胶西北三山岛金矿黄铁绢英岩中绢云母^40Ar/^39Ar年龄及其意义  

Ar/^39 Ar Age and Its Significance of Sericite in Pyrite Sericite in Sanshandao Gold Deposit in Northwest of Shandong Province

作　　者：杨振毅 于晓卫[1] 张文[1] 王立功[1] 王巧云[1] 郭瑞朋[1] YANG Zhenyi;YU Xiaowei;ZHANG Wen;WANG Ligong;WANG Qiaoyun;GUO Ruipeng(Shandong Institute of Geological Surveying,Shandong Ji'nan 250014,China;Shandong Provincial Geological Society,Shandong Ji'nan 250013,China)

机构地区：[1]山东省地质调查院,山东济南250014 [2]山东省地质学会,山东济南250013

出　　处：《山东国土资源》2020年第7期1-8,共8页Shandong Land and Resources

基　　金：科技部下达科研项目深部矿产资源三维找矿预测评价示范(2017YFC0601506);山东自然资源厅胶东地区中生代花岗岩调查及与金矿关系研究(鲁勘字[2018]19号);山东省莱州-招远金矿整装勘查区综合研究(鲁勘字[2014]7号)联合资助。

摘　　要：胶西北三山岛金矿床是胶东巨型金成矿省最大的金矿床之一,为了研究其成矿时代,利用绢云母^40Ar/^39Ar测年法测定了三山岛金矿含矿黄铁绢英岩中绢云母结晶年龄。结果表明,三山岛金矿黄铁绢英岩中绢云母^40Ar/^39Ar坪年龄为(118.35±1.21)Ma,反等时线年龄为(118.56±1.37)Ma,认为三山岛金矿的成矿年龄为(118.35±1.21)Ma。其围岩郭家岭花岗岩锆石U-Pb年龄为(127±2)Ma,与金矿成矿年龄相差9Ma。考虑岩浆在深部侵位的缓慢冷却效应不超过10Ma,认为三山岛金矿成矿事件与其围岩郭家岭花岗岩侵入事件关系密切。早白垩世随着岩石圈减薄、地幔物质上涌,地温梯度不断增高,并进一步产生大量热能,导致下地壳重熔或壳幔同熔产生大规模岩浆侵入活动及成矿流体的形成,从而使得岩石圈地幔不断消耗而减薄。在区域构造作用的影响下,壳幔同熔产生的岩浆侵位结晶形成郭家岭花岗岩。随着岩体的隆升,温度的下降,富含金质的多源成矿流体进入构造裂隙系统,并和围岩发生强烈的蚀变交代,使含矿热液的矿质浓度进一步提高,成矿流体在上升过程中有大气降水的加入,进而加速了金质的沉淀,形成一系列的金矿床。Sanshandao gold deposit is one of the largest gold deposits in giant gold metallogenic provinces in Jiaodong area.In order to study its metallogenic age,by using sericite^40 Ar/^39 Ar dating method,sericite crystallization age in the pyrite sericite quartzite of Sanshandao gold deposit has been determined.It is showed that the age of sericite^40 Ar/^39 Ar is(118.35±1.21)Ma,and the age of anti isochron is(118.56±1.37)Ma.The mineralization age of Sanshandao gold deposit is(118.35±1.21)Ma.The zircon U-Pb age of Guojialing type granite is(127±2)Ma respectively,which is 9Ma different from gold mineralization age.Considering the slow cooling effect of magma emplacement in the deep intrusion is not more than 10Ma,it is considered that the mineralization event of Sanshandao gold deposit is closely related to surrounding rock of Guojialing granite intrusive event.Accompanying with the rise of rock mass and the decrease of the temperature,the gold rich multi-source ore-forming fluid enters the structural fracture system and strongly alters with the surrounding rocks,which further increases the mineral concentration of the ore-bearing hydrothermal fluid.In the process of the rise,the ore-forming fluid is added with atmospheric precipitation,which accelerates the deposition of gold and forms a series of gold deposits.

关 键 词：^40Ar/^39Ar测年 绢云母 成矿流体 三山岛金矿 胶西北 

分 类 号：P618.510.652[天文地球—矿床学]