Earth?s surface is covered by a, mosaic of thin (100km) rocky plates known as the lithosphere. While the lithosphere beneath the continents is more-or-less permanent, the lithosphere beneath the oceans is recycled ? consumed at deep sea trenches and created at a global network of mid-ocean ridges. Several mid-ocean ridges feature asymmetric and ridge-parallel variations of crustal thickness, seismic velocity, and basalt chemistry than cannot be explained by passive spreading caused by plate divergence only. Instead, recent studies suggest that this complexity may reflect an influence of large-scale mantle flow on ridge dynamics, or result from temporal changes in ridge geometry. This project will test these hypotheses for the East Pacific Rise and the Juan de Fuca Ridge by constructing three-dimensional regional flow models with imposed global flow or evolving ridge geometries. The models by comparing predictions of geological, geochemical, and geophysical parameters against observations at these sites. This study will thus contribute to understanding mantle controls on the ridge system and the general geodynamics of the Earth. In addition to contributing new software to the community, this project will support participation by a female post-doctoral fellow and both graduate and undergraduate students. Undergraduate participants wil be specifically recruited from the minority community in the vicinity of the University of Maryland.
