Crust (geology) crustal rocks formed before 2.5 billion years ago are located in cratons. Such old continental crust and the underlying mantle asthenosphere are less dense than elsewhere in Earth and so are not readily destroyed by subduction. Formation of new continental crust is linked to periods of intense orogeny; these periods coincide with the formation of the supercontinents such as Rodinia, Pangaea and Gondwana. The crust forms in part by aggregation of island arcs including granite and metamorphic fold belts, and it is preserved in part by depletion of the underlying mantle to form buoyant lithospheric mantle. A theoretical protoplanet named
Given name by the parents at birth. In informal situations, given names are often used in a familiar and friendly manner. In more formal situations, a person's surname is more commonly used—unless a distinction needs to be made between people with the same surname. The idioms "on a first-name basis" and "being on first-name terms" refer to the familiarity inherent in addressing someone by their given name. By contrast, a surname (also known as a family name, last name, or "gentile" name), which is normally inherited, is typically shared with other members of one's immediate family. Regnal names and religious or monastic