When we could not advance while cutting Core 1191A-4R even after 3 hr of rotation, we decided to terminate coring and move on to our casing attempt. On our ensuing wireline run we were not able to engage the core barrel, so we tripped the pipe. Unfortunately, we had also deployed the LDEO DSA tool housing on our last coring attempt, and since it was unique, we would not have the opportunity for more temperature measurements using this tool. This is moderately vesicular and aphyric in hand specimen. Large vesicles, up to 4 cm long, are severely stretched.
Alteration increases gradually downward, from slight to moderate.
It consists of both replacement of the vitreous matrix and vesicle and fracture fillings. The igneous groundmass is replaced in patches by cristobalite and clay. Some fractures and vesicles are lined by crystallized marcasite which includes framboids of pyrite. Active bacterial cells were found by direct counting on two samples from depths of about 10 and 15 meters, respectively.