摘要
璜山韧性剪切带退变质作用的研究对讨论剪切带变形作用和变质作用的联系及璜山金矿成因具有重要意义.璜山剪切带退变质反应是以其广泛的同时代强烈变形为特征.转换结果:辉石→角闪石,角闪石→黑云母,角闪石→绿泥石,黑云母→绿泥石,长石→绢云母等.所有反应都是水合反应.退变质反应置换出一些金属阳离子及释放了大量SiO_2和Ca^(2+).SiO_2或以石英形式,或以流体形式存在于剪切带中.变形作用提供了流体运移的通道和贮矿场所,当退变质流体平衡瓦解时,金与黄铁矿共同沉淀于糜棱岩面理中,或沉淀于退变质作用、变形分异作用形成的微细石英脉和透镜状石英脉中,或经搬运在断裂构造中沉淀成充填石英脉.
Retrogressive metamorphic process and its relationship to gold mineralization in Huangshan ductile shear zone have been discussed with great references to the studies of deformation - metamorphism.Retrogressive metamorphic reaction was broadly coeval with strong deformation in the shear zone and resulted in the transformations: Pyroxene - hornblende, hornblende - biotite, hornblende - chlorite, biotite - chlorite, and feldspar - sericite etc.. All reactions are hydration processes. These reactions released more SiO_2, Ca^(2+), (Mg, Fe)^(2+), etc.. Silica might form quartz or remain in solution. Ductile deformation zone provided not only the conduits for flowage of metamorphic fluid produced by retrogressive metamorphic process, but also the room for deposition of gold. Au and FeS_2 were assembled and deposited in the foliations of mylonites and in quartz veins segregated out from retrogressive metamorphic process.
出处
《地质找矿论丛》
CAS
CSCD
1992年第1期1-9,共9页
Contributions to Geology and Mineral Resources Research
基金
国家自然科学基金(9488010)
