Sample F84
Hornblende and plagioclase phenocrysts are set in a trachytic matrix.
The hornblendes exhibit reaction rims,
demonstratng their "unhappiness" or disequilibrium with the matrix. There
are examples in this thin section where the hornblende has completely reacted
out and only "relicts" or "ghosts"
remain. Many of the plagioclase phenocrysts are zoned. Note the excellent example of amphibole
cleavage in the basal section shown in these photomicrographs.