Compaction driven melt localization in dunites and associated rocks in the mantle: Field observations and numerical experiments Recent numerical simulations of reactive dissolution along a solubility gradient in a viscously

Recent numerical simulations of reactive dissolution along a solubility gradient in a viscously deformable and vertically upwelling column predict that the combined effect of orthopyroxene (opx) dissolution and compaction causes melts to segregate within individual dunite channels [1]. The simulations indicate that the physical and chemical nature of the melt source and overlying peridotite determines the geometry of the dunite channel and the distribution of melts within it. In the simulations, peridotites are composed of olivine and opx, and high-porosity melt channels are “seeded” with a sustained porosity or opx perturbation at the inflow, which could be analogous to a geochemical heterogeneity in the upwelling mantle. The perturbation amplitude, the evolution of its lateral position, upwelling rate, opx-melt solubility, and opx abundance all affect the depth, geometry and evolution of the dunite channel. Dunite channels containing medial and contact proximal melt channels, as well as more exotic combinations, were produced. The spatial relationships observed in the numerical experiments may shed new light on field observations.