Comparison of our results with that of a previous study on dry, carbonated metapelite (HPLC1: 5 wt. % bulk CO2), shows the solidus temperature for HPLH1 is the lowest, and that for HPLC1 is the highest of the three starting compositions. The presence of carbonate increases the temperatures of the vapor-present solidus and phengite-out boundary of pelitic sediment, and the addition of water decreases the solidus and the carbonate-out boundary of dry, carbonated pelitic sediment. Comparison of carbonate-free, vapor-poor pelite melting with top-slab P-T paths shows that the phengite-out boundary is encountered in intermediate to hot subductions. This suggests that the deep recycling of water for intermediate to hot subduction may be limited if trace vapor ingress occurs. However, the solidus and phengite-out boundary of vapor-poor pelite are elevated by as much as ~ 50-100 ¡ãC in the presence of carbonates and the complete breakdown of phengite can only occur along the hottest slab-top P-T trajectories for carbonated bulk compositions. The carbonate-out boundary is also located above the hottest estimate of slab-top conditions. This suggests that in mixed COH vapor-poor sediment compositions, most phengite and crystalline carbonate are likely recycled into the deep mantle. One possible scenario for transporting sedimentary carbon from vapor-poor pelite into the arc is via the formation of sediment diapirs, which owing to their low density, will rise to the hotter mantle wedge and undergo partial melting and liberate CO2.