黔西南烂泥沟金矿田构造变形及演化分析

Structural deformation and evolution of the Lannigou Gold Orefield in southwestern Guizhou

烂泥沟金矿是滇黔桂"金三角"内的大型金矿床,具有重要的经济价值。其矿体产出严格受断层控制,构造控矿特征明显。本文通过对烂泥沟金矿及其邻区主要断层之次级构造现象进行详细的野外观察和力学性质鉴定,继而进行几何学、运动学分析,认为研究区构造变形特征分为伸展和挤压两类。其中,晚古生代—中三叠世安尼期早期为伸展阶段,而在安尼期中期及以后为挤压阶段,构造反转时间应为248 Ma或246 Ma稍后。根据作者地震解释剖面,烂泥沟—尾怀断层和隐伏的巧洛断层向下已经延伸到南盘江盆地变质基底,可能为成矿流体提供运移通道,且烂泥沟—尾怀断层南部有较好的地球化学异常和矿化显示,说明烂泥沟金矿深部及外围具有较好的找矿前景。

The Lannigou is a large gold deposit which has been known in"golden triangle"of Yunnan—Guizhou—Guangxi,and has important economic value.Ore-bodies of the Lannigou gold deposit are strictly controlled by faults and it has the typical characteristics of structural ore-control.Through detailed field observation and mechanical analysis of the associated structural evidences of major faults around the Lannigou gold deposit area,we suggest that the structural deformation characteristics are divided into extension and compression.Among them,late Paleozoic—Middle Triassic early Anisian is extensional stage,while since the middle Anisian is compressive stage,and the tectonic switch time should be shortly later than 248 Ma or 246 Ma.According to the seismic profile,LWF and QLF extend down to the metamorphic basement of Nanpanjiang basin,they may provide migration channels for ore-forming fluid.Moreover,there are geochemical anomalies and gold occurrences in the south of LWF.It’s concluded that the deep and peripheral of the Lannigou gold deposit have good prospecting potential.