Fig. 2b.

Photomicrographs of slightly altered samples of APF igneous rocks. These samples have not been used for mineral and glass chemical analyses, but they are showed only for comparison purposes. (g,h) basalt: plagioclase and altered mafic minerals in a hypocrystalline groundmass (g = plane polarized light, h = cross polarized light; sample APF 15b). (i,l) Basaltic andesite: sericitized plagioclase, opaques and mafic phenocrysts in a cryptocrystalline groundmass (i = plane polarized light, l = cross polarized light; sample APF 2b). (m,n) andesite: partially altered plagioclase, mafic and opaques phenocrysts in a hypocrystalline groundmass (m = plane polarized light, n = cross polarized light; sample APF 14a).