胶西北郭家岭幔枝构造控矿作用分析

Analysis on the Ore-controlling of Guojialing Mantle Branch Structure in Northwest Shandong

胶西北金矿集中区的控矿作用与深部过程密切相关。华北东部地区在经历了古生代漫长的稳定地台演化阶段后,于燕山运动时期进入了地幔热柱演化阶段,而胶西北成矿集中区则进入了以莱阳地幔亚热柱与其外围郭家店幔枝构造的发展演化阶段。核幔源Au元素以气—液的形式,经过地幔热柱—地幔亚热柱—幔枝构造—有利构造扩容带,迁移到幔枝构造的有利部位集聚成矿,从而构成了环绕郭家岭幔枝构造的一系列大、中型金矿床。同时,提出了焦家断裂为幔枝构造北西缘的主拆离(断裂蚀变岩)带,三山岛断裂是拆离带上盘铲状断裂的基本认识,并据此指出了该区进一步找矿方向。

Ore-controlling was closely related to deep processes of gold concentrated area in the northwest Shandong.The eastern area of North China platform turned into mantle plume evolution since Yanshanian movement after the long stable evolution of Paleozoic.The northwest Shandong developed Guojiadian mantle branches around the Laiyang sub-mantle plume.Through mantle plume,sub-mantle plume,mantle branch,favorable structural expanding zones, core-mantle derived gaseous or gas-liquid Au-bearing hydrothermal fluid was migrated to the ductile-brattle or brattle-ductile zones,internal or external contact zones of intrusives dense flerry fractures,contact zones between dykes and country rocks,forming a series of gold deposits.Therefore,this constitutes a series large and medium-scale gold deposit around the Guojialing mantle branch.We also put forward that Jiaojia fault structure is the main detachment zone （fracture altered rock） on the northwestern margin of mantle branch structure, Sanshandao fault structure is listric faults hanging wall on the detachment zone, and then points out the further prospecting direction.