甘肃西秦岭下拉地一带铅锌矿区构造控矿规律研究

STUDY ON ORE-CONTROLLING REGULARITY OF XIALADI LEAD-ZINC MINE IN WEST QINLING

下拉地铅锌成矿带是在晚古生代伸展构造体制背景下的产物,构造对成矿的控制作用主要表现为裂陷期同生断裂对成岩成矿的控制上,根据时间承接关系和不同时段构造控矿侧重点不同,可将伸展环境下构造控矿分为3阶段:即构造—含矿地层沉积、构造—基性火山活动及矿化、构造—次火山作用与成矿;在伸展体制下完成成矿后,随即构造体制向挤压环境转换,此时的构造控矿特征主要表现为中—小尺度的紧闭褶皱和压性逆断层对矿体空间产出的控制上。

Xialadi lead-zinc metallogenetic zone is developed under the background of extensional structures in Late Palaeozoic Era. The evidences of ore-forming controlled by structures come from the control of contemporaneous faults of chasmic stage to diagenesis and mineralization. In terms of time sequences of structures and ore-controlling features of structures in different period, the structural ore-controls under the environment of extensional system are divided into 3 stages as deposition of structural-ore-bearing strata, structural-basic volcanic activities and mineralization, structural-subvolcanism and mineralization. As soon as metallogenesis had completed under the extensional system, structural system changed into Compression environment, the structural ore-controlling features show that medium-small scale tight folds and compressional reverse faults controlled the development of ore-bodies.