Formation of mantle “lone plumes” in the global downwelling zone — A multiscale modelling of subduction-controlled plume generation beneath the South China Sea
Formation of mantle “lone plumes” in the global downwelling zone — A multiscale modelling of subduction-controlled plume generation beneath the South China Sea
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全球下降流区地幔“孤立地幔柱”的形成——南海海底俯冲控制地幔柱生成的多尺度模拟
DOI：
10.1016/j.tecto.2017.11.038
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发表时间：
2018-01
期刊：
影响因子：
2.9
通讯作者：
Z.-X. Li
中科院分区：
文献类型：
--
作者：
Nan Zhang;Z.-X. Li
几乎所有已知的中生代以来的地幔热柱都形成于两个下地幔大的低剪切速度区(LLSVP)之上。海南的羽流是一个罕见的例外，因为它不是升起在低海拔高度之上，而是位于广泛的全球地幔下流带，因此被归类为“孤立柱”。在这里，我们使用海南地热柱的例子，利用三维地球动力学模拟来研究这种通过俯冲地幔下沉带中的板块而产生的孤立柱的可行性。我们的地球动力学模型有一个高分辨率的区域域嵌入到一个相对低分辨率的全球域中，它是建立在自适应网格细化的3D地幔对流代码方面(地球对流问题的高级解算器)。我们使用最近发表的板块运动模型来定义顶部力学边界条件。我们的模拟结果表明，中生代特提斯洋俯冲和闭合形成的现今欧亚大陆下的冷板块阻止了深部地幔热物质从南中国海以北或以西向南中国海迁移。从东侧看，西太平洋俯冲系统自70 Ma前开始在未来的南中国海区附近促进下地幔热化学堆体的形成。随着这个下地幔热化学堆顶部的上升，它首先向西移动，最后停在南中国海下。模式中热化学层(可能是D“层)的存在有助于稳定羽流的根。我们的模式是第一次在区域模式中实施多尺度网格。它已被证明是在全球板块运动和地幔动力学背景下模拟区域动力学的一种有效方法。
It has been established that almost all known mantle plumes since the Mesozoic formed above the two lower mantle large low shear velocity provinces (LLSVPs). The Hainan plume is one of the rare exceptions in that instead of rising above the LLSVPs, it is located within the broad global mantle downwelling zone, therefore classified as a “lone plume”. Here, we use the Hainan plume example to investigate the feasibility of such lone plumes being generated by subducting slabs in the mantle downwelling zone using 3D geodynamic modelling. Our geodynamic model has a high-resolution regional domain embedded in a relatively low resolution global domain, which is set up in an adaptive-mesh-refined, 3D mantle convection code ASPECT (Advanced Solver for Problems in Earth's ConvecTion). We use a recently published plate motion model to define the top mechanical boundary condition. Our modelling results suggest that cold slabs under the present-day Eurasia, formed from the Mesozoic subduction and closure of the Tethys oceans, have prevented deep mantle hot materials from moving to the South China Sea from regions north or west of the South China Sea. From the east side, the Western Pacific subduction systems started to promote the formation of a lower-mantle thermal-chemical pile in the vicinity of the future South China Sea region since 70 Ma ago. As the top of this lower-mantle thermal-chemical pile rises, it first moved to the west, and finally rested beneath the South China Sea. The presence of a thermochemical layer (possible the D″ layer) in the model helps stabilizing the plume root.Our modelling is the first implementation of multi-scale mesh in the regional model. It has been proved to be an effective way of modelling regional dynamics within a global plate motion and mantle dynamics background.
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影响因子：
3.5
作者：
H. Zou;Q. Fan
通讯作者：
H. Zou;Q. Fan
识别年轻地幔柱源区的古老地幔储层和年轻的再生材料：对地幔柱和板块构造之间潜在联系的启示
影响因子：
5.3
作者：
Li, Xian-Hua;Li, Jie;Xu, Yi-Gang;Li, Xiang-Hui
通讯作者：
Li, Xiang-Hui
影响因子：
4.9
作者：
K. Kodama;P. Ward
通讯作者：
K. Kodama;P. Ward
DOI：
--
发表时间：
2006-12
期刊：
--
影响因子：
--
作者：
J. Elsenbeck;M. Behn;G. Hirth
通讯作者：
J. Elsenbeck;M. Behn;G. Hirth
影响因子：
--
作者：
S. Lebedev;G. Nolet
通讯作者：
S. Lebedev;G. Nolet