胶东区域成矿断裂带蚀变年龄研究及其矿床学意义

发布时间：2018-03-19 16:43

本文选题：胶东金矿　切入点：K-Ar同位素年龄　出处：《地学前缘》2017年02期 　论文类型：期刊论文

【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。
[Abstract]:The Jiaodong gold deposit is a mesothermal hydrothermal alteration vein deposit in the Mesozoic tectonic-magmatic activation zone. It was considered that the gold deposit belongs to the crust-source deep-melt granite hydrothermal quartz vein altered rock type gold deposit. Recent research shows that the gold deposit belongs to the crust source deep-melt granite hydrothermal quartz vein altered rock type gold deposit. The determination of the alteration age of the surrounding rock of Jiaodong gold deposit is of great significance for the study of the genesis of the deposit. The main faults of Jiaodong Peninsula are studied as follows: (1) the samples are selected as the sampling targets, which are generally developed in the altered rock belts of the Jiaodong area, and the altered belts of Huangtaishinite and strong potassium feldspathic altered rocks are selected as the sampling targets. The alteration minerals in the two types of rocks are less affected by brittle faults, and the stable chemical composition in the alteration stage can be obtained. 3) the alteration minerals in the two types of rocks develop ductile deformation at the same time of alteration. The K-Ar isotopic age data of the potash feldspar and plagioclase particles in the samples are obtained. The tectonic hydrothermal alteration period in Jiaodong region is 148.3 卤4.3Pu 52.03 卤0.70 Ma, that is, the late Yanshanian period of early Cretaceous, and the isotopic age gradually decreases from west to east, which proves that the hydrothermal alteration in the western area of Jiaodong is earlier than that in the eastern area. Based on the data of hydrothermal composition and ore-forming physical and chemical parameters, combined with the latest achievements of this study, the regional metallogenic age and metallogenic regularity are summarized: the tectonic additional hydrostatic pressure in the fracture alteration system of Jiaodong region, The temperature and pressure conditions of fluid and the distribution and variation of ore-forming elements control the regularity of hydrothermal erosion and mineralization. The above geological characteristics indicate that the Jiaodong gold deposit is a new type of ore deposit under the action of tectonics and hydrothermal solution.
【作者单位】：密苏里科技大学地质科学与石油及地质工程学院;中国地质科学院地质力学研究所;中国地质大学(北京)地球科学与资源学院;
【基金】：国家自然科学基金项目(40972061)
【分类号】：P618.51

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