Magmatic Processes at Oceanic Spreading Centers

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There are a number of major issues relative to mid-ocean ridge magmatism; such as the along-axis compositional variations, the effects of variable magma chamber recharge rates, the distribution of feeders, convective partitioning of a contiguous chamber, tectonic segmentation, trends in fractionation, mixing, and contamination. This study will address the role of variable recharge and/or spatially varying boundary conditions in generating chemical partitioning of a magma chamber. The objective is to determine the time and length scales associated with crystal and convective fractionation where the crystallization is fully coupled to the heat transfer regimes in the wallrock and to the phase diagram for real compositions. This involves the coupling of the transport equations directly to the phase relations of the system through the code SILMIN. An additional objective is to initiate laboratory experiments of convective regimes with appropriately varying boundary conditions. Questions to be addressed include: (1) How will convection be influenced by recharge? (2) How is crystallization and fractionation influenced by convection? (3) To what degree does convection partition the chamber into domains that have difference chemical evolutions? (4) What is the effect of hydrothermal convection on the chamber?