Fig. 4a. This scanning-electron photomicrograph is an image in the center of a soda-rich core of a plagioclase crystal in Fig. 3, but now magnified 1,600x. The enlarged image shows that the plagioclase (pl, dark gray) is full of holes (black) with angular boundaries parallel to the plagioclase crystal lattice and that many holes are bordered by concentrations of K (lighter gray, incipient K-feldspar, kf). Locally, Ba is concentrated in celsian (ce, white, both images), and in some places the celsian occurs on hole walls adjacent to the K concentrations. Identification of element concentrations are confirmed by microprobe studies.