黑龙江三道湾子金矿床同位素年龄对成矿时代的约束  

Metallogenic epoch of the Sandaowanzi gold deposit in Heilongjiang Province : Constraints from the evidence of isotopic age

作　　者：赵天宇[1] 赵海滨 孙丰月[3] 刘俊来[4] 

机构地区：[1]中国地质大学(武汉)地球科学学院,湖北武汉430074 [2]黑龙江省第四地质勘察院,黑龙江哈尔滨150036 [3]吉林大学地球科学学院,吉林长春130061 [4]中国地质大学(北京),北京100083

出　　处：《中国地质》2013年第4期1202-1208,共7页Geology in China

基　　金：教育部高等学校博士学科点专项科研基金项目(20110145130001);地质过程与矿产资源国家重点实验室和国家理科基地资金项目;三道湾子金矿公司科研专项基金联合资助

摘　　要：大兴安岭地区是中国东北地区重要的成矿集中区。近年来在该区又新发现了独具特点的三道湾子金矿,金几乎是以碲化物型金存在,并且金的特高品位局部可达几个百分点,为世界所罕见。对切穿含金石英脉的辉绿玢岩进行同位素年代学研究,研究结果表明,三道湾子金矿床附近辉绿玢岩中斜长石样品40Ar/39Ar年龄测试结果为(115±1.1)Ma^(118±1.2)Ma,代表了辉绿玢岩的侵位年龄。并且在矿区NE和NNE方向分布着两个光华期的火山喷发中心,在火山喷发中心附近发现有较强的硅化和黄铁矿化,从蚀变岩特征看应与三道湾子金矿化是同期蚀变,说明金矿化可能与光华期火山喷发为同期或稍晚。光华组流纹岩中锆石年龄测试结果为125.3 Ma,代表岩浆喷发时的结晶年龄。三道湾子金矿床的形成应该在光华期火山喷发之后,在辉绿玢岩侵入之前,成矿时代应该在125.3~115 Ma的早白垩世,可能更接近于前者。Daxinganling area is an essential metallogenic concentration area in Northeast China.In recent years,the Sandaowanzi gold ore deposit was discovered in this area,and gold exists as telluride.In some local places,the grade of gold has reached several percentage points.The study of isotopic chronology of allgovite which crosscuts the quartz-vein shows that the 40Ar/39Ar age of anorhtose is between 115 ±1.1 Ma and 118 ±1.2 Ma,which indicates the emplacement age of allgovite.Two volcanic eruption centers of Guanghua period were discovered in the ore district,characterized by strong silicification and pyritization.They have the same age of alteration as the Sandaowanzi gold ore district,which suggests that the gold mineralization took place identical with or later than volcanic eruption of Guanghua period.Zircon age from rhyolite formation of gold is 125.3Ma.Therefore,the formation of the gold deposit should be younger than volcanic eruption of Guanghua period and before the emplacement of allgovite,and hence the metallogenic epoch should be between 125.3Ma and 115Ma.

关 键 词：三道湾子 金矿床 同位素年代学 黑龙江 

分 类 号：P618.51[天文地球—矿床学] P597.3[天文地球—地质学]