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
Frank (given name) Frank (given name) Frank is a masculine given name. Ultimately from the Germanic tribal name of the Franks, in the early medieval Frankish Empire, the status of being "a Frank" became synonymous with that of a free man; hence also the English adjective "frank" (Middle English, from Old French "franc", 12th century). Use as a given name seems to arise already in the Carolingian period; the Old High German form "Francho, Franko" is on record from the 8th century. While "Frank" is a given name in its own right, in fact reflecting the Old Frankish form "*Frank", the given name