Figure F71. Color close-up photograph of Sample 183-1137A-42R-4 (Piece 1, 20-30 cm). Crystal vitric tuff composing basement Unit 9. Abundant potassium feldspar clasts and lithic fragments are set in a glassy matrix that has been altered to green clay (saponite/nontronite). Lithic fragments are surrounded by dark green clay-rich halos containing a trace of native copper.