Magmatic hydrothermal brecciaHot porphyry magmas at depth will blow off "steam" any chance they get. These gas explosions will create breccia pipes of various sizes. The breccia pipes may be weakly mineralized but most are not. They bring up bits and pieces (clasts) of the rock below up to several kilometres down. They can be treasure houses of free information about the rock below.
"Strongly veined clasts of porphyry" says that the porphyry is underneath the breccia pipe which is backing up the findings of 24-19 and 24-21.