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| DOI | 10.1016/j.quascirev.2020.106442 |
| Improving the reliability of bulk sediment radiocarbon dating | |
| Strunk A.; Olsen J.; Sanei H.; Rudra A.; Larsen N.K. | |
| 发表日期 | 2020 |
| ISSN | 0277-3791 |
| 卷号 | 242 |
| 英文摘要 | Radiocarbon dated chronologies are the most extensively applied dating technique when investigating the last ∼45,000 years. In lake and marine sediments, a single macrofossil or several microfossils are the preferred sample material because they have a 14C age that accurately reflects the time of deposition. However, absence of macro- or microfossils are a recurring challenge. Often, it is necessary to use bulk sediment samples for radiocarbon dating, but they frequently yield ages clearly exceeding the depositional timeframe due to occurrence of organic material of older origin. Until now, it has not been possible to assess if the dating result of a bulk sediment sample is reliable, or to adequately explain the mechanisms behind age disagreement between bulk and macro- and microfossils. In this study, we investigate the age offset between paired bulk and macrofossil ages in sediment cores from three lakes in SE and E Greenland. Furthermore, we distinguish three quantifiable main carbon sources in the samples: a) recent terrestrial organic fragments, b) recent aquatic organic matter, and c) reworked land-derived old carbon, through pyrolysis organic geochemistry, organic petrographic microscopy, and isotopic fractionization. Our results show that the offset between bulk (humic fraction) and macrofossil radiocarbon ages in three similar lakes range from 9 14C yr to 20.1 14C kyr. We observe a reduced age offset between bulk- and macrofossil ages, and thereby a higher reliability of bulk (humic fraction) ages, correlated with increased values of TOC, C/N ratio, and high CO2 release in pyrolysis (S3 value). We recommend that future studies presenting bulk sediment chronologies apply pyrolysis organic geochemistry, organic petrographic microscopy, and isotopic fractionization as demonstrated here, to select reliable sediment intervals for bulk dating and retrieve more robust results. © 2020 Elsevier Ltd |
| 英文关键词 | Age offset.; Bulk sediment; Greenland; Organic geochemistry; Paleolimnology; Pyrolysis; Quaternary; Radiocarbon dating; Radiogenic isotopes; Stable isotopes |
| 语种 | 英语 |
| scopus关键词 | Carbon; Deposition; Geochemistry; Isotopes; Lakes; Pyrolysis; Submarine geology; Dating techniques; Marine sediments; Organic fragments; Organic geochemistry; Organic materials; Petrographic microscopy; Radiocarbon dating; Sediment samples; Sediments; bulk density; carbon dioxide; depositional environment; geochronology; humic substance; lacustrine deposit; organic geochemistry; pyrolysis; radiocarbon dating; sediment analysis; Arctic; Greenland |
| 来源期刊 | Quaternary Science Reviews
 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/151389 |
| 作者单位 | Department of Geoscience, Aarhus University, Aarhus, 8000, Denmark; Aarhus AMS Centre (AARAMS), Department of Physics and Astronomy, Aarhus University, Aarhus, 8000, Denmark; Lithospheric Organic Carbon (L.O.C.) Group, Department of Geoscience, Aarhus University, Aarhus, 8000, Denmark; Globe Institute, University of Copenhagen, Copenhagen, 1350, Denmark |
| 推荐引用方式 GB/T 7714 | Strunk A.,Olsen J.,Sanei H.,et al. Improving the reliability of bulk sediment radiocarbon dating[J],2020,242. |
| APA | Strunk A.,Olsen J.,Sanei H.,Rudra A.,&Larsen N.K..(2020).Improving the reliability of bulk sediment radiocarbon dating.Quaternary Science Reviews,242. |
| MLA | Strunk A.,et al."Improving the reliability of bulk sediment radiocarbon dating".Quaternary Science Reviews 242(2020). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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