摘要
武山铜矿田块状硫化物矿床的层滑断裂系控矿机制,归结起来,就是在成矿构造圈闭中的优性面控矿。它有3个主要特点:(1)成矿定时性;(2)赋矿定位性;(3)控矿构造定性性。“优性面”是物理、化学、力学性质有显著差异,并有利于成矿的分划性结构面,它是构造、岩相和矿体三者的有机结合体。矿床的构造地球化学特征,反映了主要特征元素在控矿断裂带内的迁移趋势:离子半径小的硅、铁、镁和铝在断裂带中心富集,离子半径大的钙、钾和钠则远离中心。
Compounding of the NW-trending structunal belt with the Songjiawan-Wushan synclinorium, one of the main vortical surfaces of the Ruichang vortex structure, controls the formation and distribution of the Wushan ore field. In the northern ore zone of the ore field, the ore controlling structural type for the massive sulfide deposit is a 'bedding fault system' that devel oped as a result of bedding plane slipping, thrusting, NW-trending structural superposition, tenso-shearing and compresso-shearing. They formed mainly during the Indosinian period and were reactivated during the Yanshanian. The main rock-and ore-forming processes occurred during the period of NW-trending sructural superposition and tenso-shearing activation. The tectonic stress field during the mineralization stage mainly reflects NNW-SSE and N(N)E-S (S)W compression.Based on the discussion of the ore-controlling mechanism of the bedding fault system, a concept of the 'control of ore deposition by optimum surface' was proposed. The 'optimum. surface' is considered as the combination of the most favourable tectonic and lithologic conditions for ore formation. It is a unity of structures, lithofacies and orebodies.The rocks in the ore-controlling fault belt of the Wushan ore field consist of copper-bearing pyrite and kaolinite claystone in the centre, which pass to dolomite-marble and pure siliceous rocks near the centre and to calcite-(?)mestone and sericitized siliceous sandstone outwards This shows the following trend of migration of the main characteristic elements in the belt: elements with a small ionic radius (e. g. Si, Fe, Mg and Al) moved towards the centre of the belt, while larvae-radius elements (e.g. Ca, K and Na) moved away from the centre.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1990年第1期22-32,共11页
Acta Geologica Sinica
