A long-standing missing link in our understanding of the Wilson cycle is how a continental rift transitions to seafloor spreading. The variety of rift structures and transition timings at rift margins do not easily lend themselves to some specific degree of strain and/or magmatism as the tipping point. Invariably ignored in the process, but a potential key to the conundrum, is the isostatic response that comes with ocean loading during and after inundation. Ocean mass redistribution on variably subsiding crust drives flow in the asthenosphere in much the same way a growing icecap drives a corresponding outward mantle flow. This flow alters mantle tractions of the rift system, with disappearance of basal resistance, and even adds a push to the rifting process. Evidence for ocean inundation facilitating self-sustained seafloor spreading is observed in the Atlantic, around the Afar triple junction, and elsewhere, indicating that the ocean should not be considered simply incidental to the creation of oceanic basins.

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