Metamorphic rock the foliation is called "gneissosity"), granoblastic (includes granulite, some marbles and quartzite), and hornfelsic (includes hornfels and skarn). Metamorphic rock Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure ( or more), causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by
A Sort of Homecoming (song) A Sort of Homecoming (song) "A Sort of Homecoming" is the first song of U2's 1984 album, "The Unforgettable Fire". A live version of the track is found on 1985's four-track EP, "Wide Awake in America". It is also the only song with lyrics inside the sleeve for the album. As the opening track on "The Unforgettable Fire", "A Sort of Homecoming" epitomises the new direction U2 had taken. A far more atmospheric album than the previous overt-rock of "War", the album has a rich and orchestrated sound. Like much of the album, the song replaces the hard-hitting martial drum