fluid ore-forming system in order to portray the dynamic processes of metallogenic geology, ore-forming structure and the metallogenic fluid and to clarify tectonic evolution sequence and tectonic deformation sequence. Also, the research project will enclose three links which are metallogenic geological-body, metallogenic tectonics and ore-forming fluid. The metallogenic mechanism of thrust-fold structure has been in-depth studied from the coupling relationship of essential factors, which are ‘Time, Space and Substance’, and ‘Sources, Transportation and Storage’. This research can deeply reveal metallogenic mechanism, clarify the supernormal enrichment process of lead, zinc and silver in the ore-forming fluid evolution, conclude deposit positioning mechanism and space-time distribution, set up the metallogenic model of fluid "injecting", summarize prospecting criteria rules and the regularities of orebody location, analyze the resource potential of large-sized ore deposits. These will certainly have important guiding significances for innovatiing ore-forming system theory and finding similar type of large- and medium-sized deposits in the Sichuan-Yunnan-Guizhou poly-metallic ore-forming province, and provide theoretical support for creating Chinese characteristic deposit models.

黔西北矿集区因特殊的构造背景造就了冲断褶皱构造成矿系统和40余个中小型铅锌矿床（点），这些矿床有别于国内外已知类型的铅锌矿床，具有很高的研究价值和巨大的经济意义。拟解剖杉树林、长坪子-五里坪等矿床，以构造-流体系统演化研究为主线，通过威宁-水城、垭都-蟒洞两条冲断褶皱构造带的调查，刻画典型矿床的成矿地质动力学、成矿构造动力学、成矿流体动力学过程，理清构造演化序次及构造变形序列；围绕“成矿地质体、成矿构造及成矿流体”三环节，从“时、空、物”与“源、运、储”诸要素的耦合深入研究冲断褶皱构造的成矿机理，阐明铅、锌、银的富集机制、流体演化过程及矿床时空分布规律，初建该类矿床构造-流体“贯入”成矿模型，总结矿体定位规律和找矿标志，分析该区形成大型矿床的资源潜力。本研究必将对川-滇-黔多金属成矿域成矿理论创新与同类大中型矿床的发现具有重大的指导意义，并为创建中国特色的矿床模型提供基础支撑。

针对制约黔西北矿集区深部找矿突破的大陆动力学背景及其成矿响应机制、成矿构造体系及其对铅锌成矿系统的控制机理、铅锌超常富集成矿机制、远景区评价和矿床深部靶区圈定等系列科学问题，开展了斜落走滑构造及其成矿响应解析、典型矿床精细解剖、矿集区MT剖面探测、流体成矿实验、成矿系统构建、构造-流体“贯入”成矿机制、远景区资源潜力和重点靶区优选等研究，并应用构造地球化学、蚀变岩相填图等方法，取得如下主要研究进展： .1. 发现川滇黔成矿区构造-流体耦合成矿时代具一致性（228~194Ma）、成矿期联合构造应力场作用具统一性的特点，提出了铅锌成矿事件是印支期碰撞造山作用诱发形成的古特提斯洋关闭的成矿响应产物，矿床形成于印支期碰撞造山过程的陆内走滑构造系统，揭示了矿床时空分布规律，深化了印支期铅锌成矿的大陆动力学背景的认识。.2．解析并厘定了矿集区控矿断褶构造组合样式和NE构造带成矿构造体系，阐释了矿集区构造成生发展过程，揭示了构造分级控矿规律、矿床成矿规律及成矿构造体系对流体运移和沉淀成矿的控制机理，构建了黔西北矿集区斜落走滑构造控制型铅锌成矿亚系统，建立了铅锌矿床构造控矿模式，否定了NW构造带成矿构造体系的传统认识。.3．研制和创新了两套高温高压流体成矿实验设备和成矿动力学实验新方法，发现成矿流体pH、流体运移驱动力、水解、水岩反应共同制约着铅锌矿床的形成，揭示了铅锌超常富集成矿机制，认为铅锌水解程度不同是造成矿床品位悬殊的主要原因。.4．构建了矿床“三位一体”找矿预测地质模型及其应用步骤，提出了“矿集区深部探测与矿产评价；矿田（床）构造解析与典型矿床建模；构造地球化学-蚀变岩相填图与深部靶区圈定和重点靶区验证与技术深化”的找矿预测流程，圈定了17个找矿远景区和22个重点找矿靶区，预测该区铅锌找矿潜力巨大。.本成果必将对川滇黔成矿区成矿理论创新与同类矿床发现具有重要的指导作用，为创建特色的铅锌矿床模型提供理论支撑。