摘要
山东玲珑-焦家地区的金矿床根据其地质和剪切带特征可分为含金石英黄铁矿大脉型(玲珑)和蚀变岩型(焦家),它们均产于花岗岩中。郯-庐断裂是区域性的、可能深及上地幔的深大断裂,具有区域剪切的性质。在它的作用下,胶东地区形成了一系列剪切带和断裂带。在破头青韧性剪切带的两侧,尤其是左侧,形成了一系列雁行状排列的脆-韧性剪切带,在其中充填和交代形成了玲珑含金石英脉和网脉状以及蚀变岩型矿床。焦家剪切带、河东-河西剪切带属于脆性剪切带。在这种脆性剪切作用下岩石发生形变变成格子状,当含金的成矿流体进入这种格子状的裂隙时,与围岩发生交代作用,从而形成了焦家蚀变岩矿体。在纯的韧性剪切带中是糜棱岩;在脆-韧性剪切带中为初糜棱岩和角砾岩;而在脆性剪切带中则是碎裂岩。关于矿化在剪切带中的位置,笔者认为,焦家矿床的矿化位于脆性剪切带中,在浅部(上部);玲珑西山的含金石英脉型矿化位于脆-韧性剪切带中,即在中部;而产在韧性剪切带中的矿床(如产在破头青剪切带中的矿体)则是位于深部。
The Linglong-Jiaojia gold district is one of the most important gold producers in China. According to its geological features and the characteristics of shear zones, gold deposits in the district may be divided into the gold-bearing quartz-pyrite large vein type (Linglong type) and the alteration type (Jiaojia type). The authors have carried out regional geological surveys of some gold deposits in the district. The Tancheng-Lujiang fault is a deep fault rare in the world, running almost through half of China and possibly extending downward to the upper mantle. It is of regional shear nature. Its action resulted in the formation of the Samhandao shear zone, Huangxian-Jiaojia-Yexian shear zone and Pingdu-Potouqing shear zone as well as secondary shear zones and fault zones controlled by these major shear zones. The last two major shear zones and their derivative structures are the main factor controlling the localization of gold deposits. What controlled the formation of the Linglong gold deposit is the ductile Potouqing shear zone. On both side of it, especially on its left side were formed a series of en-echelon brittle-ductile shear zones, in which gold-bearing quartz veins and stockworks and alteration gold deposits were formed.The Jiaojia shear zone and its secondary shear zones controlled the formation of gold deposits in the Jiaojia area. The nature of the Jiaojia and Hedong-Hexi shear zones is utterly different from that of the shear zones in the Potouqing and Linglong areas. The former belongs to brittle shear zones. Under the action of such brittle shearing, rocks were deformed and show grid struc- ture. When gold-bearing ore fluids flowed into such grid fissures, replacement occurred between them and wall rocks, thus forming alteration-type orebodies.Mylonite may be found in pure ductile shear zones; protomylonite and breccia are present in brittle-ductile shear zones; and a series of extensive cataclastic rocks -with a grid structure occur in brittle shear zone. The Jiaojia gold deposit occurring in a brittle shear zone is localized at shallow depths (in the upper part) and the gold-bearing quartz vein type deposit in the Western Hills of Linglong occurring in a brittle-ductile shear zone is in the middle part,- whereas the deposit occurring in a ductile shear zone (e. g. orebodies in the Potouqing shear zone) is localized in the deep part.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1999年第2期174-188,T002,共16页
Acta Geologica Sinica
基金
中国国家自然科学基金(编号:49373172)
国际合作基金
加拿大国家自然科学
工程基金
关键词
金矿床
矿床地质
山东
构造变形
玲珑-焦家地区
ductile-brittle-ductile-brittle shear zone, Jiaojia, Linglong, gold deposit
