Nature study traces the Great Unconformity to mantle convection deep inside the Earth

4 November 2026

The Great Unconformity is a vast erosion surface found on several continents, where very old rock lies directly under much younger rock. A new paper in the journal Nature argues that the gap was opened and then preserved by slow vertical motion of the continents themselves. The authors modelled long-wavelength dynamic topography, the gentle rise and fall of the crust caused by convection in the Earth's mantle. Their models predict long continental uplift in Neoproterozoic time and long subsidence later, for Laurentia, Baltica and North China. Uplift through Cryogenian time would have exposed the rock to heavy glacial erosion, and the later sinking buried and protected the surface. Because Laurentia is large and its edges were little deformed, the study says the surface survives best and is best documented there. The work also ties the surface to the environment just before the Cambrian explosion of animal life.