夹皮沟剪切带化学成分演化研究

野外地质填图及室内工作表明,夹皮沟剪切带可以划分为早期韧性剪切带(>2500Ma)和晚期脆—韧性剪切带(2000～1600Ma).韧性剪切作用是在角闪岩相条件下形成,以位错、扩散蠕变变形为主,体系内岩石成分与体积基本保持不变,为封闭体系,与矿化关系不密切.脆—韧性剪切作用形成一系列片糜岩,岩石以微破裂及溶解—沉淀变形为主,体系内岩石成分与体积都发生变化,为开放体系,与矿化关系密切.韧性及脆—韧性剪切带的基础岩石是长英质片麻岩,但脆—韧性剪切带被韧性剪切带所限定,并在韧性剪切带基础上形成.

SHEAR ZONES AND THEIR COMPOSITION VARITATION IN JIAPIGOU GOLD DEPOSITS, JILIN PROVINCE

Grological mapping and other researches show that there exist two kinds of shear zones in Jiapigou district: one is ductile shear zone and the another is brittle-ductile shear zones. The ductile shear zone (>2500 Ma), with a amphibolite facies, consistes mainly of mylonites, with the deformed mechanism of lattice slipping and diffusion-creep. During deformation, it changed little in components and volume of rock, and belong to a closed system, and also had little relationship with gold mineraliation. The brittle-ductile shear zone (2000-1600Ma), with a greenschist facies comprised mainly ofschistoid mylonites, with the deformed mechanism of brittle-micro-fractures (including intragranular microfracture, transgranular microfracture and in-tergranular micro-fracture) and solution-precipitation. During deformation it changed greatly in components and volume of rock, belong to a open system, and had a close relationship with the gold mineralization. In space, ductiole and brittle-ductile shear zones were occured by in felsic genisses, but brittle-ductile shear zone was controlled by ductile shear zone and evoled from ductile shear zone.