甘肃大水金矿床的构造——岩浆系统及其控矿作用

Tectonic-magmatic system and its ore-controlling function in MaquDashui gold deposit in Gansu province

大水金矿床位于勉略缝合带与阿尼玛卿缝合带结合部。矿床的构造-岩浆系统及其控矿作用进行分析的基础上,结合区域构造特征,探讨了矿床控矿构造演化和机制,构建了控矿模式。研究表明:构造-岩浆系统控矿作用表现为火山活动及岩浆侵位派生的环状、放射状断裂及其交汇部位控制含矿岩体侵入和矿化带形成,岩体侵入过程中产生的侵入接触带构造控制矿体和矿化类型;构造系统从主断裂构造带系统向基底断层系统、火山断裂系统和岩体接触带系统依次演化。控矿构造作用与逆冲推覆构造及地壳拆沉构造作用有关;三叠纪后碰撞早期挤压–伸展转换环境下的构造体制转换,诱发深部岩石圈拆沉作用和软流圈地幔底侵作用,是金成矿作用和控矿构造-岩浆系统演化的重要机制。

Dashui gold deposit is located at the junction of mianlu suture belt and animaqing suture belt. This paper analyses the tectonic-magmatic system of the deposit and its ore-controlling function,discusses the ore-controlling structure evolution and mechanism of the deposit,and constructs the ore-controlling model. The results show that :(1) the mineralization process of the tectonicmagmatic system shows that the ring and radial faults derived from volcanic activities and magmatic emplacement and their intersection control the intrusion of ore-bearing rocks and the formation of mineralization belt.(3) the tectonic system evolves successively from the main fault zone system to the basement fault system,the volcanic fault system and the rock body contact zone system. The ore-controlling tectonics is related to the thrust nappe structure and crustal tectonics.(4) the tectonic system transformation under the compression-extension transition environment in the early post-triassic collision,inducing deep lithosphere sedimentation and soft flow subdivision,is an important mechanism for the evolution of gold mineralization and ore-controlling tectono-magmatic system.