二滩坝址F-20断层泥中方解石的热发光年龄测定

• 作 者: 裴静娴 许学汉 李继亮
• 机 构: 中国科学院地质研究所,中国科学院地质研究所,中国科学院地质研究所 北京,北京,北京
• 出 处: 中国科学(B辑 化学 生物学 农学 医学 地学)
• 发表日期: 1985年03期
• 关键词: 热发光 F-20 年龄测定 断层泥 二滩 热液蚀变 发光性质 断层活动 膝折带 活动时代

本文研究了二滩坝址玄武岩中方解石的热发光性质。这些方解石是中温热液蚀变的产物,当受到新断裂活动作用时,方解石晶体发生变形。实验表明,方解石受压力作用时,其天然热发光逐渐衰减,直至全部消失。根据这种原理,可以用二滩坝址方解石变形后积累的天然热发光测定最新断层活动的年龄。利用这种方法测得方解石受压变形事件发生在距今140.3万年和115.5万年之间。据此推断F-20老断层复活时期不晚于距今115.5万年。

This paper studies the thermoluminescence properties of calcite in the basalt of Ertan dam site. These calcites are the products of mesothermal hydrothermal alteration, which deform when calcined by a new fault. Experiments show that calcite under pressure, the natural thermal luminescence gradually decay, until all disappear. According to this principle, the age of the latest fault activity can be determined by natural thermoluminescence accumulated after deformation of the calcite at Er Tan dam site. Calculated using this method of calcite deformation occurred in the deformation of 1.3.3 million years and 1.155 million years ago. It is concluded that the F-20 old fault resurrection period no later than 115.5 million years ago.