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 in "Just Dance 2017". In 2009, German DJ Klaas remixed the song under the title "Klaas meets Haddaway – What Is Love 2K9". This remix charted in several European countries. In 2016, Belgian DJ Lost Frequencies released a cover titled "What Is Love 2016", as a single from his debut album "Less Is More". It was actually already produced back in 2014 as a remix for Jaymes Young's cover version of "What is Love". This version was remade for the album and became a hit on a number of European singles charts and topped the Belgian Ultratop Official Singles Chart.