新西兰俯冲带/火山弧地幔流动和熔融体生成/输运过程的三维地球动力学模拟研究

本项目拟对新西兰地区俯冲带和火山弧系统地幔流动进行高分辨率三维建模，以研究上地幔熔融体生成和输运的过程、板片-地幔楔的地震学结构与俯冲和地幔楔动力学之间的关联。该区域火山活动活跃，地球化学性质多样，数种地幔楔流的驱动因素可能并存，亚火山弧地震活动和地震波速结构的特征显著。.申请人计划在前期建模的基础上（Hansenclever等，2011，2017；Morgan等，2014，2019，2020）加入地震学和地球化学约束条件，构建目标三维模型，从而预测亚火山弧地震学构造和熔融特征。模型背景场是一个代表整个地幔的低分辨率球形壳体，高分辨率的目标研究区域嵌入其中。申请人最近（2020）已经给出了该方法用于南大西洋裂谷建模的计算示例。模型中对于地震波速度和熔融体结构、以及其幅值的预测将得到现有观测资料的检验，并为未来的该区域地震学台阵观测和地球化学数据收集设计提供指导。

This project aims to build a high-resolution geodynamic model of flow and melting in the region of New Zealand Arc, in order to study how the processes of melt generation and transport and the seismic structure of the slab-wedge region relate to subduction and mantle wedge dynamics that are shaped by the complex plate motions in this region...It targets the North Island region of New Zealand subduction zone, as this site is amongst the best areas globally to conduct such studies, whose characteristics include active volcanism with a broad spectrum of geochemical diversity, several potential drivers of mantle wedge flow, and interesting patterns in sub-arc seismicity and seismic wavespeed structure...Based on the existing body of observations on this region, the applicant intends to build upon his group’s research on 3-D mantle modelling (e.g. Hasenclever et al., 2011,2017; Morgan et al., 2014, 2019, 2020) to construct geodynamic models for mantle flow and melting beneath the arc , and their predictions for melting patterns. This type of integrated model is likely to be the best way to link seismic and geochemical constraints on the structure of the New Zealand Arc. Model predictions of seismic and melting structures and amplitudes will be used to simultaneously test the models against existing observations, and also design observational strategies for future seismic and geochemical data collection. ..To increase the resolution of the modelling in these novel models, the 3-D model domain consists of a coarse-resolution spherical shell spanning the entire mantle that includes an embedded high-resolution region around the area of interest. An example for such analogous 2020). This project aims to do wedge-scale geodynamical modelling to understand solid matrix flow, stress temperature, melting and melt transport in the mantle wedge, and how they relate to slab subduction.