JA Daily Science Report for Expedition 309, 23 July 2005


LOCATION: Site 1256


SCIENCE UPDATE: Following retrieval of the core barrel (Core 86R) all the core catcher dogs were missing and pump pressures increased ~500 psi. The deplugger was dropped twice to clear the throat of the bit. After the second pass the pressure decreased, a core barrel was dropped, and coring continued to 840.20 mbsf. Core 86R recovered 3.65 m (38%) and Core 87R recovered 3.25 m (34%), both over 9.6 m intervals. Cores 86R and 87R are part of the same fine grained, slightly altered, massive flow unit described in Core 85R (Unit 30). Some fine igneous layering is present. Veins and vesicles filled with saponite + pyrite + amorphous silica are common but generally decrease in abundance down hole in these two cores. Oxidized alteration halos are not present.