胶东区域成矿断裂带蚀变年龄研究及其矿床学意义  

The alteration age of fracture zone and its implication for the formation of gold deposits in Jiaodong area

作　　者：吕承训 Norbert H.MAERZ Kenneth J.BOYKO 吕古贤[2] 邵鹤森 LU Chengxun Norbert H. MAERZ Kenneth J. BOYKO LU Guxian SHAO Hesena(Department of Oeosciences and Geological and Petroleum Engineering, Missouri University of Science and Technology, Rolla 65401, USA Institute of Geomechanics , Chinese Academy of Geological Sciences, Beij ing 100081, China School of Earth Sciences and Resources, China University of Geosciences （Beijing）, Beijing 100083, China)

机构地区：[1]密苏里科技大学地质科学与石油及地质工程学院,美国密苏里州罗拉65401 [2]中国地质科学院地质力学研究所,北京100081 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地学前缘》2017年第2期140-150,共11页Earth Science Frontiers

基　　金：国家自然科学基金项目(40972061)

摘　　要：胶东金矿是中生代构造岩浆活化区岩浆期后中温热液蚀变脉状矿床。前人曾认为该类金矿属于壳源深融花岗岩-热液石英脉-蚀变岩型金矿。近期研究表明,胶东金矿围岩蚀变年龄的测定,对于矿床成因的研究有重要意义。为解决胶东区域断裂热液蚀变年龄问题,对胶东半岛主要断裂矿化蚀变带开展如下相关研究:(1)选择胶东地区各蚀变岩带普遍发育的黄铁绢英岩化蚀变岩带和强钾长石化蚀变岩带作为取样目标,进行区域对比;(2)该两类岩石中的蚀变矿物受到脆性断裂影响较小,能够得到蚀变阶段的稳定化学成分;(3)该两类岩石中的蚀变矿物发育有与蚀变同期的韧性变形,能够揭示蚀变阶段的构造应力应变状态。对样品中的钾长石和斜长石颗粒进行K-Ar法同位素年龄测试,获得蚀变岩同位素年龄数据。测试结果显示,胶东区域构造热液蚀变作用时期为(148.3±4.3)^(52.03±0.70)Ma,即早白垩世燕山晚期;同位素年龄自西向东逐渐变小,证明胶东西部地区的热液蚀变作用早于东部地区。通过分析已有的构造、热液成分和成矿物理化学参数等资料,结合本研究的最新成果,总结出区域成矿时代与成矿规律:胶东区域断裂蚀变系统中的构造附加静水压力、流体温度压力条件和成矿元素的分布与变化控制了热液蚀变成矿规律。上述地质特征显示,胶东金矿床是复成构造热液作用下的一种新型矿床类型。The gold deposits in Jiaodong are the mesothermal hydrothermal alteration vein deposits formed in Mesozoic tectono-magmatic activation area.The research about the isotope age of magmatic rocks and strata has fruitful achievements in Jiaodong region,but the research of the age of altered rock needs to be strengthened.Former researcher defined the gold deposits in Jiaodong area are crust source-deep meltinghydrothermal quartz vein-altered rock type gold deposit.The age of altered rock obtained by former researchers cannot give us an over view about regional metallogenic regularity.To find the method that using time of hydrothermal alteration to explain the regional metallogenic regularity,the author developed field research in the main mineralized alteration belts：（1）choose the beresitization and potassic altered rock belt which are widely distributed in fracture alteration zones in Jiaodong area to be the sample position,and they are easily to be contrasted;（2）these two kinds of altered rock have less affected by the brittle fracture,which means they have stable chemical components of alteration process;（3）the altered minerals in these two kinds of rock belts have ductile deformation with the same period of the alteration process,which can indicate the structural stress and strain status.The plagioclase and potassium feldspar particles in rock samples are the objectives of Potassium-argon dating（K-Ar dating）test.The test results show that the period of hydrothermal alteration was from 148.3±4.3 Ma to 52.03±0.70 Ma,which is the late Yanshanian of Early Cretaceous Epoch;and that the altered rock isotope age decreases gradually from west to east in Jiaodong region,which proves the occurrence time of hydrothermal alteration in west earlier than that in east.Through the research about the structure,the component of mineral hydrotherm,and the physical chemical parameters of mineralization,this paper analyzes the regional regularity and the epoch of ore formation.The conclusion indicates that the regu

关 键 词：胶东金矿 K-Ar同位素年龄 黄铁绢英质蚀变岩带 钾长石化蚀变岩带 复成构造热液作用 

分 类 号：P613[天文地球—矿床学]