The Granitic Cotectic Curve

In a recent paper (Nockolds, 1946) it was shown that certain granite-aplites associated with acid plutonic rocks of Caledonian age in Western Scotland fell on, or were very close to, the plagioclase-potash felspar-quartz cotectic curve (the granitic cotectic curve), the approximate position of which could be determined from experimental data now available. It seemed of interest to determine whether other granite-aplites from other areas behaved in the same way and chemical analyses of granite-aplites and related rocks were collected from the literature with this end in view.