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 Life love song – perhaps a "lovingly crafted paen" to Harrison's wife Pattie, as Alan Clayson puts it – or a devotional song like many of Harrison's compositions. Ian Inglis writes that the song title suggests a "philosophical debate about the meaning of life", yet its rendering as ""what is my life"" in the choruses "reshapes [the meaning] completely". Theologian Dale Allison finds no religious content in "What Is Life" but notes the "failure of words to express feelings" implied in the opening line (""What I feel, I can't say""), a recurring theme of Harrison's spiritual songs such as "That Is