A REPORT ON THE DERIVATION AND PROPER USE OF THE TERM ANORTHOSITE

The term anorthosite, coined by T. Sterry Hunt in 1862, applies only t o a specific rock type. The origin of the term and a review of the def inition of anorthosite are given, as well as six recommendations on re levant petrographic nomenclature. The recommendations call for adheren ce to the IUGS definition of anorthosite, use of modifiers where appro priate (andesine anorthosite, augite anorthosite, and so on), abandonm ent of such meaningless expressions as anorthositic gabbro and gabbroi c anorthosite, and use of the term meta-anorthosite where evidence of igneous parentage has been erased by deformation and metamorphism