构造动力体制与成矿环境及成矿作用——以三江复合造山带为例

Metallogenic environment and mineralization in different tectonic dynamic system: A case study of Sanjing compound orogeny

现代矿产地质勘查工作正在由过去的单一找矿向系统找矿转变,系统找矿依赖于对成矿环境的厘定以及对不同环境中成矿系统/成矿作用的确认和与之相应的矿床组合时空和成因联系的构筑。构造动力体制是研究成矿环境的基础,其演化决定了成矿环境的区域配置和时空变换。每一种构造动力体制下的成矿环境都可归结为挤压和拉张两种性质。在大洋构造动力体制下,成矿环境与成矿作用主要发生在板块边缘,包括离散和汇聚两种边缘。洋中脊、岛弧和陆缘弧以及在弧构造中发育的不同性质和规模的盆地是成矿的重要场所,板块自身特点、俯冲过程、深度和状态的变化是决定板块边缘成矿环境配置和成矿作用的重要因素;在大陆构造动力体制下,主要地质环境包括(大陆内部)深大断裂构造活动、地幔柱或热点、岩石圈加厚到大规模减薄、陆内造山、陆内裂谷等,不同环境形成了独具特色的成矿作用和矿床类型;在转换构造动力体制下,碰撞-伸展造山和造洋裂谷是两个相对应的构造过程,由其形成的成矿环境独具特色,成矿作用丰富多彩。以西南江三复合造山带为例,具体讨论了不同成矿环境下成矿作用特点,形成的矿床类型及相关矿床组合,可视为复合造山成矿论的雏形。

Modern mineral geological exploration is changing from single prospecting to systemic prospecting, and the systemic prospecting depends on redefinition of the metallogenetic environment and its confirming for the metallogenetic systems or mineralization along with the building of relationships of spatial-temporal and genesis of the corresponding deposit combination. Tectonic dynamic systems are base of study metallogenetic environment, which evolution decides regional metollagenetic environment spatial framework and its spatial-temporal transition. The metallogenetic environment in every tectonic dynamic system could be divided into extensional and extrusional. In oceanic tectonic dynamic systems, metallogenetic setting and mineralization mainly happened in the plate margins, which include dispersed plate margins and converging plate margins. Oceanic bridge, island arc, continental margin arc, different natures and scale basins developed in arc tectonic setting, which are all important metallogenetic space, and the plate itself features, the changing of process and depths and state about the plates subduction are important factors of deciding metallogenetic setting and mineralization in the plate margins; In continental tectonic dynamic systems, the main geologic setting including deep and giant faults tectonic activity, the mantle plumes or hot spots, the lithosphere increased to scales of delamination, intracontinental orogeny, intracontinental rifts valley etc., and various metallogenetic setting developed peculiar mineralization and deposit types; In transformed tectonic dynamic system, collision-extensional orogeny and developing oceanic rifts are two reverse tectonic processes, in which formed special metallogenetic environment and a lot of kinds of mineralization. The paper takes the Sanjinag compound orogeny as an example, mainly discusses metallogenetic features in all metallogenetic setting and in which deposit-type and corresponding deposit combination developed.