摘要
汇集了华北地台北缘 2 1个金矿床的 45个直接测年数据 ,对这些数据的可信度作了评述。选用矿石或蚀变围岩中的绢云母、黑云母、钾长石等蚀变矿物作为测年对象 ,采用 Ar- Ar、 K- Ar法或 Rb- Sr等时线法测年在目前的技术条件下是经济可行的 ,关键是要保证被测矿物确为蚀变矿物并且纯度较高。用 U- Pb法测定矿脉中的水热锆石来确定成矿年龄 ,但如何区分继承锆石和水热锆石尚不成熟。以地质观察为基础 ,充分利用上述测试数据 ,认为区内的火山浅成低温热液金矿床和多数侵入体接触带内外的金矿床成矿时代为燕山期 ;夹皮沟金矿床的成矿时代为海西期 ,可能叠加有燕山期的矿化 ;冀东金厂峪金矿床存在早期前寒武纪和晚期中生代矿化的叠加 ;张宣和乌拉山地区的金矿床成矿时代可能为燕山期 ,有待进一步研究确定。
On the north fringe of North China platform, 45 direct age determination data of 21 gold deposits have been collected. Minerals or altered minerals such as sericite, biotite and K feldspar in the altered wallrocks are selected to be objects of age determination, and the Ar Ar, K Ar, Rb Sr, U Pb isochron dating methods are adopted. The magmatic epithermal gold deposit in the region and most gold deposit inner and outer intrusive contact zone are mineralized in Mesozoic Yanshan Period. The metallogenic epoch of Jiapigou gold deposit is Upper Paleozoic Hercynian Period and probably superimposed by mineralization of Yanshan Period. Jinchangyu gold deposit in northern Hebei is superimposed by early Precambrian mineralization and late Paleozoic mineralization. Gold metallogenic epoch in Zhangxuan and Wulashan is probably Mesozoic Yanshan Period, which needs further research.
出处
《黄金地质》
2000年第2期70-76,共7页
Gold Geology
基金
国家攀登项目 !( 95- Y- 2 5)资助
关键词
金矿床
成矿时代
测年方法
gold deposit
metallogenic epoch
age determination
