The interaction between mantle plumes and lithosphere and its surface expressions: 3-D numerical modelling
The interaction between mantle plumes and lithosphere and its surface expressions: 3-D numerical modelling
复制标题
DOI：
10.1093/gji/ggab014
复制
发表时间：
2021-02
影响因子：
2.8
通讯作者：
Yongming Wang;Mingming Li
中科院分区：
文献类型：
--
作者：
Yongming Wang;Mingming Li
地幔柱上升到岩石圈底部导致可观测的表面表达，这提供了关于深部地幔结构的重要信息。然而，地幔柱-岩石圈相互作用的过程及其表面表现仍然没有得到很好的理解。在这项研究中，我们进行了三维球面数值模拟研究的羽-岩石圈相互作用引起的地表观测值（包括动态地形，大地水准面异常和熔体生产率）和羽和岩石圈的物理性质（包括羽的大小，羽过温，羽粘度，岩石圈粘度和厚度）之间的关系。我们发现，羽流引起的地面表达有很强的空间和时间变化。在到达岩石圈底部之前，地幔柱头在深部的上升导致地表动力学地形和大地水准面异常的正向和快速增加，但没有熔融产物。地幔柱头部随后撞击岩石圈底部，导致动力学地形和大地水准面异常进一步增加，并导致熔体产量迅速增加。在达到最大值后，这些羽流诱导的可观测量变得相对稳定，更多地受到羽流导管的影响。此外，虽然大地水准面异常和动态地形减少从区域以上的羽状流中心到区域以上的羽状流边缘，熔体生产总是集中在羽状流的中心部分。我们还发现，表面的表达有不同的敏感性羽和岩石圈的属性。动力地形显著增加的羽流的大小，羽流的过温和羽流的粘度。大地水准面异常也随着羽流的大小和超温而增大，但对羽流粘度不太敏感。与热柱性质的影响相比，动态地形和大地水准面异常受岩石圈粘性和厚度的影响较小。熔体产生量随羽流尺寸、羽流超温和羽流粘度的增大而增大，随岩石圈粘度和厚度的增大而减小。
The rise of mantle plumes to the base of the lithosphere leads to observable surface expressions, which provide important information about the deep mantle structure. However, the process of plume–lithosphere interaction and its surface expressions remain not well understood. In this study, we perform 3-D spherical numerical simulations to investigate the relationship between surface observables induced by plume–lithosphere interaction (including dynamic topography, geoid anomaly and melt production rate) and the physical properties of plume and lithosphere (including plume size, plume excess temperature, plume viscosity, and lithosphere viscosity and thickness). We find that the plume-induced surface expressions have strong spatial and temporal variations. Before reaching the base of the lithosphere, the rise of a plume head in the deep mantle causes positive and rapid increase of dynamic topography and geoid anomaly at the surface but no melt production. The subsequent impinging of a plume head at the base of the lithosphere leads to further increase of dynamic topography and geoid anomaly and causes rapid increase of melt production. After reaching maximum values, these plume-induced observables become relatively stable and are more affected by the plume conduit. In addition, whereas the geoid anomaly and dynamic topography decrease from regions above the plume centre to regions above the plume edge, the melt production always concentrates at the centre part of the plume. We also find that the surface expressions have different sensitivities to plume and lithosphere properties. The dynamic topography significantly increases with the plume size, plume excess temperature and plume viscosity. The geoid anomaly also increases with the size and excess temperature of the plume but is less sensitive to plume viscosity. Compared to the influence of plume properties, the dynamic topography and geoid anomaly are less affected by lithosphere viscosity and thickness. The melt production significantly increases with plume size, plume excess temperature and plume viscosity, but decreases with lithosphere viscosity and thickness.