| ESR dating of glacial moraine deposits: Some insights about the resetting of the germanium (Ge) signal measured in quartz | |
| Yi, CL (Yi, Chaolu)1,2; Bi, WL (Bi, Weili)1; Li, JP (Li, Jianping)3; Yi, CL | |
| Source Publication | QUATERNARY GEOCHRONOLOGY
 |
| 2016 | |
| Volume | 35Issue:0Pages:69-76 |
| DOI | 10.1016/j.quageo.2016.06.003 |
| Abstract | The electron spin resonance (ESR) dating of tills using germanium-doped (Ge) paramagnetic centers in quartz has advantages over other dating techniques, as quartz is common, processing is easy, and the technique has the potential for dating features several hundreds of thousands years old. ESR dating of moraines is based on the supposition that either subglacial comminution or exposure to sunlight resets the signal. However, actual dating suggests that a signal that is initially present cannot be bleached to zero by grinding alone. We found that grinding coarse samples (0.5-1 mm in diameter) to the mean grain size of fine sand (0.125-0.193 mm) reduced the signal intensity to 53-69% of its original value. From the value of the signal difference, one can devise a correction factor for ESR ages of subglacial sediment. Polymineralic grains are commonly present in till. Exposure of them to sunlight for several days can reduce the signal intensity to 7-8% of its original value within 1-2 mm thick of the sediment surface. However, within 5-8 mm of the sediment surface, exposure to sunlight for over one week only reduced the signal intensity to mean plateau values of 42-50% of the initial value. Mixing upper and lower layers of the samples during exposure to sunlight changed the signal intensity. This suggests that the amount of bleaching varies spatially. Sediments initially deposited at the margins of ice caps or ice sheets and subsequently overridden may have been sufficiently exposed to sunlight to allow ESR dating of moraines. The purity of the quartz and the grain size have significant impacts on signal intensity; intensive purification and the use of a uniform fine sand fraction are thus recommended. (C) 2016 Elsevier B.V. All rights reserved. |
| Subject Area | 自然地理学 |
| WOS ID | WOS:000381325500008 |
| Language | 英语 |
| Indexed By | SCI |
| Keyword | Grain-size Distributions Upper Urumqi River Tian-shan Quaternary Glaciation Tien-shan China Till Area Mountains Evolution |
| Cooperation Status | 国内 |
| Department | 环境 |
| Subtype | Article |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.itpcas.ac.cn/handle/131C11/7599 |
| Collection | 图书馆 |
| Corresponding Author | Yi, CL |
| Affiliation | 1.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Tibetan Environm Changes & Land Surface P, Beijing 100864, Peoples R China 2.Chinese Acad Sci, Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100864, Peoples R China. 3.China Earthquake Adm, Inst Geolo Gy, State Key Lab Earthquake Dynam, Beijing, Peoples R China |
| Recommended Citation GB/T 7714 | Yi, CL ,Bi, WL ,Li, JP ,et al. ESR dating of glacial moraine deposits: Some insights about the resetting of the germanium (Ge) signal measured in quartz[J]. QUATERNARY GEOCHRONOLOGY,2016,35(0):69-76. |
| APA | Yi, CL ,Bi, WL ,Li, JP ,&Yi, CL.(2016).ESR dating of glacial moraine deposits: Some insights about the resetting of the germanium (Ge) signal measured in quartz.QUATERNARY GEOCHRONOLOGY,35(0),69-76. |
| MLA | Yi, CL ,et al."ESR dating of glacial moraine deposits: Some insights about the resetting of the germanium (Ge) signal measured in quartz".QUATERNARY GEOCHRONOLOGY 35.0(2016):69-76. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| V.35 69-75 2016.pdf（2786KB） | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | View Application Full Text | |
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