广西龙胜地区金矿地质特征及找矿方向

GEOLOGICAL CHARACTERS OF THE GOLD DEPOSITS IN LONGSHENG AREA, GUANGXI AND THERE PROSPECTING DIRECTION

广西龙胜地区金矿属于脆—韧性剪切绿岩型,成矿物源主要为上元古界地层中的初始富集金,在"面状"渗透性构造带的地质环境中,多次强烈的构造活动驱使地下热(卤)水、区域变质水等热水溶液渗透、循环而形成成矿溶液,在构造动力作用下沿断裂、裂隙运移,在适宜构造场所沉淀富集成矿。金矿化类型有石英脉型和构造蚀变岩型两类,前者分为细网脉型、脉带型、单脉型、碎裂石英脉型;后者分为细碎屑岩质构造蚀变岩型、碳硅质构造蚀变岩型、基性—超基性岩质构造蚀变岩型。该区具有良好的找矿前景,提出了以构造活动强烈、构造形迹明显的较低级次的脆—韧性剪切断裂、裂隙带和浅变质泥质(粉砂)岩、浅变质含硅含碳泥质(粉砂)岩组合找矿的思路,并重视进行构造蚀变岩型金矿的找矿。

The gold deposits in Longsheng area of Guangxi province belong to brittletough shear zone greenstone type deposit. The ore forming matter was initially accumulated in the strata of Upper Proterozoic Suberathem .In the geological environment of plane shape pervasion structure, hydrothermal water as underground hot water (brine) and regional metamorphic water was driven by several times of intense tectonic movement to form ore fluid through pervasion and circulation. The ore fluid was transported along fractures and fissures and accumulated to form deposit at the favourable place by structure dynamic force. The gold mineralization is divided into two types. One is quartz vein type and the other is structure altered rock type. The former can be further subdivided into fine stockwork type, vein zone type, single lode type, and fractured quartz vein type deposit while the later can divided into fine debris, siliconcarboneceous and basicultrabasic structure altered rock type. The area is potential for exploration. A concept of combined prospecting is proposed with the attention being paid on the secondary brittletough shear fracture and fissure zone, intense tectonic movements and evident structure trace in weak metamorphic mudstone or siltstone, and the silicon and carbon containing ones. At the same time prospecting for structure altered rock type gold deposit should also be considered.