JA Daily Science Report for Expedition 308, 22 June 2005
LOCATION: Site U1324
SCIENCE UPDATE: The major lithology of Hole U1324B between 79.8 to 207.5 mbsf (Cores U1324B-10H to U1324-24H) is a greenish to brownish gray clay with minor layers of silt. Black, organic-rich mottling is also observed throughout most of this interval. Normal faults are present between 106 to 117.8 mbsf (in Cores U1324B-12H and U1324B-13H), and their orientations could be measured. Mud becomes present as a minor lithology in core U1324B-20H. Based on sedimentological data, the whole interval from 79.8 to 207.5 mbsf is interpreted as a hemipelagic deposit interfingered with very distal turbidites. T2P and DVTPP pressure measurements from the previous day were analyzed, and we noted that some readings indicative of pressures below hydrostatic were consistent between both tools. Comparing these abnormal readings with the deformation seen at the base of the APC cores, we inferred that the suction applied to retrieve the piston cores deformed the material sufficiently to influence pressure readings in the formation. We are currently working on a strategy to overcome this problem. The initial idea would be to take measurments only when using the XCB coring system, or in a hole dedicated to tools deployment with no coring.