铧厂沟金矿床区域韧性剪切带特征

首次对铧厂沟金矿床区域韧性剪切带进行了较为系统的研究。根据野外地质调查和室内显微构造分析 ,区内发育一条较大区域韧性剪切带 ,无论沿走向还是顺倾向均呈舒缓波状 ,强变形带和弱变形域呈镶嵌形式。区域韧性剪切带经历了右行—左行—右行多期 (次 )活动 ,剪切方位也多次变化 ;早期形成温度约 5 0 0℃ ,以右行剪切为主 ,古应力值大于 0 .0 75GPa。控矿韧脆性剪切带是区域韧性剪切带演化的产物 ,最终形成脆性断裂。区域韧性剪切作用控制矿床、矿带的分布 ,并使部分金从矿源层分溢出来 ,产生第一阶段金的富集。次级韧脆性剪切带 (控矿剪切带 )控制富矿体的分布。因此 ,铧厂沟金矿床可称为韧性剪切带型金矿床。另外 ,中 -下泥盆统三河口群第一岩段第一岩层 (D1 -2 SH1a)部分原岩有明显海底热水同沉积特征 ;在矿床之西万家山—张家山应注意寻找硅化石英粗糜棱岩型金矿石。

CHARACTERISTICS OF THE REGIONAL DUCTILE SHEAR ZONES IN HUACHANGGOU GOLD DEPOSIT AREA IN LUEYANG,SHANXI

The regional ductile shear zones in the Huachanggou gold deposit area are studied systematically for the first time in this paper. On the basis of practical geologic investigations in the field in Lueyang, Shanxi and the microstructural analyses at the laboratories, a large-scale regional ductile shear zone was discovered, which is characterized by the mosaic distribution pattern of alternating strong and weak deformation zones. The regional ductile shear zone has experienced shearing from early dextral to late sinistral and then again dextral. At the same time, shearing directions changed. At the early stage, dextral ductile shearing took place at a temperature of about 500 ℃ and the stress at about 0.075GPa. The late-stage ore-controlling ductile brittle shear zones were evolved from the previous one. Finally, all the ductile brittle shear zones become brittle faults. The distribution of deposits and ore belts as well as the first stage of gold enrichment is controlled by the regional ductile shear zone. However, the ductile brittle shear zones control the distribution of the gold ore bodies. Therefore, the Huachanggou gold deposit can be classified as ductile shear gold deposit. Moreover, obvious features of sea floor hydrothermal sedimentation can be found in part of the 1a layer. The silicified quartz-containing, coarse-grained mylonitic gold ores can be found in the Wanjiashan-Zhangjiashan district to the west of the Huachanggou gold deposit.