摘要
本文以内蒙古中部后石花金矿为例,简述了“韧性剪切构造成岩成矿作用”的新观点。研究表明,韧性剪切成岩过程包括细粒化作用、热流体作用、酸碱交代作用;韧性剪切带这种深层次断裂构造形成过程中,其推覆演化是逐渐减压过程,降压效应和剪切带本身的膨胀渗透作用,引起了剪切带内部积累的能量梯度(压力、温度、物质),导致弥漫于大面积围岩中和下地壳的液体进入韧性剪切带中。“节流阀”作用形成韧性剪切成岩成矿热液系统。韧性剪切构造对金矿的控制核心是成岩成矿为统一的热动力系统,早期以成岩为主,中晚期以蚀变和矿化为主。
Exemplified by a case history, the Houshihua gold deposit in the central-west Inner Mongolia Autonomous Region, the present paper briefly describes the the characteristics of the ductile zones, and advances the new viewpoint of a "diagenetic and ore-forming hydrothermal system of the ductile shear zones". The stuides show that diagenetic processes of ductile shearing consist of the fine granulation process, thermal fluid process, and acidic and alkali metasomatism. In the process of forming such intensive fractures as the ductile shear zones, the side of the thrusting wall was developed in the direction from the relatively deeper part to the crust to the shallower one. The pressure - dropping effect and the dilatational permeation action within the ductile zones themselves contributed to the accumulation of energy gradients (including pressure, temperature and substance) inside the shear zones. As a result, the fluid extensively diffusing in the wall rocks and the lower crust entered into the ductile shear zones. The effect of the "throttle valves" resulted in a metallogenetic hydrothermal fluid system of ductile shearing. The kernel of ore control by the structure of ductile shearing is that the diagenetic mineralization proves to be a unified thermodynamic system, with diagenesis predominant in the early stage and alteration and mineralization predominant in the middle and late stages.
出处
《地质论评》
CAS
CSCD
北大核心
2000年第2期131-140,T001,共11页
Geological Review
关键词
金矿床
矿化
韧性剪切构造
成岵
成矿作用
Ductile shear zone
tectonopetrogenisis and tectonometallogenesis
gold deposit
central-west Inner Mongolia
