Daily Report for IODP Expedition 311, October 11, 2005
LOCATION: Site U1328 (Prospectus Site CAS-06A)
SCIENCE UPDATE: After relocating the ship to the "cold vent" Site U1328, the VIT camera system was deployed to inspect the seafloor for the occurrence of chemosynthetic communities. We conducted a 130 m long camera survey along the proposed coring transect across the vent site. We did not observe any living clam colonies; however, wide-spread carbonate outcrops were observed. Before spudding the first hole, we also deployed the WSTP to collect a bottom water sample. The first APC core was spudded at 13:10 hr in Hole U1328B with 4.5 m of core returned to the surface, thus the mudline was recovered successfully. Core recovery in the second APC core was only 1.7 m with an incomplete stroke. Numerous gas hydrate pieces, some measuring up to 5-8 cm in diameter were recovered and preserved in liquid nitrogen. In addition, a number of smaller pieces of gas hydrate were used for shipboard gas and water analyses. The next core was taken with the XCB system to the target depth of the first PCS (Core U1328B-4P) at 14.5 mbsf. The APC taken after Core U1328B-4P was again an incomplete stroke with only 1.89 m of core recovered. We switched back to XCB coring and advanced the hole to the target depth for the second PCS deployment (Core U1328B-7P) at 20 mbsf. Both PCS deployments yielded core under pressure and were X-rayed and moved to the degassing laboratory. Gas hydrate was recovered in Cores U1328B-2H, 5H, 6X, and 8H. By midnight Hole U1328B had been advanced to 37.5 mbsf, with two additional APC cores. First analyses of the interstitial-waters from this gas-hydrate-rich section show very high salinities in the range of 40 to 46, similar to what was observed at Southern Hydrate Ridge on ODP Leg 204.