Mesozoic evolution of passive margin revealed by a transition from oceanic island to mid-ocean ridge basalt types in a fossil plateau, South China Sea

We present new microtextural and compositional data for pyroxenes (Tables S1–S6). Building on these, we compiled bulk-rock major and trace element data together with Sr–Nd isotopes for regional seamount basalts (Table S7), as well as a database of 286 published ages and geochemical data from Late Mesozoic large oceanic plateaus (Table S7). Table S8 lists the parameter settings for batch melting models using various mantle rock compositions as starting materials. In addition, two Pacific pyroxene-bearing enriched mantle plumes, Samoan and Pitcairn, were selected for Monte Carlo simulations (Table S9).