Daily Report for IODP Expedition 311, October 19, 2005

 

LOCATION: Site U1325 (CAS-02C)

 

SCIENCE UPDATE: Throughout the morning and into afternoon, we continued XCB coring Hole U1325B to a depth of 206 mbsf. Interspersed with the XCB cores was a DVTP run at 140.5 mbsf, which yielded high quality temperature data. We also deployed the FPC at 169.4 mbsf and the HRC at 197.4 mbsf; both pressure cores did not recover sediment under pressure. XCB core recovery within the interval from 160206 mbsf was drastically reduced to less than 27%. We attribute the reduced recovery and the problem with pressure coring to the combined effect of the sandy turbidite sections and the occurrence of gas hydrates in these sands (as interpreted from the LWD/MWD data) that is apparently dissociating during coring and blowing the core out of the core barrel during recovery. At a depth of 206 mbsf we attempted to deploy the PCS but the tool was jammed in the BHA after penetrated 20 cm into the formation. We were unable to retrieve the tool despite numerous attempts and had to terminate Hole U1325B and trip the pipe back to the surface. After checking for potential problems, the drill string will be tripped back to the seafloor, and we will spud Hole U1325C. We are scheduled to drill down to about 188 mbsf and resume XCB coring operations.