Seismological Constraints on the Small-Scale Heterogeneity in the Lowermost Mantle Beneath East Asia and Implication for Its Mineralogical Origin
文献类型：期刊论文
| 作者 | Zhang, Baolong1; Ni, Sidao1; Sun, Daoyuan2 |
| 刊名 | GEOPHYSICAL RESEARCH LETTERS
 |
| 出版日期 | 2019-05-28 |
| 卷号 | 46期号:10页码:5225-5233 |
| ISSN号 | 0094-8276 |
| DOI | 10.1029/2019GL082296 |
| 英文摘要 | Previous seismological studies have focused on the large-scale heterogeneity of the D" layer beneath East Asia. Here, we use high-frequency PcP precursors recorded at dense networks in China and Japan to constrain the small-scale heterogeneity in this region. By forward modeling of the stacks of recorded PcP precursory signal, we find that the small-scale heterogeneity in the D ''" layer beneath East Asia is characterized by a P wave velocity perturbation of 0.1-0.2% and a dominant length scale of 4-20 km. Although the resolved length scale is similar to the dimension of the subducted oceanic crust, the weak velocity perturbation is difficult to explain by basaltic rock in the lowermost mantle. Postperovskite transition of the supposed slab might also not be viable for generating weak heterogeneity; thus, new explanations are needed from geodynamics and mineral physics to account for the different strength of the large- and small-scale heterogeneity. Plain Language Summary Most global tomography models show high-velocity anomalies near the core-mantle boundary beneath East Asia, which is part of the circum-Pacific fast anomalies in the lowermost mantle. Previous seismological, mineral physical, and geodynamical studies have proposed two hypotheses to interpret the origin of high-velocity anomalies: the accumulation of old slabs and the perovskite to postperovskite phase transition. In this work, by modeling PcP precursors in recordings, we observe weak small-scale heterogeneity, which cannot be explained by these two hypotheses; thus, new mechanisms are needed to account for the different strength of heterogeneity between large scale and small scale. |
| 资助项目 | Strategic Priority Research Program (B) of Chinese Academy of Sciences[XDB18000000] ; National Natural Science Foundation of China[41574037] ; National Basic Research Program of China (973 Program)[2014CB845901] ; Key Research Program of Frontier Sciences CAS[QYZDB-SSWSYS011] ; China Postdoctoral Science Foundation[2018M640742] |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000471237500025 |
| 出版者 | AMER GEOPHYSICAL UNION |
| 源URL | [http://202.127.146.157/handle/2RYDP1HH/8048]  |
| 专题 | 中国科学院武汉植物园 |
| 通讯作者 | Ni, Sidao |
| 作者单位 | 1.Chinese Acad Sci, Inst Geodesy & Geophys, State Key Lab Geodesy & Earths Dynam, Wuhan, Hubei, Peoples R China 2.Univ Sci & Technol China, Lab Seismol & Phys Earths Interior, Sch Earth & Space Sci, Hefei, Anhui, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zhang, Baolong,Ni, Sidao,Sun, Daoyuan. Seismological Constraints on the Small-Scale Heterogeneity in the Lowermost Mantle Beneath East Asia and Implication for Its Mineralogical Origin[J]. GEOPHYSICAL RESEARCH LETTERS,2019,46(10):5225-5233. |
| APA | Zhang, Baolong,Ni, Sidao,&Sun, Daoyuan.(2019).Seismological Constraints on the Small-Scale Heterogeneity in the Lowermost Mantle Beneath East Asia and Implication for Its Mineralogical Origin.GEOPHYSICAL RESEARCH LETTERS,46(10),5225-5233. |
| MLA | Zhang, Baolong,et al."Seismological Constraints on the Small-Scale Heterogeneity in the Lowermost Mantle Beneath East Asia and Implication for Its Mineralogical Origin".GEOPHYSICAL RESEARCH LETTERS 46.10(2019):5225-5233. |
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来源：武汉植物园
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