Tracking the Provenance of Aeolian Loess in Northeastern China by Uranium Isotopes
文献类型：期刊论文
| 作者 | Li, Le1,2; Li, Gen K.3; Li, Tao4; Yi, Shuangwen5; Lu, Huayu5; Hedding, David William6; Chen, Jun1,2; Li, Gaojun1,2 |
| 刊名 | GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
 |
| 出版日期 | 2023-04-01 |
| 卷号 | 24期号:4页码:12 |
| 关键词 | surface process aeolian loess uranium isotope paleoclimate Asian dust tectonic uplift |
| DOI | 10.1029/2022GC010715 |
| 通讯作者 | Li, Le(lile@nju.edu.cn) |
| 英文摘要 | The aeolian loess deposits in northeastern China have substantial potential for reconstructing the paleoclimate in the East Asian monsoon boundary zone. Identifying the source of the aeolian dust is crucial to interpret the paleo-proxies recorded in the loess deposits in northeastern China; however, traditional geochemical tracers such as Nd and Sr isotopes cannot discriminate between the potential source areas, that is, the Otindag Sandy Land, Horqin Sandy Land, and Hulun Buir Sandy Land regions. In this study, the (U-234/U-238) activity ratio is used to constrain the provenance of the loess deposits in northeastern China. The (U-234/U-238) of the studied loess-paleosol sequences (from 0.935 to 0.910) decreases with increasing depositional age (from 10 to similar to 1,000 ka), which is consistent with predictions from uranium isotope comminution age model. A derived (U-234/U-238) of 0.935 +/- 0.003 for the newly deposited loess (zero depositional age) is most similar to that of the Otindag Sandy Land positioned at a proximal upwind direction, suggesting that the Otindag Sandy Land is the most likely source of the aeolian dust that formed the loess deposits in northeastern China. A transportation time of 432 +/- 65 ka was calculated for these deposits, indicating extensive mixing of the fine dust in the source regions, which could partially explain the relative homogeneity of loess deposits in northeastern China. The transportation time longer than several glacial-interglacial cycles suggests that reconstructions of regional paleoclimate on orbital timescales should be viewed with caution because the potential influence of climatic changes could largely be buffered. Plain Language Summary The activity ratio of the uranium isotopes (U-234 and U-238) in fine-grained particles can be used to determine the "comminution age", or the amount of time since the production of fine sediment particles (<= 50 mu m) from the breakdown of bedrock by weathering. The (U-234/U-238) activity ratio provides a new approach to track the age and origin of dust particles. In this study, we measure the (U-234/U-238) composition of the loess deposits in northeastern China and surface sand samples in potential source areas to better understand the transport of aeolian dust in the region. We find that the Otindag Sandy Land, which is in the proximal upwind direction, is the main source region for the loess deposits in northeastern China and that the dust materials have been resided in the source region for around 432 +/- 65 thousand years before aeolian transport and deposition. Our results shed light on the transport and depositional history of loess in northeastern China and provide valuable information for reconstructing paleoclimate using the loess deposits in this region. |
| WOS关键词 | SEDIMENT RESIDENCE TIMES ; WEATHERING RATES ; SERIES ISOTOPES ; NORTHERN CHINA ; ASIAN DUST ; GRAIN-SIZE ; DEPOSITS ; ATLANTIC ; DISEQUILIBRIUM ; TRANSPORT |
| 资助项目 | National Natural Science Foundation of China[41730101] ; National Natural Science Foundation of China[41991321] ; National Natural Science Foundation of China[42021001] ; National Natural Science Foundation of China[42103001] ; National Post-doctoral Program of China for Innovative Talents[BX20200163] ; UCSB Regent's Junior Faculty Fellowship |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| 出版者 | AMER GEOPHYSICAL UNION |
| WOS记录号 | WOS:000999807500011 |
| 资助机构 | National Natural Science Foundation of China ; National Post-doctoral Program of China for Innovative Talents ; UCSB Regent's Junior Faculty Fellowship |
| 源URL | [http://ir.nigpas.ac.cn/handle/332004/42395]  |
| 专题 | 中国科学院南京地质古生物研究所 |
| 通讯作者 | Li, Le |
| 作者单位 | 1.Nanjing Univ, Dept Earth & Planetary Sci, Minist Educ, Key Lab Surficial Geochem, Nanjing, Peoples R China 2.Nanjing Univ, Frontiers Sci Ctr Crit Earth Mat Cycling, Dept Earth & Planetary Sci, Nanjing, Peoples R China 3.Univ Calif Santa Barbara, Dept Earth Sci, Santa Barbara, CA USA 4.Chinese Acad Sci, Nanjing Inst Geol & Palaeontol, State Key Lab Palaeobiol & Stratig, Nanjing, Peoples R China 5.Nanjing Univ, Sch Geog & Ocean Sci, Nanjing, Peoples R China 6.Univ South Africa, Dept Geog, Florida, South Africa |
| 推荐引用方式 GB/T 7714 | Li, Le,Li, Gen K.,Li, Tao,et al. Tracking the Provenance of Aeolian Loess in Northeastern China by Uranium Isotopes[J]. GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,2023,24(4):12. |
| APA | Li, Le.,Li, Gen K..,Li, Tao.,Yi, Shuangwen.,Lu, Huayu.,...&Li, Gaojun.(2023).Tracking the Provenance of Aeolian Loess in Northeastern China by Uranium Isotopes.GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,24(4),12. |
| MLA | Li, Le,et al."Tracking the Provenance of Aeolian Loess in Northeastern China by Uranium Isotopes".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 24.4(2023):12. |
入库方式： OAI收割
来源：南京地质古生物研究所
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