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
Blank Slate Books Blank Slate Books Blank Slate Books (BSB) is a publishing company based in the UK. It publishes primarily comic books, graphic novels and comic strip collections, with an emphasis on new work by British artists and translated work by European artists. The books it publishes are noted for their “indie-friendly” content, and are frequently by small press artists whose initial work is self-published. The name of the company is a pun on "drawing" or “writing” on a blackboard. BSB is currently one of the few dedicated original comics and graphic novel publishers in the UK. Blank Slate Books (BSB) was