Porphyry deposits are commonly developed in regions that are zones of low-angle (flat-slab) subduction. A subduction zone that transitions from normal to flat and then back to normal subduction produces a series of effects that can lead to the generation of porphyry deposits. Initially, there will be decreased alkalic magmatism, horizontal shortening, hydration of the lithosphere above the flat-slab, and low heat flow. Upon a return to normal subduction, the hot asthenosphere will once again interact with the hydrated mantle, causing wet melting, crustal melting will ensue as mantle melts pass through, and lithospheric thinning and weakening due to the increased heat flow. The subducting slab can be lifted by aseismic ridges, seamount chains, or oceanic plateaus – which can provide a favourable environment for the development of a porphyry deposit. This interaction between subduction zones and the aforementioned oceanic features can explain the development of multiple metallogenic belts in a given region; as each time the subduction zone interacts with one of these features it can lead to ore genesis. Finally, in oceanic island arcs, ridge subduction can lead to slab flattening or arc reversal; whereas, in continental arcs it can lead to periods of Flat Slab Subduction.