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
Grover (given name) Grover (given name) Grover is a masculine given name. Grover first became popular as a given name in the United States during the presidencies of Grover Cleveland, in part of a long-standing American trend of naming babies after presidents. Cleveland's official first name was Stephen; he was named after Stephen Grover, a former minister at the church his parents attended. However, from childhood, Cleveland's friends addressed him by his middle name instead, and so what was originally the surname Grover became a given name. According to Social Security Administration data, the name Grover increased in frequency by 850 per 100,000