Crust (geology) Mars comprise secondary crust, as do the lunar maria. On Earth, we see secondary crust forming primarily at mid-ocean spreading centers, where the adiabatic rise of mantle causes partial melting. Tertiary crust is more chemically-modified than either primary or secondary. It can form in several ways: The only known example of tertiary crust is the continental crust of the Earth. It is unknown whether other terrestrial planets can be said to have tertiary crust, though the evidence so far suggests that they do not. This is likely because plate tectonics is needed to create tertiary crust, and Earth is the
What Shall We Do Now? sped up, to raise its key to E minor, with re-recorded vocals and guitar. The members of Pink Floyd have contributed to the confusion regarding the identity of this track, misidentifying "What Shall We Do Now?" as "Empty Spaces" on multiple occasions, such as in the track listing for the film version of "The Wall", and on Waters' "The Wall Live in Berlin". On other occasions (such as the officially released live version), the first and second parts of the track are divided and identified as "Empty Spaces" and "What Shall We Do Now?" respectively, even though they are in