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
Aya (given name) Aya (given name) Aya is a feminine given name with multiple meanings in different languages. In Old German, Aya means "sword". Aya (あや, アヤ) is a common female Japanese given name meaning "design", "colorful" or "beautiful". Aya is also in use in the Hebrew language and means "to fly swiftly" or "bird". Aya is also an Arabic feminine name written as آية meaning "wonderful", "amazing", "miracle" or "verse" (of the Quran). In Mongolian, similar to Turkish, it means goodness, music and "melody". In Chemehuevi, Aya means "tortoise". In Baoule on the Ivory Coast, Aya is given to the female born