A study of intergrowth textures and their possible origins in the Alvand plutonic complex, Hamadan, Iran

Various types of intergrowth textures occur in the Alvand plutonic complex, Hamadan, Iran. Intergrowth textures, such as myrmekite, perthite, micrographic (± granophyric), and tourmaline-microcline intergrowth, are most common in this suite. Perthite and micrographic textures show characteristics of magmatic origin, but myrmekite and tourmaline-microcline intergrowth probably have metasomatic origin. In diorites, myrmekite was possibly generated by Ca-metasomatism, but in granodiorites and granites, it may have formed by both K- and Ca-metasomatism. The presence of anti-rapakivi texture (K-feldspar overgrowth on plagioclase) in the same rocks may be related to this process, too.