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
Raven (given name) Raven (given name) Raven is a unisex given name in the English language. In the United States of America, the name is more commonly used as a feminine name, and has ranked amongst the top 1,000 feminine names given to baby girls since 1977. The name originates from the English vocabulary word "raven", which in turn is ultimately derived from the Old English "hræfn". As a masculine name, "Raven" parallels the Old Norse "Hrafn", and the Old English "*Hræfn", which both mean "raven". As a feminine name, "Raven" is among several other names derived from birds; names such as "Dove",