New look at classical Wilson Cycle concept
The classical Wilson Cycle concept, describing repeated opening and closing of ocean basins, hypothesizes spontaneous conversion of passive continental margins into subduction zones. The collapse of passive margins is essential in the closing phase of the Wilson Cycle; however, the absence of conversion of any passive margins into active ones since the Cenozoic makes the Wilson Cycle a challenging and debatable topic among geoscientists. Based on 2-D thermomechanic models we suggest a modified version of the Wilson Cycle concept in which conversion of a passive margin into a subduction zone is triggered by the mantle flow induced by neighboring subduction zones, along with slab remnants of former subduction zones in the mid-mantle. Models suggest that this is a long-term process, thus explaining the lack of Cenozoic examples. We speculate that new subduction zones may form in the next few tens of millions of years along the Argentine passive margin and the US East Coast.