TO: Tom Davies
FM: Jay Miller
JA Daily Science Report for Expedition 304, 9 December 2004.
LOCATION: Site U1309 (prospectus site AMFW-01A)
Latitude: 30° 10.120'N Longitude: 42° 07.114'W
Water depth: 1645 mbsl
SCIENCE UPDATE: Cores 304-U1309D-16R to 22R (89.0 to 131.0 mbsf, 40% recovery, average recovery for Hole U1309D is 51%) continue the series of interfingering intrusions of diabase and gabbro, with rare aphyric to sparsely plagioclase phyric basalt. Alteration is generally less pervasive than in intervals upsection. The interval cored between 108 and 117 mbsf yielded only one small piece of gabbro (hence the decrease in overall recovery), with no indication from coring parameters of poor hole conditions. Speculation as to the cause of poor recovery ranges from a jammed bit to intersection of a faulted interval; we await logging data to provide more information. Recovery in Hole U1309D, discounting the 10 m interval of low recovery, averaged 56%. Throughout the coring process there were no indications of any material falling into the hole, and consistent coring parameters suggest a clean, gauge hole. We move to our hanging wall target (Site AMHW-01A) leaving behind a borehole cased to 20.5 mbsf with a hard-rock reentry assembly and open to >130 mbsf awaiting future efforts for deep penetration at Hole U1309D.