Daily Report for IODP Expedition 311, October 5, 2005
LOCATION: Site U1327 (CAS-01B)
SCIENCE UPDATE: Hole U1327D, which has been designed as a special tools hole, was drilled to a depth of 124.3 mbsf by 02:40 hr in preparation for a run of the HRC pressure core system (Core U1327-3P). However, the recorded ship heave had increased to more than 4.5 m and it was determined that it would be impossible to keep the HRC or any of the other pressure core systems on the bottom of the hole. A review of the weather forecast indicated that the adverse conditions should subside by early afternoon. As the day advanced we were subjected to competing swells from the west and southeast, while the ship heave conditions did not improve through the evening. By 22:45 hr the heave conditions had improved with a ship's course change and preparations began to return to coring. Preliminary analysis of the interstitial waters from the near-surface ultra-high resolution sampling performed on two APC cores from Hole U1327D revealed a well defined sulfate gradient with depth, but the transition at the base of the sulfate reducing zone appears to fall at the break between the cores. Plans have been developed to quickly re-core this upper interval in a short core hole after completing Hole U1327D. PCS Core U1327C 24P was degassed throughout the day with more than 107 millimoles of gas released so far. Cores U1327B-1H and U1327C-1H through 35X (0-300.0 mbsf, 88% recovery) are Pleistocene very dark greenish gray silty clay and dark gray clay with varying diatom abundance.