黑龙江争光金矿床隐爆角砾岩特征及其地质意义

Characteristics of Cryptoexplosive Breccias in the Zhengguang Gold Deposit of Heilongjiang Province and Their Geological Implications

黑龙江争光金矿床位于大兴安岭东北缘的多宝山矿集区,矿体主要呈脉状产于燕山期闪长岩体与中奥陶统多宝山组的内外接触带上,受断裂构造控制明显。在野外地质调查过程中,发现了3个隐爆角砾岩体(J-1、J-2、J-3),角砾岩体从中心向外侧有较显著的岩石类型分带,中心为热液隐爆角砾岩,向外角砾增大,逐渐过渡为震碎角砾岩。根据胶结物的不同和穿插关系可将其分为四期,最早期为硅质胶结,中期为绿泥石胶结,其次为矿质胶结,最后为灰黑色安山质胶结,其中第二期和第三期隐爆作用与矿化关系密切。对隐爆角砾岩地质特征的研究结果表明,在Ⅱ号矿带绿泥石胶结隐爆角砾岩体深部具有寻找与矿质胶结隐爆角砾岩有关的金铜矿化体的潜力,这对争光金矿床深部及外围找矿具有一定的指导意义。

The Zhengguang gold deposit of Heilongjiang Province is located in the Duobaoshan metallogenic belt northeast of the Da Hinggan Mountains. The ore veins occur in the contact zone between the Yanshanian diorite pluton and middle-Ordovician Duobaoshan Fm.,and show a clear control by faults. Field investigations suggest three cryptoexplosive breccia bodies(Nos. J-1,J-2 and J-3),which are zoned from the central hydrothermal cryptoexplosion breccia to broader envelop of larger breccias,and further to broader envelop of shatter breccias. Based on different cements and interspersed relationships,the breccias can be divided into four stages: the early siliceous cementation,later chlorite cementation,then mineral cementation,and final dark gray andesitic cementation. The second and third phases are closely associated with mineralization. The study of geological characteristics of cryptoexplosive breccia bodies suggests that there is great potential for prospecting mineral cementation cryptoexplosive breccia bodies related to the gold mineralization in the No. II ore belt below the chlorite cementation cryptoexplosive breccia. This would provide guidance and reference for the deep and periphery prospecting in the Zhengguang gold deposit.