Metamorphic rock 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 texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath
Heat Shield Rock not. Following the identification of Heat Shield Rock as a meteorite, five similar iron meteorites were discovered by "Opportunity" (informally named "Block Island", "Ireland" "Mackinac Island", "Oileán Ruaidh" and "Shelter island"). Two nickel-iron meteorites were identified by the "Spirit" rover (informally named "Allan Hills" and "Zhong Shan"). One nickel-iron meteorite was identified by the "Curiosity" rover, tagged "Lebanon." In addition, several candidate stony meteorites have also been identified on Mars. The term "Martian meteorite" usually refers to something entirely different: meteorites on Earth which are believed to have originated from Mars, a famous example being ALH84001. Heat Shield Rock Heat