老湾花岗岩体与金成矿关系新认识及其找矿意义

New understanding of the Laowan granite body-Au mineralization relation and the significance to ore-search breakthrough

通过对老湾金矿带及南部带状展布的老湾花岗岩体野外调查,并结合对钻孔观察研究后认为:老湾花岗岩体与老湾金矿带成矿具有密切的时空和成因关系;老湾花岗岩体先行沿早期的老湾断裂充填就位,为成矿带来了热动力的同时提供了一定的矿质;其后,老湾花岗岩体沿老湾断裂向北逆冲推覆,推覆角48°~59°不等,且上陡下缓,盖在了赋矿地层龟山岩组之上;最后在燕山晚期以后又发生了NWW向的韧性剪切作用,掩盖了早期的断裂痕迹。老湾花岗岩体逆冲覆盖于赋矿地层龟山岩组之上的新认识,拓展了老湾金矿的找矿空间,预测资源量可达200t以上。

Field survey of Laowan Au ore belt and belt extension of Laowan granit body and drilling data show close time-space relation between them.The granite emplaced along the early Laowan fault that provided thermal dynamics and materials for the Au mineralization.Then the granite nappe thrusted northward along the fault at angle 48°~59°(steep at top part and gentle at bottom part)over the host strata of Guishan formation and the Late Yanshanian NWW ductile shearing eliminated the early faulting trace.This is a new understanding that will expand a lot the Au ore prospecting space.The prospect resource volume is predicted up to 200t Au metal.