JA Daily Science Report for Expedition 308, 14 June 2005
LOCATION: Transit to Ursa basin (Site U1322)
SCIENCE UPDATE: The day was spent transiting from the Brazos-Trinity IV minibasin to the Ursa basin. The transit time was used to download data stored in the MWD/LWD tools, and to proceed with a preliminary interpretation at Site U1320. The gamma ray data in Hole U1320B indicate intercalated layers of sand, silt, and mudstone in the upper part of the hole (65 to 170 mbsf). This zone corresponds with alternating sand, silt, and mud layers described in the lithostratigraphic units of Hole U1320A. The variations between these lithostratigraphic units are evident in the FMS images, which show irregular resistivity patterns. Sand-dominated layers have lower gamma ray and resistivity values than layers dominated by clay, and the largest variation is observed in density (1.1 to 2.05 g/cm3) and neutron porosity (40 to 70%). Wash out zones ~3 m thick were encountered at 110 mbsf and 170 mbsf, and correspond to sand-rich layers. Data retrieved from 170.0 mbsf to 299.6 mbsf in Hole U1920B are very homogenous, and correlate with a lithostratigraphy characterized by mud and clays and the absence of sand layers. As of 2400, the vessel had reached the location of Site U1322 (prospectus site URS-3C), and MWD/LWD operations were about to begin.