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
Where Do We Come From? What Are We? Where Are We Going? Boston, acquired it from the Marie Harriman Gallery on 16 April 1936. Where Do We Come From? What Are We? Where Are We Going? Where Do We Come From? What Are We? Where Are We Going? is a painting by French artist Paul Gauguin. Gauguin inscribed the original French title in the upper left corner: D'où Venons Nous / Que Sommes Nous / Où Allons Nous. The inscription the artist wrote on his canvas has no question mark, no dash, and all words are capitalized. In the upper right corner he signed and dated the painting: "P. Gauguin / 1897".