Cimmerian block detachment from Gondwana: A slab pull origin?

The Cimmerian blocks are ribbons-like micro-continents that detached from the northern margin of Gondwana during closure Paleotethys ocean at end Permian. While it has been hypothesized slab pull forces induced by subduction beneath Eurasia could have driven extension in lower plate after mid-oceanic ridge subduction, so far, numerical modeling studies concluded these alone not sufficient to drive continental breakup. However, previous neglect olivine phase transitions mantle and likely underestimated pull. Here, we present simulations consider evolution density associated with metamorphic reactions analyze carefully when, where, how can lead formation micro-continents. Our results show marked increase related 410 km discontinuity, addition gravitational potential energy, cause rifting plate. Nonetheless, breakup is only achieved absence horizontal shear flow base lithosphere. In successful experiments, deformation localizes 100-200 on shore due bending stress pointing out this process probably always leads small ribbons. confirm tensional force dynamics may caused detachment blocks. Since promoted basal below Gondwana's lithosphere (with respect underlying mantle), argue provides information relative motion between tectonic plates mantle. demonstrate there a significant time-lag (i.e. time needed for reach discontinuity), which rarely accounted paleogeographic reconstructions.