黑龙江十五里桥金矿床成矿地质背景及成矿机制探讨

Discussion on geological settings and metallogenic mechanism of Shiwuliqiao gold deposit,Heilongjiang Province

十五里桥金矿床处于上黑龙江盆地南缘,是近年来新发现的具有较大找矿潜力的岩金矿床,矿体赋存于伊利克得组次火山岩与上库力组火山岩内。岩石地球化学特征表明:伊利克得组次火山岩为钙碱性向碱性岩石过渡系列,总体为安山岩类;而上库力组火山岩为高钾钙碱性岩石类型,总体与流纹岩相当。区内火山岩是造山带分异出来的钙碱性岩浆,具有活动陆缘环境的特征,是早白垩世伸展环境下火山-岩浆活动的产物,形成深度为230 km左右,而十五里桥金矿床是火山活动后期拉张环境下构造、热液活动的产物,成矿物质主要来源于火山岩地层。

The Shiwuliqiao gold deposit is located in the south margin of upper Heilongjiang Basin,which was a newly discovered rock gold deposit and has great prospecting potential.The orebodies occurred in the Yilikede Group subvolcanics and Shangkuli Group volcanic geochemical characteristics indicate that the Yilikede Group subvolcanics are transition series from calc-alkaline to alkaline rocks and generally belong to andesite.The Shangkuli Group are high-K calc-alkaline series with similar lithology to rhyolite.The volcanics in the area were formed by calc-alkaline magmas deriving from differentiation of orogenic belt,possessing the characteristic of active continental margin,which is resulted from the volcano-magmatic activity in the Early Cretaceous extensional environment with metallogenic depth about 230 km.Shiwuliqiao gold deposit is formed in the tectonic and hydrothermal activities.Metallogenic materials are mainly from volcanic rock strata.