After transit from Site 1273 in dynamic positioning mode with the drill string suspended below the ship, we arrived on the Global Positioning System coordinates for the start of the Hole 1274A subsea camera survey (Fig. F1) at 0030 hr on 15 June 2003. Our survey began over a sedimented bottom and tracked ~200 m west, up the side of the western wall of the axial valley of the Mid-Atlantic Ridge, following the path of Shinkai 6500 Dive 416 (Fig. F2). During this dive all recovered samples were serpentinized peridotite. After passing an outcrop at the depth of the final sample of peridotite collected during the dive, we selected a drilling target with a thin sediment cover (<2 m) to initiate Hole 1274A.
Before beginning our coring operation, we deployed the Water Sampling Temperature Probe (WSTP) to collect a bottom water sample in support of our microbiology program. Coring continued through 155.8 meters below seafloor (mbsf) (Cores 1R to 28R) (Table T1) with little difficulty. The only problems of note were an easily cleared bit blockage experienced after recovering Core 11R and minor amounts of fill collapsing in the hole between pipe connections. Cores 15R, 20R, and 21R were cut as full ~9.6-m intervals (as opposed to the nominal half-cores that we recovered throughout the rest of the hole) due to rapid penetration through those depths (74.0–83.7 and 102.9–122.1 mbsf, respectively). After we recovered Core 28R, the hole collapsed and cut off circulation through the drill string. Pipe was pulled from the hole while attempting to restore circulation, without success, so we released the bit and abandoned Hole 1274A. The average rate of penetration for Hole 1274A was 4.9 m/hr.
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Ms 209IR-109