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) Love? she was dissatisfied with the circumstances, but was in "no way dissing Lopez." A mastered version of "What Is Love?" was included on the soundtrack to "The Back-up Plan" (2010), a film in which Lopez stars. "What Is Love?" was re-titled as "(What Is) Love?" and appeared on "Love?" (2011). "(What Is) Love?" was due to be released as a promotional single from "Love?" on April 26, 2011, but was "unlocked" and released four days earlier, on April 22, 2011 by through a campaign on Lopez's Facebook page. It was released in many European countries on April 25. The song