吉林陨石的热释光剖面与母体宇宙暴露历史示踪  

The natural thermoluminescence profiles and cosmic ray exposure history of the Jilin meteorite

作　　者：陈永亨[1] 徐敏[1] 黄荣才[1] 

机构地区：[1]广州师范学院化学系,广东广州510405

出　　处：《地球化学》2000年第6期604-607,共4页Geochimica

基　　金：国家自然科学基金资助!19773004

摘　　要：对 3个已知取样深度和 3个未知取样部位的吉林陨石样品的热释光研究表明，其自然热释光值具有宇宙成因核素含量相似的性质即深度分布效应，随着样品距离表面位置的增大而降低，这表征了母体暴露期间宇宙射线的分布状况。诱导热释光数据表明，母体表面部分的样品的峰温和峰宽高于较深部位样品，说明这些样品中发光体矿物由有序态向无序态转化趋势明显。表面位置样品明显高的热释光数据说明在母体暴露过程中，除了银河宇宙射线外，太阳宇宙射线对表面位置物质也具有重要的贡献。Natural and induced thermoluminescence (TL) data are reported for 6 samples from the Jilin meteorite. Three of the samples are from the No.1 Jilin meteorite with known depth positions in distance from the current meteorite surface, and other three from the No.1, No.2 and No.4 Jilin meteorite, respectively, with unknown depth positions. The results suggest that natural TL of the three samples with known depth positions had depth distribution such as meteoritic cosmogenic nuclides, which was smaller with increasing distance from the current surface, indicating the conditions of cosmic ray exposure of the Jilin chondrite. The data of the induced TL peak temperature and peak width of the surface samples were higher than those of the deeper position samples, indicating that the TL phosphor mineral of ordinary chondrites showed obviously ordering-disordering conversion during cosmic ray exposure of the parent body. In addition to primary galactic cosmic ray, the results of these TL profiles also suggest that the solar cosmic ray had a significant contribution. Meanwhile, TL sensitivities of the powder samples with terrestrial weathering are obviously lower than the fresh section samples (1.83～ 2.11 vs. 4.22～ 5.23 relative to the Dhajala H3.8 chondrite), showing the TL phosphor mineral is highly sensitive to weathering, but terrestrial weathering effect is very light to the TL peak temperature and peak width.

关 键 词：宇宙射线 热释光剖面 吉林 陨石 

分 类 号：P185.83[天文地球—天文学] P68