基于辐射损伤的磷灰石裂变径迹退火行为研究

Apatite Fission Track Annealing Behavior Based on the Effect of Radiation Damage

目前裂变径迹低温热年代学的理论基础是建立在温度是导致径迹退火的唯一诱因之上的。然而,辐射损伤是否能够促进裂变径迹退火尚处于争论中。文章采用云南临沧四块花岗岩样品的磷灰石裂变径迹测试分析方法,对辐射损伤与裂变径迹退火行为之间的关系进行了研究。云南临沧磷灰石单颗粒年龄71~15 Ma,封闭径迹长度9~16μm,U含量24~290μg/g。统计分析结果表明,磷灰石封闭径迹长度以及单颗粒年龄分别随相应U含量增加而减小。综合分析认为,这种变化趋势初步表明了辐射损伤能够促进裂变径迹退火,是导致裂变径迹退火的另一诱因,为辐射损伤诱发裂变径迹退火行为研究提供了新证据。

The fundamental theory of the fission-track thermochronology has been based on the principle that temperature is the only factor of fission track annealing.However,whether the radiation damage can enhance the annealing or not remains in dispute.This work studies the relationship between radiation damage and the fission track annealing behavior by the apatite fission track dating of four granite samples from Lincang county in Yunnan province.The single grain fission track ages of the samples range from 71 Ma to 15 Ma.The confined track lengths of the samples range from 9μm to 16μm and the U concentrations of the samples range from 24μg/g to 290μg/g.The analytical results of the relationship between fission track age and length and U concentration show that the fission track age and length decrease wirh increasing U concentration.The relationship preliminarily indicates that the radiation damage could cause and enhance fission track annealing as another factor in addition to temperature.This observation provides evidence for studing fission track annealing behavior caused by radiation damage.