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? with D minor and A minor chords. Where the album's main character, Pink's question about how he should fill out the gaps in his wall was of a rhetorical nature in "Empty Spaces", "What Shall We Do Now?" lists the diversions, possessions, and vices of a rock star (""Shall we buy a new guitar / Shall we drive a more powerful car / Shall we work straight through the night / Shall we get into fights / Leave the lights on / Drop bombs ..."") in response. The two tracks are easily confused. The tape speed for "Empty Spaces" was