东昆仑祁漫塔格矿带典型矿田构造背景与岩浆-热力构造特征

以矿田构造–岩相填图为主要方法,研究确定矿田构造和岩浆-热力构造类型及矿床类型,进行成矿富集中心的圈定及找矿预测,是矿田构造背景复杂地区的有效调研方法之一。东昆仑西段祁漫塔格矿带多期构造–岩浆活动强烈,断裂发育,以印支晚期岩浆侵入成矿与找矿进展较大。本次选择景忍–虎头崖、卡尔却卡B区、乌兰乌珠尔三个矿田区,进行1∶10000构造–岩相填图,填制了三个矿田区岩浆–热力构造类型分布图,认为晚三叠世岩浆侵入作用是该区多金属大规模成矿的主要内因,叠加其上的不同方向断裂控矿作用不同,近东西向和北西西向断裂控矿显著,明确了各矿田构造背景和印支期岩浆侵入形成的花岗斑岩+矽卡岩+断裂带热液成矿的模式,厘定了岩浆–热力构造的识别标志,即主要是印支晚期中酸性侵入岩、花岗斑岩、矽卡岩带、大理岩带、接触交代蚀变带、断裂破碎带叠加热液蚀变带等,圈定了成矿和找矿富集中心。

Tectonic Background and Magma-thermodynamic Structural Features of Typical Orefields in Qimantage Ore Belt,Eastern Kunlun

Structure-lithofacies geological mapping is one of the most efficient methods in study of ore field structure, magma-thermodynamic structure, and ore deposits, as well as in the ore deposit exploration and prospecting. Our studies of orogenic belts (e.g., East Kunlun, Tianshan, Qinling Mt.) and basins (e.g.,Ordos Basin) in the west and middle part of China show that each of the thermal events and thermal structures has distinct characteristics. Magma-thermodynamic structures are a series of thermal structures formed within plutons and/or country rocks or telethermal impacted areas. On basis of ore field geology and ore field structure, we put forward a classification plan for magma-thermodynamic structures. Metallic ore field magma-thermodynamic structure is easy to recognize, which show significantly different features for different type of deposit and different stage of mineralization. According to the main controlled action formed by the structure during epoch of mineralization, orefield structures can be divided into four groups, which include stress structure, thermodynamic structure, gravity structure, and combined transformed structure, according to their controlling mechanisms. Whereas, orefield magma-thermodynamic structures can be further divided into five categories and twenty four sub-categories, according to their controls on the mineralization depth, tectonic environment, and metallogenetic type. Multi-stage overlap of tectonic-magma activity and main fractures are common in the west part of the East Kunlun orogenic belt. The recent studies on typical orefield in the Qimantage ore belt of the East Kunlun orogenic belt showed that the mineralization associated with Indosinian plutons are quite promising. 1∶10000 structure-lithofacies geological mapping was conducted on three typical orefield, including the Jingren-Hutouya, the B area of Kaerqueka, and Wulanwuzhuer in the Qimantage ore belt. The main fractures with different striking directions have varied effects on mineralization. Indosinian plutons, faults with hydrothermal structure and altered belts, porphyry area etc. are the signs of the center of mineralization.