This geological texture results from rapid cooling in volcanic or hypabyssal (shallow subsurface) environments. Such systems can be below the surface with rocks ranging from hypabyssal to plutonic. This group is intruded by a granodiorite sill and Early Eocene hypabyssal dykes. They are geologically composed of igneous hypabyssal rocks, tuffs and basaltic andesite. Anorthoclase occurs in high temperature sodium rich volcanic and hypabyssal (shallow intrusive) rocks.