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 Love Is Made Of dance music. She then got a bassline which made her "want to dance", and included it in the track. She also told the website that she wrote the song about the "feeling of love, what one person can give to you that someone else can't". What Love Is Made Of" was premiered during Irish DJ Annie Mac's eponymous program on BBC Radio 1, on 10 May 2013, though its digital download only occurred on 5 July 2013. It was serviced as an extended play, where it was bundled with three remixes, by MK (Mark Kinchen), Felix da Housecat and Brackles.