Figure F9. Photomicrograph in plane-polarized light of Sample 187-1155B-6R-3, 135-138 cm (see "Site 1155 Thin Sections"), showing a quench zone grading from fresh glass to spherulitic glass to coalesced spherulites. Notice the flow-aligned acicular plagioclase on which some spherulites have nucleated. The tan-brown transition at the first appearance of spherulites is due to the palagonitization of the glass.