Deep Earth Origin of the Great Unconformity-Datasets

The Great Unconformity marks a globally extensive erosive surface (~200-1200 million years of gaps in geological rock records) that preceded the Cambrian Explosion of life. The processes proposed for the formation of the Great Unconformity include glacial erosion during the Snowball Earth, rifting and plume activity, sea-level fall, and mantle-driven dynamic topography. However, the dynamics of these processes have not been tested. Using a series of paleogeographically constrained mantle flow models from one billion years ago, we show that continental-scale uplift and subsidence associated with long-wavelength dynamic topography due to mantle convection drove the formation and preservation of the Great Unconformity. Our models predict prolonged continental-scale Precambrian uplift and long-term Phanerozoic subsidence for Laurentia, Baltica and North China. This vertical motion scenario is ideal for the formation and preservation of the Great Unconformity, which is a first-order surface expression of deep Earth processes. The large area of Laurentia and limited deformation at its margins explain why the Great Unconformity is best preserved and documented there. Our models predict cycles of dynamic topography that are broadly reflected in the preserved sediment volume across continents. The 'Deep Earth Origin of the Great Unconformity-Datasets' contains Jupyter notebooks and Python scripts that were created to post-process outputs (mantle temperature, velocity vectors and dynamic topography) of mantle flow models and investigate the role of dynamic topography in the formation and preservation of the Great Unconformity.