钾长石的年龄测定及其在地质上的意义

• 作 者: 朱炳泉
• 出 处: 中国科学技术大学学报
• 发表日期: 1965年01期
• 关键词: 年龄测定 钾长石 年龄数据 地质过程 侵入体 条纹长石 年龄值 侵入深度 过渡相 燕山期岩浆活动

前人的实验资料证明钾长石的K-Ar年龄一般都低于其真实年龄。这是由于钾长石中的放射成因氩在地质过程中丢失了。氩丢失的机理主要是固体扩散作用。钾长石用于绝对年龄测定确是不适合的;但是其偏低年龄数据往往能给我们提供关于地质体先前热历史的资料。因此对钾长石K-Ar年龄测定作进一步研究仍有其重要意义。在本文中提出了用钾长石偏低年龄来推测岩体侵入深度的可能性。

Previous experimental data prove that K-Ar ages of K-feldspar are generally lower than their true age. This is due to the radiogenic argon in the K-feldspar that is lost in the geological process. The mechanism of argon loss is mainly a solid diffusion. Potassium feldspar is certainly not suitable for absolute age determination; however, its low age data often gives us information about the previous thermal history of the geological body. Therefore, it is of great importance to further study K-Ar dating of K-Ar. In this paper, we propose the possibility of inferring the intrusion depth of rock mass by the lower ages of potash feldspar.