| 引用本文: | 魏传义，刘春茹，李长安，冷勇辉，李文朋，尹功明，韩 非，李建平.2018.石英不同Ti-Li心电子自旋共振信号光晒退特征及其测年意义[J].地球环境学报,9(6):607-613 |
| WEI Chuanyi, LIU Chunru, LI Chang’an, LENG Yonghui, LI Wenpeng, YIN Gongming, HAN Fei, LI Jianping.2018.Bleaching characteristics of quartz electron spin resonance (ESR) signals of multiple Ti-Li centers: implication for ESR dating[J].Journal of Earth Environment,9(6):607-613 |
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| 摘要: |
| 为探讨石英不同Ti-Li心电子自旋共振（ESR）信号的光晒退特征及其测年意义，对典型花岗岩类基岩样品、河流现代表层沉积物样品及地质历史时期沉积物样品的石英Ti-Li心option A、Ti-Li心option B、Ti-Li心option C、Ti-Li心option D和Ti-Li心option E的ESR信号光晒退特征进行了系统研究。结果显示：（1）不同Ti-Li心ESR信号可在较短时间内（260 h）完全晒退，表明Ti-Li心是优良的石英ESR测年信号心；（2）石英的赋存环境对同一Ti-Li心ESR信号晒退“归零”所需的时间具有明显的影响作用。相比于基岩石英和地质历史时期沉积物石英，现代河流沉积物石英因其已经接受了一定时间的光晒退作用而具有更快的光晒退“归零”速率；（3）石英同一Ti-Li心的光敏感特性会因石英经历的地质循环过程的不同而改变，相比于基岩，沉积物因经历了更复杂的地质过程而具有了深陷阱电子，所以需要更长的光晒退归零时间；（4）同一样品的不同Ti-Li心表现出了相同的光晒退特征，说明不同类型的Ti-Li心具有相同的光敏特性；（5）Ti-Li心option B在某些自然样品中不易观察，Ti-Li心option D和Ti-Li心option E信号较为微弱，因此，Ti-Li心option A是进行沉积物石英ESR测年的最佳信号心。 |
| 关键词: 石英 Ti-Li心 光晒退 电子自旋共振测年 |
| DOI：10.7515/JEE182053 |
| CSTR：32259.14.JEE182053 |
| 分类号: |
| 基金项目:中国地震局地质研究所地震动力学国家重点实验室2016年度自主课题（LED2016A08）；国家自然科学基金项目（41671011） |
| 英文基金项目:Basic Scientific Research Fund, Institute of Geology, China Earthquake Administration (LED2016A08); National Natural Science Foundation of China (41671011) |
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| Bleaching characteristics of quartz electron spin resonance (ESR) signals of multiple Ti-Li centers: implication for ESR dating |
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WEI Chuanyi, LIU Chunru, LI Chang’an, LENG Yonghui, LI Wenpeng, YIN Gongming, HAN Fei, LI Jianping
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1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China
2. School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
3. State Key Laboratory of Biogeology and Environmental Geology, Wuhan 430074, China
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| Abstract: |
| Background, aim, and scope Resetting rate of various ESR Ti-Li centers signal intensities in quartz extracted from fluvial sediments plays a key role for accuracy of sample ESR dating result. In order to evaluate if the quartz Ti-Li centers of samples have been bleached to zero before their burial, we examine sunlight bleaching characteristics of quartz ESR signals of multiple Ti-Li centers and its use for ESR dating. Materials and methods In this study, we select granitic bedrock samples, modern fluvial sediment sample and historical sediment sample and choose four commonly used Ti-Li centers, which is the option A, option B, option D and E, respectively, for ESR evaluating experiments. Results The results showed that four options of Ti-Li center ESR signal could be bleached to zero after about 260 h artificial sunlight bleaching; meanwhile, four options of Ti-Li centers showing similarly sunlight bleaching curve, which indicate that the four options of same sample have similarly sunlight bleaching sensitivity. Discussion Quartz storage carrier not only affect the zeroing rate, but also change sunlight bleaching sensitivity of quartz ESR signals. The field sunlight exposure time usually can zero four options’ ESR signal intensity of quartz Ti-Li center. Conclusions Quickly sunlight bleach zeroing characteristics make Ti-Li center one of the most useful ESR signals for ESR dating, and we propose that the option A of Ti-Li center is the best signal for quartz ESR dating used by Ti-Li center. Recommendations and Perspectives Quartz Ti-Li center ESR signal intensity have a great potential use in fluvial sediments dating, especially in Quaternary sediment dating application without tephra. |
| Key words: quartz Ti-Li centers sunlight bleaching electron spin resonance (ESR) dating |
