乐马厂银矿逆冲推覆构造特征及控矿作用

乐马厂大型独立银矿床的总体构造格架为逆冲推覆的构造体系，文章在分析区域地质构造背景和矿区地质构造特征的基础上，着重研究了该矿床叠瓦式逆冲推覆构造的地质构造特征及其控矿作用，论述了矿区逆冲推覆构造为燕山晚期形成的褶皱式逆冲推覆构造类型，其推覆运动形式为自NE向SW的右旋剪切运动，扩展方式为后展式，逆冲推覆构造为本区银矿床的形成创造了一个独特的极为有利的成矿构造环境，并控制了银矿体的形成，定位和空间分布规律，强调了以逆冲推覆断裂系统控矿为主，推覆体系统和掩复体系统次之的控矿规律。

Characteristics and Ore-controlling Role of the Thrusting Nappe Structure in the Lemachang Silver Deposit

The general structural framework of the Lemachang large_size independent silver deposit is a thrusting nappe structural system. Based on an analysis of regional tectonic setting and geological structure of the ore district, this paper deals emphatically with the characteristics and ore_controlling role of the imbricate thrusting nappe structure in the ore deposit. The thrusting nappe structure in the ore district is of the folded thrusting nappe structure type formed in late Yanshanian period, the napping is NE_SW trending right_lateral shearing movement, and the spreading is of the post_spreading style. The thrusting nappe structure created a unique and most favorable structural environment for the ore_forming process in the silver deposit, and controlled the formation, location and spatial distribution of silver orebodies. The thrusting nappe fault system played the dominant ore_controlling role, and the nappe system as well as the hidden nappe system possessed the second place in this aspect.