EAPSI:3-D Numerical Modeling of the 35-40E mid-ocean ridge segment along the Southwest Indian Ridge

大洋中脊是地球火山活动和重大地震发生的大部分地方。然而，大洋中脊只是更大的对流地幔系统的表面表现，而且人们对这个地幔的了解还很少。该项目旨在解释地幔如何向地球表面提供物质，以及地幔如何在地表附近移动。地球动力学建模是目前存在的调查洋中脊地幔过程和揭示那里地质历史的唯一方法之一。地质观测使建模更加逼真。在这个项目中，从西南印度洋海岭收集的岩石的性质将与许多模拟的岩浆成分进行比较，然后将其用于发现所观察到的岩石来源下方的地幔的性质。这将有助于更好地了解一般海脊以及热点-海脊相互作用区。与东京大学Okino博士的小组合作，将能够利用新技术追踪海脊的岩浆来源，并解释沿着海脊轴的不均匀性。这一段距离马里恩热点最近，与地球仪周围的其他热点脊区不同，它经历了低岩浆流量，岩石的化学成分与其他热点脊区的岩石非常不同。COMSOL Multiphysics©将用于计算段的物理特性。将使用MELTS软件对地球化学示踪进行正演模拟，以推断来源几何形状和成分以及熔融路径。使用MATLAB对所产生模型的重力和磁场进行正演建模，将使我们能够进一步约束地幔熔融状态的密度、深度和几何形状，从而更好地了解整个地幔系统。将地球化学和地球物理数据与模型相结合，代表了山脊建模过程的根本进步，并将地球动力学模型与观测数据相结合。这个NSF EAPSI奖是与日本科学促进协会合作资助的。

Mid-ocean ridges are where a large part of the Earth's volcanism, and significant earthquakes occur. However, the mid-ocean ridges are just the surface expression of the larger convecting mantle system and this mantle is poorly understood. This project aims to explain how the mantle supplies material to the surface of the Earth, and how the mantle moves near the surface. Geodynamic modeling is one of the only ways that currently exists to investigate the mantle processes at mid-ocean ridges and to uncover the geologic history there. Geological observations make modeling more realistic. In this project, the properties of rocks collected from the Southwest Indian Ridge will be compared with many simulated magma compositions, which will then be used to find the properties of the mantle beneath the observed rocks' source. This will grant a better understanding of the ridges in general, as well as hotspot-ridge interaction zones. Collaboration with Dr. Okino's group at the University of Tokyo, will allow for the utilization of novel techniques in order to trace the magma source of the ridge and to explain heterogeneity along the ridge axis.In 2007 and 2009, 35-40 degrees segment of the Southwest Indian Ridge where mantle-derived rocks and geophysical data were collected. This segment is the nearest to the Marion hotspot and is anomalous from other hotspot-ridge regions around the globe in that it experiences a low magma flux, and the rocks have a very different chemical composition from rocks found at other hotspot-ridge regions. COMSOL Multiphysics© will be used for calculation of the physical properties of the segment. MELTS software will be used to forward model the geochemical tracing to infer source geometry and composition and melt pathways. Forward modeling of the gravity and magnetic fields of the produced models using MATLAB will allow us to further constrain the density, depth and geometry of the mantle melt regime, leading to a better understanding of the mantle system as a whole. Incorporating the geochemical, and geophysical data to the model represents a fundamental advancement of the ridge modeling process and combining geodynamic models with observational data. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.