Extended Data Fig. 3: Termination of the protokeel detachment from the slab after the beginning of arc-continent collision.
From: Building cratonic keels in Precambrian plate tectonics
The evolution of the experiment shown in Fig. 2a, b is shown (40-Myr-old lithosphere, subducting plate velocity of 5 cm yr−1, elevated mantle potential temperature (Tp = 1,550 °C, ΔT = 250 °C)) for longer experiment run times. a, Growth of basaltic arc on the former oceanic crust at 18.2 Myr ago. b, Growth of the arc composed of basaltic and felsic volcanic rocks derived by fluid-fluxed melting of the mantle wedge and melting of the hydrated slab, respectively, at 19.8 Myr ago. We note the preservation of the protokeel thickness and its underplating by hydrated diapirs derived from slab fragments. The reduced degree of decompression melting (narrow red zones) is due to the strong upper mantle depletion. The colour key is shown in Fig. 1. The protokeel source mantle (T > 1,300 °C, melt depletion >20%) under the subducting plate is outlined in magenta for better visibility.
