| A major change in precipitation gradient on the Chinese Loess Plateau at the Pliocene-Quaternary boundary | |
| Peng, Wenbin1; Nie, Junsheng1; Wang, Zhao1; Qiang, Xiaoke2; Garzanti, Eduardo3; Pfaff, Katharina4; Song, Yougui2; Stevens, Thomas5 | |
| 2018-04-15 | |
| 发表期刊 | JOURNAL OF ASIAN EARTH SCIENCES
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| 卷号 | 155期号:2018页码:134-138 |
| 文章类型 | Article |
| 摘要 | Spatiotemporal variations in East Asian Monsoon (EAM) precipitation during the Quaternary have been intensively studied. However, spatial variations in pre-Quaternary EAM precipitation remain largely uninvestigated, preventing a clear understanding of monsoon dynamics during a warmer climatic period. Here we compare the spatial differences in heavy mineral assemblages between Quaternary loess and pre-Quaternary Red Clay on the Chinese Loess Plateau (CLP) to analyze spatial patterns in weathering. Prior studies have revealed that unstable hornblende is the dominant (similar to 50%) heavy mineral in Chinese loess deposited over the past 500 ka, whereas hornblende content decreases to < 10% in strata older than similar to 1 Ma in the central CLP because of diagenesis. In the present study we found that hornblende is the dominant heavy mineral in 2-2.7 Ma loess on the northeastern CLP (at Jiaxian), which today receives little precipitation. Conversely, hornblende content in the upper Miocene-Pliocene Red Clay at Jiaxian is < 10%, as in the central CLP. The early Quaternary abundance of hornblende at Jiaxian indicates that the current northwestward-decreasing precipitation pattern and consequent dry climate at Jiaxian must have been initiated since 2.7 Ma, preventing hornblende dissolution to amounts < 10% as observed in the central CLP. By contrast, the 7 Ma and 3 Ma Jiaxian Red Clay hornblende content is significantly less than that of the Xifeng samples, despite the fact that today Xifeng receives more precipitation than Jiaxian, with expected enhanced hornblende weathering. This suggests that the northeastern CLP received more precipitation during the Late Miocene-Pliocene than at Xifeng, indicating that the precipitation gradient on the CLP was more east west during the Late Miocene-Pliocene rather than northwest southeast as it was in the Quaternary. A comparison of magnetic susceptibility records for these sections confirms this inference. We attribute this major change in climatic patterns at 2.7 Ma to decreased northward moisture transportation associated with Northern Hemisphere glaciation and cooling in the Quaternary. This study therefore demonstrates the potential usefulness of employing heavy mineral analysis in both paleoclimatic and paleooceanographic reconstructions. |
| 关键词 | Heavy Mineral Qemscan Loess Red Clay Precipitation Quaternary Pliocene Hornblende Weathering |
| WOS标题词 | Science & Technology ; Physical Sciences |
| DOI | 10.1016/j.jseaes.2017.10.031 |
| 关键词[WOS] | PERMANENT EL-NINO ; RED CLAY ; MONSOON VARIATIONS ; HEAVY MINERALS ; SEQUENCES ; DEPOSITS ; PALEOSOL ; CLIMATE ; CYCLES ; RECORD |
| 收录类别 | SCI |
| WOS研究方向 | Geology |
| WOS类目 | Geosciences, Multidisciplinary |
| WOS记录号 | WOS:000428006300011 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.ieecas.cn/handle/361006/5205 |
| 专题 | 古环境研究室 |
| 作者单位 | 1.Lanzhou Univ, Coll Earth & Environm Sci, Minist Educ, Key Lab Western Chinas Environm Syst, Lanzhou 730000, Gansu, Peoples R China 2.Chinese Acad Sci, Inst Earth Environm, SKLLQG, Xian 710075, Shaanxi, Peoples R China 3.Univ Milano Bicocca, Dept Earth & Environm Sci, Piazza Sci 4, I-20126 Milan, Italy 4.Colorado Sch Mines, Dept Geol & Geol Engn, 1516 Illinois St, Golden, CO 80401 USA 5.Uppsala Univ, Dept Earth Sci, Villavagan 16, S-75123 Uppsala, Sweden |
| 推荐引用方式 GB/T 7714 | Peng, Wenbin,Nie, Junsheng,Wang, Zhao,et al. A major change in precipitation gradient on the Chinese Loess Plateau at the Pliocene-Quaternary boundary[J]. JOURNAL OF ASIAN EARTH SCIENCES,2018,155(2018):134-138. |
| APA | Peng, Wenbin.,Nie, Junsheng.,Wang, Zhao.,Qiang, Xiaoke.,Garzanti, Eduardo.,...&Stevens, Thomas.(2018).A major change in precipitation gradient on the Chinese Loess Plateau at the Pliocene-Quaternary boundary.JOURNAL OF ASIAN EARTH SCIENCES,155(2018),134-138. |
| MLA | Peng, Wenbin,et al."A major change in precipitation gradient on the Chinese Loess Plateau at the Pliocene-Quaternary boundary".JOURNAL OF ASIAN EARTH SCIENCES 155.2018(2018):134-138. |
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