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

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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.