4:00 PM - 4:15 PM
[BCG09-03] How to make continents from oceanic arcs
Keywords:oceanic arc, andesite, plate tectonics
In a hotter early Earth, however, the extents of melting were higher in mantle plumes, beneath spreading ridges, and in arcs. If so, the crust in such settings was generally thicker, rather than thinner, compared to the present day. Another implication of this hypothesis is that the production of continental crust might have been impossible in the early Earth if the oceanic crust had been thick. Why are the oldest rocks 4 Ga? Where had the rocks of Hadean gone? We haven’t had continental crust before 4 billion years because of the thick crust, thus the older rocks had returned to mantle by plate tectonics.