甘肃岷县马坞金矿地质特征与构造控矿模式

The Geological Characteristics and Ore-controlling Tectonic Model of Mawu Gold Deposit in Minxian,Gansu Province

马坞金矿床的地质特征与中川岩体地区金矿床的特征具有相似性。马坞金矿主成矿期石英脉中δD为-78‰^-98‰,δ18OSMOW为18.0‰~20.2‰,δ18OH2O为0.45‰~8.54‰,显示成矿流体为岩浆水、变质水和大气降水的混合水,以岩浆水和变质水为主,有少量大气降水参与;主成矿期石英脉中δ34S为+7.1‰^+7.9‰,平均+7.65‰,δ34S变化范围较小,均一性强,显示地层硫特征,成矿物质来源于舒家坝组。F1区域性深大断裂和马坞背斜共同控制了马坞金矿的产出,F1为导矿构造,马坞背斜中层间破碎带及张性裂隙和F1派生的次级构造体系为容矿构造。马坞金矿构造控矿模式的建立对下一步的找矿工作与探矿方向具有非常重要的指导意义。

Mawu gold deposit is similar to the gold deposits of Zhongchuan area with geological characteristics. In quartz reef of the main ore-forming stage of Mawu ,δD is -78？ ～- 98‰,δ^28OSMOW is 18.0‰～ 20.2‰,δ^18OH2O is 0.45‰ ～ 8.54‰. It shows that ore-forming fluids is mixture water of the magmatic water, metamorphic water and little atmospheric water,magmatic water and metamorphic water is main ,and has a small amount of atmospheric precipitation participated in. In quartz reef of the main ore-forming stage, compose of δ^34S is ＋ 7. 1‰～ ＋ 7.9‰, average is ＋ 7.65‰, compose of δ^34S show smaller change range. It shows the characteristics of formation of stratum sulfur, oreforming materials root in the Shujiaba formation. Theregional deep fault of F1 and anticline Mawu common control of Mawu gold deposit＇s output, F1 is passage structure for ore materials, interlaminar fracture zones and tensile cranny of anticline Mawu and F1-derived secondary structural system is ore-hosting structure. The upbuilding of ore-controlling tectonic model is very important for next prospecting.