MODELS OF THE PHYSICAL EFFECTS OF MELT MIGRATION AT PLATE INTERIORS, WITH APPLICATIONS TO THE EDGES OF CONTINENTAL KEELS

We explore the effects of melt infiltration into continental interiors, particularly at the edges of thicker, keel-like protrusions such as beneath Archean provinces. This study builds upon previous work showing that spatially-variable melt migration can lead to spatially-variable thermal weakening of the lithosphere. We confine our attention to advective heat transfer in porous flow in the limit that heat transfer between the melt and surrounding matrix dominates over conductive heat transfer within either the melt or the solid alone. The efficiency of heat transfer across the fluid-rock interface in the model is controlled by a heat transfer coefficient, related to the geometry and distribution of porosity. Our models quantitatively assess the viability of spatially variable thermal-weakening caused by melt-migration through continental regions that are characterized by variations in lithospheric thickness. We speculate upon the relevance of this process in producing surface patterns of Cenozoic magmatism and heatflow at the Colorado Plateau in the western US and at the edges of Archean provinces.