부산대학교 도서관

The cratonic crust is the most long-lived tectonic unit on Earth. The longevity of Earth’s cratonic crust has been attributed to neutrally buoyant and mechanically strong lithospheric keels. However, this is inconsistent with observed secular cratonic deformation and alteration. Here we analyse the density profile and dynamic evolution of the lithospheric mantle underlying cratons to show that cratonic lithosphere may have experienced continuous and cyclic deformation and evolution since the break-up of the Rodinia supercontinent ~800 million years ago. We find that the thickness of cratonic crust correlates linearly with that of the mantle lithosphere, suggesting coupled evolution. Seismic evidence for depth-dependent radial anisotropy implies that the dense lower cratonic lithosphere experienced pervasive vertical deformation consistent with delamination. Geologic data and azimuthal anisotropy further suggest repeated post-Rodinia thinning of cratonic lithosphere followed by gradual restabilization of the perturbed lower lithosphere. Geodynamic simulations support our interpretation that partial lithospheric delamination, potentially triggered by plume underplating, can generate rapid surface uplift and erosion, with subsequent lithospheric stabilization leading to gradual craton subsidence. We propose that Earth’s long-lived cratons have been maintained by this cyclic deformation style since the Neoproterozoic.
Mantle lithosphere underlying the stable continental crust of cratons is dense and has experienced cyclic deformation since the Neoproterozoic, leading to the longevity of cratons, according to geological data and geodynamic modelling.