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
The Call of Earth had a weak connection, and so delay the eventual time when the Oversoul loses control of the people of Harmony. The characters listed here are those whose primary role is in "The Call of Earth." For other characters, see Homecoming Saga. The Call of Earth The Call of Earth (1992) is a science fiction novel by American writer Orson Scott Card. It the second book of the Homecoming Saga, a fictionalization of the first few hundred years recorded in the Book of Mormon. The book focuses on several key events that happen after Nafai, Elemak, Issib, Mebbekew, Zdorab and the