Seminário do Departamento de Geofísica
Título: Pushing the Limits of Deep-Time Cratonic Reconstructions
Palestrante: Professor David Evans (Yale University)
Resumo: Global-scale paleogeography of the last 300 million years was solved to first-order by Wegener more than a century ago. We have reasonable confidence in Paleozoic reconstructions, but Ediacaran geomagnetic instability presents a formidable challenge. A novel statistical treatment of Ediacaran datasets has potential to produce accurate results. Further back in time, there remain large-scale problems in reconstructing Pangea's supercontinental predecessors Rodinia and Nuna, although some consensus is emerging about core elements of those assemblages. Beyond 2 Ga, a major question is whether a previous Kenorland supercontinent existed, or whether Earth's tectonic plates were uniformly smaller and contained separate "supercratons" all smaller than today's continents. In order to solve this deepest-time puzzle, paleogeographers must recognize a profound difference between preserved cratonic area and the likely full extent of Archean continental crust, which probably was similar to the present.
