10:45 AM - 11:00 AM
[BPT05-07] Composition of the Hadean oceanic crust and its hydrous melting experiments: Investigation for the composition of the Hadean oceanic and continental crust
Keywords:Hadean, continental crust, komatiite, hydrous melting experiment
We estimated the style of the igneous activity in Hadean and the composition of the oceanic crust, referring previous mantle convection models at high MPT (Korenaga 2009; Foley et al. 2014). The Hadean oceanic crust would have formed form the melt generated at small melt fraction under a thick (-200km) lithosphere before the onset of the plate-tectonics, and after the onset of the plate-tectonics, formed from the melt generated at large melt fraction under oceanic ridges. Then, the composition of the oceanic crust was estimated from high pressure and high temperature melting experiments (Kondo et al. Submitted) in the case before the onset of the plate-tectonics, and from calculations with pMELTS in the case after the onset of the plate-tectonics. The compositions of the melt were estimated to be komatiitic in both cases, though the MgO and FeO contents are significantly different between the two cases. We synthesized starting powders of these komatiitic compositions from oxide and carbonate powders, and performed hydrous melting experiments using the piston-cylinder high pressure apparatus. In experiments, the oxygen fugacity was carefully analyzed and assessed. In this presentation, we report the estimated compositions of the probable Hadean oceanic crust and progress of the hydrous melting experiments.