Two models in oneMantle flow modeling on different scales beneath the North Atlantic

Abstract

In this chapter, a fluid dynamical model is used to study the dynamics and structure of a mantle plume. To consider the effect of the large-scale mantle flow field on the development of a plume, the chapter uses a two-stage modeling approach. First, a global and robust model of the large-scale mantle flow field is calculated. It is followed by a regional model study containing the plume. The coupling of the two models is achieved by applying mechanical boundary conditions in the regional model that is derived from the global model. These boundary conditions provide a more realistic model configuration. In the higher resolution regional model, a finite volume multigrid method is used. To handle high viscosity and velocity gradients caused by regional features (mantle plume, oceanic ridge), local mesh refinements are successfully applied. Using of temperature and depth dependent viscosity, however, involves high viscosity contrasts between the plume material and ambient mantle, which may lead to computational difficulties. A greater amount of geophysical data is directly built into the model, and thus a more realistic model configuration is achieved in the chapter.