Abstract: 

Reconstructing Earth history during the Hadean defies the traditional rock-based approach in geology. Given the extremely limited locality of Hadean zircons, some indirect approach needs to be employed to gain a global perspective on the Hadean Earth. In my talk, two promising approaches are discussed jointly. One is to better understand the solidification of a putative magma ocean and its consequences, as the end of magma ocean solidification marks the beginning of subsolidus mantle convection. The other is to better constrain the evolution of continental crust, which helps to define the global tectonic environment because generating a massive amount of felsic continental crust is difficult without plate tectonics.  On the basis of recent developments in these two subjects, a new perspective for early Earth evolution is presented, which starts with rapid plate tectonics made possible by a chemically heterogeneous mantle and gradually shifts to a more modern-style plate tectonics with a homogeneous mantle. The relevance of this new perspective with the origin of life is also discussed.