JA Daily Science Report for Expedition 309, 31 July 2005


LOCATION: Site 1256


SCIENCE UPDATE: Three cores (109R to 111R) were recovered with 14.4 m of penetration yielding 6.6 m of core (46%).  Low and variable pump pressures led to concerns that there were problems with either the pumps or the bottom hole assembly. Although maintenance of both pumps identified and replaced a broken valve seat, low pump pressures continued to be detected when the bit was lifted from the base of the hole and the BHA was in tension.  It was decided to trip the drill string to inspect the BHA for possible cracks. Although we still do not have firm evidence for the presence of dikes, non-glassy, aphanitic, chilled margins on brecciated basalt pieces from Core 108R at 960.8 mbsf suggest an intrusive contact.