Petrology Petrology Petrology (from the Greek πέτρος, "pétros", "rock" and λόγος, "lógos", "subject matter", see -logy) is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together because they both contain heavy use of chemistry, chemical methods, and phase diagrams. Sedimentary petrology is, on the other hand, commonly taught together with stratigraphy because it deals with the processes that form sedimentary rock. Lithology was once approximately synonymous with petrography, but in current usage, lithology focuses on macroscopic hand-sample or outcrop-scale
What Is Literature? The art of writing is deeply linked to freedom and thus ventures into the fields of politics and democracy. The poet frees himself by disassociation, and the prose writer fulfills a duty to utilize language for the end of a conceived free society. What Is Literature? What Is Literature? (), also published as "Literature and Existentialism",) is an essay by French philosopher and novelist Jean-Paul Sartre, published by Gallimard in 1948. Initially published in freestanding essays across French literary journals "Les Temps modernes", "Situations I" and "Situations II", essays "What is Writing?" and "Why Write?" were translated into English and