| 摘要: |
| 在第四纪地质学中，电子自旋共振（ESR）信号特征可用于物源示踪、判断受热时间及受热历史等研究，具有广阔的应用前景，因此对ESR信号特征的研究具有重要意义。本文通过对大同火山熔岩烘烤层和未烘烤湖相层样品的石英不同ESR信号特征进行研究，并总结了高温烘烤作用对不同石英ESR信号特征的影响。研究发现：高温烘烤作用显著增强了石英Ti-Li心ESR信号灵敏度；石英Al心ESR信号灵敏度无明显变化；E′心信号灵敏度小幅度增加。另外，高温烘烤之前无Ge心信号，在高温烘烤作用之后出现了Ge心信号。光晒退实验结果显示：经过高温烘烤作用之后，石英Al心的不可晒退部分减小，且石英Al心和Ti-Li心信号光晒退“回零”速度更快。 |
| 关键词: 电子自旋共振 册田水库 高温 烘烤层 灵敏度 地质年代学 |
| DOI：10.7515/JEE182052 |
| CSTR：32259.14.JEE182052 |
| 分类号: |
| 基金项目:中国地震局地质研究所中央级公益性科研院所基本科研业务专项项目（IGCEA1417）；国家自然科学基金项目（41372178） |
| 英文基金项目:Basic Scientific Research Fund, Institute of Geology, China Earthquake Administration (IGCEA1417); National Natural Science Foundation of China (41372178) |
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| Effect of high temperature baking on characteristics of quartz electron spin resonance (ESR) signal — taking Datong volcanic baking layer as an example |
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LI Wenpeng, LIU Chunru, YIN Gongming, WEI Chuanyi, LI Jianping, LI Xinxin
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1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 10029, China
2. Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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| Abstract: |
| Background, aim, and scope Electron spin resonance (ESR) dating method is a new dating method developed rapidly in Quaternary chronology in recent decades and has received extensive attention from the Quaternary scholars. The characteristics of ESR signal can be used for source tracing, judging heating time and heating history, and has broad application prospects in Quaternary geology studies. Many studies on ESR dating are mainly focused on the determination of sediment age and dating reliability, but there are less studies on the characteristics of quartz E′ center, Ge center, Al center, Ti-Li center, which were directly related to dating. Especially for the signal characteristics of samples subjected to special effects such as high temperature and high dose radiation. In fact, the essential characteristics of the ESR signal directly determine the dating range, experimental procedure and application of the method. Therefore, it is great significance to research the characteristics of ESR signals. Materials and methods Datong volcanic group is in the Datong Basin in the northern part of China. Many researchers have studied this area, the volcanic eruptions in this area lie between Quaternary loess and lacustrine layers. The lacustrine sediment was baked by volcanic lava overlain, and the lava baked lacustrine sediment is ideal for us to study the thermal characteristics of quartz ESR signals in nature. In this paper, the ESR signatures of the lava-baked and unfired lacustrine layers in Datong volcano were studied, and the effects of high-temperature baking on the characteristics of ESR signals and the characteristics of sunlight bleaching in different quartz were summarized. Results It was found that high-temperature baking significantly enhances the sensitivity of the quartz Ti-Li center ESR signal. There is no significant change in the sensitivity of the quartz Al center ESR signal, the sensitivity of the E′ center signal increases slightly, and there is no Ge center signal before high-temperature baking. Ge center signal appeared after high temperature baking. The results of the sunlight bleaching experiment showed that after the high-temperature baking effect, the unbleaching part of the Al center was reduced, and the ESR signals back to zero faster. Discussion The increase in the sensitivity of the ESR signals will reduce the relative error of the signal measurement when use the ESR dating. Therefore, the samples which have been baked at high temperatures in the past, the ESR dating may have better results. Conclusions The sensitivity of quartz Ti-Li and E′ centers’ ESR signals enhanced after baked by volcanic lava. The quartz Ge center ESR signal appears after baked by volcanic lava. The Al center sunlight unbleached part decrease after baked by volcanic lava. Recommendations and perspectives When using ESR dating, we must pay attention to the characteristics of various signals and select the appropriate dating signals. |
| Key words: ESR Cetian Reservoir high temperature volcanic lava sensitivity geochronology |
