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本文从应力矿物、岩石组构、古应力估算及构造地球化学等方面对330产铀硅质断裂带的形成环境、发展演化及变形机制作了初步分析,并讨论了它们与铀成矿作用的关系。通过构造岩及石英、云母的微观研究,认为本断裂带经历了韧性—脆性—脆韧性—脆性的交替变换变形过程。韧性变形具有波状消光、变形纹、流动构造、B+S构造岩等显微构造和组构特征。据重结晶晶粒粒径测定,其差异应力平均值为0.5干巴。脆性变形与韧性变形明显不同,表现出破裂构造和角砾岩类发育,可见吕对尔线和石英沙钟构造以及S构造岩或均质组构等特点。早期韧性变形阶段形成的糜棱岩是一种富硅岩石,硅除主要来自后来的热液外,也来自原岩的动力分异和动热变质作用。韧性变形阶段之后接着是脆性变形阶段,岩石产生破裂构造,充填了早期脉体。成矿作用主要发生在形成碎裂糜棱岩的脆韧性变形阶段,此时的含矿断裂带是一个半开放系统,成矿的地质环境是:温度200—300℃,差异应力0.5干巴,区域差应力0.5干巴,深度1—2公里,基本上属低温浅成环境。
In this paper, the formation environment, evolution and deformation mechanism of 330 uranium silicate fault zone are analyzed from the aspects of stress minerals, rock structure, paleo-stress estimation and tectono-geochemistry, and the relationship between them and uranium mineralization relationship. Based on the microscopic study of tectonic rocks, quartz and mica, the fault zone is considered to undergo the alternating transformation and deformation processes of ductile-brittle-brittle-ductile-brittle. The ductile deformation has wave-shaped extinction, deformation pattern, flow structure, B + S tectonic rocks and other microstructures and structural features. According to recrystallized grain size determination, the average differential stress 0.5 bar dry. Brittle deformation and ductile deformation are obviously different, showing the development of breccia and breccia, showing the Lü pair line and quartz sand clock structure and S tectonic rocks or homogeneous structure and so on. Mylonite formed during the early ductile deformation stage is a silicon-rich rock. Except for the later hydrothermal fluids, the silicon comes from the dynamic differentiation and dynamic thermal metamorphism of the original rocks. Following the ductile deformation phase followed by the brittle deformation phase, the rock produces a ruptured structure filled with early veins. The metallogenesis mainly occurs in the brittle and ductile deformation stage of fractured mylonite. At this time, the ore-bearing fault zone is a semi-open system. The geological environment of ore-forming is: temperature 200-300 ℃, differential stress 0.5 bar, area Poor stress 0.5 dry Pakistan, depth 1-2 km, basically a low-temperature shallow into the environment.